Kévin Tougeron

Joan Van Baaren

Stéphanie Llopis

Aurélien Ridel

Josée Doyon

Jacques Brodeur

Cécile Le Lann

Disentangling plasticity from local adaptation in diapause expression of parasitoid wasps from contrasting thermal environments: a reciprocal translocation experiment

Keywords:

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

INTRODUCTION

Understanding the basis of phenotypic variation across varying environments is an important question in evolutionary ecology. Reaction norms (RNs) describe the degree to which a genotype (G) responds, in a plastic way, to environmental changes (E), in a manner that G × E interactions can be measured [START_REF] Via | Genotype-environment interaction and the evolution of phenotypic plasticity[END_REF][START_REF] Scheiner | Genetics and evolution of phenotypic plasticity[END_REF]. This implies that an organisms' trait expression, and thus fitness, can change with the environmental conditions at which they were selected (determining the level of the RN) and which they actually experience (slope of the RN) [START_REF] Ayrinhac | Cold adaptation in geographical populations of Drosophila melanogaster: phenotypic plasticity is more important than genetic variability[END_REF][START_REF] Nussey | The evolutionary ecology of individual phenotypic plasticity in wild populations[END_REF]. Organisms can respond to environmental changes through genetic evolution or plasticity [START_REF] Parmesan | Ecological and evolutionary responses to recent climate change[END_REF][START_REF] Sgrò | What can plasticity contribute to insect responses to climate change?[END_REF]. Disentangling the relative effects of plastic and evolutionary responses to environmental changes is crucial if we are to predict how organisms will respond to ongoing global change, including climate change [START_REF] Gienapp | Climate change and evolution: disentangling environmental and genetic responses[END_REF][START_REF] Merilä | Climate change, adaptation, and phenotypic plasticity: the problem and the evidence[END_REF]. Transplant (i.e. translocation) experiments of populations between contrasted environments enable us to study RNs and infer responses to climate *Corresponding author. E-mail: tougeron.kevin@gmail.com A c c e p t e d m a n u s c r i t p t change by comparing performance at different locations [START_REF] Kawecki | Conceptual issues in local adaptation[END_REF][START_REF] Hoffmann | Climate change and evolutionary adaptation[END_REF].

Facultative diapause is a well-documented example of developmental plasticity, allowing insects to cope with variable environments [START_REF] Nylin | Plasticity in life-history traits[END_REF]. Insects from temperate regions typically enter diapause in response to decreasing photoperiod that reliably indicates unfavourable conditions to come [START_REF] Tauber | Seasonal adaptations of insects[END_REF]. However, the photoperiodic response is often modulated by temperature and other environmental factors [START_REF] Danks | Insect dormancy: an ecological perspective[END_REF] and climate warming would diminish the reliability of photoperiod as a predictor of winter onset, leading to potential phenological mismatches [START_REF] Bale | Insect overwintering in a changing climate[END_REF][START_REF] Van Dyck | The lost generation hypothesis: could climate change drive ectotherms into a developmental trap?[END_REF][START_REF] Forrest | Complex responses of insect phenology to climate change[END_REF]. It is thus necessary to separate the respective effects of photoperiod and temperature when studying diapause RNs across environmental gradients. Few studies have examined the consequences of photoperiod-based adaptations, such as diapause, when organisms face new climates [START_REF] Grevstad | The consequences of photoperiodism for organisms in new climates[END_REF].

Timing is of the essence; diapause induction that is too early or too late can impair insect fitness and induce mortality [START_REF] Sgrò | What can plasticity contribute to insect responses to climate change?[END_REF]. Minimization of such timing costs occurs through adaptation of the incidence and initiation of diapause to local environmental seasonal variations [START_REF] Danks | Insect dormancy: an ecological perspective[END_REF]. Therefore, for a given insect species living in the northern hemisphere, there are geographical clines in diapause expression; winter diapause is induced earlier and at a lower environmental threshold in northern populations [START_REF] Winterhalter | Patterns of phenotypic and genetic variation for the plasticity of diapause incidence[END_REF][START_REF] Hut | Latitudinal clines: an evolutionary view on biological rhythms[END_REF]. A few transplant experiments in the context of diapause study have been reported (e.g. [START_REF] Chen | Diapause induction and termination in Hyphantria cunea (Drury) (Lepidoptera: Arctiinae)[END_REF] but, to our knowledge, no previous study on diapause RN has held the photoperiodic environment constant while varying the thermal environment. The experimental design described below allows us to disentangle local adaptation and plasticity in diapause expression without confounding the effects of temperature and photoperiod.

This study focused on parasitoid species of the genus Aphidius (Hymenoptera: Braconidae): Aphidius ervi (Haliday), present in both North America and Europe, and the sister species Aphidius rhopalosiphi (Haliday) from Europe/Aphidius avenaphis (Fitch) from North America. Photoperiod and temperature interact to induce diapause in these species [START_REF] Brodeur | Biotic and abiotic factors involved in diapause induction of the parasitoid, Aphidius nigripes (Hymenoptera: Aphidiidae)[END_REF]Tougeron et al., 2017b). The aim of this study was to investigate and compare the RNs of diapause expression in multivoltine populations of aphid parasitoids from contrasted winter climate areas (eastern Canada vs. western France) in outdoor semi-experimental conditions across the season for diapause induction. In this longitudinal translocation experiment, we tested responses to summer, autumn and winter climatic conditions to which they were, or were not, adapted, in order to measure the degrees of local adaptation and plasticity in diapause expression. In their native environment, Canadian parasitoids start to enter winter diapause in mid-July and 100% incidence is reached before lethal frosts occur [START_REF] Brodeur | Seasonal ecology of Aphidius nigripes (Hymenoptera: Aphidiidae), a parasitoid of Macrosiphum euphorbiae (Homoptera: Aphididae)[END_REF]. In contrast, in western France at least part of the population of some parasitoid species can remain active throughout winter due to mild conditions and host availability throughout the year [START_REF] Krespi | Variability in the development of cereal aphid parasitoids and hyperparasitoids in oceanic regions A c c e p t e d m a n u s c r i t p t as a response to climate and abundance of hosts[END_REF][START_REF] Andrade | Impact of change in winter strategy of one parasitoid species on the diversity and function of a guild of parasitoids[END_REF].

We hypothesized that: (1) Canadian populations enter diapause at higher levels and earlier in the season than French populations, due to adaptations to conditions of their area of origin; (2) diapause levels are higher and parasitoids enter diapause earlier in Canada than in France, regardless of the origin of the parasitoid population, due to phenotypic plasticity to local temperatures; and (3) mortality levels are higher for parasitoid populations tested in the foreign location.

MATERIAL AND METHODS

Meterological data

Minimum, mean and maximum temperatures were recorded every hour throughout the experiment using LOG32 data loggers (Dostmann, Germany) in France and HOBO data loggers (Onset, MA, USA) in Canada directly placed in one of the outdoor experimental cages (Bugdorm-4S, 32 × 32 × 32 cm, Taichung, Taiwan). Cages did not produce any greenhouse effect because mean temperature was similar to outdoor weather stations close to the experimental sites (mean ± SE difference between inside and outside the cages of 0.35 ± 0.24 °C over the experimental session). Temperatures for each date of outdoor releases were averaged using data for the following 14 days to have reliable information on climatic conditions experienced by developing parasitoids.

Biological Material

Three parasitoid species of the English grain aphid [Sitobion avenae (Fabricius) (Homoptera: Aphididae)] were used: A. ervi (present in both France and Canada), A. rhopalosiphi (strictly Eurasian species) and A. avenaphis (strictly North American species). The two latter species are phylogenetically, ecologically and morphologically closely related and are considered as sister species [START_REF] Kos | On the identity of cereal aphid parasitoid wasps Aphidius uzbekistanicus, Aphidius rhopalosiphi, and Aphidius avenaphis (Hymenoptera: Braconidae: Aphidiinae) by examination of COI mitochondrial gene, geometric morphometrics, and morphology[END_REF][START_REF] Tomanović | The relationship between molecular variation and variation in the wing shape of three aphid parasitoid species: Aphidius uzbekistanicus Luzhetzki, Aphidius rhopalosiphi De Stefani Perez and Aphidius avenaphis (Fitch) (Hymenoptera: Braconidae: Aphidiinae)[END_REF]. Although they are two different species, A. rhopalosiphi was considered as the French population and A. avenaphis as the Canadian population. In this way, we were able to compare the plastic response of two A c c e p t e d m a n u s c r i t p t populations of the same species (A. ervi), and of two close species that have evolved in different bioclimatic areas (A. rhopalosiphi and A. avenaphis). Four parasitoid populations were collected from cereal fields in 2015 and the colonies were started with about 50 individuals for each population. One population of A. ervi was collected in Québec, Canada (45.58°N, 73.24°W) and the other was collected in Brittany, France (48.11°N, 1.67°W). Aphidius rhopalosiphi parasitoids were collected in Brittany, France, and A. avenaphis parasitoids were collected in Saskatchewan, Canada (52.21°N, 106.66°W). Parasitoid colonies were maintained in climatic chambers at 20 °C, 16:8 h light-dark (LD) photoperiod and 75% relative humidity (RH) on cereal aphid colonies (S. avenae) collected either in Brittany (for the maintenance of and experiments on French parasitoid populations) or in Québec (for Canadian parasitoid populations). All the experiments were conducted within the 2 years after establishment of parasitoid cultures.

experiMental design

Experiments were conducted every 14 days from 20 June to 5 December, 2016 in outdoor mesocosms in Montréal (45.55°N, 73.55°W, QC, Canada) and Rennes (48.11°N, 1.65°W, Brittany, France), thus providing approximately the same photoperiodic regime (similar latitude) in both locations across the season. In France, experiments were not performed from 4 July to 29 August (four experimental dates) because no winter diapause was expected prior to this period and to avoid measuring summer diapause [START_REF] Krespi | Variability in the development of cereal aphid parasitoids and hyperparasitoids in oceanic regions A c c e p t e d m a n u s c r i t p t as a response to climate and abundance of hosts[END_REF]Tougeron et al., 2017b). The first observation (20 June) was done in France to obtain a common starting point with Canada. We were not able to obtain data for the Canadian population of A. ervi tested on 24 October, nor for A. avenaphis tested on 29 August in France.

Four days before each date of outdoor releases, 15 parasitoid females and five males from each population, less than 48 h old, were taken from the colony and placed during 24 h in three different plastic tubes (height = 10 cm, diameter = 3 cm) at a ratio of five females to three males for mating and with a dilution of honey for feeding. Parasitoid females were then placed in three fine netting Bugdorm-4S cages in the presence of 200-300 second-and third-instar larvae of S. avenae aphids of the same size and originating from the same cohort on a wheat pot for 60-72 h, with a dilution of honey, at 20 °C, 16:8 h LD. The rate of parasitism was about 40%. Female parasitoids were then removed from the cages and the three wheat pots with parasitized aphids were put together in a new fine netting cage. The four cages (one per population), protected from rain by a plastic roof, were put outside in a semi-shaded place. This procedure was repeated every 2 weeks in both locations.

Twice a week, the formation of mummies (i.e. a dead aphid containing a parasitoid prepupa or pupa) was checked in each cage. Mummies were collected from the plants, individually put in 1.5-mL plastic microtubes with a tiny hole on the top for venting and left in their respective cages. Adult emergence from the mummies was checked three times a week and mummies from which no parasitoid emerged within 15 days after the last adult emergence were dissected (or 45 days after mummy formation when no emergence occurred in a cage). The contents from mummy dissections were categorized as dead parasitoids (immature and adult stages) or gold-yellow diapausing prepupae (Tougeron et al., 2017b). Diapause incidence was calculated as the number of diapausing prepupae relative to the number of emerged individuals (thus excluding dead individuals). Mortality rate refers to the number of dead parasitoids inside the mummies relative to the total number of mummies. Mean diapause and mortality levels were calculated and analysed from 12 September to 5 December (i.e. over the experimental dates in common between France and Canada).

statistical analyses

The number of days since the beginning of the experiment was used in the models as a 'date' factor. A global model was first created; for each species separately (A. ervi, and the sister species A. rhopalosiphi/A. avenaphis), a generalized linear model (GLM, quasi-binomial family to account for data overdispersion) was fitted to the data to test for differences in diapause incidence over the season (number of individuals in diapause vs. not in diapause) on the following explanatory variables: parasitoid origin, tested location, date and their two-way interactions. The same procedure was used to analyse mortality levels. Significant differences in diapause incidence between populations at the same location were interpreted as genetic variation (local adaptation) for the expression of diapause. On the other hand, significant differences in diapause incidence between locations for a given parasitoid population were interpreted as plastic variation of diapause [START_REF] Winterhalter | Patterns of phenotypic and genetic variation for the plasticity of diapause incidence[END_REF]. A Spearman correlation test was done to analyse the links between photoperiod and minimal temperatures in France and Canada, because minimal temperatures are likely to be the best predictor of diapause increase over the season. A Gaussian GLM was applied to analyse the evolution of minimal temperatures over the experimental season using the date, the tested A c c e p t e d m a n u s c r i t p t location and their interaction as explanatory variables. The significance of each explanatory variable was tested with the 'Anova' function from the package car in R, which performs an analysis of variance of type II (R Core Team, 2017), using the F statistic for diapause and mortality quasibinomial data, and a likelihood-ratio (LR) test using a chi-square statistic for meteorological data.

RESULTS

aBiotic factors

Photoperiod and minimal temperatures were highly correlated (P < 0.001, r 2 = 0.85 and r 2 = 0.89 in France and Canada, respectively) (Fig. 1). Minimal temperatures were on average 6.5 °C lower in Canada than in France (GLM, LR = 5.8, d.f. = 1, P < 0.05) and decreased over the season in both locations (GLM, LR = 57.7, d.f. = 1, P < 0.001) although they decreased faster in Canada (-0.17 °C/day, R 2 = 0.77) than in France (-0.09 °C/day, R 2 = 0.66) (GLM interaction effect, LR = 5.3, d.f. = 1, P < 0.05). Temperatures in France were more buffered (lower minimum-maximum amplitude) than temperatures in Canada. Negative temperatures were only encountered for a few days in late November in France (down to -2.5 °C during the night) while several frost events (down to -23.5 °C) occurred almost every day in Canada from early October. First snow fall occurred on 20 November in Canada. There was no snow in France during the time of this experiment. Day length at 46.50°N (similar in both experimental locations) decreased from 15.7 to 8.8 h between 20 June and 5 December.

diapause incidence

For every species, Canadian populations had overall higher mean diapause levels than French populations when tested in Canada and in France (Table 1, Fig. 2). There was no significant interaction between the origin of the parasitoid populations and the tested locations for any species (Table 1), meaning that differences in diapause incidence between parasitoid populations were consistent across locations (Fig. 2). Additionally, diapause incidence increased over the season and this effect was independent of the population origin, but not of the tested location, as it increased faster in Canada than in France (Table 1, Fig. 3A). Data for each date (number of mummies collected, number of diapausing parasitoids and number of dead individuals) can be found in Supporting Information, Table S1.

In detail, mean diapause levels over the season were higher for A. ervi tested in Canada than in France for both the Canadian-origin populations (68.8 ± 13.5% vs. 17.5 ± 5.5%) and the French-origin population (30.7 ± 12.5% vs. 0.6 ± 0.5%), but this effect varied with the tested date because differences between locations were only seen at the end of the season (Figs 2, 3A). Mean diapause levels over the season were 61.6 ± 12.5% vs. 47.3 ± 7.1% in A. avenaphis (Canadian species) and 5.5 ± 3.1% vs. 4.2 ± 1.8% in A. rhopalosiphi (French species), in Canada vs. France, respectively. Although there was overall no difference in mean diapause between locations in these species, a location effect was observed for a few dates at the end of the season, especially for A. avenaphis (Figs 2, 3A). In Canada, diapause peaks (i.e. maximum incidence over the season) occurred one month earlier (24 October) for Canadian populations than for French populations (21 November). In both Canada and France, first entrance into winter diapause was observed earlier for Canadian-origin parasitoids (as early as 20 June) than for French-origin parasitoids (not earlier than 26 September, except for A. rhopalosiphi on 20 June which may have entered into summer diapause, as discussed below) (Fig. 3A).

Mortality levels

From late October to early December, mortality levels of each species increased similarly for both population origins and locations (Table 1, Fig. 3B). Mortality levels were significantly higher in Canada (between 59% and 95% mortality in early December) than in France (between 0% and 25% in early December) (Table 1, Fig. 3B). However, the effect of location on mortality differed depending on the origin of the parasitoid population, although this interaction was only marginally non-significant in A. ervi (Table 1). Notably, in France, end-season mortality levels were higher for Canadian parasitoid populations than for French populations. By contrast, in Canada, end-season mortality levels were higher for French populations than for Canadian populations, for any species or group of species (Fig. 3B).

DISCUSSION

We provide evidence, using parasitoid insects, that both plasticity and local adaptations can be involved in insect responses to varying climates. Our translocation study allowed us to separate the effects of local adaptations from those of plasticity on diapause incidence. As predicted, aphid parasitoid populations originating from the harsh winter area (Canada) expressed higher levels of diapause than populations from the mild winter area (France), when tested either in France or in Canada. This first pattern reflects parasitoid adaptations to climatic conditions of their respective area of origin (genotypic effect, G). Diapause incidence was overall higher for parasitoids tested in Canada than in France, especially for A. ervi. This second pattern highlights plastic responses of diapause expression under different thermal environments (environmental effect, E). To the same A c c e p t e d m a n u s c r i t p t extent, insect thermal reaction norms usually are determined by both basal genetic response to temperatures (local adaptation) and acclimation (plastic response) to experienced temperatures [START_REF] Noh | Seasonal variation in basal and plastic cold tolerance: adaptation is influenced by both long-and short-term phenotypic plasticity[END_REF]. However, we found no G × E interactions, as the plasticity following the change in environment was expressed by both Canadian and French parasitoids in a similar fashion. Such results are similar to patterns observed along latitudinal gradients. For example, northern populations of the parasitoid Nasonia vitripennis (Hymenoptera: Pteromalidae) enter diapause earlier and at higher incidence than southern populations because of local adaptations of plastic responses to seasonal photoperiodic and thermal changes [START_REF] Paolucci | Adaptive latitudinal cline of photoperiodic diapause induction in the parasitoid Nasonia vitripennis in Europe[END_REF]. We observed that, at a given date (i.e. a specific photoperiod) and for a given location (i.e. a specific temperature regime), Canadian parasitoid populations entered diapause at higher levels than French populations. In France, Canadian populations entered diapause at significant levels (up to 27.8% for A. ervi and 61.8% for A. avenaphis) even if temperatures were high enough for continuous development and adult survival (developmental thresholds are around +3 °C in this genus; [START_REF] Sigsgaard | The temperature-dependent duration of development and parasitism of three cereal aphid parasitoids, Aphidius ervi, A. rhopalosiphi, and Praon volucre[END_REF][START_REF] Zamani | Effect of temperature on life history of Aphidius colemani and Aphidius matricariae (Hymenoptera: Braconidae), two parasitoids of Aphis gossypii and Myzus persicae (Homoptera: Aphididae)[END_REF], suggesting a strong genetically determined photoperiodic effect in harsh winter populations. On the other hand, French parasitoids expressed overall low diapause levels in both Canada and France, suggesting a weak response to environmental cues. We showed that A. ervi had a higher level of plasticity to environmental changes (i.e. location effect with higher RN slopes, see Fig. 2) than the other 'sister-species'. The response to environmental change in diapause of Aphidius parasitoids could thus be different between species and could depend on their respective responses to environmental cues (temperature and photoperiod). For example, in the laboratory, it was shown that the incidence of A. ervi diapause was influenced by a photoperiod × temperature interaction but this was not found for Aphidius avenae diapause, which is triggered by these cues independently of each other (Tougeron et al., 2017b). Furthermore, in the French population of A. rhopalosiphi held in France, around 10% of the individuals entered diapause in June. This suggests the expression of summer diapause initiated in the offspring when female parasitoids encounter competitors for host resources, under summer-like conditions [START_REF] Krespi | Variability in the development of cereal aphid parasitoids and hyperparasitoids in oceanic regions A c c e p t e d m a n u s c r i t p t as a response to climate and abundance of hosts[END_REF]Tougeron et al., 2017a).

As in many arthropod species, both temperature and photoperiod interact to induce diapause in aphid parasitoids [START_REF] Brodeur | Biotic and abiotic factors involved in diapause induction of the parasitoid, Aphidius nigripes (Hymenoptera: Aphidiidae)[END_REF]Tougeron et al., 2017b), but it is difficult to disentangle them because these stimuli are highly correlated. Nevertheless, the relative importance of photoperiod and temperature at inducing diapause can differ between insect populations of the same species because the reliability of these stimuli may vary among regions [START_REF] Piercey | Factors influencing the induction of diapausing egg production in the calanoid copepod Diaptomus leptopus[END_REF][START_REF] Pruisscher | Sex-linked inheritance of diapause induction in the butterfly Pieris napi: sex-linked inheritance of diapause[END_REF]. Northern populations normally enter diapause under strict photoperiodic control and earlier than southern populations in which diapause may be more sensitive to modulation by temperature [START_REF] Hut | Latitudinal clines: an evolutionary view on biological rhythms[END_REF]. Our results suggest that parasitoids from mild winter climates may be relatively more sensitive to temperature than to photoperiod for entering diapause. This would allow parasitoids to match more accurately their overwintering strategy to actual winter temperatures.

In the laboratory, Tougeron et al. (2017b) observed very low diapause incidence in species of aphid parasitoids from a mild winter climate. Under the most winter-like conditions tested (14 °C, 10:14 h LD), no diapause was expressed in A. rhopalosiphi while an average level of 11.2 ± 4.9% was observed in A. ervi.

Here we demonstrate that although mild winter populations of these two species express low diapause levels in both Canada and France, they have the capacity to enter diapause at higher levels through developmental plasticity when exposed to lower temperatures and shorter photoperiods than when tested in the laboratory. Therefore, the capacity to enter diapause has not been 'lost' in aphid parasitoid populations from mild winter climates, but diapause is not or is little expressed in their area of origin because of advantageous climatic conditions. By contrast, our results confirm a selection process for low diapause induction thresholds (low temperature and day-length) and low plastic responses in populations from mild winter areas (Tougeron et al., 2017b), associated with changes in overwintering strategies [START_REF] Andrade | Impact of change in winter strategy of one parasitoid species on the diversity and function of a guild of parasitoids[END_REF]. This hypothesis is especially true for A. ervi, which responds strongly to the change of thermal environment (i.e. when tested in Canada), whereas A. rhopalosiphi, a species that has favoured a quiescence strategy over the diapause overwintering strategy in recent decades (Tougeron et al., 2017b), does not exhibit such a strong response to temperature. Similarly, in the pitcherplant mosquito Wyeomyia smithii (Diptera: Culicidae), a longer favourable season driven by climate warming has led to the selection of a lower critical photoperiod to enter diapause [START_REF] Bradshaw | Genetic shift in photoperiodic response correlated with global warming[END_REF].

Several studies have used transplant experiments to move populations to warmer climates and investigate organisms' evolutionary and plastic responses to new environmental conditions (e.g. [START_REF] Andrew | Potential host colonization by insect herbivores in a warmer climate: a transplant experiment[END_REF][START_REF] Logan | Natural selection on thermal performance in a novel thermal environment[END_REF][START_REF] Nooten | Potential impacts of climate change on insect communities: a transplant experiment[END_REF]. Following transplant, the value of the most plastic traits changes rapidly while the value of traits strongly associated with local adaptations are not immediately modified [START_REF] Kawecki | Conceptual issues in local adaptation[END_REF][START_REF] Charmantier | Mediterranean blue tits as a case study of local adaptation[END_REF]. For example, in the grasshopper Melanoplus sanguinipes (Orthoptera: Acrididae), body orientation toward a heat source is plastic to the temperature experienced by the insect while mobility and basking behaviours are determined by the climatic origin of the parental generation (i.e. locally adapted traits) [START_REF] Samietz | Altitudinal variation in behavioural thermoregulation: local adaptation vs. plasticity in California grasshoppers[END_REF]. For diapause, [START_REF] Chen | Diapause induction and termination in Hyphantria cunea (Drury) (Lepidoptera: Arctiinae)[END_REF] demonstrated that the moth Hyphantria cunea (Lepidoptera: Arctiinae), transferred from its temperate origin area to a subtropical location, has the capacity to enter summer diapause to cope with warmer summers, thus highlighting a plastic developmental response. However, this moth species faced environmental conditions to which it was not adapted, and high mortality was observed [START_REF] Chen | Diapause induction and termination in Hyphantria cunea (Drury) (Lepidoptera: Arctiinae)[END_REF].

When parasitized aphids were put outside in Canada at the end of the experimental season, most individuals died because of lethally low temperatures. To the same extent, insects that do not enter diapause because of too high temperatures in autumn may suffer high mortality from sudden cold spells in winter [START_REF] Bale | Insect overwintering in a changing climate[END_REF]. Higher mortality levels were observed for French populations tested in Canada, which may be poorly resistant to low temperatures [START_REF] Lann | Thermal tolerance of sympatric hymenopteran parasitoid species: does it match seasonal activity?[END_REF][START_REF] Tougeron | Comparing thermal tolerance across contrasting landscapes: first steps towards understanding how landscape management could modify ectotherm thermal tolerance[END_REF]. Such high mortality highlights timing costs of being active too late in the season, although it is not ecologically relevant because parasitoids are adapted to enter into diapause before the onset of lethal frosts. Canadian populations tested in France also incurred important mortality despite the relatively warm conditions across the experimental season. For Canadian populations in France, developmental costs might have occurred; temperatures were too high to be sustainable in a diapause state. Indeed, mild winter conditions lead to higher metabolic activity during the process of diapause, potentially increasing mortality in insects [START_REF] Bosch | Timing of eclosion affects diapause development, fat body consumption and longevity in Osmia lignaria, a univoltine, adult-wintering solitary bee[END_REF][START_REF] Williams | Thermal variability increases the impact of autumnal warming and drives metabolic depression in an overwintering butterfly[END_REF][START_REF] Xiao | Exposure to mild temperatures decreases overwintering larval survival and post-diapause reproductive potential in the rice stem borer Chilo suppressalis[END_REF]. These results strengthen the idea that there is a strong evolutionary pressure to enter early diapause in harsh winter climates, but not necessarily in mild winter climates where diapause can involve physiological (i.e. energy consumption) and ecological costs (i.e. not exploiting available hosts in the environment).

From an applied perspective, studies on diapause expression among different parasitoid populations A c c e p t e d m a n u s c r i t p t may help the biological control industry to select appropriate strains for mass rearing. In the context of climate changes, animal populations will increasingly be exposed to environmental conditions to which they are not adapted. When populations face a new climate, the genetically based photoperiod response is likely to be initially mismatched -until they adapt their response or modulate it through plasticity -because at a given location, photoperiod will not change whereas temperatures will [START_REF] Grevstad | The consequences of photoperiodism for organisms in new climates[END_REF]. Increasing costs of diapause expression under an inappropriate thermal environment are thus expected [START_REF] Bale | Insect overwintering in a changing climate[END_REF][START_REF] Sgrò | What can plasticity contribute to insect responses to climate change?[END_REF], for instance in the case of unexpected cold spells in mild winter areas, although insects have great capacities to adapt rapidly to new thermal conditions. When species have to adapt to new environments, one could expect the RN (i.e. the phenotypic response to the environment) to change genetically [START_REF] Winterhalter | Patterns of phenotypic and genetic variation for the plasticity of diapause incidence[END_REF][START_REF] Van Asch | Evolutionary response of the egg hatching date of a herbivorous insect under climate change[END_REF]. However, examples of genotypic changes when facing warmer climates (e.g. [START_REF] Bradshaw | Genetic shift in photoperiodic response correlated with global warming[END_REF][START_REF] Logan | Natural selection on thermal performance in a novel thermal environment[END_REF] remain less common than reports on plastic changes [START_REF] Hill | Responses of butterflies to twentieth century climate warming: implications for future ranges[END_REF][START_REF] Berteaux | Keeping pace with fast climate change: can arctic life count on evolution?[END_REF].

Figure 1 .

 1 Figure 1. Minimum, mean and maximum temperatures in Montréal, QC, Canada (solid lines), and Rennes, Brittany, France (dotted lines), from 20 June to 5 December 2016. Data shown at each date are the average of temperature data for the 14 days following this date. Photoperiod at 46.50°N is shown for each date (grey line).

Figure 2 .

 2 Figure 2. Mean per cent reaction norms of diapause incidence (mean ± SE) of Canadian (full line) and French (dotted line) populations of Aphidius ervi and Aphidius rhopalosiphi/Aphidius avenaphis reared under outdoor conditions either in Canada or in France. For each population origin, more than 600 and 350 mummies were collected in Canada and France, respectively.

Figure 3 .

 3 Figure 3. A, seasonal levels of diapause (number of diapausing prepupae/total number of mummies, excluding dead individuals); and B, mortality within the mummies, recorded every 2 weeks from 20 July to 5 December 2016 in the Canadian (solid lines) and French (dotted lines) parasitoid populations of left: Aphidius ervi and right: Aphidius avenaphis/Aphidius rhopalosiphi. Letters on the right of each panel indicate where the experiments were conducted: Canada (C) and France (F). Slashes (//) correspond to a lack of data (see Material and methods).

Table 1 .

 1 Generalized linear models (GLMs) on the effect of origin-locations and photoperiod and their interaction on diapause incidence and mortality levels of A. ervi (N = 1416 mummies in Canada and N = 762 in France) and A. rhopalosiphi/A. avenaphis (N = 1469 in Canada and N = 2231 in France)

	Aphidius ervi	Aphidius
		rhopalosiphi/A. avenaphis

F-and P-values are presented. The degrees of freedom (d.f.) is 1 for each test. NS = non-significant.

ACKNOWLEDGEMENTS

We thank Mathilde Gaudreau, Hervé Amat, Kévin Hoeffner and Valérie Briand for technical support. KT was supported by the French Région Bretagne (PhD scholarship ARED) and the Canada Research Chair in Biological Control awarded to JB. All field and laboratory work conducted in this study complies with French, European and Canadian laws.

SUPPORTING INFORMATION

Additional Supporting Information may be found in the online version of this article at the publisher's web-site.

Table S1. Numbers of parasitoids in each category, presented for each experimental date in Canada and France.


Conspiracy theories, storytelling and forgers: towards a paradoxical ethics of truth in contemporary European fiction

LOÏSE LELEVÉ Université Rennes 2 (univ-rennes) "It was prodigious enough that history had mimicked history; but for history to mimic literature, that is unconceivable." Thus begins, by a Borgesian quotation, French sociologist Luc Boltanski's study on enigmas and conspiracy (Boltanski 11). Strikingly, Antoine Bello's fictional forgers trilogy (Bello, Les Falsificateurs), staging a secret international organization (the "CFR") in charge of rewriting reality through a process of systematized falsification akin to a gigantic conspiracy, ends on a very similar note: "The CFR had always mimicked reality; what if, in return, reality was plagiarizing our best ideas1 ?" (Bello,Les Producteurs 381) The Borgesian rejection of a reality so infused with fiction that it ends up being potentially more fictional than fiction itself seems to have become possible in postmodern Europe, often seen as particularly prone to the diffusion and banalization of conspiracy theories (Taguieff 13). From the 90s onwards, two phenomena, partially thanks to their success in the US and the diffusion of northern American culture in Europe , seem to converge to create new worries about so complex an entanglement of fiction and reality that any sense of history might be lost.

First, as ironically illustrated in Bello's novels, conspiracy theories, the influence of which was notably reduced in post WWII Europe, make a remarkable comeback . Second, managerial and political uses of storytelling techniques, imported from the US, find themselves sharply criticized -in France, for example, in the works of Christian Salmon or Yves Citton. Both appear, more or less, as forms of "scenarization" , i.e. a misleading narrative designed to manipulate one's perception of reality . The new popularity of topics such as conspiracy theories and storytelling increase preoccupations stemming on the one hand from the so-called "linguistic" or "narrative" turns in Humanities and postmodern academic writings; and on the other hand, from new theories of fiction regarding its relationship with truth and reality2 . New concerns about a "posttruth era" lead writers and scholars to reevaluate nonfiction to expose, share and comment truth rather than fiction. In contrast, conspiracy theories have been analyzed to provide coherence and legibility in answer to the distressing perception of a chaotic contemporary reality and therefore to cater to what Arendt qualifies as a "thirst for fiction" (Arendt 671) on their followers' part: the reassurance comes at the price of a closed interpretative system substituting itself for reality. The new craving for a factual literature appears to appease contemporary readers' "reality hunger" (Shields): the defiance against attractive narrative distortions of truth is said to lead readers to turn factual literary accounts of asserted events. Fiction seems contaminated by new suspicions regarding the very possibility of a truthful and ethical writing of reality.

But a new fictional trend of falsification novels emerges in contemporary literature: narratives dealing with forgers, their forgeries, and their capacity to rewrite history and politics through fakes. Such novels seem to argue that nonfiction is not the only ethical horizon for contemporary literature in a modern environment made unreadable by its sheer complexity, which seems to debunk any perception of cause and effect in recent social evolutions3 (Taguieff 33). Consequently, I would like to put the emphasis on novels from the 2010s centered on the figure of a superlative forger, plotting a whole conspiracy or rather resorting to a conspiracy narrative to reshape the reality of his world according to his views, and practicing a true art of storytelling to substantiate his falsification. I will thus take into account the aforementioned trilogy by Bello, and a recent novel by Umberto Eco, The Prague Cemetery (Eco, Il cimitero di Praga). Those two works will enable me to tie up the three European contemporary concerns aforesaid (the conspiracy theories revival, the worry regarding the success of storytelling in multiple fields of human activity as well as "post-truth" anxieties) to theories about the intrinsic narrativity of forgery, as analyzed in the academic works of Eco himself (Eco, 'La forza del falso'). Contemporary European falsification novels, I would like to argue, are a prime example of the drive of contemporary fiction to put its relationship to truth back into play, and most of all its ability to represent, comment and shape reality. In this paper, I suggest that, by representing the fabrication of a forgery resorting to storytelling techniques to elaborate a conspiracy theory, contemporary writers challenge their readers to a playful fictive inquiry -and that the very ironic form of veridicity the unraveling of such an inquiry implies is precisely what may confer to recent fiction a new ethical dimension.

Scenario and "scenarizarion": storytelling as the end of truth

The main issue scholars can have with both storytelling and conspiracy theories is their use of a narrative pattern as a cognitive tool. Storytelling, for instance, is seen as an especially pervasive discursive form touching every area of society, to the point that some have evoked a new "narrative age" . In such an era, "story" becomes the predominant knowledge vehicle, but the fear remains that a compelling story will always be more seducing than hard facts, and that the power of stories to shape reality is dangerously minimized by storytelling practitioners and recipients (Smith). But in the suspicions cast upon storytelling, there seems to be a confusion between story and fiction (and, implicitly, between fiction and lie (Lavocat 43)): storytelling appears potentially dangerous because it is indirectly accused of fictionalizing facts, as if the mere configuring of facts into a narrative was the first step into turning them into fictions. As it is, narration is simply a form of discourse; there is no reason why it should be less veridictive than a logical dissertation; but compelling narrations -those that may seem effective enough to persuade their readers, rather than convince them -are somehow seen as luring the reader into the realm of the false or the unascertained. In this light, storytelling soon takes the aspect of a form of witchcraft, able to turn fiction into fact and fact into fiction, by exploiting the reader's narrative pleasure.

Storytelling becomes a synonymous for disinformation, a tool of deception to influence ratios of power and manipulate the masses. Salmon thus evokes the "fictionalization" of work relationships forcing employees' adhesion to their company narrative and masquerading power relationships as a collective production effort . Storytelling imposes artificial narratives 4 that pretend to transmit knowledge but instead serve as behavioral modeling and protocols (Salmon 16). Simultaneously, Citton suggests that we constantly elaborate scenarios through which we try to predict the evolution of a given situation in which we project ourselves; we are both the authors and the characters of such scenarios that, owing to their simple existence, are already shaping our reality. "Scenarization is metaleptic precisely because it articulates a (fictive) scenario, turned towards the future, with the actual facilitation of the (real) concretization of that fiction" (Citton 86). The scenario is always already shaping reality; and fiction is an encouragement to action: hearing or elaborating a fiction is always akin to project oneself into action.

Storytelling is therefore supposed to have two effects: a magical narrativization of facts that curbs reality in favor of an aggravation or a reversing of the power balance, while blinding its addressees to the reality of the ratio of power; and a reshaping of reality through the confection of perlocutionary fictions that affect the behavior and/or beliefs of their recipients. This is where concerns for the damaging effect of storytelling merge with worries caused by the vogue of conspiracy theories since the 90s. 9/11 can be considered as a paradigmatic example inasmuch as it has lead to a deep renewal of conspiracy theories 5 and is also a prime instance of the use of storytelling by authorities, medias and other fonts of power. A title such as Franck Rich's The Greatest Story Ever Sold. The Decline and Fall of Truth from 9/11 to Katrina is a perfect illustration for the growing fear of the dissolution of truth when public opinion is confronted to massive, complex events notoriously difficult to apprehend through a single linear prism. Salmon himself was not far from conflating storytelling and conspiracy theory when he wrote that "the art of narration […] has become, under the influence of storytelling, a State instrument of deceit and of opinion control […]. The Empire has confiscated the narrative." (Salmon 20) It all gets worse of course when storytelling is used by conspirators or forgers to achieve their obscure goals. This is exactly what is going on within Bello's CFR, which agents are mandated to imagine forgeries to influence the course of events and re-shape reality. In the first volume, Sliv, the first-person narrator and protagonist and a CFR "agent", learns that there was never any dog sent into orbit in 1957; Laika was a pure invention on the CFR's part to push the US government into catching up with the Soviet program. All the favorite ingredients of CFR's machinations appear in this example: a careful forging of false evidence, and a good story (a dog in space!). Indeed, CFR "agents" are divided into two kinds: the forgers per se, genius creators of false archive, vestiges or records; and the "scenarists", the providers of compelling stories allowing forgeries to be embedded into an alluring narrative guaranteeing 4 Instead of defining a written set of rules that leaves transparent the power balance and the hierarchy system in the company, storytelling management postulates that it is more effective to make the employees adhere to the company goals by making them part of a collective narrative of the company success. Instructions and orders are therefore not delivered as such but conveyed through compelling success stories in the first person, narrating the individual feats of coworkers completing tasksstories that are in fact nothing more that instruction manuals in disguise and smokescreens to the reality of the repartition of authority and power within the company. 5 Taguieff suggests several clusters of conspiracy theories typical of the post 9/11 era: theories regarding the 2003 Iraqi war and its "true" causes; the renewal of the suspicions of an international Jewish financial conspiracy in the wake of the 2008 crisis, focusing notably on the figure of B. Madoff or on banks founded by Jewish migrants in the US, such as Goldman Sachs or Lehmann Brothers; the supposed role played by groups such as the Bilderberg Group, the Trilateral Commission, the Council on Foreign Relations, etc., all somehow perceived as secret societies, in said crisis; the H1N1 pandemic (see below); Bin Laden's death (its causes, its reality); and the D. Strauss-Khan scandal .

their diffusion and their persuasive power. The narrator's nemesis, Lena, is the most talented forger of her generation; but even she is required to call on Sliv's talents for scenarization when she obtains the CFR's authorization to create ex nihilo a whole new lost civilization: to Sliv's remark "Who needs a scenario when she can grow Maya relics on volcanoes slopes?", the CFR executives only answer "One always needs a good scenario". (Bello,Les Producteurs 223) At the heart of a successful forgery in service of a successful conspiracy (here, the creation of a new ancient society, the 'Chupacs', to help promote a culture based on the democratic practice of concord, as a innovative incitation to peacekeeping), lies the art of storytelling. As Citton argued, the fictional scenario, by inciting its audience to metaleptically project themselves into the characters and situations it develops, is supposed to have a perlocutionary effect: convincing people that a concord-centered society is a viable form of democratic polis, as the Chupacs illustrate, might also be manipulating them into abandoning agonistic political practices. A writer and a liberal-minded CEO, Bello seems to suggest here that the management of a political community should be based on corporate culture and its emphasis on negotiation. Rather than the committed participation to political conflicts by the promotion or the aggravation of any form of dissent that -at least according to Sliv, here the spokesperson for the author -can only lead to a counterproductive radicalization of the differing actors and their positions (strikes, protests, demonstrations, heated debates, etc.), the model illustrated by the Chupac society postulates a consensus that must be achieved by every party through a preliminary negotiation each time a political decision has to be reached. Such a story aims at shaping political behaviors, as Salmon analyzed, by suggesting democracy lies its actors' capacity to cultivate conciliation, rather than conflict -be it racial or related to the division of society into classes, for instance: readers are strongly invited to put their convictions into perspective, rather that cultivating their differing viewpoints and promote them in an agonistic way.

For Salmon, the embodiment of the link between the art of fiction and management or political manipulation might be Robert McKee, "a famous Hollywood scenarist who became […] a storytelling management guru" (Salmon 72). This is strikingly reminiscent of one of Bello's character, Ignacio Vargas, another former Hollywood writer, who left the CFR to make money as a business storytelling consultant -from scenarist to storytelling advisor, a career history not unlike McKee's one, though Vargas never taught at university -instead, he went on writing scenarios for wealthy clients needing to sell products through narratives. Vargas matches perfectly the ruthless narration businessman described by Salmon, all too ready to play with his audience's emotions through his stories in order to strengthen their loyalty to their employer. To the cynical Vargas, the ones truly responsible for the success of storytelling manipulations are the deceived: "Let's be clear, Sliv: I don't take advantage of anyone's credulity. We fool ourselves well enough on our own. […] All stories coexist; each chooses the one that fits him best according to criteria that have nothing to do with reason." (Bello,Les Producteurs 136). To Vargas, everyone is a storyteller: we constantly falsify our own memories to shape them into better, more alluring narrations, even the most dramatic and intimate ones (Bello, Les Producteurs 137). Vargas's lack of ethics is grounded on a empirical mantra: "there is no such thing as truth" (Bello,Les Producteurs 148). The storyteller lives in an entirely fictional world, one made only of concurrent stories. Therefore, all manipulations are acceptable. In Vargas's hands, storytelling does not only threaten to blur facts and fictions: it has entirely dissolved facts.

Fiction as an inquiry: conspiracy theories, the indiciary paradigm and the production of truth

This is why Vargas, unlike Sliv, can no longer be part of the CFR. The organization activities rely on its audience believing in a difference between fact and fiction and the existence of truth, be it hidden behind veils of some sort. Their forgeries aim at turning their targets into unwitting conspiracists, by inciting them to elaborate stories challenging previous official narratives from the fakes they disseminate. Conspiracy theories are a method of explanation of an unacceptable reality through a narrative relying on over-rationalization and biased causality and intentionality6 Brotherton and French). Such a -supposedlycognitive method of reading and decrypting historical and political events allows for a carefully crafted, coherent, irrefutable narrative. The specifics of modern conspiracy theories lie in their critic dimension: the unveiling of the true nature of reality is not only a process of integration of clues within a causal effective narrative, it is also dependent on a systematized demystification (Taguieff 38). Since everything can be reduced to and introduced in a plot, conspiracy theories, by claiming that there is no such thing as an accident (Bègue et al.) and that everything is tied in together, strongly imply a deciphering of the world based on the model of the police investigation: every sign can be turned into a clue (Kreis 10).

The conspiracist is thus to be understood as a hyper-rational, hyper-aware detective; and the logical consequence of his worldview is misappropriation of the indiciary paradigm . As an investigation tool, based on the selection, arrangement and confrontation of traces of an event in order to establish a heuristic narrative explaining how a fact occurred, how an object was produced, it is advantageously used in several scientific disciplines (Ginzburg). Art historians resort to it to identify the author of a painting when they look for physical or stylistic traces left by the painter's production process on its surface (for instance, specific brushstrokes or even, in some cases, fingerprints). Psychiatrists may treat symptoms of mental illness as traces of a hidden trauma which origins must be reconstituted within a narrative. Detectives are looking for clues to reconstruct a narrative aiming at answering the key questions: what happened, how the crime was committed, and by whom? In appearance, conspiracy theories mobilize the indiciary paradigm as efficiently as the psychologist or the connoisseur, but the systematic assumption of an underlying and all-encompassing plot drives them not to discern, in the continuum of reality, relevant facts or traces likely to be reliable evidence of a past event, but to indiscriminately consider anything and everything as a proof of their presupposed theory. For the enlightened reader that the conspiracist affirms to be, the relationship between truth and lie is reversed: everything that is apparent is but a lie waiting to be denounced.

What particularly interests me, however, in contemporary literature, is not so much the mimesis of conspiracy theories as the reworking of their methods into the fabrication of a clever forgery. Indeed, in recent novels, the forgers operate a second hijacking of the indiciary paradigm: they produce fake clues to incite spectators of their forgeries to reconstruct by themselves the explanatory narrative giving the (fake) object its whole historical significance. Where the conspiracist was using the paradigm as some sort of lens through which decoding reality beyond the surface of deceptive appearances, the forger exploits his victim's tendency to apply the paradigm to everything resembling a clue to mislead him. When Sliv offers artificial vestiges and compelling stories, he fully expects his audience to practice the narrative activity of collecting his clues into an alternative narrative challenging previous perceptions of reality; they end up producing for him the conspiracy theories the narrative foundations of which he has carefully laid 7 .

An all-encompassing explanation, conspiracy theory can quickly take a mythical dimension: in an 1998 interview, Eco underlined that conspiracy theory could be interpreted as a "mythological version of a causal explanation of chance" (David et al. 308). It is exactly what he shows at work when Simonini, his protagonist who, in The Prague Cemetery, forges the early version of the infamous Protocols of the Elders of Zion, elaborates his fake. Imagining a global scheme perpetrated by Jewish leaders, he recreates a whole new mythology, complete with a Manichean vision of the world revolving around a perpetual fight between the evil Jews and the forces of Christianity and Enlightenment; an etiological discourse -the decline of civilization is the result of Jewish subversion -; archetypal characters and dramatized primal scenes (the plotting in the cemetery).

The inaugural scene in the Prague cemetery, cited, transformed and widespread by a variety of writers after Simonini to elaborate what has become a collective imagery of the Jewish conspiracy as depicted in the Protocols, draws from 7 An particularly striking example of such a strategy can in found in the first volume: to protect the Bushmen tribes from the plundering of their lands by diamond merchants, Sliv forges a letter from ethnologist G. Chemineau to C. Levi-Strauss evoking another tribe (but a fake one) finding a significant diamonds deposit in the Kalahari desert and denouncing international companies such as De Beers's efforts to get hold of said diamonds. He plans on De Beers actively exploring that desert to find the diamonds for themselves, all the while ignoring that neither tribe nor deposit actually exist. Thus De Beers themselves might actualize Sliv's claim: their very presence in the Kalahari desert will serve as proof of their pillaging intentions -and make them all the more likely to be caught redhanded at ransacking by the NGOs Sliv himself has warned. Those deceived by the manipulation are the one to give it substance: Sliv only lays the clues for them to turn them into a new reality (Bello,Les Falsificateurs 120).

the dramatic opening of the serial Joseph Balsamo by Alexandre Dumas (Eco, Il cimitero di Praga 76). It shows, as Simonini reminds his reader, during the night of May 6 th , 1770, in the Mont Tonnerre, on the left bank of the Rhine, a Stranger being caught by masked men and lead into a clearing before three hundreds "ghosts" armed with swords who submit him to a close interrogation, including questions commanding pre-determined answers and several trials such as firing a (secretly unloaded) pistol to his head to prove his obedience -all questions and rituals typical of masonic clichés well-appreciated by Dumas's readers. But the Stranger cuts the ritual short by revealing that not only does he know all the society's secrets, he is the very head by divine right of the universal masonic congregation. He proceeds to explain the reason behind this gathering of "ghosts" -in fact, under the masks, all the important members of various national lodges all over the world: to crush the altar and the throne in France, the fall of the French monarchy necessarily triggering that of all the other European ones and the Church with them. The Stranger -the eponymous Joseph Balsamo, of course -then exposes the details of his subversive plan (Eco,. And Simonini to conclude: "Forget the Mont Tonnerre, the left bank of the Rhine, the time -I thought. Let's imagine conjurors from every part of the world, representing the tentacles of their sect extended in every country, let's gather them in a clearing, in a cave, in a castle, in a cemetery, in a crypt, as long as it's sufficiently dark, let's have one of them deliver a speech that unveils their plots, and their will to conquer the world. […] Here's a form to fill ad libitum; each to his own conspiracy." (Eco, Il cimitero di Praga 95)

The forger's stroke of genius lies in his analysis of Dumas' scene as a detachable and reproducible narrative matrix "liable to give form to each and every kind of conspiracy": "the Poet had […] discovered, through the telling of a unique conspiracy, the Universal Form of any possible conspiracy." (Eco, Il cimitero di Praga 95) All that remains for Simonini is to transpose Dumas' plotting scene in the eponymous Hebraic cemetery and change the initial conspirators into Jewish leaders. Eco's pseudo-historical account of the fabrication of a famous forgery turns then into a striking mise en abyme of the narrative functioning of the false. Derived from a suspense novel, the forged conspiracy is convincing because it adheres to an easily identifiable scheming form that anyone can relate to: "Dumas had not invented anything. […] People only believe what they already know, and that was the beauty of the Universal Form of Conspiracy" (Eco, Il cimitero di Praga 96). As in genre writings where half of the reading pleasure comes from the recognition of a series of tropes, the seduction of the conspiracy theory -as well as of the forgery -is due to an effective confirmation bias (Thresher-Andrews 7).

The second stroke of genius is to turn what is at first nothing more than an anti-Semite pastiche of a conspiracy scene into a false archive. Simonini's commandeering of Dumas' art of storytelling is crowned by his transformation of his gripping narrative into the minutes of a -supposed -historical reunion, that is into the tangible trace of a secret past event accounting for the unexplainable chaos of fast-changing 19 th century society. The alternative narrative becomes a clue ready to be treated, according to conspiracists' twisted use of the indiciary paradigm, as an evidence of Jewish malevolence. Thus functions Eco's demonstration of the "power of the false", to quote his article: the efficiency of the false is tightly correlated to its narrative seduction. "Narrated forgeries are first and foremost narrations, and narrations, like myths, are always persuasive" (Eco, 'La forza del falso' 320). One effective narrative matrix is enough to format any form of ungrounded hatred or fear into the shape of a conspiracy, all the more appealing as it offers a compelling story. The Universal Form of Conspiracy is therefore an available narrative configuration all the more effective as it relies on the seduction power both of conspiracy theory as a so-called heuristic account of reality and of dramatic serial-inspired storytelling. The mythical dimension of the conspiracy guarantees its cognitive power (it can virtually explain everything) while its narrative aspect makes it easily understandable and spreadable. Conspiracy theory as a myth can thus aspire to a metaphysical insight on the reality of the world: "The essence of conspiracy beliefs lies in attempts to delineate and explain evil." (Barkun 3) Of course, that very mythical dimension is what confers conspiracy theory all its damaging effect: by postulating a Manichean struggle with an all-powerful archenemy, it allows or encourages the destruction of the scapegoat it stigmatizes; hence the key role of the Protocols in the Nazis elaboration of the Final Solution (Taguieff 56).

What appears to me as particularly relevant to the question of the ethics of contemporary fiction, however, is that Eco choses to expose this pernicious efficiency not in an academic paper -what he did, as it happens, in "La forza del falso" -but in a novel. The irrefutability of conspiracy theories often lies in the logical circle in which their contradictors may find themselves trapped: combatting pseudo-critical examination with critical examination, their arguments regularly fall short of convincing conspiracists all too ready to read them as further proofs of the existence of conspiracy (Taguieff 40). A more subtle approach, seems to suggest Eco, would be to fight fiction with fiction. If what makes both forgeries and conspiracy theories so powerful is their intrinsic narrativity, then a narrative demystification of their biased claims is more likely to affect the reader than another logical demonstration. What is at stake here, ultimately, is a passionate defense of fiction: the problem of the fake lies not in the circulation of fictions per se, but in the dangerous and morally condemnable uses of conspiracy fictions in service of political maneuvers aiming at targeting scapegoats. In Il cimitero di Praga, fiction is elevated as a powerful tool both to reestablish the origins and therefore the truth of a still active and threatening false, and to deconstruct the rhetorical and cognitive mechanisms through which conspiracy theories achieve their political goals. In an era where dangerous fake accusations are born from fictional pastiches -in the 19 th century as now; the fiction supported by the Protocols is still widespread nowadays -the best answer seems to strive to elaborate new ethical forms of fiction liable to take back the investigation process so appreciated by conspiracists and forgers and make it, rather than a twisted tool of production of fake truths, the basis of a new indiciary poetics.

Ironical ethics of truth

Recent falsification novels seem determined to avoid two symmetrical pitfalls. Firstly, the idea that there exist rigid boundaries between facts and fiction, and therefore that fiction is unreliable to provide a true account of History. All fictionalizations of the past are not deceiving: that Eco's protagonist, the supposed forger of the Protocols, is entirely fictional does not undermine the careful genesis of the forgery or the in-depth analysis of its damaging power. Secondly, they distance themselves from a potentially dangerous relativism that reduces reality to the mere sum of concurrent narratives, with no solid truth to be found anywhere. On the contrary, they blur facts and fictions in order to offer their novels to the reader as minefields requiring a careful investigation process to be deciphered properly. The conspiracists' mechanisms of trickery find themselves reversed in turn: the indiciary paradigm, proven to be insufficient per se to establish the veridicity of a given narrative, can be used as an optical instrument -in a Proustian way8 -to be given to the reader so he can construct his own interpretation of the text; storytelling as a seducing narrative machinery can be put to the service of a criticism of textual manipulations.

The Protocols may draw from Dumas; but Eco's novel is a compelling timetravel into 19 th century suspense serials: there can be found spies, secret services, doppelgangers, mysterious diaries, suspect or unfrocked abbots, abducted young women, strange occultists, bombings, etc. And yet, as the author reminds us in a final note, Simonini excepted, all the events and characters depicted are true, even the most implausible ones (Eco,Il cimitero di Praga 515). That ending note, notwithstanding the lightness of its tone, is an incisive invitation to re-read the whole novel under the light of that last revelation. All that the reader has dismissed as too unlikely to pertain to something else than fiction -say, the whole Boullan and Diana storyline, full of black masses and satanic sexual rituals -turns out to be historical after all. The reader's beliefs in his capacity to discriminate fact from fiction are thus seriously shaken. The usual criteria for establishing fictionality: plausibility, genre (a novel), enunciation (the narrator, amnesiac and insincere, is avowedly unreliable), do not allow to discern which events belong to the imaginary and which to historical facts. Given the plot subject matter, however, ascertaining the historical is crucial: faced with the reminder that the astounding story he has just read is but the genesis of one of the most perilous forgeries of recent history (Eco, Il cimitero di Praga 521), it becomes important for the reader not to treat as mere fictions facts that have contributed to shape the ghastly history of European anti-Semitism until WWII and beyond. The reader thus faces a conundrum: he cannot establish with the narrator a simple fictionality contract thanks to which he could read the whole book as a mere clever postmodern rewriting of Dumasian serials, nor can he relies on a referentiality pact guaranteeing him that everything is true -since the main character, a delusional forger (!), is invented. Hence the renewal of the investigation process, but this time the reader himself has to assemble clues into a convincing narrative.

Eco's art of storytelling was the first step of the laying out of the inquiry: thanks to his narrative technique, the reader is waded through such an amount of historical facts and digressions that the implied author has felt the need to add in appendix a recap chart distinguishing plot from story and summarizing the main plotlines. The whole complexity of 19 th century politics, philosophical and esoteric movements, unfolds before his bemused eyes in a 500 pages novel, and it's obviously impossible to reduce it to a linear, all-encompassing clarifying theory. Any attempt at coherence relies not on the abductive -and abusive -reconstruction of a simple and accusatory causality, but on the origination of the account of the Protocols fabrication in a (apparently) single point of view. Simonini's focalization gives the narrative its unity, but that very focalization is problematic: the forger suffers from a split personality. Every attempt at univocity is therefore doomed to fail; the reader cannot expect to be able to determine a single origin story for the Protocols.

The Prague cemetery is not a detective novel: it does not ask its reader to find a single culprit and a single possible account of the committing of the crime. Instead, the investigation process that is required of him demands that, firstly, he identifies the rhetorical and narrative misleading tropes thanks to which he has been presented with a complex set of facts he has to classify and analyze; and secondly, that he renounces the satisfaction of a closed conclusion in favor of a prudent acknowledgement of the complexity of historical evolutions9 . That is not to say, of course, that truth is forever out of reach: it is possible to reconstruct the story of the elaboration of the Protocols; Eco has done it after all in this novel and he had already done it elsewhere, in more academic contexts (Eco, 'La forza del falso'; Eco, Six Walks in the Fictional Woods). But it cannot be achieved through an oversimplification of past events. Thus the very narrative construction of the fiction functions as a refutation of conspiracy theories pseudo-rational mechanism: it proves impossible to read Eco's story through their lens. The investigation is diverted from its initial purpose: it must not aim at providing an effective causal explanation, but at bringing to light the inherent plurivocity of truth, without succumbing to the temptation of a relativism that would eclipse the vivid necessity of disarming the Protocols noxiousness.

Parodies of conspiracism: truth as fiction

Another means of denouncing conspiracy theories as sham rational exposures of reality is to undermine the very principles on which they are based. Taguieff discerns four axioms for conspiracist narratives: 1) "there is no such thing as an accident", and therefore nothing escapes the conspirators' programming of events; 2) everything happening is the result of a hidden -and malevolent -intentionality; 3) to uncover the truth, one only needs to establish who benefits from the conspiracy; 4) everything is connected, but the links remain hidden; in the end, there is only one enemy, and every force, including those appearing to oppose him, is a masked accomplice of its actions . Strikingly, the more Sliv enters the arcana of the CFR, the more he is lead to understand that none of those principles can truly be applied to the CFR activities, even those that resemble the most an elaborated conspiracy. Take for instance the creation of al-Qaeda by Angoua Djibo, one of the CFR's executives. At the beginning, Djibo only aims to create a convincing story to alert the US on the growing discontent caused by their politics in the Arabic world. He hopes to substantiate political theories such as Huntington's clash of civilizations and exacerbate tensions between the Western and Arabic worlds to frighten the authorities into avoiding an actual war. Exaggerating the threat was supposed to be the best way to drive Western states to preventive and restorative action before a serious conflict arose. The result is the involuntary reinforcement of a then barely existing entity that Djibo names "Al-Qaeda" and that progressively escapes him to become the organization we know.

There seems to be a conspiracy: Djibo, a powerful member of a secret and wealthy organization, lies and commits forgeries in order to manipulate whole populations and institutions into believing in his own version of reality. But what happens in the novel belies every principle of conspiracists: the creation of Al-Qaeda is very much an accident, the terrible and unwanted result of Djibo's tendency to play with fire. His intentions are therefore far from being as omnipotent as conspiracists claim conspirators to be, and they certainly aren't malevolent: the ultimate goal, after all, was to preserve peace in the world. The CFR and Djibo certainly do not benefit from his falsification: once his manipulation uncovered, an ethical crisis shakes up the CFR's "executive committee", half of its members asking for the dissolution of the organization in the light of its (involuntary) participation in 9/11. Djibo's very problem is the disconnection between his action -creating a false threat -and its results: conspiracists' abductive usual reasoning would here be powerless to explain the "true" causes of the formation of Al-Qaeda -that is those presented by the novel as such. One cannot not deduce from the result -the development of the terrorist organization -the initial decision -preserving peace by agitating threats -with an abductive reasoning, since the link between those two elements has been randomly established. Bello thus ironically stages in his novel a conspiracy that could by no means be accounted for thanks to a traditional conspiracy theory: the very from of conspiracist reasoning is here denounced as inoperative.

The CFR is a conspirator organization: it creates schemes and forgeries to influence the course of events. But its conspiracies could as well be seen as anticonspiracies: they do not derive from a coherent will to dominate the world. Throughout the first volume, Sliv is haunted with the question of the true finality of the CFR: what all-encompassing secret project do serve his scenarios and forgeries?

The answer might at first prove disappointing: the CFR has no finality at all. The perpetuation of the CFR throughout the centuries relies on its lack of definite purpose: no one can challenge the relevance of the organization and therefore threaten its existence if there is concretely nothing to oppose. The only encompassing value of the CFR is a concord born of the practice of relativism; every member is free to pursue his own fights10 provided that they do not directly clash with others'; the balance between differing aspirations and endeavors being the sole ferment of unity for the Consortium. Whereas, in Eco's narrative, the Universal Form of Conspiracy was an adaptable matrix ready to shape each and every accusatory historical explanation, in Bello's the conspiracy is reduced to a pure form, a mere conspiracy matrix aiming at nothing in particular and everything in general. Conspiracy thus becomes a practice amongst others; a paid activity that might finds itself temporary purposes but has no set aim.

In a sarcastic way, this is a radicalization of a traditional conspiracy theories postulation: the reductio ad unum principle that govern them implies that every structured conspiracy is to be subsumed under a more global one -Barkun's "superconspiracy" (Barkun 6). Already in the 19 th century, anti-Semitic conspiracists had theorized that every secret society was, in the end, a mere "copy" of the "Hebraic society" (Gougenot des Mousseaux 503; Taguieff 91). At the end of the day, most of the conspiracies are ontologically void, they only reproduce a larger plot unknown to them. The CFR, in that respect, seems to embody that fundamental emptiness of the conspiracy structure, merely duplicating processes of fabrication of lies and forgeries as a well-oiled machine functioning ad libitum. The difference is that there is no original conspiracy for the CFR to mimic; in a very postmodern way, it is a copy without an original, a sign referring to nothing but its own shallowness. At the very opposite of conspiracy theories meant to separate good from evil and heroes from villains, the CFR treats concord -the converging of differing viewpoints -as a conspiracy, a flexible plot where every opinion can be balanced with others. Secret does not conceal malevolent intentions but the vacuity of the encompassing matrix, the disappointing nature of the deception. One again, fiction proves to be the best possible demystification for conspiracists' manipulations: by exposing the nature of conspiracy as a mere rhetorical and narrative matrix, it denies it any inherent ability to produce truth and veridicity.

Conspiracy theory is therefore emptied from its cognitive dimension: the only truth about reality is that is it but the shape one gives to concurrent narratives. It can be influenced and curved, but it cannot be trapped into a single account. It is a liquid set of interpretations none of which is true per se, but some of which are ethically preferable to others. As such, fiction appears as the best environment to stage the fluidity and ever-changing nature of reality. It is particularly apparent in Bello's use of another event having given rise to numerous conspiracy theories: the Pandemic H1N1/09 virus. An ill-managed massive prevention and vaccination campaign in several states had created the condition of an international panic; but the discrepancy between the frightening presentation of the threat by medias and political authorities (a potentially mortal flu) and the reality of the disease (limited contamination, low mortality) had been received as a form of cognitive dissonance in public opinion that conspiracy theories offered to resolve. The claim "the true responsible party for the pandemic are pharmaceutical laboratories aiming to massively sell vaccines to panicked states by creating a false mortal flu" is a powerful explanation capitalizing on the distrust in international companies and state institutions and effectively reconciling the breadth of the authorities' overreaction and the relatively benign nature of the virus .

Ironically, Bello choses this time to go along with the conspiracists: in his trilogy, the pandemic is Vargas's last creation for pharmaceutical clients. But of a particular interest is Sliv's reaction, sincerely appreciative of Vargas' talent for conspiracy: "for every Vargas concocting a sanitary disaster, another scenarist would have us believing that we were shielded from pandemics. The balance between their contradictory stories was called reality." (Bello,Les Producteurs 356) There is no outrage at the machination on Sliv's part: rather than denouncing Vargas' lies as the danger they may represent for public safety and economy, he prefers to consider them as a kind of pharmakon, a poison liable to serve as an antidote to others, equally damaging, distortions of truth. In Les Producteurs, unlike in Les Éclaireurs, conspiracy is not shown as the empty frame it is anymore; rather, it is reality itself that appears deprived of any substantial content. Conspiracy theories at best are useful tools to cast suspicions on a foolish doxa. At worse, absurd endeavors to reconstitute a truth within a reality that offers no stable thread upon which to build. Relativism appears as the only truth of reality, and fiction, with its unique ability to mingle opinions and perspectives, as the best introduction to the acceptation of a liquid, moving world. As such, it offers itself as a playful remedy to the anxieties traditionally leading people to adhere to conspiracy theories.

Again, that is not to say that such a cognitive and ontological relativism directly translate into an ethical one: the flexibility of the CFR's conception of truth allows its agents to promote actions in favor of environment, discriminated groups, peacekeeping, etc., even in spite of their own personal convictions. In the trilogy, Sliv helps the emancipation of the Bushmen people, contributes to the UN adhesion of East Timor, and preserve a key archive of the Nanking Massacre from total destruction. But none of those actions would have been possible without him lying and forging documents. The only record of the Massacre having been lost, it is a fake video recreation of the lost original that will allow scholars to document the Japanese exactions. The narrator's avowed objective to "carry out reality" (Bello,Les Éclaireurs 488) is certainly not to be understood as an allegiance to scientific methods. "Carrying out reality" rather means to compensate for lacks of evidence of past facts.

Sliv distinguishes between narration and fact: if actual facts need to be brought to light to preserve a sense of balance amongst human endeavors -and not because of their supposed intrinsic value -narratives are but supple discursive forms for organizing facts into compelling stories. When said facts are missing, forgery becomes an effective and simple way to fill the gaps in the story. "Truth" is therefore a complex construct, the sum of antagonizing stories arranging facts differently and mixing up facts and fakes. An ethical attitude, the text suggests, is therefore not one of exposure of the fictional nature of some narratives -reality itself is a form of fiction -but a determination to carry the general direction of a given story towards a from of restoration of a lost balance. Such relativism may be seen as highly perilous by those attached to fight the corrosive power of conspiracy theories; but it is also a powerful tool of rehabilitation of marginalized facts.

All in all, Sliv's attitude constantly oscillates between a profound faith in concord and consensus; and a bemused assessment of the versatility of reality and opinion, especially at the age of Internet. In any case, his relativism can also be seen as an effective answer to conspiracists "caricatural rigid thinking". After all, Protocols specialist Taguieff himself, to fight conspiracists, calls for "plurality in viewpoints and flexibility in judgments"… (Taguieff 202) Rather than a caustic demystification on conspiracy theories, one could read Bello's trilogy as a playful suggestion for a democratic and heuristic use of them. Conspiracy theories are double-edged: undeniably harmful (Brotherton and French), they might also serve to remind us of the power play behind institutions grounding their political or social influence on unchallenged epistemic authority; of the danger to treat facts as mere self-evident, self-revealing truths (Moore); and of the democratic advantage of dissent.

Eco and Bello therefore build two symmetrical ethical defenses of fiction and the fictional use of a conspiracy narrative as opposed to a modern defiance for stories and storytelling. The former argues that fiction is the best demystification tool available: rather than a inescapably unconvincing rational argument against conspiracists, fiction, because of its ability to offer complex and compelling poetics of investigation leaving the reader with the responsibility for the reconstitution and the preservation of truth, is the best guarantee against the seductions of conspiracy theories narratives. Better even than scholar essays, fiction is an effective veridictive type of discourse, suggesting new and ethical ways of uncovering and producing truth.

In contrast, Bello presents a more labile conception of reality, where truth is nothing more than a regulating ideal and where investigation consists not in the collecting of clues, but in the gathering of sufficient information to forge credible evidence in support of a made-up story aiming at restoring balance, consensus and concord. Of course, such visions depend upon differing political viewpoints: Eco's fight against a dangerous relativism treating the Protocols as a possible interpretation of 19 th and 20 th centuries events originates into a vivid awareness of the perils of the minimization of discrimination and symbolic violence; it is also part of a humanist legacy promoting values such as intellectual honesty. Bello is a French liberal business owner living in New York and attached to a right-wing form of political pragmatism, transposing company governance principles to the ruling of the state. The reconciling of differing viewpoints, the achievement of a consensual synthesis after a round of negotiations, are pragmatic models that he applies to the ethics of his fictions. In both cases though, fiction is less the "true lie" it has often be described as, than a complex means of production of a polysemous, labile truth, ethical because it is, at its core, polyphonic.

Unless specified otherwise, all translations are mine.

A recent discussion of a necessary boundary between fiction and fact can be found in Lavocat.

Such as, to quote Taguieff, "the individualization of traditional religious beliefs" or the "weakened adhesion" to great national or cultural narratives in the postmodern era.

The conspiracist interpretation of the 2008 crisis may provide an illuminating example of such a method. A complex set of events that can hardly be reduced to a simple causes-to-effects explanation, or to a linear chain of actions and responsibilities, it is also a scandalous setback involving the ruin of thousands of people. The unacceptability of the crisis therefore lies both in the damages it has done to actors perceived to be disconnected from its causes and therefore innocent, and in the lack of an explanation behind such damages likely to point out culprits and so to restore justice. Such a feeling of unaccountability lays the basis for the restorative narrative of conspiracy theory. By negating the possibility of random events and presuming that every element of the crisis is the result of an actual intention, be it hidden, it reads the crisis as the premeditated consequence of a set of decisions. Unraveling the crisis thus means attributing responsibilities to a set of designated actors; it means sorting out of a complex continuum of loosely related or unrelated events connected and meaningful actions. There is no such thing as an accident, the conspiracists say, either because of their own political agenda, or because they sincerely believe in the theories they receive and diffuse; thus they over-rationalize every aspect of a given reality that scandalizes them into a rational action. When others see only chance or too complex an imbrication of actors and events to be untangled, the conspiracist treats every aspect of the crisis as a clue to be interpreted and inserted into a comprehensive, simplifying plot, entirely headed towards a pseudo rational cognitive resolution of the mystery the crisis constitutes. The solution is given in advance, the culprit pre-designated; and the conspiracist presents himself as the detective able to unmask him. As Taguieff reminds us (see above), biased causality and intentionality are the tools through which B. Madoff, who happens to be a Jew, becomes the clear responsible for a crisis whose roots are supposedly traceable back to a plot involving Jewish international finance, embodied by banks such as Goldman Sachs. The theory is not irrational per se; but, under the pretext of reporting the pernicious activity of secret social groups, it resorts to biased rational tools and criticism -it pretends for instance to demystify the true powers at play in globalized capitalist society -to indict scapegoats. Thus conspiracy theories are devices that, relying on the presumption of a hidden meaning behind all things, transform chaos into order, and failure (of the international finance institutions) into success (of supposed conjurors such as Madoff) to reinstate meaning where there was only confusion before.

One remembers the famous assertion of the Temps retrouvé: "The writer's work is merely a kind of optical instrument which he offers to the reader to enable him to discern what, without this book, he would perhaps never have perceived in himself."(Proust 283)

Of course, one can see a perceptible echo with Eco's theories on reading and the open or closed work(Eco, Lector in fabula).

For instance, in the 12 th chapter of the first part of Les Falsificateurs, Sliv's meets Magawati and Youssef, two CFR agents who soon become his closest friends, in a contest to reward the best first forgery by a new agent: Sliv defends the Bushmen's people rights, Youssef focuses on individual liberties and deforestation and Magawati, an avowed feminist, presents an biodiversity protection project.

Abstract

In postmodern Europe, two phenomena seem to have converged to challenge fiction's ability to deliver truthful accounts. The renewed popularity of conspiracy theories and the vogue of storytelling as a management tool appear to blur the boundaries between facts and fiction. In response, contemporary interest for factual literature might be the symptom of a "reality hunger" that resorts to nonfiction rather than to fiction to analyze and discuss social evolutions. However, there also emerges in contemporary literature a new fictional trend of falsification novels, narratives dealing with forgers and their forgeries. Such novels are proof that nonfiction is not the only ethical horizon for contemporary literature to deal with the difficult question of the divulgation of truth. Contemporary European falsification novels may well be a prime example of the drive of contemporary fiction to put its relationship to truth back into play. In fact, representing the fabrication of a forgery resorting to storytelling techniques to elaborate a conspiracy theory allows writers to challenge their readers to a playful fictive investigation using an ironic form of veridicity to confer to literature a new ethical dimension, relying on the unveiling of the deeply polysemous nature of reality.

Bio-bibliography

A former student of the École Nationale Supérieure, and a French literature agrégéé, Loïse Lelevé is preparing her Ph.D. thesis at Rennes 2 University with Emmanuel Bouju as her advisor. Her research focuses on the figure of the forger in contemporary Italian, French and British novels and artworks. She is the author of several published articles, amongst which « Fictions de l'énigme : vers une poétique du faux tableau » (RLC XC, n° 1, janvier-mars 2016), and « Images meurtrières et discours historique à la fin du XX e et au début du XXI e siècle » (Fin de siècle : fin de l'art ? Destins de l'art dans les discours de la fin des XIX e et XX e siècles, Cyril Barde, Hermeline Pernoud, Sylvia Chassaing (eds.), Paris, Presses de la Sorbonne Nouvelle, 2018).