Partial local mate competition in the wasp Trichogramma euproctidis: the role of emergence sex ratio on female mating behaviour.

International audience1. Parasitic wasps with structured populations are generally assumed to follow the local mate competition (LMC) model: females lay only the minimal number of sons necessary to inseminate all daughters in the emergence patch, and increase this number when faced with additional broods from unrelated females. After emergence, daughters mate with local males before dispersing for host location and oviposition. The main predictions from the model have been verified for many species. 2. Conflicting evidence exists on the status of the egg parasitoids Trichogramma regarding their on-patch versus off-patch mating. Although the life-history traits of several species indicate that mating must occur on the emergence patch, recent data suggest that mating could occur outside the natal patch. 3. In this study, we measured the level of off-patch mating in the egg parasitoid Trichogramma euproctidis using two isofemale lines in a greenhouse experiment. The impact of the sex ratio on the level of off-patch mating was also tested. 4. The overall off-patch mating proportion was 40.5% with a range between 0 and 85.7%, and was influenced by the sex ratio on the emergence patch: the more males available at emergence, the less off-patch mating occurring. 5. The mating structure of this species can be described as partial LMC

Diet experiment data

Data collected in the laboratory in Montreal, Quebec (Canada). "Ladybirds" = Coleomegilla maculata; "Parasitoid" = Dinocampus coccinellae

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

An important question in evolutionary ecology is to understand the drivers of phenotypic variation in contrasting environments. Disentangling plasticity from evolutionary responses in such contexts provides a better understanding of how organisms adapt to changing climates. Many aspects of the seasonal ecology of insect populations are essential for their persistence in temperate environments, including their capacity to overwinter. Phenotypic plasticity should result in locally adapted diapause levels to experienced environmental conditions. Using an outdoor reciprocal translocation experimental design, we compared diapause expression of Canadian and French populations of aphid parasitoid species of the genus Aphidius in both their native and foreign bioclimatic regions, the insects thus experiencing varying temperature conditions under similar latitude (i.e. same photoperiod). From June to December 2016, diapause and mortality levels were recorded every 2 weeks. We found both genotypic (population origins) and environmental effects (experimental locations) on diapause reaction norms of parasitoid species. The incidence of diapause was higher in Canadian populations (up to 90%) than in French populations (< 20%) at both locations, suggesting local adaptation to harsh (Canadian populations) or mild (French populations) winter climatic conditions in the area of origin. Phenotypic plasticity played an important role in mediating diapause incidence at different temperatures but similar photoperiods, as diapause was induced at higher levels in Canada than in France, independently of the origin of the parasitoid. We conclude that both plastic and evolutionary responses could be involved in the adaptation of parasitoid overwintering strategies to different thermal environments and to ongoing climate warming

Plasmodium infections and fluctuating asymmetry among children and teenagers from Senegal

International audienceAlthough fluctuating asymmetry is a sensitive indicator of stress, its links with health remains controversial, especially in humans. Here, we explored for the first time the association between fluctuating asymmetry and malaria infections in humans, from 107 participants involved in a long term medical survey in Senegal. No clear relationship was detected. Depending on traits considered, associations were not significant, or (marginally) significant but not in the same directions. We discuss the possible reasons for the global weakness of the signals detected in this study