Living with predators at the larval stage has differential long-lasting effects on adult life history and physiological traits in two anopheline mosquito species

Olivier Roux (1, 2) , D Renault (3, 4) , Karine Mouline (1, 2) , Abdoulaye Diabaté (2) , Frédéric Simard (1)

1 MIVEGEC - Maladies infectieuses et vecteurs : écologie, génétique, évolution et contrôle
2 Institut de Recherche en Sciences de la Santé (IRSS) / Centre Muraz
3 ECOBIO - Ecosystèmes, biodiversité, évolution [Rennes]
4 IUF - Institut universitaire de France

1. Under predation stress, individuals increase their metabolic rate and adopt different resource allocation strategies to favor their direct survival to the detriment of growth, reproduction and self-maintenance. Species and sexes are both faced with different physiological and life history demands and should adopt different strategies which lead to carry-over effects on adult metabolic reserves and on oxidative status. 2. Malaria mosquitoes Anopheles coluzzii and An. gambiae are sibling species. In nature, their larvae are exposed to different levels of predation risk and An. coluzzii larvae are more capable of surviving predation threats than An. gambiae, because of a better ability to gauge the threat level and to produce an adapted behavioral response. Impact of this response on adult physiology is however unknown. 3. Here, we investigated the carry-over effects of larval predation stress: first, on life history traits such as development length, size and weight at emergence, fecundity and survival; second, on metabolic resources at emergence such as lipids, proteins, carbohydrates and amino acids; and third, on oxidative status with the total anti-oxidant capacity and the oxidation of proteins in the two species and in both sexes. 4. We found that on one hand, it took more time for An. coluzzii to develop in presence of a predator and they emerged with a smaller size but a similar weight as control individuals. On the other hand, An. gambiae exposed to predators developed as fast as controls but with both a smaller size and a smaller weight. Fecundity was negatively impacted in both species following exposure to predation threats. Teneral reserves were affected depending on the species and the sex. The total anti-oxidant capacity of individuals exposed to stress was lower than in the controls but a significant level of damages to proteins was detected in An. gambiae males only. 5. Our findings suggest that predation stress induces very different physiological responses even in closely related species and between sexes. Allocation of resources in larvae may differ and depend on the species’ aptitude to develop in presence of predators and on the sex, since males and females might adopt different strategies to fulfill their fitness.

Mots clés: Anopheles coluzzii; Anopheles gambiae; Carry-over effect; Life history traits; Malaria vectors; Oxidative stress; Predation stress; Teneral reserves

Domaines: Biodiversité et Ecologie

Olivier Roux, D Renault, Karine Mouline, Abdoulaye Diabaté, Frédéric Simard. Living with predators at the larval stage has differential long-lasting effects on adult life history and physiological traits in two anopheline mosquito species. Journal of Insect Physiology, 2021, 131, pp.104234. ⟨10.1016/j.jinsphys.2021.104234⟩. ⟨hal-03222789⟩