COS 157-6 - Influence of development temperature on fitness parameters of Aphidoletes aphidimyza (Diptera; Cecidomyiidae) males and on their mating abilities in a context of climate change

Background/Question/Methods

According to the temperature-size rule, development time and adult body size of ectotherms decrease when developing at high temperatures. The general morphology can also be modified (allometric growth), even if the proportions between body parts are maintained (isometric growth). In the context of climate change, this raises concerns about the consequences it can have in terms of fitness and mating choice. For instance, development time, size, and morphology of males of Aphidoletes aphidimyza influence their access to a mate. Sexually dimorphic antennae, wings and their relation to the body size are potentially important traits for mating success. However, for A. aphidimyza, no data are available on developmental plasticity of these traits. The predictions are that pupae obtained at high temperature should be smaller and they should develop faster than those obtained at low temperature. Moreover, males at high temperature should be smaller, present shorter antennae and smaller wings than at low temperature. To test these hypotheses, A. aphidimyza individuals were reared under three different temperatures. Characteristics of pupae and parameters related to development and emergence as well as morphology of adult males were then determined. Mating capacities of males reared at high and low temperature were also tested

Results/Conclusions

It results from these analyses that pupae are globally smaller at higher temperature and that the duration of the pupal stage is shorter at high than at low temperature. The highest rate of emergence was observed at a temperature close to the optimum (approximately 23 °C). Furthermore, males reared at higher temperature are globally smaller, with longer antennae and narrower wings compared to their body size, but with more symmetric antennae than those obtained at lower temperature. These differences did not affect their mating success. However, smaller males reared at high temperature appear to be more active when tested in an olfactometer, even if their choice toward sexual pheromones was no more frequent that bigger males from low temperatures. The results observed are discussed regarding to climate change and the use of this species in biological control programs.