Potential impacts of climate change in larval development and oviposition choice of an aphidophagous hoverfly species Episyrphus balteatus (Diptera : Syrphidae)

Numerous studies have shown that climate change could, directly or indirectly, contribute to
disturb insect’s biology and interactions with plants. An increase of mean temperatures and
atmospheric carbon dioxide concentration is known to have various effects on insects-pests
biology, behavior and communication. However, the impact of climate change on their natural
enemies is still poorly understood. Following IPCC temperatures and CO2 predictions for the
next decades, we first investigated (i) the impact of an elevation of temperature, here 20°C,
23°C and 26°C on the weight, size, and consumption in aphid (Acyrthosiphon pisum Harris),
of the larvae development of the hoverfly Episyrphus balteatus (De Geer). We also tested (ii)
the hypothesis that a combination of CO2 concentration (450 and 800ppm) and temperature (20
and 23°C) may affect the oviposition choice of E. balteatus gravid females on bean plant (Vicia
faba L.) infested with aphids. Dual-choice bioassays were used for each temperature and CO2
combination. We found that temperature has no effect on the larval development of E. balteatus,
but has an effect on the weight and size of the final larval stage. Furthermore, contrary to CO2
concentration, an elevation of temperature also has an effect on the site choice and number of
eggs layed on the plants. Our results suggest that an elevation of temperature has an impact on
hoverfly biology and oviposition. Temperature may impact plant volatile profile, as well as
aphid honeydew, indirectly impacting hoverfly attraction. These outcomes offer new overview
about multitrophic interactions under worldwide climate change.