High temperatures adversely affect the hoverfly Episyrphus balteatus (Diptera: Syrphidae) fitness and aphid prey consumption

Numerous studies have shown that an increase of environmental temperature could directly disturb insect larval development. Natural enemies of insect pests, particularly predators of aphid populations, are not spared. Following temperature predictions of Belgian climate change scenario, the goal of this study is to measure life-history traits, such as the mass, body length and aphid consumption (Acyrthosiphon pisum (Harris, 1776)) (Hemiptera: Aphididae) of Episyrphus balteatus (De Geer, 1776) (Diptera: Syrphidae) larvae under three constant temperature treatments (i.e. 20, 23, and 26 degrees C). We detected no significant differences between 20 degrees C and 23 degrees C on the hoverflies larval development, their aphidophagous potential, as well as their mortality, pupation and emergence rates, while 26 degrees C had a deleterious effect on these parameters and the fitness of E. balteatus except for the total of consumed aphid per larva. Therefore, the high temperature could be disadvantageous for larval predation efficiency of E. balteatus. The outcomes of this study provide a new overview about ecological features of E. balteatus in the context of biological control under Belgian climate change.