Influence of temperature on survival and cuticular chemical profile of social wasps.

The cuticle of social insects is a barrier against desiccation and a channel for chemical communication, two characteristics fundamental to the success of this group. The compounds present in the cuticle interact dynamically in order to achieve a balance between these two functions. Thus, viscosity correlates with waterproofing, whereas fluidity correlates with effective communication. Temperature variation can cause the cuticular hydrocarbon (CHC) layer of the cuticle to change in order to maintain body homeostasis. Thus, in this study, we tested the hypothesis that wasps with different body sizes and nest types will differ in their tolerance to temperature variation and ability to respond by changing cuticular chemical composition. To test this hypothesis, workers of three species of social wasps with different body sizes and nests, both with or without envelope, were subjected to different temperatures under controlled conditions. Cuticular compounds were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Results show that tolerance to temperature variation is not directly related to either wasp size or nesting type. An increase in the percentage of linear alkanes and a decrease in the percentage of branched alkanes were correlated with increased temperature. Thus, instead of either body size or nest type, tolerance to temperature variation seems to be mediated by the changing chemical composition of the cuticle.