Cuticular hydrocarbons (CHCs) as sexual signals

Updated: Nov 2, 2019

To what extent does the survival-attractiveness tradeoff exist in cricket CHCs?

Crickets in prep before being immersed in hexane to remove their CHCs

Insects have a waxy hydrophobic layer on their exoskeleton that maintains water balance and prevents desiccation. Since this lipid layer is made of hydrocarbon chains and exists on the epicuticle, these compounds are known as cuticular hydrocarbons (CHCs). However, CHCs serve a dual function as sexual signals.

"Cuticular hydrocarbons provide arthropods with the chemical equivalent of the visually extravagant plumage of birds" (Thomas & Simmons 2011)

When male and female crickets touch antennae, they exchange CHCs as olfactory/gustatory cues. Females are demonstrably attracted to males with more short-chain CHCs. However, longer-chain CHCs are better at desiccation prevention, as they have higher melting points. Therefore, males can invest in CHCs as sexual signals, but may run the risk of desiccation.

Is there a strong survival-attractiveness tradeoff in cricket CHCs? I am answering this question by testing a) female responsiveness to and b) desiccation prevention ability of crickets' natural CHC profiles. If this tradeoff exists, I expect to see that crickets with naturally more attractive profiles will have high female response but low survivorship in dry conditions, and vice versa.