What makes mated and unmated female bees smell different? Metabolomics Australia’s University of Western Australia node is providing analytical services for CIBER’s project to determine if a difference in cuticular hydrocarbon profiles between mated and unmated queen honeybees is a result of substances transferred in a male’s ejaculate during copulation.

Cuticular hydrocarbons are chemical compounds found on the cuticle of most terrestrial arthropods. Originally thought to protect the animal against desiccation, it is now becoming increasingly clear that these chemical cues are also used during short range communication. In many species of insects, mated and unmated females differ in their cuticular hydrocarbon profiles, and this variation provides males with information on a female’s mating status. In social insects such as bees, differences in cuticular hydrocarbon profiles of mated and unmated queens may also provide workers with important information on queen fecundity.

In many species, substances other than sperm make up a substantial portion of the ejaculate transferred to females during copulation. The chemical content of the non-sperm portion of the ejaculate is typically complex, containing numerous substances with a wide variety of actions and are known as seminal products. The actions of some of these substances are concerned directly with sperm, including effects on sperm survival, probability of fertilization and sperm transport. However, seminal product substances are also known to influence important physiological and behavioural responses in females, and there is some evidence to suggest that these substances may influence a female’s chemical profile. To determine this, CIBER will artificially inseminate bees using different mixtures of ejaculates to determine if sperm, seminal fluids, or a mixture of these substances influences the chemical profiles of female bees.

This project is being run by Melissa Thomas (School of Animal Biology), Boris Baer (CIBER) and Maja Babis.