Chemicals on the cuticle of ants: their role in hygiene, navigation and kairomone signalling to termites

This thesis describes investigations of how chemicals present on the cuticle of ants impact three important features of social living in insects: hygiene and disease resistance; navigation; and interspecies chemical signalling. Eusociality brings many benefits, but also has the potential to make insect colonies vulnerable to disease. In Chapter 2 of this thesis I investigate the role of the antimicrobial agent micromolide, in the Yellow meadow ant, Lasius flavus. Micromolide is found to be present on the cuticle of L. flavus workers, and is also found to be deposited onto a substrate by walking ants, revealing a possible mechanism for maintenance of sanitary nest conditions. Chapter 3 of this thesis focuses on navigation in L. flavus, specifically route-memory formation and the possibility of home-range markings providing a chemical cue via which ants can navigate from a food source to the nest. It was found that allowing ants to follow a pheromone trail to food increased the number of navigational errors made by returning ants, and that home-range markings did not provide effective guidance to ants returning to the nest. In Chapter 4, I report on a project undertaken during field work in Brazil into how cuticular hydrocarbons (CHCs) of the ant Camponotus arborious can act as kairomones when detected by Nasutitermes corniger, a common termite species. Experiments showed that N. corniger is less likely to repair experimentally opened tunnels in the presence of C. arborious CHCs, with 4 of 7 colonies tested blocking up tunnels, rather than rebuilding over CHC marked areas. Finally, Chapter 5 of this thesis discusses potential future projects, following on from the work presented in Chapters 2, 3 and 4.