The behaviour and chemistry of recruitment and alarm in social insects

This thesis initially focuses on the chemical ecology of two species of ant which are common in the United Kingdom; Lasius flavus, the yellow meadow ant and Lasius niger, the common black ant. The first data chapter explores the constituent chemicals present in 3 major exocrine glands located in the gaster of L. flavus and discusses their potential functions. The work presented here also highlights the need for the comparative study of the chemical composition of glands. The second data chapter investigates how chemicals present in hindgut extractions of Lasius niger vary with the temporal caste they belong to (nurse or forager), and subsequently looks at how those chemicals may be suited to the tasks performed by that caste. The third data chapter describes the development of a highly sensitive methodology to identify low-concentration pheromones that uses a combination of analytical chemistry and behavioural bioassays. This methodology was used to identify two attractive pheromones of L. flavus, one is a trail pheromone used during foraging while the other is an alarm pheromone used to warn nest-mates of danger. The trail pheromone is the lowest concentration pheromone to be successfully identified in ants to date. This chapter also highlights the need to perform comparative behavioural bioassays to demonstrate the true function of putative pheromones. The final data chapter then investigates the source of alarm signals in Nasutitermes corniger termites and assesses the differential responses of workers and soldiers. This chapter then goes on to elucidate the colony-level effects of alarm on the regularity of repairs made to experimentally manipulated foraging galleries.