CHEMICAL COMMUNICATION IN INSECT COMMUNITIES: A GUIDE TO INSECT PHEROMONES WITH SPECIAL EMPHASIS ON SOCIAL INSECTS

Abstract

SUMMARY Chemical communication plays an important part in the lives of insects, and particularly in lives of those that live in groups or social organizations. Chemicals which are used in communication in the general sense are called semiochemicals, and there are a number of subdivisions recognized under this title. Pheromones are a category of semiochemicals which are used for communication between individuals of the same species. Pheromones are in turn subdivided into primer and releaser pheromones. The former produce a relatively long‐lasting physiological change in the receiver, and the latter stimulate the receiver to some immediate behavioural response. Far more is known about releaser pheromones at present because they are easier to study. Nine categories of releaser pheromone are recognized here, used by both social and non‐social insects. Sex pheromones are widely used to bring the sexes together for mating, and they have been extensively studied in Lepidoptera. Invitation pheromones, encouraging the species to feed or oviposit at an explored site, are not extensively known. Aggregation pheromones are designed to bring individuals together into groups which may be temporary in sub‐social insects, or permanent in social insects. Dispersal or spacing pheromones are used by other species to reduce intraspecific competition for scarce resources. Alarm pheromones are a broad and sometimes unclearly defined group which communicate alarm or attack, chiefly in colonial species. Trail pheromones, applied to a surface by an individual, to be followed by another, are confined to Hymenoptera, Isoptera and a few Lepidoptera as far as is known. Territorial and home range pheromones may be widely distributed, but as yet few of them have been recognized. Surface and funeral pheromones are even less well known. Surface pheromones may play a large part in species or colony recognition. We can expect the number and complexity of pheromones to be much greater in social insects, a part of the subject which until now has received relatively less attention. As our understanding of the subject grows we may expect other categories to be added to this list.