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

• 1 Chemical communication plays an important part in the lives of insects, and particularly in lives of those that live in groups or social organizations.
• 2 Chemicals which are used in communication in the general sense are called semiochemicals, and there are a number of subdivisions recognized under this title.
• 3 Pheromones are a category of semiochemicals which are used for communication between individuals of the same species.
• 4 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.
• 5 Far more is known about releaser pheromones at present because they are easier to study.
• 6 Nine categories of releaser pheromone are recognized here, used by both social and non-social insects.
• 7 Sex pheromones are widely used to bring the sexes together for mating, and they have been extensively studied in Lepidoptera.
• 8 Invitation pheromones, encouraging the species to feed or oviposit at an explored site, are not extensively known.
• 9 Aggregation pheromones are designed to bring individuals together into groups which may be temporary in sub-social insects, or permanent in social insects.
• 10 Dispersal or spacing pheromones are used by other species to reduce intraspecific competition for scarce resources.
• 11 Alarm pheromones are a broad and sometimes unclearly defined group which communicate alarm or attack, chiefly in colonial species.
• 12 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.
• 13 Territorial and home range pheromones may be widely distributed, but as yet few of them have been recognized.
• 14 Surface and funeral pheromones are even less well known. Surface pheromones may play a large part in species or colony recognition.
• 15 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.
• 16 As our understanding of the subject grows we may expect other categories to be added to this list.