An analysis of territoriality in libellulid dragonflies (Anisoptera: Libellulidae)

Over 30 species of libellulids (18 genera) have been studied with particular reference to territoriality. Attempts to analyse territoriality are difficult because the approach adopted by individual investigators varies and thus their results may not be directly comparable. Furthermore, the range of territorial patterns is wide and their expression is complex and variable. The pattern of territoriality in a given species or individual is created by the interaction of, (1) spatial, (2) temporal and (3) biological factors. Within these three primary determinants influencing territoriality, many other, secondary factors operate with varying degrees of importance on the overall pattern. Also, tertiary and quaternary factors are often the ultimate means of determining a territorial pattern. Spatial factors include territory type, territory size, size of insect and population density. There is a continuum of variation between discrete territories and communal territories supporting a hierarchical group of individuals. Temporal factors include waterside (daytime) and roosting-site activity. Biological factors, particularly, are numerous and complicated, and include secondary levels labelled as residentiality, territorial activities (non-sexual) and sexual activities.