Collins New Naturalist Library (106) – Dragonflies by Corbet Philip & Brooks Stephen

Author:Corbet, Philip & Brooks, Stephen [Brooks, Stephen]
Language: eng
Format: epub
ISBN: 9780007405237
Publisher: Harper Collins, Inc.
Published: 2011-02-17T00:00:00+00:00

Site attachment

The males of most species of Anisoptera and also calopterygid Zygoptera show site attachment to a varying extent. They return repeatedly over a prolonged period to the same site and defend this site against incursions by conspecific males or even Odonata of different species. Within this site (the territory) the holder dominates other members of the same species and has prior access to females. The extent to which the territory is fixed in time and space varies and may depend on the number of interactions with other males and females or on exposure to sunlight. In some species, for example Libellula quadrimaculata (Fig. 111), the dominant male may tolerate subordinate males within the territory.6 The vigour with which the male defends the territory can vary with time and between species, and may depend, among other things, on the density of mature males. Territorial behaviour results in males becoming localised on a particular site and spaces them out through that site. Holding a territory becomes increasingly beneficial to the holder as the site gets more crowded and competition for females intensifies.7

The degree of site attachment is usually related to male density. Species that occur at low male density at the rendezvous (such as Aeshnidae and Cordulegastridae) typically exhibit weak site attachment, whereas those that

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