Resource-based territoriality in the butterfly Lycaena hippothoe and environmentally induced behavioural shifts

Lycaena hippothoe males show aggressive territorial behaviour. We found the predominant mate location tactic to be perching; however, with increasingly more favourable weather conditions perch phases were ever more frequently interrupted by short patrol flights. In contrast to previous studies we found no switch between perching and patrolling. Rather, each territorial male used a flexible combination of both and the portion of time allocated to each behaviour depended on extrinsic factors. Consequently, territoriality was not given up during patrolling. This strategy seemed to be related to enhanced mating opportunities and relatively large territories (ca. 10-20 m(2)). Territories were located within patches of flowering nectar plants (resource-based territoriality). Other parameters (such as vegetation height, larval host plant density and distance to the nearest bushes) were not important in this context. Defending nectar sources is an uncommon territorial system in butterflies, and its evolution is attributed to the widely dispersed occurrence of receptive females, which concentrate at rich nectar sources. Given the strong dependence of reproductive output on adult resources in L. hippothoe, it is a straightforward strategy for males to monopolize nectar sources in spite of their high investments. (C) 2001 The Association for the Study of Animal Behaviour.