Lycosid Spiders are Friends and Enemies of the Endangered Pygmy Bluetongue Lizard (Tiliqua Adelaidensis)

Abstract

The pygmy bluetongue lizard is an endangered species and the smallest member (average snoutto-vent length 95 mm) of the genus Tiliqua. It uses spider burrows with a single entrance for shelter and as sites to ambush passing prey. There is a little information about interactions between this lizard and the lycosid and mygalomorph spiders which construct the burrows they use. Surveys of the diet of pygmy bluetongue lizards show they eat lycosid spiders, and one record of a partly consumed juvenile pygmy bluetongue lizard found in a lycosid burrow suggests spiders eat lizards. This paper describes the first record of adult pygmy bluetongue lizards being killed by lycosid spiders. It suggests a complex relationship of lizards and spiders in that the lizards rely on potentially lethal co-inhabitants of their grassland habitat to construct the burrow refuges that they require. Conservation management of this endangered lizard will need to consider both the advantages and disadvantages of maintaining spiders in lizard population sites.