Male burrow digging in a sex-role reversed spider inhabiting water-margin environments

Abstract

Allocosa brasiliensis is a sex role-reversed wolf spider that inhabits sandy water-margin environments. Males are larger than females and they dig deep burrows, whereas females construct shallow silk capsules. Females are the mobile sex that initiates courtship. Copulations occur inside male burrows and females prefer to copulate with males that construct deep burrows, suggesting high selective pressures acting on male digging behaviour. Our aim was to describe male digging behaviour and burrow architecture in A. brasiliensis. We recorded burrow construction of 10 males under laboratory conditions. Male burrows were vertical and tubular, with only one entrance, and in four cases showed a bowl-shaped chamber lateral to the bottom of the burrow. We distinguished eight behaviours associated with burrow construction. We found high frequencies of occurrence of sand extraction and high duration of silk deposition. Burrow characteristics are discussed in the light of the sexual strategies and habitat characteristics of the species.