Spatial distribution, burrow depth and temperature: implications for the sexual strategies in twoAllocosawolf spiders

Abstract

Allocosa brasiliensis and Allocosa alticeps are two burrowing wolf spiders that inhabit Uruguayan sandy coasts. Male efficient digging is necessary because copulation and oviposition occur inside their burrows. We examined burrow distribution, density and temperature variation according to burrow depth. Adult burrows were more frequent at the slope of sand-dunes in A. alticeps and at the base in A. brasiliensis. The base provides better digging conditions, whereas A. alticeps adults could prefer the slope to avoid intra-guild predation. Temperature buffering increased with depth, providing thermal stability in such a harsh environment as coastal dunes.

Ghost‐busting: patch occupancy and habitat preferences of Ocyale ghost (Araneae: Lycosidae), a single site endemic in north‐western Madagascar

“…Our results show an association between O. ghost occupancy and the aspect of the slope, with a preference for west-facing slopes. Some Lycosidae species have been shown to prefer certain sides and slopes of sand dunes for their burrow site (Aisenberg et al 2011). The same study also showed a clear difference between burrow site location and age class of Lycosidae spiders.…”

“…Lycosidae (Aisenberg et al 2011), but we did not measure burrow temperature, and thus our inferences about the role of aspect is speculative.…”

“…Individuals were then gently lowered onto bisecting rulers for final confirmation by three other observers. We did not survey for spiderlings in our study as they are often excluded from optimum habitat by larger individuals (Aisenberg et al 2011). Each survey at a given plot took approximately five minutes.…”

Habitat Preference and Effects of Coastal Fragmentation in the Sand-Dwelling Spider <i>Allocosa brasiliensis</i> (Lycosidae, Allocosinae)

“…Along with this, field observations suggest a potential high rate of relocation of the burrows, something expected if we consider the changeable conditions of coastal environments. [29] indicated that adult burrows of A. brasiliensis were more frequent at the base of sand-dunes where humidity values were higher. Furthermore, they observed that temperature buffering increased with depth, providing thermal stability and good conditions for eggs development.…”

“…Allocosa brasiliensis (Petrunkevitch, 1910) is a very common wolf spider in the Southern Uruguayan coastline. This nocturnal species constructs burrows in the sand [26]- [29], and shows sex-role reversal: males are bigger than females and females are the mobile sex that initiates courtship [30]. Copulation take place inside male burrows [30] [31] and males show reversed sexual cannibalism (they prey on rejected females) [18] [32].…”