Original Paper

Behavioral Ecology and Sociobiology

, Volume 62, Issue 1, pp 29-35

First online:

Daring females, devoted males, and reversed sexual size dimorphism in the sand-dwelling spider Allocosa brasiliensis (Araneae, Lycosidae)

  • Anita AisenbergAffiliated withLaboratorio de Etología, Ecología y Evolución, Instituto de Investigaciones Biológicas Clemente Estable Email author 
  • , Carmen VieraAffiliated withSección Entomología, Facultad de Ciencias
  • , Fernando G. CostaAffiliated withLaboratorio de Etología, Ecología y Evolución, Instituto de Investigaciones Biológicas Clemente Estable

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Sexual selection theory predicts that a higher investment in offspring will turn females into the selective sex, while males will compete for accessing and courting them. However, there are exceptions to the rule. When males present a high reproductive investment, sex roles can reverse from typical patterns, turning males into the choosy sex, while females locate males and initiate courtship. In many spiders, males are smaller than females, wandering in search of sedentary females and maximizing the number of copulations. In the present study, we present findings on the sand-dwelling wolf spider, Allocosa brasiliensis, evidencing a reversal in typical courtship roles reported for the first time in spiders. Males were bigger than females. Females located males and initiated courtship. Copulation always occurred in male burrows and took place mainly in long burrows. Males donated their burrows to the females after copulation, closing the entrance before leaving with female cooperation from inside. Males would provide females with a secure place for ovipositing, being exposed to predation and diminishing their future mating possibilities until constructing a new burrow. The cost of vacating the burrow and losing the refuge in an unpredictable habitat, such as sand dunes, would explain the courtship roles reversal in this spider species. Results turn A. brasiliensis as a promising model for discussing the determinants of sex roles and the pressures that drive their evolution and maintenance.


Wolf spider Sex roles Sexual size dimorphism reversal