Bionomic aspects of Prorachias bristowei (Araneae: Mygalomorphae: Nemesiidae): burrow density and shape, food items, body size and reproduction

Abstract

A population of Prorachias bristowei Mello Leitão 1924, a monotypic trapdoor spider, was studied in earthen road banks in southeastern Brazil. We assessed burrow densities, depths and widths, morphometric measures of spider bodies and recorded life history traits. Most burrows belonged to intermediate juveniles, followed by adults and a few juveniles. Egg sacs (mean of 131 eggs) and newly hatched spiderlings received parental care within the maternal burrow. Entrance diameters and burrow depths were significantly correlated with cephalothorax width and length, the length of the first leg and length of chelicera and number of eggs. Food items were Isopoda, Coleoptera, Hymenoptera and Ensifera. The clumped behavior and low dispersal ability can make the spiders vulnerable to anthropogenic modifications of their habitats.

Keywords:

• density
• trapdoors
• population structure
• Arachnida
• spiders

Acknowledgments

We thank Rafael Indicatti and Sylvia M. Lucas for species identification. For financial support we thank the University Center of Lavras (UNILAVRAS) and Fapemig, as well as Conselho Nacional do Desenvolvimento Científico e Tecnológico (CNPq Grant #301776/2004-0 to ADB).