Soil preference and burrow structure of an endangered tarantula, Brachypelma vagans (Mygalomorphae: Theraphosidae)

Abstract

Brachypelma vagans is an endangered tarantula included in Appendix II of CITES because of its popularity as a pet. However, little is known about its ecology, in particular microhabitat choices. In this work we analyse the structure of the vegetation surrounding burrows of this tarantula, as well as soil preference for the burrow at different sites in relation to the density of the species. We also offer the first description of the burrow of this spider. Brachypelma vagans mostly uses open sites with low vegetation for establishing its burrow, rather than primary or secondary forest. The burrows are essentially built in sites with deep clay soils, whereas sandy soils or soils with a high density of roots and stones are avoided. The soil characteristics may be the key factor determining the presence of B. vagans. The burrow of B. vagans is deep and complex, exhibiting various chambers, even if only one seems to be used by the occupant. The structure of the burrow and soil characteristics are obviously related. These results could help determine the real distribution of B. vagans within its geographic range, and might be useful for a better management focused on protection and reintroduction.

Keywords:

• Arachnida
• Brachypelma vegans
• burrow structures
• conservation
• Mexican Redrump Tarantula
• microhabitat
• soil characteristics
• Yucatan

Acknowledgements

We are grateful to the people of the villages 11 de Mayo, Ley de Fomento Agrario, San Miguel, and Cristóbal Colón for granting us access to their land, and for their hospitality during our stay. Thanks to Holger Weissenberger of El Colegio de la Frontera Sur (ECOSUR) for producing figure 1. R.R. benefited from a grant given by ECOSUR to S.C. through the research assistant programme PALI.