Brachypelma vagans cikkek

Két, a madárpókosoknak kedvező cikkbe futottam bele a minap. Az egyik a B. vagans talajválasztásával és üregének szerkezetével foglalkozik (ez akár még a fogságban tartáshoz is adhat ötleteket), a másik pedig egy emberhez közeli populációval.

• M'rabet, S. M., Hénaut, Y., Sepúlveda, A., Rojo, R., Calmé, S. & Geissen, V. 2007. Soil preference and burrow structure of an endangered tarantula, Brachypelma vagans (Mygalomorphae: Theraphosidae) Journal of Natural History, 41(17–20): 1025–1033

Összefoglaló:
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.

• M'rabet, S. M., Hénaut, Y., Rojo, R. & Calmé, S. 2005. A not so natural history of the tarantula Brachypelma vagans: Interaction with human activity Journal of Natural History, 39(27): 2515–2523

Összefoglaló:
We describe the structure of a population of Brachypelma vagans (Ausserer, 1875) in relation to the intensity of human activity and report characteristics of the burrows in Campeche, Mexico. During September and October 2003, we established sampling areas in five different classes of vegetation type/land use: mature forest (MF), secondary forest (SF), backyard (BY), and a football field divided into corner area (FC) and goal area (FG). The densities of spiders and the proportion of different age/gender classes of individuals on the sites were compared. Morphological data among adults and juveniles were contrasted, and differences in morphology between juveniles were tested according to land use class. We compared the nearest distances between neighbouring burrows and between burrows and trees. Also, we studied the orientation of the burrows, and compared the diameter of the burrow entrance. Brachypelma vagans was found exclusively in the open areas with densities that ranked from 0.02 to 0.1 individuals per square metre, being among the highest ever reported for Theraphosidae. However, there was a negative relationship between density and intensity of human activity. The population of this tarantula shows segregation in occupation of space. Females occupied exclusively the backyards, whereas juveniles occupied sites according to their stage of development. The youngest juveniles occupied the backyards, while the pre-adults occupied the football field. The distance between burrows was highly variable at all the sites. However it tended to be shorter in the backyards. The orientation of burrows was in all sites preferentially directed northwards. The diameter of the burrow entrances was a relatively good indicator of the sex and age of its occupier, and related almost directly to the dimension of the body. This study provides better knowledge of the structure of B. vagans populations in a human-modified environment and gives new information on the natural history of these spiders.

A teljes cikke(ke)t megkaparinthatja az, aki lefordítja az összefoglaló(ka)t, és elküldi nekem (dielonn[kukac]gmail[pont]com).