Microhabitat use and intraspecific associations in the whip spiderHeterophrynus longicornis(Arachnida: Amblypygi) in forest fragments formed by the Tucuruí Dam lake, Pará, Brazil

The effect of forest fragmentation on the abundance of the whip spiders Heterophrynus longicornis (Butler 1973) in land-bridge island fragments created by the lake formed by Tucuruí Dam, Pará, Brazil, was investigated. These fragments have been isolated for at least 23 years, on small islands that range in size from 12.9 to 91.3 ha. The abundance of whip spiders was calculated in 100 m transects on eight islands, both in the edge and in the interior of the islands. There were no differences in whip spider abundance between the edge or interior of islands, but the whip spiders strongly preferred areas with greater numbers of trees, trees with a DBH between 10 to 50 cm, and trees with termite nests. Over 31% of the whip spiders were found in association with other individuals on the same tree. Individuals were found in mother–offspring associations, mating pairs, and in mixed-age sex groups.