Coexistence of two species of whip spiders (Genus Heterophrynus) in the neotropical rain forest (Arachnida, Amblypygi).

Heterophrynus longicornis Butler and H. alces Pocock are sympatric and syntopic in Serra do Navio in the central part of Amapá, N.-E. Brazil. Both species are of similar sizes during part of their life cycles. Competition is probably reduced by utilization of different hiding places and strata. In H. longicornis, adults are tolerant towards conspecifics. Male and female are usually found close to each other and, under laboratory conditions, courtship behaviour can be observed even when the female is not receptive. H. alces, on the other hand, is very intolerant, and usually only single specimens are found. Under laboratory conditions, cannibalism is frequent. The ecological implications of these differences are discussed.