New observations of frog and lizard predation by wandering and orb-weaver spiders in Costa Rica

Estudos sugeriram que a predação por aranhas pode ser uma força importante na regulação da historia de vida de anuros e largartos Neotropicais, mas descrições detalhadas das relações predador-presa são escassas. Decrevemos aqui novas observações em que aranhas contribuem para a mortalidade de anuros e lagartos no nordeste da Costa Rica e corrigimos ou esclarecemos três erros de identificação de aranhas da literatura. Os predadores mais frequentemente observados foram aranhas-andarilhas (Ctenidae), que parecem ser predadoras generalistas de anuros e lagartos. Uma aranha-de-teia-orbicular (Araneidae) também contribuiu para a mortalidade de anuros, provavelmente depois que o animal ficou preso na teia. Estudos mais detalhados são necessários para elucidar o papel que a predação por aranhas exerce sobre a demografía de anuros e lagartos em florestas Neotropicais.Studies have suggested that predation by spiders may be an important force regulating life history in neotropical frogs and lizards, but detailed descriptions of predator-prey relationships are few. Here we describe novel observations where spiders contributed to the mortality of frogs and lizards in northeastern Costa Rica, and we corrected or clarified three identification errors of spiders from the literature. The most frequently observed predators were wandering spiders (Ctenidae), which seem to be generalist predators on frogs and lizards. An orb-weaver spider (Araneidae) also contributed to frog mortality, likely after the frog became entangled in the spider’s web. More detailed studies are needed to elucidate the role that spider predation contributes to frog and lizard demography in neotropical forests

Habitat use in an assemblage of Central American wandering spiders

Volume: 41Start Page: 151End Page: 15

Spiders feeding on earthworms revisited : Consumption of giant earthworms in the tropics

Predation on earthworms is common in some generalist predator species, as for example several ground beetle species (Coleoptera: Carabidae) that frequently feed on earthworms. In spiders (Araneae), however, such behavior is far less well documented. A survey of reports on spiders feeding on earthworms yielded a total of 44 naturally occurring predation events. Spiders from 14 families were observed feeding on earthworms in nature, and species from two additional families consumed earthworm prey in captivity. Earthworm predation by spiders has been observed in temperate, subtropical, and tropical regions in 18 different countries. Tropical spiders from the families Theraphosidae (Mygalomorphae) and Ctenidae (Araneomorphae) accounted for 59% of the reported predation events. Reports from French Guiana document the capture of giant earthworms (0.6-1 m in length) by the giant tarantula, Theraphosa blondi (Latreille, 1804). Predation on giant earthworms by large tarantulas has also been observed in rainforest habitats in Brazil, Ecuador, Peru, and Venezuela. Wandering spiders (Ctenidae) are known to feed on earthworms in Belize, Brazil, Costa Rica, French Guiana, Guyana, and Singapore. Quite obviously, larger-sized mygalomorph and araneomorph spiders in humid tropical rainforests are predators with broad feeding niches-including earthworms and vertebrate prey in addition to arthropod prey-and this is presumed to improve the survival of these spiders. By comparison, reports of earthworm predation in temperate climate are rarer, and recent molecular studies of the diet composition of lycosid and linyphiid spider species in Swedish arable fields suggest that earthworms are not a common prey of these species