Observations on a commensal relationship of the microhylid frog Chiasmocleis ventrimaculata and the burrowing theraphosid spider Xenesthis immanis in southeastern Peru
Biotropica
1989
Journal Article
21
1
2-8
Reserva Nacional Tambopata animals amphibians anurans frogs invertebrates arthropods spiders Arachnida Chiasmocleis ventrimaculata Xenesthis immanis animal behavior predation habitat use habitat preferences commensalism ecology small spatial scales Madre de Dios Bibliography
Former investigations show a predator-prey relationships between many spiders and frogs; this contribution refers to the association of the microhylid frog Chiasmocleis ventrimaculata and the burrowing spider Xenesthis immanis: the observations were done between 4 May and 30 July 1986. The movements of each animal were registered since they left their burrows until they returned or finished the observations. Many of the spiders concentrated their activity in the surroundings of the burrow with open vegetation, the frogs showed a tendency to use more dense vegetation areas; nevertheless, the observations show that both species use simultaneously the same diurnal retreats and forage overlapping areas. The spider Xenesthis easily feeds itself on some species of anurans and the observations implicate the role of chemical defenses in Chiasmocleis against the attacks of Xenesthis. The evidences suggest that commensalism is more important in the biology of the frogs than in the spiders, even though taking possession of the burrow of a spider does not seem necessary for its survival, this constitutes an important and advantageous microhabitat for a certain part of the population. The benefits that the spiders could get from sharing their burrows with frogs are not yet known. This commensalism is similar to those that can be observed between terrestrial frogs and burrowing spiders in North America.