Considerations on locomotion activity, preference of ecotopes and territorial aspects of Phoneutria nigriventer (Keyserling, 1891) , (Araneae, Ctenidae)
Ramos, E.F.; Almeida, C.E.; Gouvêa, E.; do Carmo-Silva, M.
Revista Brasileira de Biologia 58(1): 71-78
1998
ISSN/ISBN: 0034-7108 PMID: 9699318 Document Number: 497459
Phoneutria nigriventer causes serious accidents in the south and southeastern regions of Brazil and several authors have contributed to the knowledge of its venom. The bionomics works on P. nigriventer have been done in the State of São Paulo (also in Uruguay) and they carry, almost exclusively, laboratory observations. This work was done in environmental conditions in Barra Mansa, south of Rio de Janeiro State, Brazil, having field and laboratory observations. Thus, it provides data on territorial behavior and preference of ecotopes of these arachnids in the region. The methodology used consisted in capture-mark-recapture of youngs and adults samples in field. For the conclusions concerning change of ecotopes only the recaptures were considered. The marked individuals that were not recaptured in the determined refuge where there were other youngs, were not considered dispersed because they are in constant molts. The results revealed the following: 1. In laboratory, the spiderlings performed cannibalism after the second ecdyse extra egg sacs and the considerable increase of this index, which probably determines dispersion, occurs from the fifth to the sixth week after emerging of egg sacs; 2. Synanthropic habits of the species in the region; 3. Preference for living on the ground instead of trees and other high places; 4. The youngs are much more active than the adults and expose themselves more often to unsheltered places. The adult females do not usually move more than 2 meters away from their shelter, and usually come back at night, while the youngs move away in a larger radius and do not always come back to the shelter.