The effect of kleptoparasitism on prey consumption and web relocation in a Peruvian population of the spider Nephila clavipes (L.) (Araneae: Araneidae)
Oikos
1979
Journal Article
37
179-182
Reserva Nacional Tambopata animals invertebrates arthropods Arachnida spiders Nephila clavipes Araneae Araneidae Argyrodes animal behavior predation parasites parasitism ecology small spatial scales Madre de Dios Bibliography
In the TRZ a high degree of instability has been observed in the situating of webs in a population of Nephila clavipes spiders (Araneae: Araneidae). The number of prey captured and consumed by this species is related to the number of kleptoparasitic Argyrodes spp. spiders present on the webs. Between September and December 1979, captures were observed on 65 different Nephila webs, constructed by 42 individuals (11 adult females and 31 immature individuals). Those spiders that moved their webs during the study consumed appreciably fewer prey than those that kept their webs in the same place. The total capture did not however differ significantly between the two groups. 86% of all the prey captured by female Nephila were small hymenoptera and diptera; many other insects were able to avoid the web and escape before being attacked. During the period of observation, 71% of the insects caught in the web were captured. The critical value for midday consumption was six victims in a period of two hours. Of 33 spiders that consumed more than six victims during the period of observation, none re-situated their webs whereas two thirds of the 32 spiders that consumed six victims or less re-situated their webs during the study. A significant reduction in the number of prey consumed by female Nephila was observed for each additional Argyrodes spp. cohabiting their webs, which suggests that a high degree of correlation exists between the kleptoparasites and the proportion of individual Nephila that change the situation of their webs.