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Population Ecology

, Volume 43, Issue 1, pp 97–103 | Cite as

Competition for a limited space in kleptoparasitic Argyrodes spiders revealed by field experiments

  • T. Miyashita
ORIGINAL ARTICLE

Abstract

Most kleptoparasitic Argyrodes spiders rely exclusively on host spider webs for obtaining their food. Because their densities occasionally reach high levels within a restricted area, competitive interactions may be important for determining the density of these unique spiders. Here I used two Argyrodes species commonly found on webs of the large orb-web spider Nephila clavata to clarify whether inter- and intraspecific competition influences abundance and within-web distribution by using observational data and field experiment. Removing Argyrodes flavescens from the host webs induced a remarkably high immigration of that species while density on control webs remained almost at the same level, which is evidence for strong intraspecific competition. Larger individuals of A. flavescens were located more frequently at the capture area of the host webs where it is easy to access prey ignored by the host spider, and spiders immigrating into webs from which that species had been removed were smaller in body size, suggesting interference competition for space among conspecific kleptoparasites. Argyrodes bonadea increased in number on webs from which A. flavescens had been removed, and the increase was correlated with the number of A. flavescens removed. This finding is evidence for interspecific competition that is rarely reported in spiders. A multiple regression model including numbers of a conspecific parasite as well as web and body sizes of the host spider could not detect competitive interactions between species, suggesting the importance of experimental approaches.

Key words Interspecific competition Intraspecific competition Removal experiment Regression model 

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Copyright information

© The Society of Population Ecology and Springer-Verlag Tokyo 2001

Authors and Affiliations

  • T. Miyashita
    • 1
  1. 1.Laboratory of Biodiversity Science, School of Agriculture & Life Sciences, University of Tokyo, Tokyo 113-3657, Japan Tel. +81-3-5841-7544; Fax +81-3-5841-8192 e-mail: tmiya@uf.a.u-tokyo.ac.jpJP

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