Article
Ontogenetic Shifts in the Costs of Living in Groups: Focal Observations of a Pholcid Spider (Holocnemus pluchei)
The American Midland Naturalist
(2000)
Abstract
Holocnemus pluchei spiders (Family Pholcidae) facultatively live in groups:
sometimes they live alone and sometimes they share webs. In the field groups vary in size
and composition and include spiders of all ages and either sex. Group membership is flexible
and individuals move frequently among groups. To understand group formation and maintenance
it is necessary to understand the costs of group membership. We used focal animal
sampling to investigate the cost of group living for spiders of different ages across a range
of group sizes. Both spider age and group size affected the costs incurred by group-living
spiders. There was no variation among groups of different sizes in the percentage of time
focal small or large spiders spent in costly behaviors (moving, web maintenance, bouncing
or interactions with conspecifics), but medium-sized spiders spent more time engaged in
costly behaviors with increasing group size. Medium and large spiders also had more interactions
with greater numbers of different conspecifics when they were in groups larger than
three, whereas small spiders interacted rarely with conspecifics regardless of group size. These
results suggest that there are significant ontogenetic shifts in the costs of group living in H.
pluchei.
Keywords
- Holocnemus pluchei spiders,
- Araneae: Pholcidae,
- ontogenetic shifts
Publication Date
2000
DOI
http://dx.doi.org/10.1674/0003-0031(2000)143[0405:OSITCO]2.0.CO;2
Citation Information
Elizabeth Jakob, Julie A. Blanchong, Mary A. Popson, Kristine A. Sedey, et al.. "Ontogenetic Shifts in the Costs of Living in Groups: Focal Observations of a Pholcid Spider (Holocnemus pluchei)" The American Midland Naturalist Vol. 143 Iss. 2 (2000) p. 405 - 413 Available at: http://works.bepress.com/elizabeth_jakob/2/