10.5061/DRYAD.G00QR
Gunnarsson, Bengt
University of Gothenburg
Wiklander, Kerstin
University of Gothenburg
Data from: Foraging mode of spiders affects risk of predation by birds
Dryad
dataset
2014
2014-12-12T16:28:06Z
2014-12-12T16:28:06Z
en
https://doi.org/10.1111/bij.12489
61440 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Avian insectivores are top predators of arboreal arthropods in different
forest ecosystems. The selective effects of bird predation in relation to
foraging behaviour in canopy-living spiders were studied in a 2-year field
experiment using exclosures in a spruce forest in southern Sweden. Three
different hunting strategies – free-hunting, two-dimensional web,
three-dimensional web – were included in the analysis. Comparisons of bird
predation rate (ratio ln (abundance net-enclosed branch/abundance
control)) showed considerable variation between spider groups.
Free-hunting spiders suffered most from avian insectivores and predation
rate was significantly higher than in spiders with two-dimensional webs.
Spiders with three-dimensional webs were exposed to a predation rate in
between those of the two other hunting strategies. Generally, the
experimental effect was significantly higher in spring samples than in
autumn, suggesting a stronger predation pressure in winter. The high
variation in susceptibility to predation by insectivores implies that
selection on behaviour of spider individuals is strong. Web building in
itself is probably part of the protective mechanism, suggesting that webs
have dual functions. We conclude that the risk of bird predation is a
selective force on foraging behaviour of spiders in a forest canopy
system.
BJLS Predation risk in spidersNumber of spider individuals in relation to
hunting strategy on spruce branches (bird predation-free and control)