CPL - Chalmers Publication Library
| Utbildning | Forskning | Styrkeområden | Om Chalmers | In English In English Ej inloggad.

Foraging mode of spiders affects risk of predation by birds

Bengt Gunnarsson ; Kerstin Wiklander (Institutionen för matematiska vetenskaper, matematisk statistik)
Biological Journal of the Linnean Society (0024-4066). Vol. 115 (2015), 1, p. 58-68.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: Araneae, avian insectivores, differential mortality, hunting strategy, spider webs, spruce canopies



Denna post skapades 2015-04-07. Senast ändrad 2016-06-28.
CPL Pubid: 214864

 

Läs direkt!


Länk till annan sajt (kan kräva inloggning)


Institutioner (Chalmers)

Institutionen för biologi och miljövetenskap (GU)
Institutionen för matematiska vetenskaper, matematisk statistik (2005-2016)

Ämnesområden

Biologiska vetenskaper

Chalmers infrastruktur