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Abstract

Generalist arthropod predators are potential drivers of population dynamics in a wide variety of ecosystems but their feeding habits are often difficult to reveal as they are small, mobile, and live among dense vegetation or in soils. DNA-based gut-content analysis is a powerful tool that enables studies on arthropod predator-prey interactions. We studied lycosid spiders ( spp.) in agroecosystems to see if they consumed cereal aphids () and Collembolans at random, i.e., in proportion to their abundance in the field. We also tested if consumption of the target prey items was affected by the presence of alternative food. Spiders were captured in farmers' fields and their gut-contents screened by PCR with and Collembola primers. On all sampling occasions, concurrent assessments of total prey availability were carried out. Spider predation rates on always exceeded 50 %. Spiders also tested positive for Collembola but to a lower and more varying degree. In general, did not consume and Collembolans in relation to their abundance in the field. Aphid predation was much higher than expected whereas consumption of Collembolans was considerably lower. The presence of alternative prey influenced consumption of the aphid. It was concluded that prey consumption by spiders generally cannot be assumed to simply mirror prey availability. The spatial distribution of the target prey needs to be considered as well as the abundance, composition, and nutritional content of potential alternative food items.

Keywords

Predator-prey interactions; Pardosa; Rhopalosiphum padi; Collembola; Alternative prey; Gut-content analysis

Published in

Journal of Pest Science
2012, volume: 85, number: 2, pages: 253-260
Publisher: SPRINGER HEIDELBERG

SLU Authors

UKÄ Subject classification

Agricultural Science

Publication identifier

  • DOI: https://doi.org/10.1007/s10340-012-0431-4

Permanent link to this page (URI)

https://res.slu.se/id/publ/56373