Abstract

Pollen beetles, Meligethes aeneus (Fabricius) (Coleoptera: Nitidulidae), are major pests in oilseed rape (OSR), Brassica napus L. (Brassicaceae). Among the predator species in the generalist predator complex present in OSR fields, wolf spiders (Araneae: Lycosidae) are found on the ground and cobweb spiders (Araneae: Theridiidae) build webs in the foliage. Here we study the incidence of predation of pollen beetles by these two spider groups using DNA-based molecular analysis. Wolf spiders of the genus Pardosa and the cobweb spider, Theridion impressum L. Koch, were each collected in three winter OSR fields over a period of about 3 weeks. Pollen beetle densities as well as the occurrence of predators and alternative prey were monitored. In total, 13.8% of the collected Pardosa spp. tested positive for pollen beetle DNA in the PCR analyses, whereas 51.7% T. impressum were positive. The likelihood of detecting pollen beetle DNA in the gut contents of both spider groups was positively related to pollen beetle larval density. The implications of these results for conservation biological control and future studies of food webs in OSR are discussed.

Keywords

Meligethes aeneus; Theridion impressum; Pardosa spp; molecular gut content analysis; predation; Nitidulidae; Lycosidae; Theridiidae; Brassica napus

Published in

Entomologia Experimentalis et Applicata
2011, Volume: 138, number: 3, pages: 256-262
Publisher: WILEY-BLACKWELL

SLU Authors

• Öberg, Sandra

  • Department of Ecology, Swedish University of Agricultural Sciences
    
  • Norwegian Institute for Nature Research (NINA)

• Lundhagen, Anna

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Ekbom, Barbara

  • Department of Ecology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Agricultural Science


Publication identifier

DOI: https://doi.org/10.1111/j.1570-7458.2011.01098.x

Permanent link to this page (URI)

https://res.slu.se/id/publ/58817