Present address: National Park Neusiedlersee-Seewinkel, Hauswiese, A-7142 Illmitz, Austria.
Carabid beetle condition, reproduction and density in winter oilseed rape affected by field and landscape parameters
Article first published online: 28 DEC 2011
© 2011 Blackwell Verlag, GmbH
Journal of Applied Entomology
Volume 136, Issue 9, pages 665–674, November 2012
How to Cite
Haschek, C., Drapela, T., Schuller, N., Fiedler, K. and Frank, T. (2012), Carabid beetle condition, reproduction and density in winter oilseed rape affected by field and landscape parameters. Journal of Applied Entomology, 136: 665–674. doi: 10.1111/j.1439-0418.2011.01694.x
- Issue published online: 29 OCT 2012
- Article first published online: 28 DEC 2011
- Received: September 5, 2011; accepted: November 14, 2011.
- Amara similata ;
- condition factor;
- oilseed rape pests;
- Poecilus cupreus ;
- reproductive potential
The carabid beetles Amara similata and Poecilus cupreus are abundant in Central European winter oilseed rape (OSR) fields and potential antagonists of OSR pests. Therefore, they were investigated in 29 OSR fields relative to the influence of field and landscape parameters on their nutritional condition, reproductive potential and activity density. Nutritional condition was measured by a condition factor (CF). Fecundity of female beetles was expressed by the number of ripe oocytes in the ovaries. Activity density comprised the number of individuals caught with pitfall traps during their peak of reproductive period. Soil productivity and pest abundance (as a proxy of local prey availability) were considered as field parameters. Landscape parameters comprised the distance to the next fallow and the percentage of crop area around each study field. In eight of ten cases, pest abundance proved to be the most important factor explaining carabid characteristics, indicating that P. cupreus and A. similata consume insect pests in OSR fields. Pest abundance influenced the CF of both species and sexes positively. Oocyte numbers of A. similata were negatively related to the distance to the next fallow. Oocyte numbers of P. cupreus tended to increase with increasing pest abundance. Activity density of female A. similata was negatively influenced by soil productivity. Activity density of male A. similata and of female and male P. cupreus was negatively influenced by pest abundance. When analysing exclusively the influence of severe OSR pests (Meligethes aeneus, Ceutorhynchus napi and Dasineura brassicae), abundance of larval M. aeneus and C. napi was most important in explaining the CF and activity density of male A. similata, and male and female P. cupreus. M. aeneus and C. napi could be an essential prey for the carabids studied which may reduce the pests, thereby contributing to the protection of OSR from pest herbivory.