Increasing the availability of food and the reproduction of Poecilus cupreus in a cereal field by strip-management
1994
Zangger, Adrian | Lys, Jon-Andri | Nentwig, Wolfgang
In a 8 ha field the availability of food and the reproduction of the most abundant carabid beetle Poecilus cupreus L. (Carabidae, Coleoptera) was compared between a strip-managed area (cereal area subdivided by strips of weeds and wild flowering herbs) and a conventionally treated cereal area. Data on phenology, biometry, quantity of the gut content and egg production were collected during the main reproduction period (April-July). Females were found to be significantly larger and heavier in the strip-managed area than in the control area. The higher weight (corrected for size) indicated better feeding conditions in the strip-managed area, which was confirmed by having better filled crops. The state of egg development and the numbers of eggs in the ovaries indicated a prolongation of the reproduction period in the strip-managed area, whereas females caught in the cereal area contained significantly fewer ripe eggs. The results of egg-laying tests in the laboratory showed the same trend but did not confirm any significant differences because of a high rate of individual variation. All measurements from females point to a higher availability of food in the strip-managed area and to an enhanced reproductive potential at this site. For males, on the other hand, the results did not reveal such a uniform trend.
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