Field defects as habitats for parasitoids: insights from a field experiment in oilseed rape crops

GONZÁLEZ, EZEQUIEL; STROBL, MARTIN; JANSTA, P.; KADLEC, TOMÁS; KNAPP, MICHAL

Olomouc

Conferencia; 7th Conference of the Czech Ecological Society (ČSPE); 2019

Non-crop habitats within agricultural landscapes can increase biodiversity and provide important ecosystem services in adjacent fields. Field defects are temporary non-crop patches where the crop is poorly developed and other plants emerge. Despite that these defects can be common, their relevance as habitat for insects is unknown. Here, we studied the assemblages of parasitoids in artificial field defects within oilseed rape (OSR). In five fields, we created field defects at the edge and interior of the fields by destroying OSR plants in 18x18 m plots in early spring. Parasitoids were sampled with white and yellow pan traps and sweep sampling in spring and summer at field defects and OSR controls. We collected 5,949 individuals corresponding to 206 species. The most abundant species were parasitoids of OSR pests: Diospilus sp.1 (12.3% of total abundance), Trichomalus perfectus (11.5%), and Mesopolobus morys (9.5%). We found a significant interaction between habitat type and sampling period for richness and abundance. During spring, numbers of species and individuals were slightly higher in field defects compared to OSR. In summer, richness and abundance increased and were ca. four times higher in field defects than in OSR. No differences between edge and interior were detected. This suggests that field defects can have an important role as habitats for parasitoids within agricultural fields, especially after crop flowering. This study was funded by grant GAČR 18-26542S.