Caterpillars play an important role as primary consumers and also as food source for higher trophic levels. In agricultural landscapes, field margins can constitute an important habitat for caterpillars due to their permanent vegetation and plant species richness in comparison to agricultural sites. However, caterpillars occurring in field margins can be affected by pesticides via consumption of contaminated plant material or direct exposure during the applications. Indirectly, they are affected by the loss of food plants caused by herbicides. Because of their lower mobility compared to the adult stage, caterpillars rely notably on the presence of suitable habitats and a high quality of food plants for their development. Hence, they are especially susceptible to influences of agricultural activities.

This research project aimed to find out whether field margins act as habitat for the development of caterpillars and whether margins of several crop plants differ in their suitability as habitat. The caterpillars were sampled in field margins of different crops (cereals and fruits) as well as in control areas (meadows) in a study area around Landau (southern Rhineland Palatinate). Furthermore, caterpillars were surveyed in experimental field margin surrogates established in a perennial field study to assess effects of herbicide, insecticide, and fertilizer inputs. The caterpillars of the real field margins and the field margin surrogates were identified to family and (if possible) species level after sampling. Additionally, the existence of potential food plants was noted for every sampling site.

Field margins constitute caterpillar habitats for a range of Lepidoptera species. Overall, 725 caterpillars belonging to 14 families were recorded in the real field margins and the control meadows during three sampling periods in 2011. However, next to orchards less caterpillar individuals could be found in comparision to cereal field margins and meadows which is probably a result of higher insecticide inputs in orchards. This finding is coherent with the results of the field margin surrogates in which caterpillar occurence was reduced in plots receiving an insecticide input.

Related publications

Hahn, M., Schotthöfer, A., Geisthardt, M., Schmitz, J., Lenhardt, P. & Brühl, C.A. (2012). Caterpillars and protection goals: The role of field margins as habitats and the effects of pesticide applications. Poster presentation, 6th SETAC World Congress and SETAC Europe 22nd Annual Meeting 2012, Berlin, Germany.

Schotthöfer, A., Hahn, M. & Brühl, C. (2011). Raupendiversität in Feldsäumen verschiedener Landwirtschaftlicher Kulturen. Poster presentation, SETAC GLB Meeting 2011 Landau (Pfalz). more Info