The value of planted grass field margins as a habitat for sawflies and other chick-food insects.

Abstract

The planting of grass field margins is encouraged in a number of EU member states including the UK. These strips are known to support populations of overwintering insects but their value for other insect groups has been little studied. This study presents results from a survey of 116 grass strips planted along field margins and across cropped fields, looking at insects used by gamebirds as chick-food. In particular, the survey considered whether such strips were good for graminivorous sawflies, which need semi-permanent areas of suitable larval host plants without winter soil disturbance. Sawfly larvae were caught in over 88% of the surveyed strips at much higher densities than in modem UK cereal fields. They were most abundant in older strips with a high proportion of grass cover but a low percentage of cocksfoot (Dactylis glomerata) present . Numbers of other chick food insects were also quite high, although conservation headlands are likely to be more suitable for providing food for gamebirds than planted grass strips. Planted grass margins have potential benefits in helping in the conservation of sawflies, which are in serious decline on farmland in the UK.