The suitability of field margin flowers as food source for Chrysoperla lacewings
Abstract: Lacewings are among the most common natural enemies of pests in arable fields.Whereas the larvae are voracious predators of aphids and other insects, the adults are dependingon nectar and pollen for survival and reproduction. In this study the suitability of flowers of 16plant species is examined as food source for the common Chrysoperla carnea with non-choicesurvival tests. The results indicate that only umbellifers and other flowers with well exposednectaries are suitable as sugar sources, allowing the lacewings to survive for more that 20 daysand to produce eggs. On composites, even those with very short florets, survival and reproductionwas clearly reduced. This indicates that their nectar was probably beyond reach, but that thepollen allowed the insects to survive longer than without food. Exceptions were composites withextrafloral nectar, as they allowed lacewings to survive much longer. The results are discussed incomparison with the results for hoverflies. These laboratory bioassays can, when performed forkey natural enemies, be used to optimize the composition of field margins for the support ofnatural pest control.