The suitability of field margin flowers as food source for Chrysoperla lacewings

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 depending on nectar and pollen for survival and reproduction. In this study the suitability of flowers of 16 plant species is examined as food source for the common Chrysoperla carnea with non-choice survival tests. The results indicate that only umbellifers and other flowers with well exposed nectaries are suitable as sugar sources, allowing the lacewings to survive for more that 20 days and to produce eggs. On composites, even those with very short florets, survival and reproduction was clearly reduced. This indicates that their nectar was probably beyond reach, but that the pollen allowed the insects to survive longer than without food. Exceptions were composites with extrafloral nectar, as they allowed lacewings to survive much longer. The results are discussed in comparison with the results for hoverflies. These laboratory bioassays can, when performed for key natural enemies, be used to optimize the composition of field margins for the support of natural pest control.
Current status and potential