Functional plants to conserve green lacewings Chrysoperla carnea (Neuroptera: Chrysopidae) in greenhouses

Abstract: Evaluation of flowers to conserve green lacewings has focused on adult feeding.
Nevertheless, plants can offer benefits besides floral resources, such as shelter and oviposition sites. Moreover, flower resources may also benefit the larvae as a complementary food. Here we assessed C. carnea larval survival on isolated floral resources, as pollen. The refuge and oviposition effect of plants were also tested, along with sweet pepper with release-recapture experiments in cages inside the greenhouse. In release-recapture experiments C. carnea adults Insects showed a significantly higher probability of selecting Cochlearia officinalis and T. kolibri relative to C. arvensis and R. sanguineus. We didn’t find significant differences in egg numbers laid between companion and crop plants. The larval survival experiment revealed significant differences in survival among treatments. Compared with the negative control (water), treatments pollen + sugar-water, sugar-water, and pollen + water exhibited significantly improved survival, while pollen alone did not differ from water. These results suggest that C. carnea larvae may benefit from access to sugar resources in natural environments in case of a shortage of prey, whereas pollen alone does not appear to support larval survival. A wider study would be needed to understand C. carnea preference for refugy and oviposition, but in general, in our study the adult lacewings show a preference for resting in the sweet pepper plants.