Olfactory Response of the Green Lacewing Chrysoperla Externa to Volatile Organic Compounds of Eucalyptus Urograndis

Abstract

The evaluation of the direct effects of the relationship between plants and predators without considering the participation of herbivores can provide vital information for the study of ecological interactions and integrated pest management. In this context, the present work studied the behavioral responses of Chrysoperla externa (Neuroptera: Chrysopidae) larvae to the volatile organic compounds of young and mature, undamaged and damaged leaves of Eucalyptus urograndis (Myrtaceae), and investigate the chemical composition of leaf essential oils and their effects on the green lacewing. The responses of the C. externa larvae to the odors emitted by leaves were evaluated by an experimental behavior test using a Y-tube olfactometer. The essential oil was extracted by hydrodistillation of the young and mature leaves with and without damage. The larvae respond attractively to the volatiles emitted without the participation of herbivores, and it selected preferentially odors emitted by young leaves with simulated herbivory. The chemical composition was analyzed using gas chromatography coupled with mass spectrometry. This research identified 32 compounds; some of them had not been identified in other studies. Young leaves had a higher content of essential oil compared to mature leaves. Among the compounds identified, eucalyptol, α-Terpineol, Aromadendrene, and α-Terpinyl acetate are the major compounds. An inversion in the content of eucalyptol (which decreases) and α-terpinyl acetate (which increases) is observed when young and mature leaves are damage. Thus, this work contributed with basic data on the potential use of eucalyptus forests as maintainers of natural chrysopids populations.

Synergistic impact of semiochemicals of plant parts and prey on chemotaxis response of Chrysoperla carnea

“…The results of the present study describe that the response of C. carnea larvae to fresh leaves and old leaves was significant as compared to other citrus plant parts. Borges et al (2021) studied that C. externa larvae preferred the volatiles of both intact and damaged young leaves of Eucalyptus tree over mature leaves. The attraction of larva to damaged young leaves could be due to that volatiles produced by damaged young leaves was higher than that to mature leaves.…”