ARS | Publication request: Prothoracic gland semiochemicals of green lacewings (neuroptera: chrysopidae)

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 24, 2009
Publication Date: October 22, 2009
Citation: Aldrich, J.R., Zhang, Q., Torres, J., Winterton, S., Han, B., Miller, G.L., Chauhan, K.R. 2009. Prothoracic gland semiochemicals of green lacewings (neuroptera: chrysopidae). Journal of Chemical Ecology. 35(10):1181-1187.

Interpretive Summary: Green lacewings (GL) are valuable predators sold commercially for biological pest control, principally for aphids in greenhouses. Despite their importance for biocontrol, the approximately 1200 species of GLs are difficult to identify and their classification is confused. We analyzed the defensive chemicals produced by various green lacewings from North and South America, Australia, and China, and showed that different kinds of GLs produce different mixtures of chemicals. The results of our analyses show that the chemical “fingerprints” of GLs are helpful in identifying these insects, and suggest modifications in their classification that more properly align related GLs. The results of this research make it easier to identify the common GLs in a region, which is of interest to researchers working on ways to more effectively utilize GLs for improved biocontrol. The research is also of interest to scientists studying the classification of GLs because the unique chemicals produced by GLs appear to indicate how closely related various members are to one another.

Technical Abstract: Adult chrysopids have paired prothoracic glands (PG) that are thought to produce defensive secretions (allomones). We analyzed PG extracts of the following green lacewings from North and South America, Australia, and China: Ceraeochrysa cubana (Brazil); Chrysopa (= Co.) oculata, Co. nigricornis, Co. incompleta, Co. quadripunctata (USA), and Co. septempunctata (China); Chrysoperla (= Cl.) rufilabris (USA) and Cl. sp. (Brazil); Plesiochrysa ramburi and Mallada spp. (Australia). PG secretions are characteristic for species within a genus, except for Chrysopa spp., and (Z)-4-tridecene is ubiquitous. Earlier reports in the literature that Co. oculata and Co. nigricornis produce 1-tridecene were shown to be in error. Chrysopa PG secretions are distinguished by the presence or absence of N-3-methylbutylacetamide, plus skatole (3-methylindole). Skatole is also identified for the first time from the Plesiochrysa and Ceraeochrysa. The PG secretion in Plesiochrysa ramburi is characterized by the presence of 4-undecene instead of (Z)-4-tridence, and N-3-methylbutylpropanamide instead of the acetamide, resembling the PG secretions of Chrysopa nigricornis, Co. septempunctata and Co. incompleta. The chemotaxonomic value of PG semiochemicals is discussed, including evidence for subgroups within the genus Chrysopa as it now stands.