Submitted to: Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2008
Publication Date: 1/10/2009
Citation: Huang, C.H., Yan, F.M., Byers, J.A., Wang, R.J., Xu, C.R. 2009. Volatiles induced by the larvae of asian corn borer (ostrinia furnacalis) in maize plants affect behavior of conspecific larvae and female adults. Insect Science. 16:311-320. Interpretive Summary: The Asian corn borer (ACB), Ostrinia furnacalis, (Guenée), is a major pest of corn (also called maize) in Asia (e.g., Philippines, China, Japan). The moth feeds especially on sweet corn where it can drastically reduce yields by 50% or more. Other related species in the genus Ostrinia are the European corn borer, O. nubilalis, which is also a major pest in USA on corn (Zea mays L.) Knowledge gained about ACB should be applicable to management of other corn borer species. The objective was to study the release of volatile chemicals by corn when feed upon by ACB caterpillars as compared to mechanical damage or no damage. The second objective was to determine the effect of released volatiles on the behavior of young caterpillars and adult females when laying eggs. Nineteen volatile chemicals were identified from corn plants attacked by medium sized (third-instar) caterpillars for 48 hr, with terpenes being the major chemicals. Coupled gas chromatographic (GC)-electroantennographic detection (EAD) analyses in which a moth antenna is exposed to chemicals passing through the GC instrument revealed some EAD (voltage) differences between female and male ACB antennae in response to larval-induced corn volatiles. In laboratory behavioral tests, very young ACB larvae were attracted to extracts of powdered adsorbents that had collected air laden with volatiles from ACB-damaged plants, and to synthetic farnesene (a chemical released from corn by feeding of ACB), but were repelled by (Z)-3-hexan-1-ol (a predominant volatile released from corn). In laboratory female egg-laying tests, females laid fewer eggs on plants damaged by larvae than on mechanically damaged plants or undamaged plants. Adult ACB females deposited fewer eggs on wax paper treated with (E)-2-hexanal or (Z)-3-hexan-1-ol than on wax paper treated with hexane solvent (control). The results suggest that changes in volatile composition of corn induced by ACB larvae affected attraction of ACB larvae and oviposition behavior of ACB female adults. The differences in sensitivity between ACB adults and larvae to induced corn volatile components are probably because of the very different needs and habits of caterpillars and adults. The feeding-induced chemicals could potentially be used to alter egg-laying behavior of females or disrupt the natural movement of young caterpillars.
Technical Abstract: Larvae of the Asian corn borer (ACB), Ostrinia furnacalis, (Guenée), feeding on maize (Zea mays L.) induced volatiles from the plants that affected orientation behaviors of ACB larvae and oviposition of ACB adult females. Nineteen volatile chemicals were identified from maize plants attacked by third-instar ACB larvae for 48 hr, with terpenes being the major components. Coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses revealed some EAG differences between female and male ACB antennae in response to larval-induced maize volatiles. In laboratory orientation bioassays, ACB neonate larvae were attracted to extracts of Porapak Q adsorbents that had collected air from ACB-damaged plants, and to synthetic farnesene, but were repelled by (Z)-3-hexan-1-ol. In laboratory oviposition bioassays, gravid females laid fewer eggs on plants damaged by larvae than on mechanically damaged plants or undamaged plants. Adult ACB females deposited fewer eggs on wax paper treated with (E)-2-hexanal or (Z)-3-hexan-1-ol than on wax paper treated with hexane (control). The results suggest that changes in volatile composition of maize induced by ACB larvae affected conspecific orientation of larvae and oviposition behavior of adults. The differences in sensitivity between ACB adults and larvae to induced maize volatile components are discussed.