Abstract
Hexane extracts of leaves of 307 accessions from 73 host plant species of Helicoverpa zea were analyzed by gas chromatography (GC) and used for H. zea oviposition and neonate larvae orientation bioassays. The gas chromatographic (GC) retention times of compounds statistically associated with behavioral activity were identified by correlation of GC peak area with oviposition and larval orientation preferences. Although taxonomically diverse in their origin, compounds for study were purified from extracts of species of the genus Lycopersicon, due to their relative abundance. The structures of eight long-chain alkanes associated with oviposition preference were assigned by mass spectrometry, and the structures of five similarly associated organic acids and a terpenoid alkene were identified by 1H and 13C nuclear magnetic resonance spectroscopy. The structures of a number of other phytochemicals from the plant leaves were identified for comparative purposes, including a previously unknown terpene, 7-epizingiberene. Bioassays were performed on the isolated acids and on the alkane wax fractions of several Lycopersicon species, and significant differences were found in oviposition stimulation for both classes of compounds. Of the hundreds of compounds found in the extracts, none were observed to act as oviposition deterrents. The results of these bioassays may be useful in explaining the broad host range of H. zea, as well as the process and evolution of host plant selection for oviposition.
Original language | English (US) |
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Pages (from-to) | 513-539 |
Number of pages | 27 |
Journal | Journal of Chemical Ecology |
Volume | 22 |
Issue number | 3 |
DOIs | |
State | Published - 1996 |
Keywords
- Corn earworm
- Helicoverpa zea
- Host-plant selection
- Insect chemoreception
- Kairomone
- Lepidoptera
- Lycopersicon
- Nicotiana
- Noctuidae
- Oviposition
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Biochemistry