ELECTROANTENNOGRAM RESPONSES OF MALE SPHINX PERELEGANS HAWKMOTHS TO FLORAL AND GREEN-LEAF VOLATILES

Electroantennograms (EAGs) from field-collected male Sphinx perelegans hawkmoths were recorded in response to 10 individual floral scent com pounds identified from Clarkia breweri (Onagraceae), 21 additional vol atiles characteristic of other night-blooming flowers, and eight 'gree n leaf' volatiles. Measurable EAG responses were elicited to all compo unds tested, but the most effective antennal stimulants were benzyl ac etate, linalool, methyl salicylate and trans-2-hexenal. Mean, pooled E AGs to oxygenated terpenoids, aromatic esters and fatty acid derivativ es were larger in magnitude than those in response to aromatic aldehyd es/alcohols, monoterpenes and nitrogen-bearing compounds. The rank ord er of male S. perelegans' EAGs did not differ significantly from that of previously recorded responses of male Hyles lineata to the same sce nt compounds, and EAG magnitudes were generally larger for S. perelega ns than for H. lineata. Both hawkmoth species are shown to have broad olfactory receptivities and could potentially respond to a wide array of plant volatiles;Is floral attractants.