ATTRACTION OF ANASTREPHA-SUSPENSA (DIPTERA, TEPHRITIDAE) TO VOLATILESFROM AVIAN FECAL MATERIAL

Flight tunnel bioassays confirmed attraction of female Caribbean fruit flies, Anastrepha suspensa (Loew), to volatiles from aqueous solution s of avian fecal material and methanol extracts of avian fecal materia l. Attraction was highest to freshly prepared and 72-h-old solutions o f crude material. In direct comparisons between aqueous solutions of c rude material and weight-equivalent amounts of methanol extract, more females were captured in response to volatiles fr om elude material in tests of (0-, 24- and 72-h-old solutions. Ammonia release rate was gr eater. From the crude material than from the methanol extract in teats of 0-, 24- and 48-h-old solutions, The greatest amount (+/- sd) of am monia was released from freshly prepared aqueous solutions of crude ma terial (777 +/- 250 mu g/h from 75 mg of crude material) but dropped w ithin 24 h (288 +/- 96 mu g/h from 75 mg of crude material) and then s tayed close to that level. The greatest amount of ammonia released fro m methanol extracts was obtained from freshly prepared solutions (229 +/- 70 mu g/h from 75 mg crude material weight equivalent), also dropp ed within 24 h (98 +/- 12 mu g/h from 75 mg crude material weight equi valent) and then stayed fairly constant. Numbers of flies captured by either solution were directly correlated with ammonia release within t he first 48 h of testing only indicating that ammonia was partially ol wholly responsible for attraction to the crude material during the fi rst 48 h of testing. An increase in capture of females by volatiles fr om avian fecal material after 72 h in aqueous solution, which was obse rved in all tests, indicates that some chemical(s), other than ammonia , remain to be identified that are involved in fruit fly attraction.