Ecological significance of male attractant in the defence and mating strategies of the fruit fly, Bactrocera papayae

After being acclimatized to feeding on fruit flies, the Asian house gecko, Hemidactylus frenatus Dumeril & Bibron (Gekkonidae:Squamata), consumed fewe r methyl eugenol (ME) fed male fruit flies, Bactrocera papayae Drew & Hanco ck (Tephritidae: Diptera) than when offered ME-deprived males. After one-da y exposure to only ME-fed males, the geckos avoided feeding on female flies when in the presence of ME-fed males. When mechanically disturbed, the ME- fed males spontaneously ejaculated a rectal secretion which contains phenyl propanoids that deter the predator. The ME-fed males also competed significantly better than normal (ME-deprive d) males for virgin females. Male B. papayae converts ME to three other phe nyl propanoids which act in concert as a sex pheromone to attract females d uring courtship and as an allomone to the gecko.