Electroantennogram response and attraction of Anastrepha suspensa to volatiles of various sugar sources and aged sugar solutions

With the aim of finding new, sugar‐based volatile attractants for economically important tephritid fruit fly species, we used electroantennography (EAG) to quantitate olfactory responses of female Caribbean fruit fly, Anastrepha suspensa (Loew) (Diptera: Tephritidae), to volatiles of six sugar sources (refined white and brown cane sugar, coconut sugar, date sugar, date jaggery, and cane panela). Laboratory‐strain and wild flies, both sexually immature and mature, were tested for EAG responses to the volatiles of dry crystallized sugar sources and 10% (wt/vol) aqueous solutions that had aged in the laboratory for 0–7 days. In general, wild flies exhibited higher EAG responses than laboratory flies, and immature females responded more strongly than mature females. With the exception of date jaggery and cane panela, volatiles of dry sugar sources and 0‐ and 1‐day‐old solutions elicited lower EAG responses than any of the aged solutions. Most solution volatiles elicited the strongest EAG response after 2 days of aging. Of the treatments evaluated, volatiles of the 5‐day‐old date jaggery solution elicited the highest‐amplitude EAG responses (39%) in A. suspensa females. On the basis of the latter, we tested the attraction response of mature and immature females to date‐jaggery solutions aged over 2 and 4 days in two‐choice flight tunnel bioassays. With both mature and immature females, the 2‐day‐old solution was more attractive than the 4‐day‐old jaggery solution, but significantly more mature females (70% of captures) were attracted to 2‐day‐old jaggery solution. We discuss our results with respect to the improvement of fruit fly lures and attractants by incorporating elements from aged date‐jaggery sugar.