Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2005
Publication Date: 6/1/2005
Citation: Kendra, P.E., Montgomery, W.S., Mateo, D.M., Puche, H., Epsky, N.D., Heath, R.R. 2005. Effect of Age on EAG Response and Attraction of Female Anastrepha Suspensa (Diptera:Tephritidae) to Ammonia and Carbon Dioxide. Environmental Entomology. 34: 584-590 Interpretive Summary: The Caribbean fruit fly, or caribfly, is a quarantine pest of citrus in Florida, and impacts the production and marketability of guava and other tropical fruit crops. Current ammonia-based lures vary considerably in their ability to capture caribflies in the field. Scientists at the Subtropical Horticulture Research Station, Miami, FL, initiated research to identify factors responsible for the variability. They used electroantennography (EAG) and flight tunnel bioassays to examine the effect of age on female attraction to ammonia and carbon dioxide, released from a commercial ammonium bicarbonate lure. EAG response to ammonia was greater in sexually immature flies, and response to carbon dioxide was greater in mature flies. In flight tunnel tests, both age groups were attracted to ammonia, but immature fly captures declined with increasing ammonia concentration, suggesting it may become repellent at high doses. Carbon dioxide alone was not sufficient to attract flies, but carbon dioxide combined with ammonia was more attractive than ammonia alone, but only for the mature flies. These age-related differences in response to ammonia and carbon dioxide may account for some of the variability observed with commercial lures, and facilitate the development of improved lures for tropical fruit flies.
Technical Abstract: Current ammonia-based lures vary considerably in their ability to attract Anastrepha fruit flies in the field. This report presents electroantennography (EAG) and bioassay results which examine the effect of age on fly response to ammonia and carbon dioxide, two volatiles released from commercial ammonium bicarbonate lures. EAG measurements from female Caribbean fruit flies, A. suspensa (Loew), showed that ammonia generated a significantly larger EAG response in sexually immature flies than in mature flies. Conversely, carbon dioxide elicited stronger EAG responses in mature females. In flight tunnel bioassays, both age groups responded positively to ammonia in doses ranging from 3-192 g/h, but response of immature flies declined with increasing ammonia concentration, suggesting repellency at high doses. This resulted in a uniform distribution of mature captures over the dose range tested, but a large percent capture of immature flies in the lower doses. Carbon dioxide, ranging from 5-120 g/h, did not capture any flies when presented alone. However, carbon dioxide in combination with ammonia was more attractive than ammonia alone, but only for sexually mature flies. These age-related differences in response to ammonia and carbon dioxide may account for some of the variability observed in field tests.