Age of Response of Male Bactrocera latifrons (Diptera: Tephritidae) to ¿-ionol + Cade Oil Relative to Age of Sexual Maturity

Authors: McQuate, Grant; BOKONON-GANTA, AIME` - UNIVERSITY OF HAWAII-MANO; Jang, Eric; MESSING, RUSSELL - UNIVERSITY OF HAWAII-MANO

Submitted to: International Journal of Tropical Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2008
Publication Date: 3/10/2008
Citation: Mcquate, G.T., Bokonon-Ganta, A.H., Jang, E.B., Messing, R.A. 2008. Age of Response of Male Bactrocera latifrons (Diptera: Tephritidae) to Alpha-ionol + Cade Oil Relative to Age of Sexual Maturity. Intern J. of Tropical Insect Sci. 28:12-18.

Interpretive Summary: Bactrocera latifrons (Hendel) is a tephritid fruit fly of primarily Asian distribution that became the most recent alien tephritid fruit fly species of economic importance to become established in Hawaii and was recently found to have invaded the continent of Africa, being detected in Tanzania in 2006. B. latifrons infests solanaceous fruits which includes eggplant, peppers and tomatoes. Among tephritid fruit flies, it is common for there to be a chemical to which males show strong attraction. This attractant can be used to monitor field populations or help suppress field populations through male annihilation. Males of the majority of Dacine fruit flies (an important subfamily of the tephritid fruit flies) respond to either methyl eugenol or cuelure. Bactrocera latifrons, however, shows little to no response to these lures. Instead, B. latifrons responds to alpha-ionol, with the response synergistically enhanced by the addition of cade oil. One question that has been studied for some fly species that respond to methyl eugenol or cuelure is whether the males will respond to the male attractant before they are old enough to mate. If they respond to the male attractant before they are old enough to mate, the attractant could be used, in conjunction with a toxicant, to kill the flies before they can contribute towards production of future generations. In this study, using wind tunnel tests and dissections of females for the presence of live sperm, we assess the extent to which B. latifrons males respond to their male lure, alpha-ionol + cade oil, before they are old enough to mate. We found that no female B. latifrons were mated by day 14 while 14 day old male flies achieved over 75% of the peak response to alpha-ionol + cade oil. This suggests that alpha-ionol + cade oil mass trapping (i.e., male annihilation) has some potential to remove males from the field before they can contribute to increasing field populations through matings, as previously found with oriental fruit fly, B. dorsalis (Hendel), and its respective male lure, methyl eugenol.

Technical Abstract: Although males of the majority of Dacine fruit flies respond to either methyl eugenol or cuelure, B. latifrons shows little to no response to these lures. Instead, B. latifrons responds to '-ionol, with the response synergistically enhanced by the addition of cade oil. To further understand the effectiveness of '-ionol + cade oil as an attractant, we documented the age of male response (using wind tunnel bioassays) relative to the age of sexual maturity (assessed through spermathecal dissections) using wild B. latifrons adults recovered from turkeyberry, Solanum torvum, fruits. Relative to the peak response observed at day 28, male response exceeded 50% of the peak response by day 7 and exceeded 75% and 90% at days 14 and 21, respectively. No females younger than 16 days old were mated. Based on a sigmoidal regression of percentage of inseminated females versus age, 50% of the females were inseminated by 18.8 days old, with the percentage increasing to 75% and 90% by 19.8 and 20.9 days old, respectively. At 24 days and older, 100% of females were mated. The observation that no female B. latifrons were mated by day 14 while 14 day old male flies achieved over 75% of the peak response to '-ionol + cade oil suggests that '-ionol + cade oil mass trapping (i.e., male annihilation) has some potential to remove males from the field before they can contribute to increasing field populations through matings, as previously found with oriental fruit fly, B. dorsalis (Hendel), and its respective male lure, methyl eugenol.