|LU, FANG - ENT DEPT, UNIV FLORIDA
Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/4/2001
Publication Date: N/A
Interpretive Summary: Males of the Caribbean Fruit Fly, an important pest of citrus in Florida, release chemicals called pheromones to attract females for mating. These pheromones are critical for reproductive success. In order to identify weak links in the pheromone production system of males it is critical that the mechanisms used to produce and release pheromones and the tissues responsible for the production of pheromones are identified. Scientists at the Center for Medical, Agricultural and Veterinary Entomology USDA-ARS in Gainesville FL have been studying how pheromones are produced and released by male flies. They have discovered that males deposit oral secretions onto leaves and that these secretions contain pheromone components that are attractive to females. Their research has also shown that the amount of pheromone in oral secretions is related to the time of pheromone production during the day and with reproductive age of the males. Thus, males have the highest amount of pheromone in the oral secretions when they are reproductively mature and are releasing pheromones to attract females. This research has provided important information on how males attract females for mating and will allow for additional studies to determine how the pheromones are biosynthesized and what factors affect the production of pheromone.
Technical Abstract: Chemical analysis of hexane extracts of the oral secretions from male Caribbean fruit flies resulted in identification of pheromone components including: anastrephin, epianastrephin, suspensolide, bisabolene, and farnesene in a ratio of 63:396:4:8:1. Extracts of the crop from male flies contained these same components. No pheromone was detected in the extracts of female oral secretions. Bioassay of the oral secretions indicated that females were attracted to oral secretions from males but not from females. The amounts of anastrephin and epianastrephin in male oral secretions changed with age and time of the day, and were correlated with the amounts of volatile pheromone components released by male flies. The amounts of suspensolide, bisabolene, and farnesene in the crop tissue were greater than those in the crop liquid, while amounts of anastrephin and epianastrephin in the crop tissue and crop liquid changed during the day. Generally, the amounts of suspensolide and bisabolene decreased, and the amounts of anastrephin and epianastrephin increased from 9 am to 6 pm in both crop tissue and crop liquid. The amounts of anastrephin and epianastrephin from crop tissue or crop liquid incubated with suspensolide were significantly higher than those of control. The data show that oral secretions deposited on leaves by males contained terpenoid pheromone components which attract females and that suspensolide was converted to anastrephin and epianastrephin by enzymatic degradation in the crop of male flies.