Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/29/2008
Publication Date: 10/23/2008
Citation: Yee, W.L., Chapman, P.S. 2008. Seasonal Amounts of Nutrients in Western Cherry Fruit Fly (Diptera: Tephritidae) and Their Relation to Nutrient Availability on Cherry Plant Surfaces. Environmental Entomology 37:1086-1098.
Interpretive Summary: Western cherry fruit fly is an important quarantine pest of sweet cherries in the Pacific Northwest. Knowledge about the feeding ecology of this fly is important because it can be used to help understand how food bait sprays can be used for fly management on cherry trees. Personnel at the Yakima Agricultural Research Laboratory in Wapato, WA, are determining the feeding ecology of cherry fruit flies by comparing nutrient levels in flies with those on cherry trees over time. We found that flies contained similar amounts of protein and sugar over the season even though the amounts of nitrogen and sugar on cherry leaves and fruit increased over time. Results are important because they suggest flies feed similarly over the season despite the changes in nutrients on trees, and that bait sprays may be equally effective when applied early and later in the season.
Technical Abstract: Relatively little is known about the nutritional ecology of fruit flies in the genus Rhagoletis. In this study, nutrient amounts in male and female western cherry fruit fly, Rhagoletis indifferens Curran, and the availability of nitrogen and sugar on surfaces of leaves, fruit, and extrafloral nectaries (EFNs) of sweet cherry trees were determined from late May to late June in Washington state. Protein amounts in male and female flies did not differ over the season. Nitrogen was present on leaves, fruit, and EFNs all season, but amounts on leaves and fruit were lower in late May than the rest of the season. Sugar amounts in flies did not differ over the season. Sugar was also present on leaf, fruit, and EFN surfaces all season, but amounts on all three were lower in late May than later in the season. Fructose and glucose were the predominant sugars on all plant surfaces, although sucrose was also present in nectar from EFNs. In outdoor and field cage experiments, more flies survived when cherry branches with leaves and fruit were present than when they were absent. Results suggest that R. indifferens in central Washington maintains stable protein and sugar levels during the season because sufficient amounts of nutrients are found on leaf, fruit, and EFN surfaces in cherry trees throughout this time. As a result, increases in nutrient availability caused by ripening and damaged cherries later in the season apparently do not result in increased nutrient intake.