Submitted to: Physiological Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/4/2008
Publication Date: 6/1/2009
Citation: Yee, W.L., Chapman, P.S. 2009. Food Deprivation Effects on Carbohydrate Levels and Their Relation to Mortality of Western Cherry Fruit Fly, Rhagoletis indifferens, Exposed to Spinosad Bait. Physiological Entomology 34:163-173. Interpretive Summary: Western cherry fruit fly is an important quarantine pest of sweet cherries in the Pacific Northwest. Personnel at the Yakima Agricultural Research Laboratory in Wapato, WA, are determining the effects of temporary food deprivation on feeding responses and mortality of flies exposed to a protein bait spray laced with toxin. Flies deprived of food for only 10 h had decreased carbohydrate levels and that these levels were associated with increased responses to protein bait. These findings are important because they suggest flies need to sugar feed frequently to maintain their carbohydrate levels or their responses will increase, and that flies in environments with low abundance of food may be easier to control than flies in more food-rich environments. This information can be used to improve use of bait sprays to control flies on cherry trees.
Technical Abstract: The nutritional state of tephritid fruit flies affects various behaviors. The objectives of this study were to determine food deprivation effects on carbohydrate levels and their relation to feeding responses to spinosad bait (GF-120® Naturalyte® Fruit Fly Bait), measured indirectly by mortality, in western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae). Sugar levels in 1–2-day-old flies exposed to sugar for 1 h and then deprived of it for 10–24 h were 37.6–81.6% lower than at 0 h. Sugar levels in 14–15-day-old flies that had had free access to yeast extract and sugar and were then deprived of it for 10–30 h were 18.8%–86.6% lower than at 0 h. Mortalities of 1–2-day-old flies exposed to sugar for 1 h and then deprived of it for 10–24 h increased from 25.0–82.7%. Mortalities of 14–15-day-old flies deprived of food for 10–30 h were equally high at 82.7–93.3%. Food deprivation effects on glycogen were similar, although glycogen amounts were much lower. Results suggest R. indifferens needs to feed multiple times on carbohydrate foods during a day to maintain their carbohydrate levels or their responses to spinosad bait will increase, and that there may be fly age-related effects on carbohydrate levels and responses to spinosad bait. Key words Tephritidae, sugar, starvation, metabolism, behavioral responses.