Attraction of apple maggot flies, Rhagoletis pomonella (Diptera : Tephritidae) of different physiological states to odour-baited traps in the presence and absence of food

Adults of apple maggot fly Rhagoletis pomonella (Walsh) of differing physio logical states were marked and released in blocks of apple trees ringed by sticky red spheres. Spheres were either unbaited, baited with butyl hexanoa te (synthetic host fruit odour) or baited with both butyl hexanoate and amm onium carbonate (synthetic food odour). All trap and lure treatments were c ompared in the presence or absence of food (bird faeces) in the blocks. Sim ultaneously, the response of wild immigrant flies to treatments was measure d and wild females were dissected to determine state of ovary development. Large proportions (25-40%) of released mature male and female R. pomonella were recovered in blocks having traps baited with butyl hexanoate. Ammonium carbonate did not enhance trap captures and presence of food had little ef fect on response to synthetic odours by mature R. pomonella. Immature flies of each sex responded weakly to traps and to both types of synthetic lures and may have been arrested in blocks having food. Wild flies of both sexes exhibited a response pattern very similar to mature released flies, regard less of eggload (in the case of wild females). Results indicate that wild R . pomonella immigrating into apple orchards are primarily mature, and not h ungry for protein. Behavioural control strategies are discussed in that con text.