Visual response of the tomato fruit fly, Neoceratitis cyanescens, to colored fruit models

摘要

To determine how mature females of the tomato fruit fly, Neoceratitis cyanescens (Bezzi) (Diptera: Tephritidae), detect host fruit after arriving in their host plant habitat, behavioral responses to colored models were observed in a laboratory flight chamber. Host-seeking females oriented themselves preferentially towards bright orange spheres (3.7 cm in diameter), irrespective of their natal host fruit: tomato, bug weed, or black nightshade. Females oriented themselves preferentially towards the orange sphere when placed against a fluorescent yellow background as opposed to a black background, but the distribution of responses to the set of colored spheres did not vary significantly with background color. In a choice situation between bright orange spheres of various sizes (1.9, 3.7, and 7.5 cm in diameter), females landed preferentially on the bigger sphere. However, they preferred a yellow color when the latter was associated with two-dimensional models, probably mimicking leaves. The attractiveness of orange spheres depended more on the proportion of reflected light in the spectral region around 610 nm than brightness of color in itself. Low light intensity significantly influenced the activity of the flies but not their visual preference. The strong response of females to bright orange spheres confirmed the importance of visual characteristics in short-range mechanisms of host-plant location in specialist insects. Responses to fruit visual stimuli are discussed relative to other Tephritidae, host-finding strategy, and pest management.