A Comparative Analysis of the Responses of Lucilia cuprina (Wiedemann) and Chrysomya rufifacies (Macqart) (Calliphoridae) to Different Reflectance Levels of Green and Yellow Light Hues

Proximate visual cues play a crucial role for flies (Order: Diptera) in locating suitable foraging and oviposition sites. This study examined the behavioural responses of two sheep myiasis-causing blowfly species in Australia, Lucilia cuprina (Wiedemann) and Chrysomya rufifacies (Macquart), to six different reflectance levels of green and yellow hues. Both species were influenced primarily by reflectance intensity and proximity to the light source. Lucilia cuprina displayed a nonsignificant preference for moderate yellow (p = 0.25), whereas Ch. rufifacies showed a significant attraction to moderate green (p = 0.004) when presented with a two-choice comparison between moderate green and yellow. When exposed to three reflectance levels under each hue, both species responded most strongly to mid-range intensities in green but not yellow, with no significant differences observed among light and dark shades (p > 0.05). Zonal analyses revealed a significant aggregation of individuals near the light source (Zone C; p < 0.05), indicating that spatial orientation cues may be stronger determinants of attraction. Overall, L. cuprina was more responsive to moderate yellow and Ch. rufifacies to moderate green, but both species were predominantly guided by light-related spatial and intensity cues. These findings provide valuable insight into the visual ecology of blowflies and may be useful in optimising colour and reflectance parameters in the design of future commercial fly traps.