# 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

## TL;DR

This study compares how two blowfly species respond to different green and yellow light shades, finding that each prefers a specific color intensity for attraction.

## Contribution

The study identifies specific color intensities that attract two blowfly species, offering insights for improving fly trap designs.

## Key findings

- Lucilia cuprina is most attracted to medium intensity yellow light.
- Chrysomya rufifacies is most attracted to medium intensity green light.
- Both species are influenced by light intensity and proximity to the light source.

## Abstract

Sheep blow fly strike is a serious problem for sheep welfare worldwide. Two of the most important blow fly species involved are Lucilia cuprina (Wiedemann) and Chrysomya rufifacies (Macquart). Of the many cues flies use to locate a host, vision is important, with colour being useful to find places for feeding and laying eggs. Commercial fly traps often use bright colours to attract flies, but the most effective colours differ among species and are not well understood, although green and yellow are known to attract flies. The aim of this study was to examine how these two fly species respond to different shades of green and yellow. Three shade levels of each colour were presented under controlled conditions. The results showed that L. cuprina was most attracted to medium intensity yellow, while Ch. rufifacies was most attracted to medium intensity green. These findings improve our understanding of how blowflies respond to colour and may be used to design more effective fly traps.

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.