Innate preference and learning of colour in the male cotton bollworm Helicoverpa armigera

We investigated colour discrimination and learning in adult males of the nocturnal cotton bollworm moth, Helicoverpa armigera, under a dim light condition. The naive moths preferred blue and discriminated the innately preferred blue from several shades of grey, indicating that the moths have colour vision. After being trained for 2 days to take nectar at a yellow disc, an innately non-preferred colour, moths learned to select yellow over blue. The choice distribution between yellow and blue changed significantly from that of naive moths. However, the dual-choice distribution of the trained moths was not significantly biased to yellow: the preference for blue is robust. We also tried to train moths to grey, which was not successful. The limited ability to learn colours suggests that H armigera may not strongly rely on colours when searching for flowers in the field, although they have the basic property of colour vision.