Forage, forage against the dying of the light - nocturnal colour vision in the giant honeybee Apis dorsata |
Sajesh Vijayan1, G S Balamurali1,2, Jewel Johnson1, Almut Kelber2, Eric Warrant2, Hema Somanathan1. 1Behavioural and Evolutionary Ecology Lab, IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), IISER Thiruvananthapuram, Thiruvananthapuram, Kerala, India; 2Lund Vision Group, Department of Biology, University of Lund, S�lvegatan, Lund, Sweden |
We discovered nocturnal colour vision in the Asian giant honeybee Apis dorsata – a facultatively nocturnal species – at mesopic light intensities, down to half-moon light levels. Nocturnal colour vision in A. dorsata is interesting because, despite being primarily diurnal, its colour vision capabilities extend into dim light, while the ‘model’ European honeybee Apis mellifera is reported to be colour-blind at twilight. By employing behavioural experiments with A. dorsata workers, we found that the bees can discriminate the trained colour from other stimuli even at night. Nocturnal colour vision in bees has so far only been reported in the obligately nocturnal carpenter bee Xylocopa tranquebarica. The discovery of colour vision in these two bee species, despite differences in the extent of their nocturnality, and the limitations of their apposition compound eye optics, opens avenues for future studies on visual adaptations for dim-light colour vision, their role in pollination of flowers at night, and the effect of light pollution on nocturnal activity in A. dorsata, a ubiquitous pollinator in natural, agricultural, and urban habitats in the Asian tropics and sub-tropics. |