Colour preference and foraging constancy in the Asian giant honey bee <i>Apis dorsata</i>

Tropical pollinators forage in spatiotemporally variable environments requiring flexible strategies that remain understudied in the tropics. Floral constancy - the temporary restriction to a single flower type - influences foraging success and plant-pollinator interactions. We examined colour preferences and constancy in wild colonies of the Asian giant honeybee, Apis dorsata, testing how reward concentration and learning shape these behaviours and whether the spectral composition of the floral community correlates with bee colour preferences. Using blue-yellow dimorphic artificial flower arrays, we tested whether: (1) reward quality modulates spontaneous colour preference and constancy, with low-reward promoting reliance on spontaneous biases and high-reward promoting exploratory choices; (2) recent experience modifies these biases, and (3) the floral community colour composition corresponds with bee preferences. Bees trained to a neutral UV-grey stimulus were expected to revert to their spontaneously preferred colour. Bees showed strong preference for and high constancy to blue. This short-wavelength bias was strongest under low-reward and weakened at high-reward concentrations, demonstrating reward-dependent shifts in behaviour. We propose reward concentration modulates arousal, with low-reward favouring spontaneous preferences and high-reward promoting exploratory sampling. Bees readily learned to prefer yellow with training, and sequential exposure to both colours eliminated overall preference, indicating that recent experience disrupts constancy. The community was dominated by short-wavelength flowers, consistent with possible pollinator-mediated selection linked to the blue preference in A. dorsata. Overall, colour preferences in Apis dorsata are flexible, shaped by reward quality and recent experience, with key consequences for floral constancy and plant-pollinator interactions.