Stick insects are conventionally thought to adopt camouflage to avoid predation and consequently constrain foraging and mating activities to the night. For example, during copulation, winged male stick insects may additionally exhibit behaviours such as flapping of wings and vigorous abdomen shaking, which could reduce their camouflage and thereby increase predation risk. Thus, more brightly coloured species represent an opportunity to understand how stick insects avoid detection and predation when mating. We examined the mating behaviour of the stick insect Marmessoidea rosea, which are largely green with pink wings. While this species mates both in the day and night, the latency to mate was shorter and mating was more likely to occur in night. In addition, male stick insects shift their mating behaviours according to the time of day, with more conspicuous behaviours constrained to night copulation events. We therefore suggest that brightly coloured stick insects may modulate mating behaviours to optimise mating opportunities, while selectively displaying conspicuous behaviours at night to reduce exposure and detection by potential predators.
Colourful stick insects reduce daytime mating activity to lower predation risk