Scientists from the University of Sydney have made a remarkable discovery: Danaida monarch butterflies are observed to consume living caterpillars of their own species, potentially to enhance the production of mating pheromones.
During their observations, entomologists noticed that the butterflies include caterpillars in all states of being – dying, dead, and alive – as part of their diet. These caterpillars primarily feed on poisonous plants, such as various milkweed varieties. The chemicals present in these plants act as deterrents against predators and eventually contribute to the vibrant colors on the butterflies’ wings.
These same chemical compounds play a role in male butterflies producing pheromones, and even in their adult stage, the butterflies seek out not only fragrant flowers with nectar but also natural sources of poison. They do this by damaging leaves with their claws, causing sap to emerge, which they absorb with their long tongues.
However, a curious observation was made in the forests of North Sulawesi (Indonesia), where the butterflies chose their own offspring instead of plants, marking the first instance of such behavior.
Prior to this discovery, entomologists had encountered monarch butterflies on the remains of dead insects, though they belonged to different species, making it unclear if they died from an attack or naturally.
This newfound behavior prompts scientists to reevaluate the ecology of the monarch butterfly, as it could be an indication of a lack of nutrients in their natural habitat. It is known that caterpillars may exhibit aggression towards one another when resources are scarce.
