Despicable Butterflies: Feeding on Larvae of the Same Kind and Harvesting "Wedding Gifts"

Recently, biologists have observed for the first time that milkwort butterflies feed on live caterpillars( larvae of the species).

Monarch butterfly

Recently, biologists have observed that milkwort butterflies feed on live caterpillars (larvae of the species), which is likely to increase mating pheromones in the body. "This is also the first time this behavior has been observed." First author Yi-Kai Tea, a PhD candidate in the School of Life and Environmental Sciences at the University of Sydney, said. The paper was published in the journal Ecology.

Caterpillars feed on poisonous plants and use them to accumulate chemicals for self-defense. Caterpillars with this chemical are toxic to predators such as birds and difficult to swallow. In addition, such chemicals also help male butterflies produce mating pheromones as "gifts" to females during courtship.

In addition to innate toxicity, male butterflies also look for other resources to replenish these chemicals. Most often, their first choice is the plant — butterflies perform a behavior known as "leaf grabbing," in which they destroy the plant with their sharp claws, causing it to release sap, which is then absorbed with a long, curly tongue." Tea said. However, in the forests of North Sulawesi, Indonesia, butterflies seem to be interested in caterpillars.

"This behavior does not quite fit the traditional predatory, parasitic, or reciprocal models, and therefore presents new challenges to evolutionary theory." We named it 'kleppharmacophagy', which means stealing chemicals used for consumption. The researchers speculate that the ultimate purpose of this peculiar behavior is also to obtain "love medicine."

Allegedly, there have never been previous reports of butterflies eating live caterpillars. In 2019, Tea and colleagues observed this unusual phenomenon in the coastal forests of North Sulawesi. He saw adult male milkweed butterflies clutching at leaves and caterpillars, both alive and dead, apparently absorbing their bodily fluids. "The caterpillars will quickly twist their bodies and try to stop those butterflies, but it may seem futile," he said. Caterpillars are effectively equivalent to bags of 'leaves' containing potent chemicals. For adult butterflies, they may simply be an alternative source of chemicals. ”

Although it has been documented that milkweed butterflies feed on other insect carcasses, this is the first time they have been observed sucking their own larvae. For now, it's unclear whether this behavior directly led to the death of the caterpillar. "Still, these simple observations offer many opportunities for future research."

Editor: Tangerine Reviewer: Seamus Editor:Chen Zhihan

Journal Source: Ecology

Issue No. 0012-9658

Link to the original article: https://phys.org/news/2021-09-butterflies-young-chemicals-gifts.html

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