Common crow species
Because the climate here is not as extreme. ” One hypothesis is that they migrate to escape the monsoons, while another says migration helps butterflies make use of resources available in different regions, their migration has several similarities, but we cannot say with certainty that they migrate to escape extreme climatic conditions,.
A 2023 paper published in the Journal of Insect Conservation says, “A huge number of danaine butterflies undertake seasonal migration between the eastern plains and the Western Ghats in Southern India” every year. “The movement between Western Ghats and eastern plains might be the largest butterfly migration system in India, but has received little research and attention, posing a challenge for their effective conservation and management,” says the paper. The reason is not yet understood, says Yathumon. “Certain resources may be limited in one area but abundant in another,” says Yathumon. These plants are more diverse in the Western Ghats,” says Yathumon. “During migration, many butterflies are killed after being hit by speeding vehicles, something we have recorded repeatedly during our studies,” says Yathumon.
If you’ve come across a swarm of butterflies recently that seemed to be going somewhere, and not just resting on a plant, you could have been witnessing the annual migration of that species. In South India, the westward movement generally takes place around Oct and Nov, sometimes beginning as early as Sept. The eastward migration occurs around March, April and May. though important for maintaining biodiversity, remains understudied in India While migration patterns of birds are much discussed those of butterflies. But why do butterflies migrate? “Worldwide, several butterfly species migrate. The best-known example is the monarch butterfly, which migrates to escape harsh climatic conditions in North America. It moves south towards Mexico, where the winter is comparatively milder. In South India, we see species that belong to the same subfamily as monarchs. Butterflies depend on specific plants on which they lay their eggs and on which their caterpillars feed, called larval host plants. The distribution of these plants could influence migration. “There are plants such as crotalaria that contain alkaloids needed by the butterflies. Other concerns include pesticide use and traffic. The spread and establishment of invasive plants is yet another threat to butterfly habitats and larval host plants, while climate change-driven extinctions of butterfly species are also widespread.
Like most other insect species, butterflies too face threats today, especially the destruction of the habitat of their larval host plants, inside and outside forests.