Lepidoptera Species and Climate Change

• 12 Oct 2020

Why in News

According to a recent study, rising average temperatures in the Himalayan region have driven several dozen species of butterfly and moth to habitats higher up the mountains.

• The Himalayas are home to more than 35% of Lepidoptera species (butterflies and moths) found in India.

Key Points

• Lepidoptera:
  
  • Lepidoptera is the order of insects that includes butterflies, moths and skippers.
  • The name Lepidoptera is derived from the Greek, meaning “scaly winged,” and refers to the characteristic covering of microscopic dustlike scales on the wings.
    
    • Due to their day-flying habits and bright colours, the butterflies are more familiar than the chiefly night-flying and dull-coloured moths, but the latter is far more varied and abundant.
    • The skippers are a worldwide group intermediate between butterflies and moths.
  • Importance:
    
    • They are ecologically important because they transform large amounts of plant matter into the animal matter and in turn serve as food for many other groups of animals.
    • The adults of many species are important for their role in pollination, which occurs as they visit flowers for nectar.
• About the Study:
  
  • It was carried out by the Zoological Survey of India (ZSI) and was funded by the Ministry of Environment, Forest and Climate Change.
  • The four-year study tracked 1,274 species of moth and 484 species of butterfly in Jammu and Kashmir (J&K), Himachal Pradesh, Uttarakhand, Sikkim, North Bengal, and Arunachal Pradesh.
  • It also identified 80 new species of butterfly and moth.
• Findings of the Study:
  
  • At least 49 species of moth and 17 species of butterfly have shown “considerable new upward altitude records”, with a difference of more than 1,000 metres between their current and previously recorded mean habitat altitudes.
    • Few species of moths like the mulberry silkworm moth and tiger moth have started to inhabit altitudes more than 2,000 m higher than the previous mean.
    • Butterflies like the Common Map, Tailless Bushblue and the Indian Red Admiral butterfly have seen the difference ranging from 900-1500 m in their habitats.
  • The extension of the range of Lepidoptera due to climate change has been observed all over the world and Indian data from this evidence-based study confirms this trend and shows which species are moving, and how.
    • Butterflies are sensitive species that are extremely susceptible to changes in climate. They are, therefore, good indicators of long-term change in climatic conditions.
  • The ZSI predicts a decline of as much as 91% for example, in the suitable area for the Notodontidae family of moths in J&K, Himachal, and Uttarakhand by 2050.
    • The findings will be used as a baseline indicator to track the impact of climate change on animal species over the coming decade.
  • The study has identified two species richness hotspots:
    • One is in West Bengal’s Darjeeling hills, where more than 400 species records were documented.
    • Another one is in Kumaon, Uttarakhand, where more than 600 species records were found.
  • The study also revealed an increase in the richness of Lepidoptera biodiversity from the Western to the Eastern Himalayas.
• Factors behind the Upward Movement:
  • Receding ice caps and glaciers leading to a scarcity of water in the Himalayas has been a major reason for the altitudinal shift of the Lepidoptera.
  • The increase in average temperature has resulted in an altitudinal shift in vegetation that once grew at lower altitudes in the Himalayas are now found only higher up in the mountains.
  • Increasing human habitation has contributed to the shift as well.
    • For example, Shimla and Darjeeling are two big hotspots of rich butterfly diversity but expanding towns have encroached on virgin territory, and the space for the butterfly has shrunk.
  • Poaching and selling have led to the reduced or negligible population at the lower altitudes.
    • Butterflies like the Red Apollo are highly prized by collectors and are often poached. One butterfly sells for up to 100 pounds on the international market.

Source: IE