The Weeds the Butterflies Feed On: An Awkward Finding From Raimona
An Assam survey documenting butterflies and their host plants finds invasive species functioning as key nectar sources — which complicates the case for removing them
What happened
Conservation questions in the exam are usually framed as choices between development and protection. This one is harder and more interesting: a conflict between two conservation goals, where removing an invasive plant — unambiguously the right thing on the standard framework — may remove the food supply of the pollinators the park is also trying to protect. An aspirant who can hold both halves of that tension writes a better answer than one who reaches for the standard invasive-species template.
Why removing an invasive is not a simple good
Displaces native vegetation · degrades larval host plants · accelerates woody encroachment · Target 6 obligation
Functions as a key nectar source for adult butterflies · abrupt removal withdraws food before native replacement exists
Source: Raimona National Park survey as reported by The Hindu, 18 July 2026; Kunming-Montreal Global Biodiversity Framework, Target 6
Two distinctions carry the exam weight here.
●The first is between a larval host plant and a nectar plant: a butterfly's caterpillar eats the leaves of specific host plants, often a narrow range, while the adult feeds on nectar from a much wider set of flowering plants.
●A species can therefore be entirely dependent on a native host plant for reproduction while drawing much of its adult nutrition from something else, including an invasive.
●The second is the standing of invasive alien species in international policy: they are recognised under Target 6 of the Kunming-Montreal Global Biodiversity Framework, adopted in 2022, as among the leading global drivers of biodiversity loss, alongside habitat change, overexploitation, pollution and climate change.
●Raimona National Park was notified in 2021 in Assam's Bodoland Territorial Region, in the Eastern Himalaya foothills, contiguous with protected forest across the Bhutan boundary.
A larval host plant sustains reproduction and a nectar plant sustains the adult — which is why an invasive can be ecologically harmful and simultaneously load-bearing for pollinators.
◎ In Simple Words
Butterflies need two different kinds of plants: one kind for their caterpillars to eat, and another kind whose flowers give the adults sugary nectar. Scientists studying a national park in Assam found that some of the flowers the adult butterflies rely on come from foreign plants that were never supposed to be there. Those foreign plants cause problems for the forest, so people want to remove them, but doing it all at once could leave the butterflies hungry.
Factual Pointers
Practice · 2 questions
With reference to butterfly ecology, which one of the following statements is correct?
Consider the following statements:
1. Invasive alien species are recognised under Target 6 of the Kunming-Montreal Global Biodiversity Framework.
2. Raimona National Park lies in the Bodoland Territorial Region of Assam and was notified in 2021.
3. Invasive alien species are, by definition, incapable of providing any resource used by native fauna.
Which of the statements given above are correct?
Mains Practice Questions
Invasive alien species are recognised as a leading driver of biodiversity loss, yet removal can withdraw resources on which native fauna have come to depend. Discuss how protected-area managers should sequence invasive control in light of this tension.
Species inventories record what is present; resource-association surveys explain why. Examine the significance of this methodological distinction for conservation planning in India.
Discuss the institutional challenges of invasive species management in landscapes that span autonomous council areas and international boundaries.
MCQ Practice
3 questions on this article
With trap analysis, approach guide, and UPSC angle
Frequently Asked
· People also askWhat is the difference between a larval host plant and a nectar plant?
A larval host plant is what a butterfly's caterpillar eats, and the range is usually narrow — often a single plant family. A nectar plant is what the adult feeds on, and adults draw from a much wider set of flowering plants. A species can therefore depend on different plants at different life stages.
GS3 · EcologyThis distinction is what makes the Raimona finding possible: an invasive plant can be a significant nectar source for adults while contributing nothing as a larval host, and may simultaneously be displacing the native host plants the caterpillars require.
SOURCE Raimona National Park survey, reported by The Hindu
Where is Raimona National Park?
In the Bodoland Territorial Region of Assam, in the Eastern Himalaya foothills, notified as a national park in 2021. It adjoins protected forest across the international boundary with Bhutan, making it part of a transboundary conservation landscape.
GS3 · Protected areasIts location in an autonomous council area means forest administration runs through an additional governance tier, which matters for invasive-species management requiring landscape-scale coordination.
SOURCE Government of Assam · Bodoland Territorial Region
Why are invasive alien species considered a threat if native animals use them?
Because an invasive is defined by its damaging spread outside its natural range, not by whether anything eats it. Invasives displace native vegetation, alter habitat structure and can degrade the specific larval host plants insects require, even while supplying nectar or cover to some species.
GS3 · Biodiversity governanceTarget 6 of the Kunming-Montreal Global Biodiversity Framework commits parties to controlling or eradicating invasives at priority sites. The Raimona finding qualifies how that should be done, not whether it should be done.
SOURCE Kunming-Montreal Global Biodiversity Framework, Target 6
What is Target 6 of the Kunming-Montreal Global Biodiversity Framework?
Adopted in 2022, Target 6 commits parties to reduce the introduction and establishment of invasive alien species, and to eradicate or control them on priority sites such as islands and protected areas, in order to reduce their impacts on biodiversity and ecosystem services.
GS3 · International environmental agreementsIndia has no dedicated invasive species legislation, managing the issue through forest departments and protected-area plans under the Wild Life (Protection) Act, 1972 and the Biological Diversity Act, 2002 — a gap frequently noted in policy commentary.
SOURCE Convention on Biological Diversity, COP15 (2022)
Why are butterflies used as ecological indicators?
Because they respond rapidly to changes in vegetation composition, microclimate and habitat structure, and because their caterpillars depend on specific host plants, tying the community tightly to local flora. Shifts in butterfly assemblages therefore register habitat change earlier than most vertebrate indicators.
GS3 · Ecological monitoringThe corollary is that adult counts alone can mislead: if invasives supply nectar while native host plants decline, adult numbers may hold up while reproduction falls, so larval-stage monitoring is needed to detect the trend.
SOURCE Standard ecological monitoring literature