CUBE ChatShaala Summary – 21st July 2025
Key Discussions from the Session
1. Sexual Dimorphism in Common Mormon Butterfly ( Papilio polytes )
Male and female Common Mormon butterflies exhibit significant morphological differences, especially in wing pattern and coloration.
The female mimics other distasteful species ( like Pachliopta spp. ) as a defense mechanism (Batesian mimicry), a classic example of evolutionary adaptation.
Participants highlighted forewing, hindwing, and body segmentation (head, thorax, abdomen) clearly to show structural differences.
2. Symmetry & Metamerism as Foundational Concepts
Butterflies show bilateral symmetry, while organisms like Moina and Starfish can exhibit radial or modified radial symmetry.
Metamerism (segmentation) was classified into:
External Metamerism: Seen clearly in butterfly wing veins, legs, and body segments.
Internal Metamerism: Highlighted through earthworm anatomy (segments 7–11 containing aortic arches—hearts).
Earthworm (Phylum Annelida) was discussed as a model for understanding internal segmentation, with special reference to adaptation due to need and necessity.
3. Live Example from CUBE Research: Sneha’s Case Study
Sneha shared documentation of a butterfly raised from a Common Mormon caterpillar (2023).
Observation : The emerged butterfly had yellow submarginal spots on hindwings instead of the expected red ones.
Query : Is this an adaptation or mimicry of another species?
She emailed Dr. Krushnamegh Kunte , who confirmed it as a male Papilio polytes, citing individual variation as the reason for color difference.
“This is a male Papilio polytes. The submarginal spots exhibit individual variation in color and size. Some individuals completely lack these spots; your butterfly shows this individual variation.”
About Dr. Krushnamegh Kunte
Associate Professor & Principal Investigator, Biodiversity Lab, NCBS-TIFR, Bengaluru.
Renowned lepidopterist and evolutionary biologist.
Key contributor to Butterflies of India and Biodiversity Atlas – India.
Research interests include mimicry, sexual dimorphism, speciation, and conservation genetics.
Ph.D. from Harvard University; field leader in butterfly biodiversity documentation.
Websites:
Provocative Questions to Ponder
What evolutionary pressures might drive sexual dimorphism in butterflies like Papilio polytes?
How do internal vs. external metamerism reflect an organism’s lifestyle or ecological niche?
Could mimicry ever backfire if the mimicked species itself declines or disappears?
Is individual variation in butterflies ( e.g., yellow vs. red dots ) a sign of genetic plasticity, or could it be an early stage of speciation?
How can citizen science data like Sneha’s documentation contribute to national biodiversity databases?
What I Learned Personally from Today’s ChatShaala
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Evolution is not a fixed trait—it constantly plays with patterns and colors, even within a single species.
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The way students like Sneha use observation, questioning, and direct contact with scientists is inspiring. It highlights the power of student-led research.
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Understanding metamerism through real dissection of earthworms and tracking butterfly body segments brings textbook biology to life.
The discussion bridged developmental biology, ecology, and taxonomy, all in a real-world context.
Reference