Blue glassy tiger (Ideopsis similis)

Blue glassy tiger (Ideopsis similis)
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🦋 Blue Glassy Tiger (Ideopsis similis) – Overview

The Blue Glassy Tiger is a graceful butterfly species in the Danainae subfamily (the same group as monarchs and common tigers). Known for its translucent blue-white patterned wings, it glides gently through forests, gardens, and coastal habitats in South and Southeast Asia, including Thailand, India, Sri Lanka, and Malaysia.


🔍 Identification

FeatureDescription
Wingspan70–85 mm
ColorTranslucent pale blue wings with black veining and borders
BodyBlack with white spots
FlightSlow, gliding, and graceful – typical of milkweed butterflies

Very similar to the Dark Glassy Tiger (Parantica agleoides), but I. similis has a lighter blue tone and slightly longer wings.


🌿 Habitat

  • Commonly found in:
    • Mangroves
    • Coastal scrub
    • Open woodlands
    • Gardens and parks
  • Typically prefers humid, lowland areas but can also be seen in hill forests.

🍃 Host Plants (Larval Food)

The caterpillars feed on toxic plants, particularly from the Apocynaceae and Asclepiadaceae (milkweed) families, such as:

  • Tylophora indica
  • Marsdenia tinctoria

These host plants make both larvae and adults unpalatable to predators due to sequestered toxins.


🐛 Life Cycle

  1. Eggs laid singly on host plants.
  2. Caterpillars: Black with white and yellow bands, with fleshy filaments (like other Danainae).
  3. Pupa: Shiny green with golden spots.
  4. Adults emerge after about a week and can live several weeks.

🧠 Behavior & Ecology

  • Feeds on nectar from flowers like Lantana, Asystasia, and Clerodendrum.
  • Participates in mimicry complexes with other milkweed butterflies (e.g., Tirumala and Danaus species).
  • Unpalatable to birds, and often seen in butterfly congregations at forest edges or puddles (puddling behavior).
See also  Northern chequered skipper (Carterocephalus silvicola)

🌏 Distribution

Widespread in:

  • India
  • Sri Lanka
  • Nepal
  • Thailand
  • Malaysia
  • Indonesia
  • Parts of southern China and Taiwan

🧬 Interesting Facts

  • Adults can absorb pyrrolizidine alkaloids from certain plants or decaying material, used for chemical defense and pheromone production.
  • Often mimicked by palatable butterflies for protection — classic example of Müllerian mimicry.

Would you like to see a comparison chart between Ideopsis similis and other lookalikes like Parantica agleoides or Tirumala limniace (Blue Tiger)?

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