7.1 Butterflies

Insects are the most abundant group of animals. They account for nearly three quarters of all life forms on earth. Their body is divided into three segments: head, thorax and abdomen. All insects have three pairs of legs and usually two pairs of wines.

Butterflies are among the most beautiful and frequently seen insects. The zoologoical order of Lepidoptera (Lepidoptera "scale wing") includes butterflies (sub-order Rhopalocera) and moths (sub-order Heterocera). Lepidoptera contains as many as 120,000 species: 100,000 species of moths and 20,000 species of butterflies.

Seven percent of the world's butterflies occur in India (1,400 species). In India, the maximum butterfly diversity occurs in the Western Ghats and Eastern Himalayas. The wide range of habitats in the Western Ghats is the reason for the rich butterfly fauna that occurs here. All ten butterfly families found in India are represented in the Western Ghats, and practically all butterflies recorded in South India occur here. Nilgiri and the hill ranges of the Kanara region of Karnataka are particularly rich. Both the largest Indian butterfly (Common Birdwing) and the smallest (Southern Grass Jewel) occur in the Western Ghats.

Butterflies

Value of butterflies

· Butterflies pollinate flowers and help plants produce fruit and seeds.

· Some species of butterflies are poisonous. They are being studied to produce ecologically safe pesticides. Certain species are used for experiments in genetic engineering.

· Butterflies-and especially caterpillars, their larval form-are important sources of food for other animals such as birds.

· Butterflies add color to wilderness areas in the Western Ghats.

· Some butterfly caterpillars are pests on cultivated crops.

Suggested reading

Gay, Kehimkar and Punetha. Field guide to common Indian butterflies. WWF-India.

Wynter-Blyth. Butterflies of the Indian Subcontinent. Bombay Natural History Society.

Mimicry in butterflies

Some butterflies mimic other species to protect themselves from predators. Two types of mimicry are:

· Batesian mimicry: Edible species look like inedible species. E.g., the Common Mormon mimics the Crimson Rose.

· Mullerian mimicry: Two or more inedible species look alike. E.g., the Striped Tiger and Plain Tiger look similar.

Inedible species are normally brightly colored (red and black, orange, blue and black). They contain toxic chemicals.

Some butterflies and larvae resemble non-living things. For instance, the Oakleaf butterfly resembles a dried leaf; the Common Mormon larva resembles a bird dropping.

Life cycle of butterflies

Threats

· Habitat destruction in the Western Ghats is probably the single most important threat to butterflies. Some butterflies rely only on certain plants; for instance, the Plain Tiger lays its eggs on the Giant Milkweed-larvae hatch and feed only on these plants. If a plant species disappears, the butterfly species that depends on it may also be eliminated.

· People like to collect butterflies as ornaments and wall hang ings. Over-collection, especially of large, colorful butterflies, threatens many species. Both commercial and casual collectors are to blame.

Conservation

· Preserve the habitat in the Western Ghats. This is no doubt the best way of saving many species of butterflies.

· Educate people on the role and importance of butterflies and discourage collection.

Butterfly farms

Butterfly farms are a unique and interesting way to introduce butterflies to people and breed endangered species in captivity.

A butterfly farm is an enclosed area which houses a variety of butterflies. Conditions to sustain these beautiful insects are artificially provided. Visitors can enter the farm and experience the thrill of butterflies sitting on their shoulder or head. Singapore, Malaysia, Papua New Guinea, the United Kingdom and the United States have butterfly farms.

Some butterflies of the Western Ghats

Common Birdwing
Common Mormon
Common Rose
Five-bar Swordtail
Emigrants
Lemon Pansy
Gray Pansy
Common Leopard
Tamil Lacewing
Black Rajah
Eggflies
Southern Rustic
Common Evening Brown
Common Pierrot
Southern Grass Jewel
Striped Tiger
Common Crow
Orange Tips
Blue Mormon
Crimson Rose
Common Banded Peacock
Common Jezebel
Grassyellows
Yellow Pansy
Common Sailer
Tree Nymph
Common Nawab
Baron
Castors
Tawny Coster
Bushbrowns
Common Cerulean
Plain Tiger
Blue Tiger
Skippers
Red Helen

Butterfly or moth?

Butterfly

· clubbed antennae
· most are diurnal

Moth

· tapering or feather-like antennae
· most are nocturnal

Butterfly or moth?

Prepared by Srinivasan Karthikeyan