Butterfly predation by an insectivorous plant, Drosera indica L.

Abstract

Insectivorous plants are usually found in habitats like barren open country, paddy fields and other marsh areas and as such are believed to supplement their diet with animal feed. Some insectivorous plants are found in extremely diverse environments while others are known to occupy narrow ecological niches. The insectivorous plants like Drosera indica L., D. burmanrii Vahl, D. peltata Smith and many species of the genus Utricularia are reported from Kerala. The traps of these plants are leaf (entire or part) or modified leaf-like organs to lure, guide, hold and digest the prey. During our routine faunal observations and collections of plant material in the vicinity of Madayi Para, a flat-topped table like laterite hillock of Kannur District in northern Kerala, on 28 August 1999, we came across exceptionally large numbers of Drosera indica plants in the south-western slope of the hill in association with other herbaceous plants such as Eriocaulon spp., Rhamphicarpa longiflora (Arn.) Benth., Sopubia delphinifolia (L.) G. Don, and another group of most common insectivorous plants of the area- Utricularia spp., which literally paint the whole plateau in shades of blue, violet and white with their flowers. Most of the Drosera plants were specked with small insect remains. On one plant at about a height of 10 cm., we found a female Pale Grass Blue Butterfly ( Zizeeria maha) entangled in the sticky gland tipped tentacles of the plant. The antennae of the insect were stuck on the upper branches of the plant while the abdomen and part of the wings were just trapped in the lower branches of the plant. After a few minutes of struggle the butterfly was immobilized and the tentacle like leaves coiled towards the insect for the initiation of digestion process.