DECIPHERING CLIMATE PATTERNS THROUGH CHANGING BEHAVIOUR OF BUTTERFLIES
By Dr. Smruti Smita Mohapatra
“If nothing ever changed, there would be no butterflies”.
Butterflies are the beautiful, bright coloured diurnal insects of the animal kingdom. Over the ages, butterflies have been the prime subject in hope, mythology, literature, folklore and visual arts for their anthropocentric values. There are more than 20,000 species of butterflies worldwide. While some are yet to be discovered, few have become extinct without being discovered. Rhopalocera is the scientific study of butterflies. These days it has emerged as a hobby. Morphologically, Indian butterflies have two clubbed, plain antennae, compound eyes and 4-6 joint legs. The thin body is divided into three parts – Head, Thorax and abdomen. They fall under the order Lepidoptera, originating from Greek words lepido (Scaly) and ptera (Wings). They possess two pairs of wings – fore wing and hind wing. Each wing consists of base, cell, apex, disc, costa, dorsum, tornus and termen. The tail is attached to the hind wing.
Peru has the highest number of butterflies in the world – 3700 species. Interestingly, India is home to around 1300 butterflies due to varied habitats of which the north eastern states host more than 800 species of butterflies and the Western Ghats has 336 species. The beautiful butterflies of North East India are Yellow Gorgon, Himalayan Popinjay, Green dragontail and Kaiser-i-Hind. Some of the endemic species in the Western ghats are Nilgiri Cloded Yellow, Tamil Oakblue, Travancore Tawny Ace and Tamil Catseye. Egg, larva (caterpillar), pupa and adult are the four typical stages of the life cycle of a butterfly. The gradual process is known as metamorphosis. There are six different families of butterflies – Papilionidae (Swallow tails), Pieridae (Whites and yellows), Nymphalidae (Brush footed), Lycaenidae (Blues), Hesperiidae (Skpippers) and Riodinidae (Metal marks). The female butterflies lay eggs on specific plant. Every butterfly has a select larval host plant on which the female lays eggs. They smell the leaves before laying eggs through their legs. Caterpillars open the egg shell from within its jaws. Once they are out, they feed on their own nutrient rich egg shells. Butterflies generally feed on flowers, leaves and fruits of host plants, bird droppings, animal scat, rotten meat and alkaloid plants. The common larval host plants are Nerium oleander, ginger lily, curry leaves, lemons and ornamental palm. Ixora, Heliotropium spp., Clerodendrum spp., Cosmos and Stachytarpheta indica are the common nectoring plants. Butterflies obtain their natural colour and pigments from the larval host plants which is passed on to the adult stage. The behaviour of the butterflies is largely influence by the host plants.
Sadly the short life span of the butterflies is threatened by illegal international butterfly trade, increasing industrial activities, biotic pressure, man-animal conflict, animal grazing, habitat loss, deforestation, general ignorance, lack of support and non-implementation of laws. Birds, spiders, monkeys, praying mantis, dragon fly, frog and lizard are the natural predators of butterflies. Though short lived, butterflies are the excellent indicators of the quality of environment. Climate change influences the annual migration of butterflies even far across Antarctica. Extreme cold climate makes the butterflies move from one region to another for survival and search of food source. The Indian butterflies of Western Ghats move to the Eastern Ghats during late summers and return back in autumn. Few butterflies fly across continents and continents. Be it courtship or mating through pheromones, most butterflies fly around to lay eggs on specific host plants. They exhibit eclosion, multivoltinism, stridulation and pollinator constancy. The other common behaviours of butterflies are influenced by extreme climate change. Hilltopping or patrolling is a typical defensive trait of butterflies while looking for female butterflies. Mimicry by the palatable butterflies to ape the unpalatable ones prevents them from predators. Mud puddling is a playful behaviour of newly hatched male butterflies. They engage in the intake of salts from wet soil. These salts help in healthy egg production which is genetically passed on to females during mating.
Butterflies are poikilotherms. Sunlight is the source of their energy to fly. Warming up their body temperature based on the surrounding temperature is known as basking. Basking is common in cooler hours of the morning. Changing their body temperatures with respect to the environmental temperature leads to the survival of butterflies. Each butterfly has seasonal forms – dry and wet season form where some of them even tend to look different. Aberrations in butterflies occur due to extreme weather conditions especially when the temperature changes in pupal stage. Some butterflies are deformed due to physical injuries in their pupal stages. A swarm of butterflies in a region is an index of a healthy ecosystem. They help maintain the ecological relationships. They are a significant part of food chain. Environmental equilibrium is maintained by the butterflies through pollination of agricultural crops and flowers. Butterfly tourism is an emerging industry. Butterfly watching trail is a stress busting activity.
Conservation of the winged jewels of the natural ecosystem is essential. The butterflies have been legally protected by the Red List of IUCN, Indian Wildlife (Protection) Act, 1972 and Biological Diversity Act, 2002. Reduced pasture grazing, afforestation of specific host plants, zero pesticides use and encouraging agroforestry improve the natural environment for the butterflies. Butterfly conservation through education is the need of the hour. The study of butterfly and plant interaction is of prime importance for conservation. Conservation education among the local communities and research must be promoted. Introducing butterfly gardens, museums, butterfly farming and safari parks can protect the butterflies from decline. As earthlings we have power to change the world and recreate habitats for the endangered butterflies. Butterflies contribute directly to food security. They are crucial in the conservation of biodiversity as pollinators next to bees. Therefore raising awareness about the importance of protecting butterflies is highly necessary to decelerate the fast pace of extreme global climate change.
Dr. Smruti Smita Mohapatra Ph.D. Scholar Department of Veterinary Physiology Faculty of Veterinary & Animal Sciences WBUAFS Kolkata, West Bengal- 700037, India Email: simplysmruti@gmail.com
