By A. K. Chakravarthy
Anthropogenic activities challenge all the wildlife around the world including fireflies. The population of fireflies in forests and other natural areas is studly declining globally including India. Scientific information and studies on fireflies in India have not been conducted systematically so far. The scientific community, foresters, administrators, naturalists, and others have not paid the attention to fireflies they deserve. People in different countries are attracted to fireflies because of their synchronous switch on and switch off lights in massive numbers, thousands or millions. To the general public fireflies are associated with eco-tourism. Foresters and local people celebrate the event as firefly day, firefly count, firefly walk, and so on. Fireflyers International Network organize World Firefly Day as an annual celebration. Even in the western ghats region of South India, in the evergreen tropical forests of Kerala, Karnataka, Tamil Nadu and Maharashtra firefly days are conducted at a few sites during monsoon and winter depending upon the rains. India should be concerned about fireflies because they are ecologically and economically vital. Populations are declining and not much is known even on the basics of fireflies like species diversity, bioecology and behaviour. The first firefly festival was documented to take place in the woodlands of Dover Motor Speedway in 42 hectares, Delaware, USA, 100 million years ago. Environmental Management & Policy Research Institute (EMPRI), Bengaluru, India, is organizing the World Firefly Day on 22 July 2022. On this occasion a webinar on Fireflies, Ecology, and Environment is being organized to create awareness about fireflies (Link for registration: https://forms.gle/nw8zH6kgn9WCCxzK8). Here is a brief note about the fireflies, threats causing their decline and mitigation strategies.
Fireflies: A Brief
Fireflies are beetles belonging to order Coleoptera, super-family Elateroidea, family Lampyridae. Globally there are about 2400 described species under 11 sub-families. In India, about only around 35 species have been described. Fireflies are known by forest star, lighting bugs, fire devils, flying embers, moon bugs, glow flies, blinkers, etc. Fireflies are two types, those that produce light and those do not.
They are indicators of climax vegetation, found in tropical as well as temperate regions. Fireflies produce cold light with no infrared or other harmful frequencies. At times, adults serve as pollinators, predators and are essential for stable ecosystem functioning. Adults are responsible for eco-tourism.
Adults are generally identified by pronotum dorsally extending forward covering head. Head, without median ocellus. Base of antennae separated on head. Adults with leathery elytra and luminous organs in ventral side of abdomen, generally more pronounced in males than females. Larvae are generally flat, cylindrical or worm-like with distinct segmentation and lateral expanded pleurae. Larvae in aquatic species are often with reduced sclerites and might have gills. Adults are found in moist grassy patches, verges, hedge banks and larvae under soil, stones, etc. life stages may be in terrestrial or aquatic habitats, arboreal or subterranean. Larvae are carnivorous feeding on snails, slugs, earthworms, ants, termites, gastropods and decaying organic matter.
Larvae and adults may be diurnal or nocturnal or crepuscular and larvae may be carnivorous, phytophagous or saprophagous. Lifecycle may include eggs, larvae, pre-pupae, pupae and adults and entire life-cycle may be 110-230 or 150-200 days. Adults exhibit courtship behavior. Firefly group is characterized by the endogenous secretion of enzyme, luciferase, luciferin is a monocarboxylic acid. Fireflies emit light either to attract prey, warn predators or for courtship and mating.
Threats:
Habitat loss, pesticide use, invasive, climate change.
Artificial light at night.
Urban development
Human interference and habitat fragmentation.
Mitigation:
Should be declared as protected species by law.
Large scale in-situ conservation.
More research and outreach activities to create awareness.
Firefly habitats having tourist potential should be declared ‘Protected habitats’.
Further reading:
Sara Lewis (2016) The Silent Sparks, Princeton University Press. Pp 239.
Prof. A.K. Chakravarthy (Retd. Entomologist, Indian Institute of Horticulture Research, Bengaluru) and Principal Investigator of the project on 'Identification and Bioecology of Fireflies in the Western Ghats, South India', from Environmental Management & Policy Research Institute (EMPRI), Bengaluru, India.
Email: chakravarthyakshay@gmail.com
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