Dragonflies (Odonata) as Ecosystem Indicators

Recent studies on dragonflies (order Odonata) highlight their 360-degree ultraviolet-sensitive vision and highly sensitive visual system. Recent ecological surveys indicate declining dragonfly populations and the disappearance of certain species, including a Western Ghats endemic that is now rarely observed.

Key Facts of Dragonflies:

Dimension	Key Details
Taxonomy	Comprises the order Odonata, which includes both dragonflies and damselflies.
Species in India	Comprises approximately 600 species in India.
Distribution in India	Comprises significant species diversity in the Northeast and Western Ghats regions.
Example species	Comprises the Blue Hawklet (Hylaeothemis apicalis), which is endemic to the Western Ghats and is now rarely observed.
Evolutionary background	Comprises insects among the earliest known flying organisms, originating approximately 300 million years ago.
Life stage and habitat	Comprises aquatic nymphs inhabiting wetlands, ponds, and streams.
Adult characteristics	Comprises adults functioning as aerial predators and possessing four independently moving wings.
Feeding and pest regulation	Comprises nymphs consuming mosquito larvae and crop pests, particularly in paddy fields; and adults preying on leafhoppers and other harmful insects.
Ecosystem indicator role	Comprises indicators of healthy ecosystems and sustainable agricultural practices, with presence reflecting overall ecological condition.
Threats	Comprises population decline associated with pesticide use, particularly systemic compounds such as fipronil; negative impacts from increased droughts and unpredictable rainfall patterns; and predation by various other organisms.
Vision and opsin genes	Comprises panoramic vision (360 degree) facilitated by more than 16 opsin genes, in contrast to 4 found in humans, and comprises ultraviolet light detection.
Research status	Comprises ongoing research continuing to uncover additional biological insights regarding this species.