The Kole wetlands, spread over Thrissur and Malappuram districts, is home to 30 species of dragonflies and 14 species of damselflies.
The 44 species of odonates, belonging to 33 genera and eight families, were documented from the Kole wetlands, a Ramsar site, during an year-long study to document the diversity of odonates and seasonality.
Kerala Dartlet (Agriocnemis keralensis), a damselfly endemic to the Western Ghats region, Green-eyed Spreadwing (Platylestes platystylus), a damselfly only recently recorded from the State, and the rare Dusky Lilysquatter (Paracercion calamorum) are the interesting species observed by the study team.
The study highlights the importance of the Kole field as an agro-ecosystem supporting other faunal groups in addition to birds. Species richness showed a peak in the post-monsoon season and a dip in the summer as per the study published in the latest edition of ‘Journal of Threatened Taxa’.
Role in pest control
Thousands of the migratory dragonfly Wandering Glider (Pantala flavescens) fill the skies over the Kole fields in the months of October-November. They feed on small insects and their role in controlling pests in agricultural fields needs to be investigated further, says Subin K. Jose and Vivek Chandran A., researchers at the Department of Geology and Environmental Science, Christ College, Irinjalakuda, and Sujith V. Gopalan, executive member, Society for Odonate Studies.
One-fourth (25.14%) of the total number of odonate species known to occur in Kerala was recorded from the Kole wetlands in the study. Odonates, which depend on freshwater to complete their life cycle, are excellent indicators of environmental health and can be used for monitoring pollution, habitat degradation and climate change, according to the researchers.
In the study conducted from February 2019 to February 2020, 30 sampling locations were chosen randomly intending maximum spatial coverage of the Kole wetland in the Ponnani Kole and Thrissur South Kole.