A crimson-tailed marsh hawk. Picture by Gaurab Jyoti Kalita

Guwahati, Sept. 15: They are the helicopters of the insect world.

Researchers and officials of Manas have stumbled upon 41 species of dragonflies and damselflies in the first survey of its kind in a protected area in Assam.

With their bulging eyes, long tails, and tapered wings, they look like helicopters. In fact, they manoeuvre like helicopters, too — they can fly backwards and change direction in just one body length of air space.

Dragonflies and damselflies are commonly known as odonates — a flagship group and an important component of the aquatic ecosystem.

Odonata consists of three groups — Anisoptera (which includes dragonflies), Zygoptera (which includes damselflies), and Anisozygoptera — a relict group represented by only two living species.

The rapid survey was done from August 28 to September 1 by Gaurab Jyoti Kalita of North Orissa University, Monsoon Gogoi of Assam University, Silchar, Kushal Choudhury of Kokrajhar Science College, Bipul Das of Aaranyak and the Manas forest department staff.

Of the 41 species, 18 were that of dragonfly and 23 of damselfly.

The 18 species of dragonfly belonged to two families while the 23 species of damselfly belonged to six families. Globally, there are approximately 6,500 species.

“Finding 41 odonates within one forest range in a national park indicate the potential of a habitat to support biodiversity. We will keep updating the survey and there is every possibility of finding more. All this gives us hope that the park has still a rich habitat,” Sonali Ghosh, the deputy director of Manas tiger reserve, told The Telegraph.

The official said like most insect orders, the Odonata (dragonflies and damselflies) remain poorly studied and therefore come under IUCN’s “least concern and data-deficient” categories.

Reviews also show that although Assam has a very suitable habitat for odonates with lots of ponds, streams, rivers and wetlands, there is very little work done in documenting them.

While dragonflies have a large and sturdy body, damselflies have a slender and smaller body.

Dragonflies have fast and long-lasting flights, damselflies are characterised by slow and fluttering flights.

Odonates occupy almost all kinds of habitats ranging from permanent running water and lakes to small, temporary rain pools.

These are the most common insects that fly over forest, rangeland, meadows, crop fields, stream and rivers and one of the dominant groups of aquatic and terrestrial insects.

“Odonates are important indicators of water quality and pollution levels. They inhabit diversified habitats near water bodies ranging from stagnant pond water to flowing streams. Most odonates such as gomphids, macromids, most calopterygids, chlorocyphids and euphaeids indicate pure unpolluted waters and good habitat quality. A little change of ecosystem, can lead to disappearance of these,” Gaurab Jyoti Kalita said.