Dragonflies help save ecosystems

As natural sentinels of freshwater resources, the ancient insects signal the health of aquatic ecosystems

- Sheree Bega

Long before there were dinosaurs, there were dragonflies. That's one of the things about the ephemeral insects, with their long, slender bodies and gossamer-thin wings, that fascinates entomologist Charl Deacon.

Dragonflies, known for their striking aerial acrobatics and near 360-degree vision, are one of the oldest groups of winged insects on Earth.

“The dragonfly group is ancient, and based on fossil records, their origin dates back around 300 million years ago,” said Deacon, a postdoctoral research fellow at Stellenbosch University.

“The staggering age of the first dragonflies provide us with a look into how life was in the distant past. Contemporary dragonflies retain most body features of ancient dragonflies — except their size — emphasising that they are highly successful insects.”

Dragonflies, a blanket term for both “true dragonflies” and “damselflies”, are a relatively small group of insects, consisting of about 6 400 species worldwide.

For Deacon, what makes these expert fliers interesting is that they are valuable insects for assessing water and land quality. “Groups of dragonfly species in a defined habitat can tell us a lot about deteriorating environmental conditions and the requirements to restore degraded areas.”

To ensure the long-term survival of dragonflies and other creatures that share their habitats, they must be included more widely in biodiversity conservation efforts and policies. This is the key recommendation from a group of dragonfly experts from 17 countries, including South Africa, Mexico, Australia and the United States.

Their recent review, published in the journal Insect Conservation and Diversity, proposes a five-point action plan to promote dragonflies in freshwater and riverbank conservation.