Andhra Pradesh

Do swarms of caddisflies in Vijayawada hint at something?

Caddisflies resting on a fencing near VMC office in VIjayawada.   | Photo Credit: K.V.S. GIRI

Caddisflies swarm the flyover near the Police Control Room (PCR), and the bridges on the canals that pass through the city every evening and night. They come in groups and are attracted to light.

Road users, particularly motorcyclists, are finding it difficult to drive their two-wheelers on the flyover and the adjacent areas. The problem is no different on the bridges on Ryves Canal, Eluru and Bandar canals. As the caddisflies are in good numbers and move closely together, the visibility of motorcyclists has been affected sometimes and they have to slowly push through to cross these stretches. The caddisflies blanket the pavements and roads so thoroughly that sometimes it looks like a white paint.

According to information, the caddisflies, which are insects with aquatic larvae, have emerged in huge numbers by the eastern canal, and other canals in the city. The civic authorities, however, have not taken any steps to control their population. In fact, the authorities are ‘clueless’ and could not take up any special drives to disinfect the canals, which is said to be one of the possible reasons for the caddisfly problem.

K. Praveen Kumar, an entomologist who works with Bayer, says that the caddisflies are found near water bodies or places where stagnant water is found. Certain species are also aggravated due to ecological imbalances, so that could also be a possible reason. Usually the flies are not harmful to people. They tend to form swarms of large numbers and are attracted towards light, he says.

Problems in ecosystem

The caddisflies are important indicator species, signalling to scientists that an ecosystem has problems. There are species that are more tolerant to pollution and those that are less tolerant not only to pollution but also to water level changes. Some survive downstream of dams very well, others are totally excluded, opines an entomologist at the National Institute of Plant Management, who did not want to be quoted.

The entomologists say that caddisflies are useful as bioindicators since some are sensitive to water pollution and some species indicate undisturbed habitat, and some indicate degraded habitat. A field assessment is necessary to arrive at the conclusion regarding the caddisflies that swarm the bridges and roads in the city, they opine.

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Printable version | May 16, 2021 11:18:31 PM | https://www.thehindu.com/news/national/andhra-pradesh/do-swarms-of-caddisflies-in-vijayawada-hint-at-something/article34314316.ece

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