Rare beetle species found in Devagiri

Reema Narendran
04 Nov 2009

THIRUVANANTHAPURAM: A team of scientists from St Joseph’s College, Devagiri in Kozhikode, has found a rare beetle, that was last sighted in India in 1869. Nothing was known about it since, leaving the scientific world in confusion about its very existence.

The team of Sabu K Thomas and Abhitha Prabhakar, which found these little creatures emerging out of termite nests, soon published their findings in the international journal, Zootaxa.

The fact that these bugs, belonging to the Helluodes genus, lived in termite nests was one major reason for the ‘lack of visibility’ of these creatures. “Nothing could be seen on the ground. Inside the termite nests, they were very safe from other predators and so they hardly moved out.

This is probably the reason why zoologists didn’t find them for a long time,” said Sabu K Thomas. Even our national museums do not have preserved specimens of the bug.

While other ground beetles are good predators and therefore very fast-moving, all that these termite-eaters had to do was wait inside a termite nest and grab an unsuspecting termite that came into the nest.

Naturally, they became sluggish and slow-moving, leaving the zoologists in total darkness about their whereabouts. It was quite by chance that Sabu K Thomas came across the beetle at Devagiri.

“I found them in the litter near a termite nest. We collected all these beetles by hand. The Helluodes specimens were found to be very lethargic and made no attempts to hide under stones or litter even when cornered,” recollected Sabu.

Later on, these beetles were collected from the coffee estates in Idukki too. When the scientists sent the details to a Canadian expert, he wrote back ‘It’s a rare one that you have there’.

Studies on this beetle and comparisons with other bugs in the family, the Devagiri team and Danyang Zhao of the South China Agricultural University, found some very interesting facts about the genus and the species coming under it.

They, in fact came to the conclusion that the one they found, Helluodes devagiriensis was one of a kind.

Probing into the bug’s family connections within the country, the scientific team found that apart from the Western Ghats, relatives of the bug are found only in Assam, giving strength to the theory that the evergreen forests were continuous before the Deccan trap formation in between.

Deccan traps happened because of volcanic eruptions around 66 million years ago, leaving the Central Indian Plain dry, that ultimately led to the extinction of many non-flying creatures. “The Deccan Trap formation is said to be the possible reason for the discontinuous distribution of animals as in the case of Nilgiri Tahrs, which are found in Western Ghats and then in Himalayas,” said Sabu.

Tracing the family history of this bug - exclusively found in Western Ghats - to two others found in the Indian mainland and Sri Lanka even suggests divergence of the beetle family, that occurred when Sri Lanka and India were separated by a rise in sea levels. While the parental stock (Helluodes westwoodi) remained in India, the Devagiri beetle evolved into a separate species in the Western Ghats and the Sri Lankan one (Helluodes taprobanae) evolved into another species in the island country.

The scientists also found that unlike the usual trend in beetles, where sexual identification is difficult, in the Devagiri beetle, the male and the female are clearly distinct.

This rare group of bugs have now been noticed in the rubber plantations at Thodupuzha, in the moist deciduous forests in Vazhachal, and recently at Thopramkudy.

These specimens have been deposited in the collections at Devagiri college and in the National Pusa Collection, Indian Agricultural Research Institute at New Delhi.

http://www.expressbuzz.com/edition/story.aspx?Title=Rare+beetle+species+found+in+Devagiri&artid=RDRlphXCmXE=