Young researchers explain sights and sounds of Lankan bats
As fans celebrated well-loved cartoon character Batman's 80th birthday worldwide, two young Sri Lankan researchers say bats are master pathfinders and get at their prey by using echolocation which involves emitting sound and then analysing the reflected sonar signal captured through special sensors.
The Sunday Times met the two researchers at the Association of Tropical Biology and Conservation’s Asia Pacific chapter ( ATBCAP) conference which was concluded recently in Thulhiriya.
“Different bat species emit signals with different frequencies in echolocation and these can be used to identify them in the field,” said Tharaka Kusuminda whose trailblazing research has led him to decipher the patterns of the Painted Bat’s call.
He said it was the first time that the Painted Bat’s eco-sounding had been deciphered and the second occasion that such a method had been used in the worl d . “Previously we needed to have visual evidence or need to catch the bat to find out conclusively whether a species is presence in one location. But we can now record the bat sounds in any area in Sri Lanka and can find out the presence of the Painted Bat in those locations by analysing bat sounds” said Mr. Kusuminda.
Explaining that this technique was increasingly being used to monitor distribution of bats around the world, Mr. Kusuminda said his team had also deciphered the patterns of echolocation of other Sri Lankan bats and was continuing to do so for other species.
Sri Lanka is home to 31 species of bats. Most bats being insectivorous feed on insects. There are also four species of fruit bats. A majority of bats – especially the insectivorous bats, use ecolocation techniques to navigate, said Mr. Kusuminda.
The painted bat (Kerivoula picta) -- with an orange head and orange markings on its wings -- is probably the most beautiful bat species in Sri Lanka. Painted bats prefer to make dried banana leaves their hideouts and come out in the evening. They seem to be having a good distribution in Sri Lanka. The lack of confirmed records had been a major drawback in establishing their distribution, but the new technique would be helpful to map their distribution, Mr. Kusuminda said.
It is only a few years ago that the 31st bat species in Sri Lanka was discovered by bat researcher Gayan Mithra Edirisinghe. It was a chance encounter.
“While studying bats in Maduru Oya area, we came across a roadkill. A bat had hit a speeding vehicle and had been crushed by its wheels. As its characters were different from other known bats, we carried out further studies. The research showed that it had features similar to an East Asian bat species called Phoniscus jagorii. So the new species was named as Phoniscus cf. jagorii. The ‘cf ’ -- meaning ‘closer to’ -- was added to the name, since science needs more studies to distinguish them as a separate species.
The species has even been assessed for an inclusion in the upcoming Red List of threatened fauna. Mr. Edirisinghe said he was confident that this particular bat was a new species. But he said more research was required to establish this.
In an average home garden, a number of bat species can be observed. “Of the 31 bat species, only four feeds on fruits while the others are insectivorous. The insectivorous bats particularly feed on harmful insects. They consume a large number of mosquitoes in one night; so they are actually our friends’ Mr. Ediriweera said.