The discovery of a new species is always exciting but finding them in your backyard makes it more thrilling.
That’s what happened to a group of researchers from Ashoka University when they found not one but three new species of bush crickets, two of them within the grounds of the university itself in Sonipat, Haryana, and one in Shillong, Meghalaya.
The discovery of the three species started in the Khasi Hills, where Aarini Ghosh, the lead author of the study, heard a non-stop droning noise that sounded like it was coming from two different crickets. The sound had two distinct layers to it: one was a “broadband continuous trill” which was followed by the second part with an “amplitude modulated trill”.
Speaking to The Hindu over a video call, she described finding the first species called Hexacentrus khasiensis.
“We were surveying the land trying to capture the soundscape of the area when we heard a buzzing noise from a bush that sounded like two crickets. As we were trying to find the two crickets, we realised the sound was coming from only one which was the Hexacentrus khasiensis..”
Picture of all 3 species in Wild- Hexacentrus khasiensis male (A) and female (B), Hexacentrus ashoka male (C), Hexacentrus tiddae male (D). | Photo Credit: biorxiv.org
The study paper, which is yet to be peer-reviewed, has been published on the biorXiv preprint repository. It describes the three new species as part of a predatory bush cricket genus called Hexacentrus.
While numerous species of Hexacentrus exist around the world, only seven have been found in India. The current discovery takes the number to 10.
These crickets are mostly bright green in colour with brown segments and camouflages well among bushes, the paper notes.
Ranjana Jaiswara, another researcher involved in study, said, “Since crickets from the Hexacentrus genus are predatory, they have longer mandibles which help them to hold their prey more firmly. Their forelegs have sharp spurs which help them to capture prey. They also have unique leaf-shaped wings which help them camouflage from their predators like bats, frogs and snakes.”
On their return to the Ashoka University, the researchers heard the familiar call of Hexacentrus khasiensis. near the hedges that lined the campus while out surveying.
Once again, they set out to find the source of the call.
The researchers found two new species of crickets in the genus of Hexacentrus with distinct calls. Though sister species and orginating in very different ecosystems, Hexacentrus ashoka (named after the university) and Hexacentrus tiddae (named after the local word for locusts and crickets), produced very different sounds from Hexacentrus khasiensis..
Like its relatives in the Khasi Hills, Hexacentrus ashoka also had two layers to their call but the components were different. The first part was a group of low magnitude chirps with varying duration while the second part consisted of high amplitude, well-defined sharp chirps that sounded like “short buzzing sounds”.
The distribution of the three species, including their type localities. Distribution densities are colour-coded: Hexacentrusashoka and Hexacentrus Tiddae in Sonipat district are in dark blue; Hexacentruskhasiensis distribution in the East-Khasi hills is in yellow, the West-Khasi hills in red, the Ri-Bhoi in sky blue, and the South Garo hills in purple. | Photo Credit: biorxiv.org
While the call of Hexacentrus Tiddae was a ‘regular amplitude modulated pattern of continuous syllables, alternating between longer, higher amplitude syllables and quicker, low amplitude syllables’, the paper noted.
“With high levels of agricultural activity and very low tree cover in this region, it really impresses on us to look and conserve species that are not only found in diversity-rich areas but also degraded ecosystems like Haryana,” said Bittu Kaveri Rajaraman, Associate Professor of Psychology and Biology at Ashoka University who was also part of the study.
The discovery of the three new species of crickets in the degraded ecosystem of Haryana and ecological rich East Khasi hills have considerably added to the diversity of crickets found in India taking the number from seven to 10. It also fills in certain gaps in the acoustics evolution of animals.
“Meghalaya is the junction of the Indo-Burma and Eastern Himalaya biodiversity hotspot which flows further into the Southeast Asian hotspot. In the case of the Hexacentrus khasiensis., we are assuming that the unique droning sounds of the crickets is a result of an amalgamation of the three biodiversity hotspots. This research gives us an idea about the connection between the three biodiversity hotspots and the acoustic evolution that evolved from that,” Ms Ghosh said.
Talking about the impacts of the discovery, Dr. Rajaraman said, “In the future, we hope to look at how communication signalling has evolved. This gives a wide variety of acoustic signals from which its neural basis and different components can be studied and interpreted.”
The group of researchers involved in the study included Aarini Ghosh, Ranjana Jaiswara, Monaal, Shagun Sabharwal, Vivek Dasoju, Anubhab Bhattacharjee, and Bittu Kaveri Rajaraman.
- The discovery of the three species of cricket started in the Khasi Hills, where Aarini Ghosh, the lead author of the study, heard a non-stop droning noise that sounded like it was coming from two different crickets.
- While numerous species of Hexacentrus exist around the world, only seven have been found in India. The current discovery takes the number to 10.
- The group of researchers involved in the study included Aarini Ghosh, Ranjana Jaiswara, Monaal, Shagun Sabharwal, Vivek Dasoju, Anubhab Bhattacharjee, and Bittu Kaveri Rajaraman.
