Researchers have discovered two new species of soil-dwelling termites in the biologically rich and biogeographically unique Western Ghats. The identification of the two new termite species from the Western Ghats of Kerala – christened Krishnacapritermes dineshan and Krishnacapritermes manikandan – has swelled the ranks of the Krishnacapritermes genus that so far had only two species.
The insects are named after KA Dineshan and Manikandan Nair, the field staff at Zoological Survey of India, Western Ghats Regional Centre, Kozhikode, who initially collected them during their routine sampling surveys.
The samples were later studied by researchers, Amina Poovoli of ZSI, Kozhikode, and K Rajmohana of ZSI, Kolkata, and confirmed to be new species. The discovery has been published in the journal Oriental Insects.
When the researchers looked at the samples, K dineshan and K manikandan were morphologically distinct from each other. The genus Krishnacapritermes is endemic to the Western Ghats. Under this genus, only two species Krishnacapritermes maitii and Krishnacapritermes thakuri were known so far.
Explaining the morphological differences among the four species, Poovoli said, K dineshan is the largest of the four species. It somewhat resembles K thakuri. However, their morphological differences in shape and width of the parts of labium, mouthpart that is attached to cranium, length and width of head, make them distinct. K manikandan is comparatively smaller than the other three species and is anatomically close to K maitii.
The researchers also generated DNA barcodes for all the population of the Krishnacapritermes samples they had, to study genetic variations if any, and study phylogeny of the species to make sure that the species are not inbreeding.
Like the scanner that identifies consumer purchases in a supermarket, DNA barcoding technology helps identify species. It involves taking a short sequence of DNA from a specific gene or genes and comparing it a sequence of DNA from the same gene in other species. Phylogeny helps in evolutionary studies.
For this analysis, researchers extracted sequence of DNA from termites’ head and the thorax.
The DNA barcoding, as one of the co-authors KP Dinesh, a phylogeneticist at ZSI, Pune, puts it, “is a continuing process.” In the process, they could generate barcodes for K thakuri and K dineshan population, and not for K manikandan. Further studies will take some time to proceed.
“Many times, morphological distinctions likely point to genetic distinctions. Using morphological distinctions as a proxy, we keep on testing,” said Dinesh, adding that genetic barcodes data in endemic termites is still in its infancy.
Home for termites
In addition to being home to plants, birds, the Western Ghats is a home to termites too. The Indian termites share a very small proportion of the global fauna, with 52 genera or 16 percent comprising 332 species. According to the 2016 paper, State of Isopteran Biodiversity in the Indian Subcontinent, 11.2% of the species – 172 species – are endemic to the Indian subcontinent.
Heterogeneity of landscape and habitat preference of the termites could be among the key factors for their occurrence in specific locations, explained Poovoli. It was thought that, mainly from the studies of Chhotani in 1997, that the genus was distributed only in Silent Valley and the Tamil Nadu parts of the Western Ghats.
“The review of the literature and the data from our studies suggest that the genus could be a narrow endemic in the central and southern Western Ghats,” Rajmohana said.
Of the four known species of Krishnacapritermes, K thakuri is the most abundant species. It’s known from different locations for more than 300 km of aerial distance with elevations ranging from 30 metres to 800 metres in the Ghats. K maitii is found from two locations of more than 70-km aerial distance and at a height of 1,000 metres.
K dineshan too is known only from two locations – of more than 70-km aerial distance –at 1,000 metre elevations. However, K manikandan is known only from a single locality at a little higher elevation of 1,400 metres, which is highest for any species of the genus.
“In general, termite diversity is drastically low in high elevations. But in our studies the genus Krishnacapritermes, with its higher species being soil dwellers, is showing affinities towards higher elevations,” said Amina and Rajmohana.
Krishnacapritermes species dwell in soil and they don’t gorge on wood. They prefer humus or organic munch, such as highly-decayed wood that resembles soil.
Soldier termites, in genera like Indocapritermes chhotani and Pericapritermes silvestri, under Termitinae, don’t have what is called anterolateral portion – at the front and side – on their upper lip. The study observed that Krishnacapritermes species had similar anatomy. However, not all the species had a similar anterolateral portion. On some, they were broken on the side. The researchers observed differences in the anterolateral portion in the soldiers of the same colony. This genus closely resembles Pericapritermes in some morphological characteristics.
Why is this important?
Finding an endemic species is a valuable scientific contribution in itself. “This is a restart in terms of the excellence and expertise of Indian taxonomists of ML Roonwal and OB Chottani. It is of immense value. It is a capacity building in a difficult area of taxonomy of termites, wherein polymorphism creates complexities and difficulties in diagnostics and species diversity aspects,” said Vilayanoor Ramamurthy, an insect taxonomist. A retired professor, Ramamurthy was formerly associated with the Indian Agricultural Research Institute in New Delhi.
“The polymorphism and plasticity in the termite life stages, sexes [and] castes lead to complexities in the identification and classification at different hierarchical levels,” he said.
Discontinuous genetic variation leads to different types of individuals in a single species and is called polymorphism. It is due to a gene having two or more possibilities of a trait. Plasticity refers to the adaptive nature of an organism to its natural surrounds, thought to be happening, in its life span.
In the termite caste system, the lowest rank is workers, followed higher up by soldiers. While the workers build nests, locate food and care for the young, soldiers guard the nest. “The discovery of two endemic species will add to the species diversity components of biodiversity,” Ramamurthy added.
This article first appeared on Mongabay.
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