Scorpion species from Western Ghats highlight need for more research
- Of the seven scorpion species described since last year, from the Western Ghats, three are bark-dwelling scorpions and the remaining are rock-dwelling.
- Scorpions are a highly understudied taxon in India. The rock-dwelling species are highly prone to endemism and extinction.
- Illegal wildlife trade, habitat degradation and conflict with humans are some of the threats that scorpions face.
Since March 2020, scientists from the Institute of Natural History Education and Research (INHER), Pune have described seven new species of scorpions from the Western Ghats â six from the Sahyadris in Maharashtra and one from the southern Western Ghats near Bengaluru. These discoveries highlight the need for dedicated surveys and integrated taxonomic research on scorpions to be able to effectively conserve them.
Among the newly described species, Isometrix tamhini and Isometrus amboli are bark scorpions found in the dense semi-evergreen forests of Tamhini and Amboli, and are indicators of the health of the forest. âAll bark scorpions live in pure evergreen forests or pure deciduous forests wherever there are all primary natural trees and loose barks which have places for dwelling. The species we discovered from the Western Ghats are an indication of a good forest â especially the bark scorpions of the genus Isometrus. An ancient taxon dwelling in these forests shows that this forest still has potential,â shared Shauri Sulakhe, the lead author of five research papers describing seven new species of scorpions discovered in the Western Ghats recently.
Isometrus kovariki, the third new species discovered, also a bark scorpion, was found on the outskirts of Bengaluru city on a 10-15-year-old Acacia auriculiformis plantation. This discovery was a result of a collaboration between INHER, Pune and Shomen Mukherjee, who is associated with Azim Premji University and Ashoka Trust for Research in Ecology and the Environment, Bengaluru. Isometrus kovariki differs from all the other Isometrus species by a raw genetic distance of 10 to 16%, observed in the molecular and statistical analysis data. So though they may look very similar to the naked eye they are different species that cannot breed with each other. Different species of scorpions may have differences in biochemical properties, proteins in their bodies, genetic codes, type of venom secreted, and behavioural differences.
The remaining four species discovered last year were âlithophilic scorpionsâ or rock-dwelling scorpions. âWhile all scorpion species we found are endemic, the lithophilic scorpions are point endemic. My biggest fear is that rock dwelling species are the most vulnerable to extinction and that we are losing these species even before we have the chance to discover and describe them. Dedicated surveys will yield more undescribed species of scorpions,â said Sulakhe. Point endemic means that several species exist as a single population at the location where they are found.
Neoscorpiops phaltanensis, Chiromachetes ramdasswami, Chiromachetes parakrami, and Scorpiops telbaila were all found in rock crevices of the northern Western Ghats.
âRock dwelling scorpions are highly endemic because they are confined to their rocks, so it becomes like an island ecosystem for them,â explained Sulakhe. âImagine small islands inside the vast ocean where there are no ships or other means to cross the waters. That is how rock boulders are for these scorpions. Over the years, when they are confined to these boulders, the mutations which favour the climatic conditions or microhabitat get selected and species diverge from their ancestors and cannot breed with them anymore. This is how new species are formed,â he added.
Pratyush Mohapatra, scientist working with the Zoological Survey of India, who is not associated with the recent scorpion discoveries, said that this research brings us closer to better understanding the scorpion diversity in our country. âBased on these studies, it is also evident that there are many endemic species in this group. We need to have action plans to conserve these endemic species,â he added.
Zeeshan Mirza, researcher at the National Centre for Biological Sciences, Bengaluru and Member of the IUCN Species Survival Commission Spider and Scorpion Specialist Group, also not associated with the discoveries, said that the general sense we have about scorpions is that they are a dry desert species. But the recent discoveries show that so many new species occur in the high elevation plateaus of the Western Ghats.
Of these five papers, four have been published by Euscorpius, a journal devoted to scorpion research, and one by the Journal of the Bombay Natural History Society.
Biological pest controllers
Scorpions are ubiquitous. They are found in almost every microhabitat on all continents (except Antarctica) around human habitations and urban locations, in forests, deserts, hilly terrain, and grasslands. âScorpions are even found on radioactive wastelands where most life is destroyed. As a prehistoric species, they have lived through several catastrophes, geological differences and tectonic movements around the globe,â notes Sulakhe.
Scorpions have survived for over 400 million years with very few changes in their body structure. Apart from their size, they look almost the same as their prehistoric ancestors.Â NCBS researcher Mirza said, âAncient scorpions were gigantic and lived in the seas and fed on dinosaurs. The conditions that destroyed the dinosaurs did not manage to wipe out scorpions.â
Scorpions are also an important part of the food web as predator and prey, notes Mohapatra of ZSI. They feed on various insects that are potentially harmful to humans, and serve as a food source for other animals such as owls, honey badgers, civets, and even monkeys, he added. Sulakhe says that scorpions are largely prey for a lot of nocturnal birds as well as some diurnal birds. They are predators for a lot of insects and geckos that move out at night.
While scorpions are biological pest controllers, Mirza notes, âWe do not have estimates of how many insects scorpions feed on, and so we cannot calculate the impact each individual scorpion has on its ecosystem. There are some scorpions that feed on scorpions, so they keep a check on scorpion numbers. The extinction of a scorpion species will indeed have an impact but we cannot quantify this impact because the data to do so is missing,â he added.
Habitat loss and illegal trade
Though scorpions are not specifically covered by Indiaâs Wildlife Protection Act or any international biodiversity protection laws, they are threatened and extremely vulnerable to extinction, the experts warn.
Deshbhushan Bastawade, renowned scorpion taxonomist associated with INHER who retired from the Zoological Survey of India, said that scorpions were once abundant even inside Pune city, but are now rarely seen within the city limits. âWhen I studied scorpions between 1973 and 1975, several specimens were available on the hills and near the lakes in Pune. Now it is really difficult to spot them. I even remember the prevalence of scorpions near my home, but now it has been years since one has been spotted anywhere in the city areas,â he shared.
With increasing urbanisation, scorpion species are either getting extinct or migrating away from the cities, said Bastawade. âScorpions are an extremely secretive species that ventures out only during the night to prey on insects. Any disturbance to their habitat is a big threat to their populations. Their habitats have been completely destroyed in cities as a result of urbanisation,â shared Bastawade. He said that the movement of scorpions is very restricted, so there is high endemism among them. They move hardly a few kilometres from their homes. That is why they are isolated populations with high endemicity. Every 20-40 kilometres the constitution of scorpions changes.
Apart from urbanisation, scorpions are also under threat to be illegally traded in the global pet trade. âAt times, scorpions are also poached for their venom, which is highly valuable as it is medically useful. They are sold or smuggled as exotic pets,â said Shubhankar Deshpande, research student with INHER and one of the authors of the papers describing the new species. Shauri Sulakhe added that scorpions are even used to make silicon-coated keychains and paperweights.
Some of the illegal trade of scorpions feeds the discovery of new species, warns Mirza. âIt is critical that an IUCN red list assessment of scorpion species is done to prevent their illegal trade,â he said.
With several species of scorpions occurring outside protected areas, it has been difficult to legally protect them using existing Indian biodiversity laws. âAirport personnel are trained to look for weapons, bombs, liquids, gold, drugs, or larger animals. Scorpions and spiders have no bones and since X-rays show bones, it is difficult for their illegal trade to be detected at airports,â says Zeeshan Mirza. An additional challenge is posed by the fact that Indiaâs laws have not been amended to include the recommendations of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), to which India is a signatory.
âThe smuggling of exotic species is not punishable in India because the Indian biodiversity law covers only Indian species. We cannot arrest anyone for trading CITES species because there is no law to arrest them under in India,â notes Mirza.Â However, carrying live animals and biological material violates aviation rules and anyone doing so can be booked for this offence.
Unfortunately, the data to chalk out an effective conservation plan for scorpions is missing. âOnce we have an assessment of the species, we can think about how many species need protection. The INHER research group has found so many species in the Western Ghats of Maharashtra, it makes you believe that there are a lot more species yet to be discovered,â said Mirza.
Medical importance of scorpions and human-scorpion conflict
Pragya Pandey, PhD student at the Guru Gobind Singh Indraprastha University School of Environment Management, New Delhi says that among other threats scorpions face, a major threat is caused by scorpion-human conflict. Especially in rural India where scorpions come in contact with humans, scorpion stings and human mortality due to envenomation are a major problem.
Himmatrao Bawaskar, a physician from Mahad (a town in the Konkan region of Maharashtra) who is internationally renowned for his work on curing scorpion envenomation, shared his experience with scorpion-human interactions, saying, âWhen I started working in 1976, almost daily one patient would present with scorpion envenomation and we did not know how to treat them. But now, science understands how to treat scorpion stings and there have been no scorpion envenomation deaths for the past five years in this area.â Scorpion stings used to be fatal for children under the age of 10, as well as for adults who step out of their homes in rural areas for working in the fields.
âUnfortunately, scorpion stings are an unavoidable work hazard for people living in rural areas because there is an inherent danger in venturing out at night in nature and coming in contact with snakes and scorpions,â said Sulakhe.
Scorpions need to be conserved not only for their role in the ecosystem but also because their bodies have several medically useful properties which can help us treat conditions such as cancer. âThe bioactive agents in scorpion bodies have immense potential to treat several untreatable ailments such as brain cancer. There is a lot of scope for research in this area. Their proteins and bonds need to be studied at a molecular level for this purpose,â said Sulakhe.
Banner image: Photo of Scorpiops telbaila, one of the new species of scorpions, taken under UV light. Photo by Shubhankar Deshpande.