Bats : An important species for humankind - Daily Current Affair Article

Why in news?

Recently, a study in Thailand has depicted that pest bio- control provided by just one species of bat prevented the loss of 2900 tons of rice per year and savings of $1.2 million annually.

Bat droppings are widely used as a fertilizer for agricultural crops as they have high concentrations of nitrogen and phosphorus.

Although , the recent Covid pandemic opened our eyes and made us aware about the various viruses bats carry.

Bats-

  • The scientific name for bats is Chiroptera, which is Greek for “hand wing.” That’s because bats have four long fingers and a thumb, each connected to the next by a thin layer of skin.
  • They are the only mammals in the world that can fly, and they are remarkably good at it.
  • Their flexible skin membrane and movable joints allow them to change direction quickly and catch mosquitoes in midair.

Classification of bats-

  • Microbats.
  • Megabats.
  • Most bats are microbats, which eat insects like moths, that come out at night.
  • Vampire bats are the only species of microbats that feed on blood rather than insects. They prefer to drink from cattle and horses, not humans.
  • To navigate dark caves and hunt after dark, microbats rely on echolocation, a system that allows them to locate objects using sound waves. They echolocate by making a high-pitched sound that travels until it hits an object and bounces back to them.
  • Megabat is the common name for any of the largely herbivorous Old World bats comprising the suborder Megachiroptera of the order Chiroptera (bats), characterized by true wings and flight (as with all bats), large and prominent eyes, claws generally on the second digits supporting the wings, and an excellent sense of smell.

Distribution of bats-

  • Megabats, or pteropodids (from the sole extant family Pteropodidae), are located in tropical and subtropical areas of Africa and from southern and central Asia to Australia, including in various Pacific islands, Indonesia, and the Philippines.
  • Microbats are found all across the world except for Antarctica and the Arctic.
  • The 950 species of bats found worldwide are said to have originated from one of the oldest surviving species.
  • India is one among the 25 mega-biodiversity hotspots that harbour the richest and most highly endangered eco-regions of the world.
  • India is home to about a hundred species of bats, including 12 fruit bats, such as the fulvous fruit bat Rousettus leschenaulti, Indian flying fox Pteropus giganteus, etc.
  • Fruit bats are frugivorous or nectarivorous, in other words, they eat fruits or lick nectar from flowers.

Ecological significance of bats-

  • As seed dispersers, frugivorous bats aid the distribution of plants (and therefore, forests) by carrying the fruits with them and spitting the seeds or through ingesting the seeds and eliminating them elsewhere.
  • Nectarivores are directly important for plant reproduction through pollinating plants they visit. They bear long tongues that are inserted deep into the flower; pollen thereby passed to the bat is then transported to the next blossom visited, pollinating it. This relationship between plants and bats is a form of mutualism
  • They play important ecological roles as prey and predator, arthropod suppression, seed dispersal, pollination, material and nutrient distribution, and recycle.
  • Benefits of bats-
  1. They are principal pollinators.
  2. They are insects’ ingestors i.e , they eat so many insects.
  3. They are human helpers as one of the bat called vampire bat have some anticoagulant in its saliva which scientists have discovered that it can treat heart patients in future.

Role of bats in disease spread such as Corona, Ebola-

  • Bats of certain species are well recognized as being capable of transmitting rabies virus, but recent observations of outbreaks and epidemics of newly recognized human and livestock diseases caused by viruses transmitted by various bats have raised some crucial questions regarding these mammals.
  • Bats are natural reservoirs of some pathogenic viruses like Nipah, Hendra, Ebola, Marburg and the coronavirus that causes severe acute respiratory syndrome.
  • ‘Spillovers’ from bats to people either occur directly, through contact with infected bats or indirectly through intermediate hosts such as domestic animals or wildlife that have been contaminated by blood, saliva, urine or faeces of bats.

Reasons for immunity of bats from such diseases-

  • Because bats were among the earliest mammalian species to develop, it is possible that their innate and acquired immune responses have important qualitative or quantitative differences from those of the rodents and primates.
  • Bats have different set points in their immune responses which results in control of the level of virus replication without clearance of infectious virus in order to prevent immunopathological responses in infected tissues.
  • Despite being reservoirs of viruses, they never fell sick because, they have evolved mechanisms to avoid the damage caused by toxic by products by suppressing immune system.
  • This suppression of immune system results in continuous auto-immune response which helps them combat infections and control viral infections.
  • This ability to limit excessive inflammatory response helps them to not over react with virus and protects them from multiple chronic age related diseases.

Reasons for spillover of diseases from bats to humans-

  • Outbreaks of several zoonotic diseases have increased in recent decades often as a result of bushmeat consumption as well as human encroachment into natural habitats involving deforestation and agricultural intensification.
  • Humans have significantly modified the landscapes- cutting of forests, clearing of lands for agricultural practices and infrastructural development – all these things results into disturbances to bat roosts, which eventually forces them to change their homes.
  • Mining activities, quarrying, destroys their natural cave structures
  • Scientists have shown that when bats are stressed due to disturbances in their habitat , then they shed viruses which they carry with them.

Indigenous practices related to human-bat interface-

  • Indigenous peoples had understood the significance of giving enough space to all animals including bats.
  • Some have isolation practices such as quarantine following hunting.
  • The Bomrr clan of Nagaland have traditionally celebrated the annual bat harvest for many years.
  • They gather at a place called Mimi to smoke a cave full of bats, kill them for consumption.
  • Then to, after consumption of bats, these people are immune to diseases caused by bats.
  • So, the National Centre for Biological sciences, an aided centre of Department of Atomic Energy are carrying out sero- ecological studies.
  • They are exploring microbial diversity associated with bats, investigating which part of this diversity is potentially pathogenic.
  • The NCBS is also in the process of sequencing whole genomes of bat viruses.
  • This will help in building a bank of virus genomes for any possible future outbreak.
  • Local practices and traditions could help us to guide and understand the situation by reducing the risk of infectious disease spillover from bats in future.

Precautions related to interaction with bats-

  • Several sensible precautions that can minimize our direct interactions with bats are- avoiding handling or eating bats, and not eating fallen fruits already bitten by bats or fruits likely to be contaminated by bat fluids.
  • This will gradually reduce the disease spillover.
  • In long terms- we should work towards restricting and reversing land use practices that are bringing us in greater contact with bats.

Conclusion-

  • We can regain the ecological balance with nature and animals through a combination of habitat restoration and co-existence with the wildlife.
  • Integrated approaches such as concept of One Health, where human health is linked to that of environment and animals can result in best possible solutions.
  • A global commitment is needed to regulate and monitor the habitat loss of wildlife and preserving and restoring the natural ecosystem and biodiversity.

Sources- The Hindu, National geographic, ncbi.nlm.nih.gov, researchgate, bats.org.uk, downtoearth, newworldencyclopedia.or

General Studies Paper 3
  • Environment