Delhi: Of agaves, bats & tequila

There’s a strong connection between bats, plants, and man

Of agaves, bats & tequila
Arjun tree with a colony of bats at Janpath, New Delhi

By Rajesh K Chaudhry

The well-laid arterial roads with majestic tree-lined avenues of New Delhi are a testament to the accentuation paid by the then-town planners while designing the new capital city in 1912-13. All the important roads of Lutyen’s Delhi are lined with single rows of trees of jamun, neem, Arjun, imli, pilkhan, kigelia, peepal, baheda, etc.

While some species like neem, Arjun, or jamun have been repeated on different roads, the others like mahua and chir are restricted only to certain specific stretches. No matter the tree species, today, these avenues stand out from those added later on during the expansion of Delhi. One such ‘original’ avenue is Janpath, lined with Arjun (Terminalia arjuna) trees on both sides.

Nothing unusual about it except what even the original town planners would not have anticipated, that today, a small stretch of this road is a roosting ground to thousands of bats which one can see perched upside down from the higher branches of these trees. The Arjun trees between Claridges Hotel roundabout to National Museum are particularly ‘laden’ with the large colonies of such bats. It seems unbelievable that such a busy road, given the volume of traffic which passes through it, is a habitat of these nocturnal creatures.

Apart from Arjun, one can notice the colonies of these bats on other trees like Ficus, imli, and jamun interspersed on this road, especially near the roundabouts. Diving deep into literature reveals that these are ‘Indian Flying Fox’, also called ‘Greater Indian Fruit Bat’ (Pteropus medius, formerly Pteropus giganteus), one of the largest bats in the world. Placed under the ‘vermin’ category in the Wildlife (Protection) Act 1972, these bats prefer to roost on tall trees either in outdoor gardens or close to water bodies to which they can swoop down to lap up the water while flying. These bats are frugivorous or nectarivorous in nature, feeding on fruits, blossoms, or nectar from flowers. As their feeding nature involves squeezing pieces of fruit into their mouths, pulp-rich fruits such as mango, fig, jamun, banana, and imli are their natural choices in this belt. Interestingly, these bats are relied on for seed propagation by many plants for this very feeding habit. They are the prime pollinators of several nectariferous plants such as Haplophragma adenophylla, whose flowers open in the night, or Kigelia pinnata, the scent from the flowers of which is most notable at night, pointing towards their adaptation for bat pollination. Both these species, members of the same plant family Bignoniaceae, are visited for their nectar by bats. Incidentally, one can see Haplophragma avenue on Jaswant Singh Road next to Andhra Bhawan and Kigelia on Subramaniam Bharti Marg opposite Khan Market, both sites not far from Janpath. An interesting example in the list of plants that pollinate through chiropterophily is agave, a common plant in Delhi that can be seen on almost every alternate road divider or intersection. Chiropterophilous means “bat loving”, derived from Chiroptera, the scientific order to which the bats belong. The chiropterophily of Agave stands out because Agave is just a rosette of fleshy leaves, unlike the tall trees preferred by bats as perches. The bats feed on the nectar from their flowers and, in the process, help pollinate. The plant is monocarpic, meaning, after pollination, the main plant dies off.

There are about 22 species of Agave, many of them nearly impossible to tell apart. Some people believe the taxonomists have done too much splitting in the case of agaves. Agave also has a role in the production of tequila. This association of bats and agaves takes us to Mexico. Authentic tequila is produced from Agave tequilana, commonly called blue Agave. The plant is ‘cultivated’ on a large scale in Jalisco province in Mexico, the home of tequila. Although a locally popular fine drink called ‘Pulque’ is produced by fermenting the sap that oozes out prodigiously once the flower bud of blue Agave is excised, the plant is much better known today for a more stable and muscular drink, ‘Mezcal’.

The long-nosed bats—Leptonycteris—are the primary pollinator of the blue Agave plant in Mexico. The bats visit the plants for their nectar during flowering. Tequila is produced by hacking off the plant’s fleshy leaves, leaving an oversized pineapple-shaped core axis—’heart’—which is mashed, fermented, and distilled to make the drink.

The tequila connection thus has three main actors: the bats, the plants, and the man. The relationship between bats and tequila may seem obscure at first, but the bat-plant association is so strong that the disappearance of one would threaten the survival of the other. In fact, literature says Agave and bats have co-evolved for thousands of years. So next time you sip a tequila sunrise or a margarita, pause to reflect on the contribution made to the tequila industry by some long unacknowledged friends, the bats. The above is a perfect example, an epitome of the delicate role played by each living species on this planet in the sustenance of the ecosystem, no matter how nugatory or ‘vermin’ we may assume it to be.

The author is a retired Indian Forest Service officer

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First published on: 29-01-2023 at 00:15 IST