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Sunday, November 13, 2022

at Snail's pace ! .. ..the invading species

William Henry Benson was a civil servant in British India and an amateur malacologist.  


Likely that you have seen them in your gardens – pictured here is a fairly large one !  .. a Snail.  A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs.   "snail" in a  general sense, includes not just land snails but also numerous species of sea snails and freshwater snails.  Snails have considerable human relevance, including as food items, as pests, and as vectors of disease, and their shells are used as decorative objects and are incorporated into jewelry!!  The snail is associated with lethargy. The snail has also been used as a figure of speech in reference to slow-moving things.   

நத்தை மெல்லுடலிகளில் வயிற்றுக்காலிகள் வகுப்பைச் சேர்ந்த விலங்கினமாகும். இவற்றின் முதிர்விலங்குகளில் சுருளி வடிவிலமைந்த ஓடு காணப்படும். ஓட்டின் கீழாக தசைப்பாதம் காணப்படும். நத்தை என்பது பொதுவாக கடல் நத்தை, தரை நத்தை, நன்னீர் நத்தை என்பவற்றைக் குறிப்பிடப் பொதுவாகப் பயன்படும். ஓடிலாத நத்தை வகைகளும் காணப்படுகின்றன.


கிழக்கு ஆப்பிரிக்க நத்தை இந்தியாவில் ஆக்கிரமிப்பு உயிரினமாக மாறி, பயிர்களையும் பல்வேறு வகையான தாவரங்களையும் சிதைத்துக் கொண்டிருக்கின்றன. இவற்றால் தாவரங்கள் மட்டுமின்றி, அந்தத் தாவரங்களைச் சார்ந்திருக்கும் மற்ற உயிரினங்களும் முற்றிலுமாகக் காணாமல் போகின்றன. கிழக்கு ஆப்பிரிக்காவைத் தாயகமாகக் கொண்ட இந்த நத்தை வகை, இந்தியாவில் 19-ம் நூற்றாண்டில் இங்கிலாந்தைச் சேர்ந்த ஆய்வாளர் ஒருவரால் கொல்கத்தாவுக்குக் கொண்டு வரப்பட்டது. 

‘Snail’s pace’ is a contraction of ‘at a snail’s pace,’ which means very slowly. A snail is a mollusc that goes so slowly that its progress is almost imperceptible. When we think of snails, we imagine slow-moving creatures who live life at their own pace and are never in a hurry, which leads us to the meaning of this idiom. It refers to someone doing tasks at a very slow pace or perhaps being a little lazy.  The connection of the slow movement of human actions to the slow pace of a snail appears in Shakespeare’s play, Richard III : 

Delay leads impotent and snail-paced beggary

Then fiery expedition be my wing, 

At the beginning of the play Richard is the Duke of Gloucester. His brother Edward is now king of England after winning a series of wars between his people and the Lancasters. Richard is jealous of his brother and feels that he has not had a chance in life because he was born deformed so he has decided to to usurp his brother and grab the throne. !!  He succeeds and finally gets the crown and becomes king. He continues his pursuit of power, however, killing other members of his family. The quoted passage shows his restlessness and impatience. 

Thousands of miles away in Venezuela, a "plague" of giant African snails that pose potential health risks to humans is causing alarm where sustained rains have facilitated their proliferation. The first colonies of the sub-Saharan Achatina fulica snail were discovered at the beginning of November on the shores of Lake Maracaibo in western Venezuela. Since then, more snails have been found in agricultural areas in the region, as well as in neighboring Tachira state.  The giant African snail is considered an invasive species because of its reproductive capacity—up to 600 eggs every two weeks—and its relatively long lifespan of six years on average. It can be devastating to crops and also carries parasites that can cause meningitis, encephalitis and intestinal disorders in humans. 

Elsewhere, a team of researchers led by malacologist Jean-Michel Bichain from the Museum of Natural History and Ethnography in France named the newly discovered animal Archaeocyclotus brevivillosus – its species name combining the Latin words small (brevis) and shaggy (villōsus). A snail preserved in amber with an intact fringe of tiny delicate bristles along its shell is helping biologists better understand why one of the world's slimiest animals might evolve such a groovin' hairstyle. This unusual mollusk fossil, found in the Hukawng Valley of Myanmar, has lines of stiff, miniscule hairs, each between 150 and 200 micrometers long, following the swirl of its 9 millimeter long, 3.1 millimeter high shell.  It's not the first hairy snail discovered, either, joining an exclusive club of the coifed gastropods. 

If you remember the Civil servant mentioned at the start, William Henry Benson was an amateur malacologist. He made large collections of molluscs and described numerous species from the U.K., India and South Africa. He joined Haileybury College in 1819 and joined the East India Company at Bengal. He  worked in a number of positions including a District Collector and Officiating Judge in Meerut, Bareilly and other parts of northern India. During his stay in India he collected specimens of numerous land snails some of which he sent to Hugh Cuming in England.  On the return from a trip to Mauritius he brought a couple of living Achatina fulica which he gave to a friend in Calcutta in April 1847 who subsequently released them in a garden at Chowringhee. The species is today a pest in many parts of India. 


With regards – S. Sampathkumar


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