Page 23 - The Villager April 2021
P. 23

Nature




                                                             maturity five to eight months after hatching. and that’s how a
                                                             plague of giant african land Snails can develop in a relatively
                                                             short period of time.
                                                               the giant african land Snail is now found on every continent
                                                             around the globe (except for  antarctica).  apart from being
                                                             smuggled across borders by exotic pet traders, it is transported
           Little achatina                       By tiMur V. VoronKoV
                                                             over large distances via cargoes of agricultural products and, as it
                                                             can survive in a state of aestivation (dormancy to avoid excessive
                                                             heat and dryness) for years, just as authorities declare that they
                                                             have the infestation under control, when weather conditions
                                                             improve, out they pop again.

                                                             WHY ARE THEY SUCH A THREAT TO HUMANS AND THE
                                                             ENVIRONMENT?
                                                               •  They are voracious feeders, consuming around 500 different
                                                                species of plants. Not only do they climb into and devastate
                                                                agricultural crops such as coffee, cocoa and rubber plantations,
                                                                they also love fruit, vegetables, nuts and grains.  they are
                                                                known to eat the bark and stems of trees, seaweed, lichens,
           Achatina fulica eggs             By Ken WalKer, MuseuM Victoria  fungi and even other snails.
                                                               •  Because they need calcium for their shells, they are capable of
                                                                eating the plaster off buildings, as well as sand, concrete and
                                                                even bones.
                                                               •  They  are  hosts  to  a  number  of  parasites,  including
                                                                Angiostrongylus cantonensis, a nematode (roundworm) that
                                                                causes eosinophilic meningoencephalitis in humans.

                                                             HOW CAN ONE ERADICATE AND DISPOSE OF THEM?
                                                               •  The first message here comes across loudly and clearly – DO
           Giant African Land Snail (Achatina fulica) in Hyderabad.  Not SImPly throw them IN yoUr rUbbISh DeStINeD For
           Opposite page: Achatina fulica seen in a suburban garden   laNDFIll!
           on the Highveld.
                                                               •  Spraying them with vinegar is suggested, or sprinkling them
                                                                with Diatomaceous earth could be a solution.
             one of the largest terrestrial gastropods, the giant african   •  Surround your plants with rings of wheat bran or corn bran –
           land  Snail (Achatina fulica) hails  from  east  africa  and its   you can buy these products from health food stores. they are
           natural habitat stretches all the way from the north-eastern   eaten by slugs and snails and the ingested bran then causes
           region of Kwazulu Natal through mozambique, tanzania and   desiccation and death. this is a totally organic solution, and
           Kenya to Somalia and ethiopia. It has an average lifespan of   if wildlife eat the corpses, they are getting extra nutrition.
           5 – 7 years, although it can live longer in ideal conditions. this   however, you need to replenish the bran regularly in rainy
           snail can grow up to 20cm in length and its shell can extend   weather.
           up to 7cm in height. when it is fully grown, its shell will have   •  Although this has not been discussed in any of the research
           between 7 and 9 spirals, which are normally dark or medium   material available, speaking as a true South african male, I
           brown with stripes at intervals.                     would suggest incinerating them along with any eggs that
             although classified as hermaphrodites, (having both   you find. and then burying the ash under a reasonable layer
           male and female sex organs), reproduction requires cross-  of soil in a corner of the garden.
           fertilisation.  mating involves both a ‘getting to know each
           other phase’ and copulation which normally takes place at   whatever you do, with the giant african land Snail featuring
           night. From a single mating, the individual that received the   prominently on the list of Top 100 Most Invasive Species in the
           sperm can produce batches of fertilised eggs over a period of   World, it’s recommended that the handling (using suitable gloves
           months, although the sperm can also be stored by the snail for   and other protection) and disposal of these ‘cute snails on steroids’
           up to two years before fertilising any eggs.      should be done with caution.
             between 100 and 500 eggs are laid at a time. the eggs hatch
           one to three weeks later and the baby snails reach sexual   Resources:   www.aphis.usda.gov   www.cabi.org   www.biokids.umichu.edu


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