Page 35 - Waterfall Issue 4 2021

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
Little achatina By tiMur V. VoronKoV
around the globe (except for Antarctica). Apart from being
smuggled across borders by exotic pet traders, it is transported
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
Achatina fulica eggs By Ken WalKer, MuseuM Victoria
and grains. They are known to eat the bark and stems of
trees, seaweed, lichens, 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?
Giant African Land Snail (Achatina fulica) in Hyderabad.
Opposite page: Achatina fulica seen in a suburban garden in Johannesburg. • The first message here comes across loudly
and clearly – DO NOT SIMPLY THROW THEM IN
One of the largest terrestrial gastropods, the Giant African YOuR RuBBISH DESTINED FOR LANDFILL!
Land Snail (Achatina fulica) hails from East Africa and its • Spraying them with vinegar is suggested, or sprinkling
natural habitat stretches all the way from the north-eastern them with Diatomaceous earth could be a solution.
region of kwazulu-Natal through Mozambique, Tanzania • Surround your plants with rings of wheat bran or
and kenya to Somalia and Ethiopia. It has an average lifespan corn bran – you can buy these products from health
of five – seven years, although it can live longer in ideal food stores. They are eaten by slugs and snails and
conditions. This snail can grow up to 20cm in length and its the ingested bran then causes desiccation and death.
shell can extend up to 7cm in height. When it is fully grown, This is a totally organic solution, and if wildlife eat the
its shell will have between seven and nine spirals, which are corpses, they are getting extra nutrition. However, you
normally dark or medium brown with stripes at intervals. need to replenish the bran regularly in rainy weather.
• Although this has not been discussed in any of the
Although classified as hermaphrodites, (having both research material available, speaking as a true South
male and female sex organs), reproduction requires cross- African male, I would suggest incinerating them along
fertilisation. Mating involves both a ‘getting to know each with any eggs that you find. And then burying the ash
other phase’ and copulation, which normally takes place under a reasonable layer of soil in a corner of the garden.
at night. From a single mating, the individual that received
the sperm can produce batches of fertilised eggs over a Whatever you do, with the Giant African Land Snail featuring
period of months, although the sperm can also be stored prominently on the list of Top 100 Most Invasive Species
by the snail for up to two years before fertilising any eggs. in the World, it’s recommended that the handling (using
suitable gloves and other protection) and disposal of these
Between 100 and 500 eggs are laid at a time. The eggs ‘cute snails on steroids’ should be done with caution.
hatch one to three weeks later and the baby snails reach
sexual maturity five to eight months after hatching. Resources: www.aphis.usda.gov www.cabi.org www.biokids.umichu.edu

Waterfall Issue 4 2021 33