IT WASN’T just the pink-and-grey colour scheme. Or even the loose tiles. The
thing that Martyn Robinson hated most about his bathroom was the mould. Dark
spots speckled the grout and a fuzzy, grey film clung to the shower curtain. No
sooner had he scrubbed it off, back it came. “It was Mould City,” says Robinson,
a naturalist at the Australian Museum in Sydney.
Hardly surprising, really. Robinson and his partner Lynne McNairn had chosen
to live in an old, two-storey, brick-and-fibro house in Narraweena, a soggy
suburb to the north of Sydney. The bedrock is so close to the surface that when
it rains, water oozes out of the ground and turns the garden into a bog. Damp
comes with the territory, and in a poorly ventilated bathroom, mould was
inevitable. It was one long battle against the fuzzy fungus until, one day,
Robinson decided to take on domestic help. He started with one, then three, and
eventually a whole army of cleaners. They were small, cost only bed and board,
and didn’t use nasty chemicals around the house. They were slugs: a motley crew
of striped ones, red ones and big, fat grey ones.
As a naturalist, Robinson is keen to experiment with biological controls of
all sorts. Since he settled in Narraweena, he has offered houseroom to a whole
menagerie of creatures in return for their doing a few chores. His ultimate aim
is to build up a trouble-free staff of animals that can be left alone to get on
with the job. Already, he has turned up previously hidden talents among some of
the local fauna.
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The slugs were his first employees. “Some slugs love mould. They thrive on
it,” says Robinson. “I noticed a few came into the house and headed for the
bathroom. A friend of mine had seen slugs eating mould in his house so I thought
I’d test it out.” Worried that the molluscs would never make it across the vast
expanse of carpet that lay between them and the bathroom, he gathered them up
and carried them to their new home. “Lo and behold, it worked. They kept the
mould down. They didn’t get rid of it completely but we only needed to do a
little work. They are particularly good at cleaning grout, silicone sealer and
other hard-to-reach places,” he says.
Slugs have a strong homing instinct, foraging in the damp night air and
spending the deadly desiccating daylight hours in a cool, moist retreat.
Robinson provided his new staff with comfortable lodgings in the shape of a
little ceramic pot perforated with stars and crescent moons—the sort more
usually used to waft perfumed oils around the place. “They soon learnt that was
home,” he says. Each night, the slugs crawled out of the moons and stars and
slithered off on their fungal foray. At daybreak, they crept home where they
were safe from bare feet and torrents of hot water. In the breeding season, the
slugs took a break from housework, heading down the drain and out of the vent
pipe to seek a mate in the garden. After a brief romantic interlude, some came
back, unable to resist Robinson’s increasingly furry shower curtain. Those that
failed to return were replaced with new recruits from the garden.
Since he took on his first few slugs, Robinson has tried out several species,
hoping to find the perfect home help. The leopard slug is a good mould-grazer,
but tends to slip out of the bathroom at night to explore the house. “You might
step on it during its nightly wanderings, so it wasn’t ideal,” says Robinson.
The little striped slug—not so little at 3 to 5 centimetres long—was
better. It has a healthy appetite for mould and goes about the job as
energetically as a slug can. The red triangle slug, which can grow up to 10
centimetres, was a bit too picky. “It will eat mould but it won’t go on the
ground. It’s good for shower curtains but won’t clean the other parts of the
bathroom.” The best slug for the job turned out to be Limax flava, the
much-maligned great grey slug familiar in European gardens and introduced to
Australia. L. flava is a big, beefy slug, 9 centimetres at full
stretch, so it eats a lot of mould. But it’s also pretty sluggish, for want of a
better word, and doesn’t wander far at night, so there’s little risk of finding
one squashed into the carpet the next morning.
At one point, great greys, stripys and a young red triangle shared the
workload and Robinson was more than happy with their efforts. They were
efficient and didn’t stain the carpets as cleaning with bleach did. Eventually,
though, it was time for a new bathroom: that pink-and-grey just had to go.
Freshly plumbed and neatly tiled in green and white, the new bathroom is airy
and bright. The old plastic shower curtain has gone, replaced by a shiny, glass
cubicle. “We do have a silicone strip around the shower tray which is hard to
clean and the slugs do that brilliantly,” says Robinson.
Even so, redundancies loomed. It was time to downsize the staff. The
celestial slug house has gone, and the slimmed-down workforce consists of three
small stripy slugs. “They are small enough to fit in the groove of the sliding
door without getting squashed,” says Robinson. “Occasionally they get fed up and
crawl down the plughole, but generally they do a good job.”
Robinson has been well and truly bitten by the slug bug and hopes other
people will give them a try. “It’s an alternative for those who can’t be
bothered scrubbing or who don’t like chemicals,” he says. “They don’t remove all
the mould, but they do keep it down to an acceptable level.” For those who don’t
fancy the sight of fat grey slugs in the bath, he is working on a range of
designer slugs in fetching bathroom colours. L. flava varies naturally
from grey to yellow, and also comes in albino. “The yellow form is quite
attractive,” says Robinson. “And the white ones can be tinted by feeding them
vegetable dyes—although you have to keep this up or they revert to white
.”
Apart from the odd silvery trail up the bathroom wall and a few droppings
that are easily swilled away during the morning shower, slugs don’t have any
real drawbacks—unless you collect vintage wines. “They like the mouldy
labels,” warns Robinson. “They eat them, and then you don’t know what’s in the
dzٳٱ.”
With Sydney’s warm, damp climate—and especially on Robinson’s boggy
patch of land—there’s plenty of work for a large household staff. Keeping
down cockroaches, for instance. Roaches come in all sizes, from the thumb-sized
Periplaneta species to the smaller but more persistent Blattella
germanica. “They’re a problem—for other people,” says Robinson. His house
is so well protected, he sees about one cockroach a month. The first line of
defence is a colony of leaf-tailed geckos—prickly-looking lizards with
flat, leaf-shaped tails. These particular geckos don’t have sticky feet and can
only cling by their claws to rough surfaces. They live outside on the brickwork,
where they are active at night. “They form a sort of moat of geckos that insects
have to get past before they can make it into the house,” says Robinson.
Any that do get in risk an encounter with the “lounge lizards”, secretive
skinks that skulk by day behind the lounge (that’s a sofa to non-Australian
speakers). The skinks emerge in the evening to hunt a whole range of unwelcome
guests, including cockroaches, spiders and silverfish. “You hardly notice they
are there. But they’ll eat anything that’s moving on the ground,” says
Robinson.
Cockroaches might be unpleasant, but termites are a householder’s worst
nightmare. Given half a chance, they’ll eat the house—unless something
eats them first. In Narraweena, termites have a natural enemy in the little
black ant. If the ants come across a band of termite workers, they’ll follow
them down into their galleries where they’ll eat termites at every stage of
development from egg to adult. Above ground, any termite king or queen setting
out to found a new nest is fair game. If they land anywhere near the ants
they’re done for—and that’s one fewer nest to worry about. Robinson and
McNairn are happy to share their home with a few black ants in exchange for a
termite-free house, although the ants themselves can become a nuisance. “They’ll
eat our food too—from the sugar to breakfast cereals—and they get
everywhere. You might find them living in the teapot, for instance. But we
tolerate them. They patrol the places a human cleaner can’t get to,” says
Robinson.
Scuttling insects and stationary eggs are relatively easy to deal with, but
in Australia it’s hard to avoid flying insects, especially mosquitoes. Most
people keep them out with wire screens. Robinson’s insect screens are woven from
silk and tailor-made by orb spiders. Webs on either side of the ramp leading to
the first-floor entrance create an insect-screened corridor to the house. Golden
orb spiders are best for this job. They build fairly permanent webs, and
although they don’t always build them in the right place or at the right angle,
the webs can be moved into position by carefully detaching the supporting
strands and fastening them to a more suitable twig or stem. Garden orb spiders
do their bit too, but they have a serious drawback—they build a new web
each night, eating the old one the following morning. “This means we sometimes
walk straight into a web at night that wasn’t there during the day,” says
Robinson.
There are plenty of pests left to keep a whole range of wildlife fed, from
dragonflies to bats, to fish and frogs which live in the garden’s pools and
ponds, even insect-eating sundews and pitcher plants, which thrive on the boggy
ground. And about this time of year, the anti-mosquito task force is swelled by
the arrival of several species of Toxorhynchites—unusually large
mosquitoes with glittering iridescent bodies and wings. There are dozens of
species of Toxorhynchites around the world and they share one endearing
habit: as larvae they have a voracious appetite for the young of other
mosquitoes. The adult insects suck plant sap and nectar, not blood, and they lay
their eggs in small pools, containers filled with rainwater, tree holes and even
waterlogged footprints in the lawn. The offspring of other mosquitoes don’t have
much of a chance. A single Toxorhynchites larva can eat its way through
400 smaller mosquito larvae before it reaches adulthood. “Although we’ve still
got plenty of mosquitoes, there are fewer than there might have been,” says
Robinson.
Apart from their battery of biological controls, Robinson and McNairn
restrict their fight against pests to mechanical methods—squashing snails,
for instance—or at most, sloshing ecologically friendly soapy water over
bad infestations of scale insects. The result is a garden filled with native
species, from mud-burrowing spiny crayfish to seven species of insect-eating
lizard. Native honeybees, rescued from a fallen tree, nest in two hives that
Robinson has provided, each potentially giving him a litre of lemony-tasting
honey a year. Native wasps have moved into other artificial nest sites—and
keep down harmful caterpillars. “We provide what the animals want, and they
come,” says Robinson. “And the more diversity there is, the less likely we are
to have pests. Pests may get used to chemicals, but they never get used to being
ٱ.”
And there’s a bonus. There’s always a ready supply of new additions to the
household staff. “We’ll probably never have a scrupulously clean and tidy house
but we have one that’s comfortable, entertaining and doesn’t give us too much
ɴǰ.”
For anyone thinking of following Robinson’s example, it’s probably best to
check that it’s OK with any other humans living in the house. Fortunately,
McNairn shares Robinson’s enthusiasm. “I like having the critters around,” she
says. “They make our life interesting, and generally you don’t even know they
are there. They just quietly get on with their jobs and every now and then you
see one of the geckos or slugs and think, that’s nice, they’re still here.”
Unless they are spiders, that is. “There was a bit of a problem when a large
banded huntsman spider I’d introduced to the garden took up residence in a
drawer,” admits Robinson. “When Lynne went to take out her favourite grey
jumper, part of it moved under her hand,” he recalls. Her piercing scream
persuaded him to put the spider at the farthest part of the garden. “It never
returned,” he says, “probably because its sound receptors are still ringing.”