20 Australian GeographicCockroaches are considered
pests and often squashed under
foot without a care, yet some native
varieties are surprisingly attractive.
AUSTR ALIAN COCKROACHES
N
EXT TIME YOU reach for insecticide to
smite a cockroach out of existence, think
twice. Although some are introduced pests,
others have been here for millions of years, and are
deserving members of Australia’s intricate ecosys-
tem. There are more than 530 known species in
Australia, about 90 per cent of which are found
nowhere else – and experts believe there may be
twice that number yet to be discovered.
Cockroaches are closely related to termites and
have a characteristic flattened body. Their lives are
short but varied and often unique. Some have
elaborate mating rituals and others use chemical
sprays to defend themselves. Some species take
parental care of their young. They range in size
from the tiny Nocticola, at just 3mm long, to the
giant burrowing cockroach at a whopping 8cm and
33g – one of the world’s heaviest insects. They can
also be far more colourful than the non-native
invaders you might see darting about at night.
The dazzling greens, reds and even blues of some
species hint at the incredible diversity to be found.
Cockroaches occupy every type of terrestrial
habitat Australia has to offer, from rainforest
canopies to caves and beneath the red dirt of the
outback. There’s even an Australian aquatic
cockroach that’s yet to be properly studied.
One man who’s spent his life exploring the
secrets of these fascinating insects is entomologist
David Rentz, author of A Guide To The Cockroaches Of
Australia. “They are extremely abundant and crucial
in the breakdown of leaf matter in the Australian
environment,” says David. “They are also a major
food source for vertebrates, such as lizards, frogs
and birds, and invertebrates, such as centipedes,
scorpions and predatory beetles.” Most have
interesting life histories that we know little about.
Although it’s unlikely you’ll see the species
pictured here in your kitchen cupboards, they are
some of the more extraordinary Australian
members of this much-maligned insect family.Beautiful
bugs
TEXT BY DAN DOWN ILLUSTRATIONS BY MICHAEL BURLEIGH
MITCHELL’S DIURNAL
COCKROACH
Polyzosteria mitchelli
Surely the most dazzling of all
Australian roaches, Mitchell’s diurnal
cockroach sports a yellow-patterned,
green-blue carapace, with striking
blue legs. It has a wide range
stretching from WA, through SA and
into NSW, and can be seen scurrying
about around shrubs during the day.
Head to the Nullarbor Plain for a
chance to spot this colourful insect.CONFUSING SUN COCKROACH
Pseudolampra rothei
This medium-sized cockroach has
vibrant dark-red-and-yellow-striped
armour, mottled with black marks. Its
head is a rich red-brown with three
lighter stripes at the top. This
stunning species can be found in SA’s
vast Lake Eyre Basin, but hasn’t been
seen outside of the state. The
‘confusing’ part in the name refers to
the fact that it looks very similar to
other ’roaches in its genus – a
problem entomologists love to tackle.COMMON ELLIPSIDION
Ellipsidion humerale
This colourful species varies in appearance and is
widespread, having been identified in WA, the
NT, QLD and as far afield as New Guinea. You’ll
know it when you see it because it has a striking
orange-yellow back and its antennae are often a
two-tone black-orange. The species is active
during the day and doesn’t live in leaf litter –
look for it on flowers and leaves, where you
may find it supping on pollen.