back to organism index
MADAGASCAR HISSING COCKROACHES
Phylum Arthropoda is subdivided into a dozen or so classes of
organisms, including spiders, isopods, millipedes, centipedes,
crustaceans (crabs, shrimps, and their kin), and insects. Class
Insecta, the largest class of organisms on the planet, is subdivided
into 26 orders, one of which is Orthoptera. Members of the Orthoptera
include grasshoppers, katydids, crickets, mantids, walkingsticks,
and cockroaches. They all develop through incomplete metamorphosis,
starting life as a tiny immature replica of the adult, and progressing
through a series of nymphal instars leading up to adulthood.
The principal player in the Diversity of Life Course
is the Madagascar hissing cockroach. These magnificent insects
are large, sleek, clean, slow-moving, and sexually dimorphic.
And they hiss. Some students may resist handling them initially,
but as they see others in their group handling the roaches, they
will gain confidence and join the fun.
There are hundreds of species of cockroaches worldwide. They
are essentially nocturnal scavengers, opportunistically eating
fruits, grains, and decomposing plant debris. Few cockroaches
fly, but many are incredibly fast runners. The hissing cockroach,
however, one of the largest of its group, is a plodder, never
moving quickly enough to startle a person or to escape.
The Madagascar hissing cockroach is a large, wingless cockroach
with a life cycle that is somewhat different from other roaches.
The female gives birth to live young after carrying the eggs and
newly hatched nymphs for about 60 days. She can give birth to
3060 nymphs at a time. The nymphs molt six times over the
next half year or so before reaching maturity. Hissing cockroaches
live 25 years.
You can identify male and female roaches by their thorax. The
male has a prominent pair of ridges on the top/front of his thorax
just behind his head, which are sometimes described as "horns"or
"eyebrows." The female has only a slightly raised ridge.
Unlike most of the orthopterans, roaches are silent, with the
notable exception of the hissing roach. It hisses by drawing air
into the abdomen through spiracles on both sides of the fourth
segment, and then forcing it out with a fairly loud hiss.
Why do these roaches hiss? Scientists wondered
what advantages a roach might gain from hissing. Males and females
(and older nymphs) hiss when disturbed, but scientists also noticed
that male roaches sometimes hiss when there is no threat imposed
by another animal. They also observed that males hiss in the presence
of a female. This led scientists to hypothesize that hissing was
involved in courtship, perhaps used by males to establish a territory
or to ward off other males.
To test their ideas about hissing and mating behavior, scientists
covered up the spiracles on the fourth segment of one male roach
and left them open on another male. Both male roaches were placed
in a cage to see which would become dominant. The hissing male
almost always became dominant.
In other experiments they found that the male that hissed the
loudest almost always drove off the other males. When a hissing
male and a nonhissing male were placed in a cage with a female
roach that was ready to mate, the hissing male was able to fight
off the roach that couldn't. The hissing male was more likely
to mate with the female, and pass on his "hissing" genes.
In fact, females would not mate with a male that couldn't hiss.
Caring for cockroaches. Hissing roaches need
food, water, warmth, and cover. Use a terrarium as the habitat;
its size will depend on the number of roaches you will be housing.
- Get a large aquarium that has a secure fine-screen cover.
In the kit is a plastic 6-liter basin with a lid. Hissing roaches
are excellent climbers and can easily scale the side of a glass
terrarium. One way to prevent this is to apply a band of petroleum
jelly 4 cm (1-1/2") wide all the way around the inside
of the terrarium near the top. Roaches will not cross the sticky
- Cover the bottom of the terrarium with sand, soil, or wood
shavings. Put in lots of stuff for the roaches to crawl into
and under for cover. Slightly flattened paper-towel tubes, paper
egg cartons, chunks of tree bark, and the like will work. Roaches
are thigmotaxic, meaning they like to have physical contact
with some structure for security. Hissing cockroaches are more
likely to hiss when there are objects in the habitat container.
- Place food in a shallow dish like the lid of a margarine container.
Small bits of vegetables, bread, dry dog food, crackers, and
fruit are good. Don't worry if the fruit starts to mold; the
roaches seem to like it that way.
- Place a cotton ball or piece of sponge in a small dish (like
a small plastic cup, cut so it is a centimeter tall). Keep a
little water in the cup at all times.
- Place the terrarium in a warm location. If the temperature
is likely to drop below 20°C (68°F), keep a low-wattage
lamp on one end of the terrarium.
Breeding. If you are interested in breeding
your cockroaches (a good idea, as they can be costly to acquire!),
set the terrarium up as described, but cover the bottom with soil
rather than sand. Keep the terrarium soil and bark slightly moist
(not wet) at the end away from the food, water, and heat. Hissing
cockroaches give live birth, and the newborns seem to thrive in
a slightly moist environment.
Before the investigation. In preparing for the
food-preference part of the investigation, put your roaches on
short rations. Remove food and water sources 2 or 3 days before
that part. The roaches can go without food for 2 or 3 weeks, and
without water for a week. Make sure they are not deprived of access
to food and water for longer than 5 days.
Cockroach sources. Contact a local high school
or college life-science department to see if you can get a gift
or a loan of a dozen cockroaches. Pet stores sometimes have them
for sale, and biological supply companies usually sell them as
well. You might also search the Internet for Madagascar hissing
cockroaches. A surprising number of sites offer roaches for sale.
Shop aroundprices vary widely. Also be aware that currently
some states will not allow hissing cockroaches to be shipped into
the state (Florida for example).
If at the end of the course you have no desire to maintain the
colony, try to find a colleague, biological supply house, or zoo
to take your colony. The roaches are valuable, and you should
easily find them a new home. If you are left with no alternative
besides euthanasia, bag and label the colony and place it in a
freezer for a couple of days. Cockroaches should never be released
What to do when they arrive. Release roaches
into prepared container (see above) with plenty of ventilation
but with a tight lid, as they are quite strong and can otherwise
Back to top