Madagascar Hissing Cockroach

ORDER: Blattodea

FAMILY: Blaberidae

GENUS: Gromphadorhina

SPECIES: portentosa

Like all insects, there are 6 legs, 3 body regions and 1 pair of antennae on head. They are wingless, about 1 to 3 inches long. A short pair of appendages on the last body segment, called cerci, sense vibrations in the air. The large bumps of the pronotum (area behind and above head) are biggest in males even though females are often larger than males.


Herbivorous. Scavengers, they feed on fallen decaying fruit and vegetation, aiding decomposition in the rain forest and helping build soil.

Cockroach mating can occur year-round while the climate is warm. Mating usually occurs at night when the insect is the most active. When a female is ready to mate, she emits a special scent to attract males. They mate tail-to tail and remain this way for 20 to 30 minutes. The female lays her fertilized eggs in a long yellowish egg case called an ootheca. Females can produce up to 30 ootheca in one lifetime, which equals over 750 young! The ootheca will be drawn back in and kept inside the body for at least 60 days, at which time 15-40 cockroach nymphs will emerge. Nymphs are to inch long and flat, looking much like sow bugs in the beginning. Nymphs stay with their mother for about 6 months after hatching. Nymphs will molt six times in six months, by the ninth month the nymph is sexually mature. After molting any missing legs or other parts will be regenerated. Life span - about 2-3 years. They live in large colonies, with several smaller colonies within it. Only one male will dominate a territory of several females. If another male tries to enter, the dominant male will push the intruder out of his territory. Males have large, hard prenatal bumps on their heads which they use in fights with other males. Females often move between different male dominated territories.

The hissing noise is made by depressing its abdomen and expelling air out of the spiracles with which it uses to breath. Hissing is used to communicate during mating, by males to defend territories, and can startle predators, giving the insect a chance to escape.

Over 3,500 species of cockroaches worldwide.

The Madagascar Hissing Cockroaches can be found in the bug house in the Wayne and Gladys Valley Children's Zoo.

Although Hissing Cockroaches are not threatened at the moment, the forests they inhabit are among the most threatened habitats in Madagascar. The forests are threatened due to slash-and-burn agriculture and mining activities. This animal has not yet been evaluated by the IUCN.


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