Species: Gromphadorhina portentosa
Madagascar hissing cockroaches are large cockroaches (2-3 inches long and 1 inch wide), which are native to the island of Madagascar, off the coast of Africa.
Males look different from females (sexual dimorphism). Males have prominent protrusions on the thorax, which are called pronotal humps. Females have very small bumps or none, with a much smoother thorax. Males can also be differentiated from females by their brushier antennae.
Metamorphosis: Paurometabolous (gradual)
Egg, nymph, adult
Females appear to bear living young, but nymphs actually emerge from an egg case called ootheca. In most cockroach species the female drop the ootheca on the ground or deposit and glue it to something. In the Madagascar Hissing Cockroach, the ootheca is retained within the body of the female until eggs hatch.
The nymphs molt six times during the course of their lives. At the last molt they become sexually mature adults. Adults never molt.
Males establish territories and defend them from other adult males. Females are gregarious and do not fight.
As their name suggests, the Madagascar Hissing Cockroaches produce a hissing sound. That is accomplished by pushing air forcefully through a pair of modified spiracles, which are small openings through which air is taken into the trachea. Insects have several spiracles arranged along the sides of the thorax and abdomen.
When do they hiss?
- Defense - to avoid predators and to defend territories
- Communication - to signal danger, for example
- Courtship and mating
Females and nymphs hiss only when disturbed.