Deep dive

Do hissing cockroaches live in groups?

They are not loners. Hissers cluster together, the males sort out a pecking order, and they signal to each other by smell, touch, and sound. This is what social life looks like for a roach.

Written by Ilya Finkelstein · Updated June 2026

Do they live in groups?

In the wild, Madagascar hissing cockroaches live on the rainforest floor, under logs, bark, and leaf litter, where they are found clustered together rather than spread out evenly.^[1] They are gregarious: individuals tolerate, and may actively prefer, the company of others, which is why keepers routinely house many in one enclosure without the constant fighting that solitary species show when forced together.^[1]

What pulls a group together is mostly the environment. A warm, humid, dark shelter is a scarce resource worth sharing, so roaches pile into the same good spots. Studies of the closely related giant hisser (Gromphadorhina oblongonota) show that these roaches move away from light and actively seek contact with surfaces and each other, which packs them into shared dark refuges (Figure 1).^[2] Many other cockroaches add a chemical layer to this, leaving scent cues that mark a resting site as good, but whether G. portentosa uses such aggregation cues has not been directly tested.

Is there a pecking order among the males?

Living in a group does not mean living in peace. Adult males compete for status, for the best shelter, and for access to females, and they settle these contests with ritualized fights: they face off, push and ram each other with the raised bumps on the thorax (the "horns"), and hiss.^[3] Larger males with bigger horns tend to win (Figure 2), and over repeated encounters a group of males settles into a dominance hierarchy, a rough ranking that decides who controls space and who backs down.^[3][4]

The hiss is woven into this. Dominant males hiss more than subordinate ones, and the sound carries rough information about a male's size, which can let a smaller male yield before a fight turns physical.^[5] For the mechanics of the fights and the horns, see the deep dive on male combat and horns; for the sound itself, see how the hiss works.

How do they communicate?

Hissing cockroaches use at least three channels. The first is smell. Their surface is coated with a species-characteristic blend of waxy cuticular hydrocarbons, the same kind of compounds that in many insects carry information about species and sex.^[6] In G. portentosa these waxes have been studied mainly for how they help the feet stick, and whether the roach actually reads them as signals to tell male from female or group-mate from stranger has not been shown directly, so this remains a reasonable but unconfirmed role.^[6]

The second is touch. Roaches constantly sweep their long antennae over surfaces and over each other, and this antennation is how they inspect a neighbor at close range. The third is sound, the hiss, which males use in combat and courtship and which both sexes give when disturbed.^[5] The channels work together: a courting male, for example, both hisses and makes antennal contact with the female.^[5]

Do mothers look after their young?

Hissing cockroaches give birth to live young: the egg case is carried and hatches inside the female, a pattern called ovoviviparity, so newborn nymphs emerge directly into the group rather than from a hidden egg case left behind.^[7] Newborn nymphs are often found close to the mother and clustered with their siblings in the hours and days after birth.^[7]

How much of this is active maternal care, and how much is simply the mother and her nymphs sharing the same favored shelter, is not firmly settled, and we flag it as an open question below.^[7] For how live birth works, see the deep dive on ovoviviparity.

Are they social the way ants and termites are?

No, not in the strict sense. Ants, termites, and honeybees are eusocial: they live in colonies with overlapping generations, cooperative care of the young, and a reproductive division of labor into castes such as queens and workers. Hissing cockroaches have none of that, no workers, no queen, no sterile helpers.^[1] They are gregarious and they form dominance relationships, which is a simpler kind of social life: living together, signalling, and sorting out rank, but without a colony.

There is a nice twist for the classroom here. Termites, the textbook example of insect society, are themselves highly modified social cockroaches, nested deep inside the cockroach family tree. So the roach lineage did evolve full sociality, just not in the branch that gave us the hisser.

Open questions

References

1. Durrant KL, Skicko IM, Sturrock C, Mowles SL (2016). Comparative morphological trade-offs between pre- and post-copulatory sexual selection in giant hissing cockroaches (Tribe: Gromphadorhini). Scientific Reports. PubMed
2. Free D, Wolfensohn S (2023). Assessing the welfare of captive group-housed cockroaches, Gromphadorhina oblongonota. Animals. PubMed
3. Young JJ, Craven CA, Koenig JA, Addemir M, He BZ, Miakotina OL, et al. (2026). Combat behaviors predictive of fight outcome in Gromphadorhina portentosa. microPublication Biology. PubMed
4. Logue DM, Takahashi AD, Cade WH (2011). Aggressiveness and size: a model and two tests. The American Naturalist. PubMed
5. Clark DC, Moore AJ (1995). Genetic aspects of communication during male-male competition in the Madagascar hissing cockroach: honest signalling of size. Heredity. PubMed
6. Gerhardt H, Betz O, Albert K, Lämmerhofer M (2016). Insect adhesion secretions: similarities and dissimilarities in hydrocarbon profiles of tarsi and corresponding tibiae. Journal of Chemical Ecology. PubMed
7. Yoder JA, Glenn BD, Benoit JB, Zettler LW (2008). The giant Madagascar hissing-cockroach (Gromphadorhina portentosa) as a source of antagonistic moulds: concerns arising from its use in a public setting. Mycoses. PubMed

This deep dive backs the group-housing guidance in the care guide.