Hissing
The Madagascan giant hissing roach is notable for its unique ability to produce an audible hiss. This sound is produced by pushing air forcefully through a pair of modified spiracles (openings in the abdomen of insects that are normally used for breathing). In the classroom the hissing response is most often observed when roaches, unaccustomed to being handled, are picked up. This is one of the few defensive behaviors that this harmless insect has to avoid predators. The roach also tucks its small head and antennae under the thorax. The thorax then resembles the large head of some aggressive and noisy animal!
Madagascan hissing roaches also use hissing as a means of communication. Hissing in response to a disturbance may signal the presence of danger to other roaches. Adult male roaches hiss during aggressive encounters (defending territories against other males), and during courtship and mating. Females and late-stage nymphs hiss only when they are disturbed or threatened.
Nelson and Fraser (1980) reported that the Madagascan giant hissing roach has evolved a sound-signaling system that appears to serve for communication and maintenance of social structure. They measured the acoustical characteristics of hisses associated with some social displays in the species and described how hissing was incorporated in the social displays.
Nelson and Fraser identified five distinct hisses that were highly correlated with specific interactions, depending on whether defensive signaling, territoriality, or courtship was occurring. Males that were muted so that they were unable to hiss were almost never successful at mating with females. The researchers concluded that, while behaviors other than sound production (such as olfactory clues) are important in courtship and aggressive interactions, sound plays an important role in communication, and it may be necessary at one point in courtship.
Care and Handling
Most of the time (75 percent), Madagascan roaches are not very active. A clear shoebox is fine for a pair of roaches; a few holes are needed to provide air. If the lid is not very tight-fitting and secure, tape the lid shut around the edge. If a pet box with a snap-on lid is used for pregnant females, place a square of muslin or light cotton over the top of the cage.
Wood chips or bark are good substrates for the bottom of the cage and provide hiding areas. Gravel, pine shavings, or crushed corncobs are also acceptable coverings for the bottom of the cage. You may also provide half an egg carton or a cardboard roll from paper towels for hiding spots, and you may add a branch for climbing. In a cage with just a few roaches, the substrate should be replaced about every four to six months as needed. If your roaches have been breeding, the material should be sieved to avoid throwing away small nymphs.
Place the cage in a warm location, as Madagascan roaches are tropical. They seem to do well at room temperature (72-76 degrees F). At higher temperatures (80 degrees F) they are more active and may breed; and at lower temperatures (66 degrees F) they are sluggish and will probably not breed. Although they survive brief exposure to lower temperatures (above freezing), do not keep Madagascan roaches at temperatures lower than 65 degrees F or higher than 85 degrees F. Unless you plan to breed the roaches or have a poorly heated room, you should not need an additional source of heat.
Madagascan roaches are nocturnal, meaning they are most active at night. One way to observe the night-time activities of the insects during the day is to reverse the photocycle (Bell 1981). Outfit a fairly dark room or closet with a 100-watt light and timer that will turn the light on from about 6:00 PM to 6:00 AM for 12 hours of light. The roaches will be active from about 8:00 AM to 4:00 PM. Best results for behavioral observations will be obtained if the terrarium stays in a dark room, with a red light for illumination during daylight hours. A 40-watt red incandescent bulb may be purchased in most stores with a varied selection of lighting supplies. You can see the roaches, but they perceive that it is night and go about their normal nocturnal activities.
