Synonyms and other taxonomic changes
Cockroaches are sometimes considered a suborder, Blattaria, of order Dictyoptera
, which BugGuide treats as a superorder. Many sources still treat termites as a separate order (Isoptera). The Guide follows classification provided in(1)
Explanation of Names
is from Latin blatta
, 'cockroach'; English name, through folk etymology
from Spanish cucaracha
Cockroaches are usually dark brown or reddish in color and have flattened oval bodies and long swept-back antennae. The head is usually concealed by the pronotum
which extends far forward. When wings are present, they are held flat over the back, overlapping one another.
worldwide and throughout NA
Though considered tropical insects, cockroaches can flourish in any environment where there is sufficient food and warmth. Most North American cockroach species live in woodlands and are not pests. Those found indoors may be anthropophilic "pest" species or those that migrate inside inadvertently.
Of species found indoors, German cockroaches are commonly found in homes throughout the world:
Adult and nymph
See the Blatella Info page
to differentiate from similar cockroaches.
American cockroaches are common cockroaches found in homes (and outdoors) throughout the tropics and subtropics, including throughout the southern US.
See the Blattidae Info page
to differentiate from similar cockroaches.
While these two species are by far the most commonly encountered in homes, it is not uncommon to encounter other species in homes. Some of the more commonly reported species indoors are:
Brown banded cockroaches (world-wide)
Asian cockroaches (in southern US)
Oriental cockroaches (world-wide)
Smoky brown cockroaches (in southern US)
Turkestan cockroaches (southern California to Texas)
Florida woods roach (Florida and neighboring states)
Cockroaches are omnivores, with many species consuming detritus primarily and other insects opportunistically.
Female cockroaches produce ootheca (egg case) that hold 12-25 eggs.
Oothecae are carried by females of many cockroach species, and can help identify cockroaches to genus.
Nymphs develop to maturity through simple metamorphosis
where the adults have similar body types as the juviniles, although this may be hidden by the development of wings in the adults:
molts into an adult, and wings expand
and eventually harden
. (All cockroaches look white after they molt until their new exoskeleton hardens.)
Predators, parasites, and parasitoids
The factors that structure communities of cockroaches are not well understood. As generalists feeders, the populations may be limited by the effects of predators, parasites, and parasitoids rather than a limitation in nutrients. Cannibalism is reportedly common, although the circumstances under which this occurs behavior occurs in these semi-social insects are not clear. Some of the more interesting invertebrates that feed on cockroaches:
Ensign wasps are commonly found around homes with cockroach infestations. These wasps are looking for the egg cases (ootheca) of cockroaches. Once these are located, the wasps lay their own eggs within the capsule. When the Ensign wasps hatch, they devour the developing cockroaches.
Cockroach wasps temporarily paralyze the adult cockroaches using venom. While paralyzed, the wasp makes a second sting, this time using venom inserted into a precise location in cockroach’s brain. The antennae of the cockroaches are then clipped, and when the paralysis wears off, the wasp leads the cockroach to its lair. The cockroach makes no attempt to flee as an egg is laid upon it. When the eggs hatch, and the helpless cockroach is devoured by the young maggot-like wasps.
Horse hair worms develop inside cockroaches (and other groups of insects) living off the hemolymph (blood) as the insect grows. Once it reaches adulthood, the worm can change the cockroach’s behavior, driving it into the water where the cockroach will drown, and the worm will wriggle free to continue its life cycle.
Vertebrates also are important predators of cockroaches:
To defend themselves against generalist predators, the nymphs of many species exude defensive secretions onto their posterior tergites. This adhesive material gums up mouthparts of attacking centipedes, etc. and may contain additional repellant/toxic compounds.
synanthropic spp. discussed in(6)
Atkinson T.H., Koehler P.G., Patterson R.S. (1991) Where the roaches are. The geography of U.S. cockroaches. Pest Control 59: 36-40.
, synanthropic spp. (Rust & Reierson 2007)(7)