Cockroaches are generally rather large insects. Most species are about the size of a thumbnail, but several species are bigger. The world's heaviest cockroach is the Australian giant burrowing cockroach, which can reach 9 cm (3.5 in) in length and weigh more than 30 g (1.1 oz). Comparable in size is the Central American giant cockroach Blaberus giganteus, which grows to a similar length but is not as heavy.
Cockroaches have broad, flattened bodies and relatively small heads. They are generalized insects, with few special adaptations, and may be among the most primitive living neopteran insects. The mouthparts are on the underside of the head and include generalised chewing mandibles. They have large compound eyes, two ocelli, and long, flexible, antennae.
The first pair of wings (the tegmina) are tough and protective, lying as a shield on top of the membranous hind wings. All four wings have branching longitudinal veins, and multiple cross-veins. The legs are sturdy, with large coxae and five claws each. The abdomen has ten segments and several cerci.
Behavior
Cockroaches live in a wide range of environments around the world. Pest species adapt readily to a variety of environments, but prefer warm conditions found within buildings. Many tropical species prefer even warmer environments and do not fare well in the average household.
Cockroaches are mainly nocturnal and will run away when exposed to light. A peculiar exception is the Asian cockroach, which is attracted to light.
The spines on the legs were earlier considered to be sensory, but observations of their locomotion on sand and wire meshes have demonstrated they help in locomotion on difficult terrain. The structures have been used as inspiration for robotic legs.
Cockroaches leave chemical trails in their feces, as well as emitting airborne pheromones for swarming and mating. These chemical trails transmit bacteria onto surfaces.[citation needed] Other cockroaches will follow these trails to discover sources of food and water, and also discover where other cockroaches are hiding. Thus, cockroaches can exhibit emergent behavior,[11] in which group or swarm behavior emerges from a simple set of individual interactions.
Daily rhythms may also be regulated by a complex set of hormonal controls of which only a small subset have been understood. In 2005, the role of one of these proteins, pigment dispersing factor (PDF), was isolated and found to be a key mediator in the circadian rhythms of the cockroach.
Cockroaches have broad, flattened bodies and relatively small heads. They are generalized insects, with few special adaptations, and may be among the most primitive living neopteran insects. The mouthparts are on the underside of the head and include generalised chewing mandibles. They have large compound eyes, two ocelli, and long, flexible, antennae.
The first pair of wings (the tegmina) are tough and protective, lying as a shield on top of the membranous hind wings. All four wings have branching longitudinal veins, and multiple cross-veins. The legs are sturdy, with large coxae and five claws each. The abdomen has ten segments and several cerci.
Behavior
Cockroaches live in a wide range of environments around the world. Pest species adapt readily to a variety of environments, but prefer warm conditions found within buildings. Many tropical species prefer even warmer environments and do not fare well in the average household.
Cockroaches are mainly nocturnal and will run away when exposed to light. A peculiar exception is the Asian cockroach, which is attracted to light.
The spines on the legs were earlier considered to be sensory, but observations of their locomotion on sand and wire meshes have demonstrated they help in locomotion on difficult terrain. The structures have been used as inspiration for robotic legs.
Cockroaches leave chemical trails in their feces, as well as emitting airborne pheromones for swarming and mating. These chemical trails transmit bacteria onto surfaces.[citation needed] Other cockroaches will follow these trails to discover sources of food and water, and also discover where other cockroaches are hiding. Thus, cockroaches can exhibit emergent behavior,[11] in which group or swarm behavior emerges from a simple set of individual interactions.
Daily rhythms may also be regulated by a complex set of hormonal controls of which only a small subset have been understood. In 2005, the role of one of these proteins, pigment dispersing factor (PDF), was isolated and found to be a key mediator in the circadian rhythms of the cockroach.