Cockroaches' defining characteristics are their nymph life stage, their scavenging nature and their global abundance. They share taxonomical similarities with a variety of insects, such as dragonflies, beetles and even fleas, but cockroaches' wings and mouthparts link them to their closest insect relatives. A handful of cockroach families, distinct due to their size, habits and habitats, exist within the Blattodea order.
A Diverse Class
Members of the Insecta class share a number of common characteristics, but within this class, species exhibit tremendous diversity. The three-segmented body -- head, thorax and body -- is the defining characteristic of all insects. Head antennae and wings are also common to all insects, although not all insects can fly, despite having wings. Cockroaches straddle this characteristic: Some, such as the commonly seen oriental cockroach (Blatta orientalis), can't fly, and others, including the equally common American cockroach (Periplaneta americana), can fly.
Because their wings are veined and folding, cockroaches fall into the pterygota subclass. They share this characteristic with all flying insects, such as bees, dragon flies, beetles and lice. This characteristic differentiates roaches from mayflies and dragonflies, which have wings that cannot fold flat against the body.
Neoptera includes all pterygota, apart from butterflies and moths. The only distinction between neoptera and pterygota is the presence of the pleural wing-folding muscle. The members of this infraclass remain diverse and include wasps, fleas, cockroaches, termites, stick insects and waterbugs.
The Roach and Close Relatives
This superorder contains the cockroach and some of the cockroach's closest relatives. This classification distinguishes roaches from less similar insects. Although the majority of insects in this classification cannot fly, they are still classified by the configuration of their wings. All members of this superorder, which includes cockroaches, termites and mantises, have mouthparts for chewing, leathery wings and the ability of the female to carry eggs on the abdomen.
The Immediate Roach Family
Cockroaches exist entirely in two main families; Blattidae, which includes the American cockroach (Periplaneta americana), and Blatellidae, or so-called wood cockroaches, which includes the German cockroach (Blattella germanica). The majority of pest species are from the Blattidae family. A smaller family of roaches, Cryptocercus, exists under the Blattodea order. These are more closely related to termites than other roach families.
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