Blattodea

Blattodea Temporal range: 228–0 Ma PreЄ Є O S D C P T J K Pg N Late Triassic – Recent
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Subclass:	Pterygota
Infraclass:	Neoptera
Superorder:	Dictyoptera
Order:	Blattodea
Suborders
Cockroaches Isoptera
Synonyms
Blattaria (cockroaches only)

Blattodea is an order of insects that contains the cockroaches and the termites. Formerly, the termites were considered a separate order, Isoptera, but genetic and molecular evidence suggests an intimate relationship with the cockroaches, both cockroaches and termites having evolved from a common ancestor. The Blattodea and the mantises (order Mantodea) are now all considered part of the superorder Dictyoptera. There are approximately 4,400 species of cockroach in almost 500 genera, and about 3,000 species of termite in around 300 genera.

Taxonomy

Fossil cockroach from Carboniferous of France

Cladistic analysis of five DNA sequences in 107 species representing all the termite subfamilies, all 6 cockroach families, including 22 of the 29 subfamilies, and 5 of the 15 mantis families (as out-groups) showed that the termites are nested within the cockroaches, and that the Cryptocercidae is a sister group to the termites. The mantids were shown to be the sister group to Blattodea. Cryptocercus also shares characteristics such as species of gut bacteria with the termites.

The evolutionary relationships of the Blattodea (cockroaches and termites), based on Eggleton, Beccaloni & Inward (2007), are shown in the cladogram: The cockroach families Lamproblattidae and Tryonicidae are not shown but are placed within the superfamily Blattoidea. The cockroach families Corydiidae and Ectobiidae were previously known as the Polyphagidae and Blattellidae.

Dictyoptera

Blattodea Blattoidea Termitoidae (Termites) Termitidae Rhinotermitidae Kalotermitidae Termopsidae Hodotermitidae Mastotermitidae Cryptocercoidae Cryptocercidae (brown-hooded cockroaches) Blattidae (Oriental, American and other cockroaches) Blaberoidea Blaberidae (Giant cockroaches) Ectobiidae (part) Ectobiidae (part) Corydiodea Corydiidae (Sand cockroaches, etc) Nocticolidae (Cave cockroaches, etc) Mantodea (Mantises)

Cockroaches

American cockroach

Arthropods similar to living cockroaches dominated the insect communities of the Carboniferous era. Modern cockroaches radiated from them by the middle of the Mesozoic. The cockroach is flattened dorso-laterally and is roughly oval with a shield-like prothorax that covers the head. The antennae are many-segmented, long and slender, and the mouthparts are adapted for chewing. The fore-wings are normally leathery and the hind wings membranous. The coxae of the legs are flattened to enable the femurs to fit neatly against them when folded. Cockroaches are hemimetabolous; there is no pupal stage and the nymphs resemble the adults apart from their size and the absence of wings.

Termites

Termites

All species of termite are to some degree eusocial and involve cooperative behaviour among a male and female pair of reproductives, and the workers and soldiers that form the other members of the colony. Some species have small, simple colonies where the workers and soldiers are capable of becoming reproductives themselves. Others have large complex societies where each member has a role that does not change throughout its life. Termites can be considered to be "eusocial, juvenilized cockroaches".