Friday, November 22, 2019

Superorder Dictyoptera, Roaches and Mantids

Superorder Dictyoptera, Roaches and Mantids Dictyoptera means network wings, referring to the visible network of veins present in the wings of this order. The superorder Dictyoptera includes orders of insects related by evolution and features: Blattodea (sometimes called Blattaria), the cockroaches, and Mantodea, the mantids. That being said, the world of science is ever-evolving, and taxonomy is no exception. This branch of the insect taxonomic tree is currently under revision. Some insect taxonomists also group termites in the superorder Dictyoptera. In some entomology references, the Dictyoptera may be ranked at the order level, with the mantids and roaches listed as suborders. Description: Perhaps no other pairing of insects seems as unlikely as cockroaches and mantids of the order Dictyoptera. Cockroaches are almost universally reviled, while mantids, also called praying mantises, are often revered. Taxonomists rely only on physical and functional characteristics to determine groups of like insects, however. Compare a cockroach and a mantid, and youll notice both have leathery forewings. Called tegmina, these wings are held like a roof over the abdomen. Roaches and mantids have long and spiny middle and hind legs. Their feet, or tarsi, nearly always have five segments. Dictyopterans use chewing mouthparts to consume their food, and have long, segmented antennae. Both cockroaches and mantids also share a few anatomical features that you would only see through close examination and dissection, but theyre important clues to establishing the relationship between these seemingly different insect groups. Insects have a platelike sternite near the end of their abdomens, under the genitalia, and in the Dictyoptera, this genital plate is enlarged. Roaches and mantids also share a special digestive system structure. Between the foregut and midgut, they have a gizzard-like structure called a  proventriculus, and in the Dictyoptera the  proventriculus has internal teeth that break down solid bits of food before sending them along the alimentary canal. Finally, in roaches and mantids, the tentorium – a skull-like structure in the head that cradles the brain and gives the head capsule its form – is perforated. Members of this order undergo incomplete or simple metamorphosis with three stages of development: egg, nymph, and adult. The female lays eggs in groups, then encases them in foam which hardens into a protective capsule, or ootheca. Habitat and Distribution: The superorder Dictyoptera contains nearly 6,000 species, distributed worldwide. Most species live in terrestrial habitats in the tropics. Major Families in the Superorder: Blattidae - Oriental and American cockroachesBlattellidae- German and wood cockroachesPolyphagidae - desert cockroachesBlaberidae - giant cockroachesMantidae - mantids Dictyopterans of Interest: Blatta orientalis, the Oriental cockroach, gains access to homes through plumbing pipes.The brown-banded cockroach, Supella longipalpa, is called the TV roach. It likes to hide inside warm electronic appliances.Brown-hooded cockroaches (Cryptocercus punctulatus) live in family groups. Females give birth to live young; the nymphs take 6 years to reach maturity.The Mediterranean mantid takes its scientific name, Iris oratoria from an unusual marking on the underside of its wing. Literally, the name means talking eye, a smart description of the eyespot which is displayed when the mantid feels threatened. Sources: Dictyoptera, Kendall Bioresearch Services. Accessed online March 19, 2008.Kaufman Field Guide to Insects of North America, by Eric R. Eaton Kenn KaufmanDictyoptera, Tree of Life Web. Accessed online March 19, 2008.Evolution of the Insects, by David Grimaldi, Michael S. Engel.External Anatomy - The Insects Head, by John R. Meyer, North Carolina State University Department of Entomology. Accessed online November 9, 2015.Unlikely Sisters – Roaches and  Mantises, by Nancy Miorelli, Ask an Entomologist website. Accessed online November 9, 2015.

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