Termites

Termites are eusocial insects that are classified at the taxonomic rank of infraorder Isoptera, or as epifamily Termitoidae within the cockroach order Blattodea. Termites were once classified in a separate order from cockroaches, but recent phylogeneticstudies indicate that they evolved from close ancestors of cockroaches during the Jurassic or Triassic. However, the first termites possibly emerged during the Permian or even the Carboniferous. About 3,106 species are currently described, with a few hundred more left to be described. Although these insects are often called “white ants”, they are not ants.

Like ants and some bees and wasps from the separate order Hymenoptera, termites divide labour among castes consisting of sterile male and female “workers” and “soldiers”. All colonies have fertile males called “kings” and one or more fertile females called “queens”. Termites mostly feed on dead plant material and cellulose, generally in the form of wood, leaf litter, soil, or animal dung. Termites are major detritivores, particularly in the subtropical and tropical regions, and their recycling of wood and plant matter is of considerable ecological importance.

Rodents

Rodents (from Latin Rodere, “to gnaw”) are mammals of the order Rodentia, which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents (2,277 species); they are found in vast numbers on all continents except Antarctica. They are the most diversified mammalian order and live in a variety of terrestrial habitats, including human-made environments.

Species can be arboreal, fossorial (burrowing), or semiaquatic. Well-known rodents include mice, rats, squirrels, prairie dogs, chipmunks, chinchillas, porcupines, beavers, guinea pigs, hamsters, gerbils and capybaras. Other animals such as rabbits, hares, and pikas, whose incisors also grow continually, were once included with them, but are now considered to be in a separate order, the Lagomorpha. Nonetheless, Rodentia and Lagomorpha are sister groups, sharing a most recent common ancestor and forming the clade of Glires.

Cockroaches

Cockroaches are insects of the order Blattodea, which also includes termites. About 30 cockroach species out of 4,600 are associated with human habitats. About four species are well known as pests.

The cockroaches are an ancient group, dating back at least as far as the Carboniferous period, some 320 million years ago. Those early ancestors however lacked the internal ovipositors of modern roaches. Cockroaches are somewhat generalized insects without special adaptations like the sucking mouthparts of aphids and other true bugs; they have chewing mouthparts and are likely among the most primitive of living neopteran insects. They are common and hardy insects, and can tolerate a wide range of environments from Arctic cold to tropical heat. Tropical cockroaches are often much bigger than temperate species, and, contrary to popular belief, extinct cockroach relatives and ‘roachoids’ such as the Carboniferous Archimylacris and the Permian Apthoroblattina were not as large as the biggest modern species.