This is a guest post by Coby Schal, Blanton J. Whitmire Distinguished Professor of Entomology at NC State. He and co-authors published a paper comparing the genomes of the German cockroach and the drywood
This is a guest post by Coby Schal, Blanton J. Whitmire Distinguished Professor of Entomology at NC State. He and co-authors published a paper comparing the genomes of the German cockroach and the drywood termite in Nature Ecology & Evolution.
Termites are “social cockroaches.” They evolved from ancestral solitary cockroaches some 150 million years ago, at least 50 million years before bees, ants and wasps evolved similar intricate societies independently of termites. Termites live in complex societies characterized by division of labor of castes and close coordination of tasks among members of the colony. For example, the queen and king monopolize all reproduction within the colony, while workers and soldiers maintain and defend the colony. This separation of responsibilities within the colony requires clear recognition of who’s who and mechanisms to suppress worker reproduction when a fertile queen is present, and stimulate new queens to develop when the resident queen dies. At the same time, termites have a relatively simple lifestyle – they eat wood and rarely venture in the open. These changes from the ancestral solitary cockroach should be reflected in the organization of the termite genes, the genome.
The German cockroach has a very different lifestyle from the termite. It is the quintessential omnivore, eating all foods, scavenging and even engaging in coprophagy – eating communal feces – to obtain symbiotic microorganisms and nutrients from members of its group. This cockroach is a global indoor pest that has significant adverse effects on human health. Cockroaches produce potent allergens that can trigger allergies and asthma, especially in children living in cockroach-infested homes. They thrive in unsanitary conditions and therefore they not only transmit pathogens to people, but have evolved a broad range of immune mechanisms to prevent from being infected themselves. Finally, cockroaches have evolved many mechanisms to resist the broad array of offensive chemicals they encounter in their environment, including an expansive arsenal of insecticides we use in our efforts to eradicate them.
A paper in Nature Ecology & Evolution reports the sequencing, annotation and analysis of the genomes of the German cockroach, Blattella germanica, and the drywood termite, Cryptotermes secundus, within the context of the evolution of sociality in termites from solitary cockroaches. The team, including NC State entomologist Coby Schal and principal research scholar Ayako Wada-Katsumata, compared these genomes and those of 15 other insect species so that the evolution of gene families could be analyzed along the transition from non-social cockroaches to social termites. Of particular interest in this paper are the chemosensory genes, which are u