50 More Urban Species, #1: German Cockroach

[urbpan]

Female German cockroach. Blatella germanica Body length about 1.5 cm.

If a pest animal has a common name with a country in it, you can almost be positive that it is not from there. The German cockroach is probably native to East Africa* (or possibly tropical Asia**) and is thought to have been transported to Europe at least a millennium ago.* This cockroach is one of about a dozen species of cockroach that likes to live in the great indoors, among several thousand others that never do. In temperate places, they make up the vast majority of indoor infestations. Only in very warm and wet places are they joined by their much larger distant cousin, the American cockroach (from West Africa).

German roaches, like most others are nocturnal and spend the day tucked away in nooks and crevices. A behavior called "thigmotaxis" makes them seek out locations where they can feel pressed upon by the walls of their hideout, and by the bodies of other German cockroaches. They communicate and congregate through the use of pheromones, finding good locations to breed and feed by following scent trails left by others. After mating, females develop egg cases that they carry until they are ready to hatch, instead of leaving their eggs to the whims of the environment, as many insects do.

Like many successful urban animals, they can feed on nearly anything, including many substances associated with filth and neglect. In the absence of refuse and feces they will happily eat the glue from bookbinding, the greasy fingerprints from a countertop, or the skin from a sleeping person's face. They can survive on the shed skins and dead bodies of one another until a better food source avails itself.

Their presence in restaurants and food storage facilities is cause for health code enforcement, and can result in considerable economic loss. Large infestations in homes hav been implicated in severe asthma, particularly among inner city children. The appetite that cockroaches have for both food and feces makes them potential spreaders of pathogenic bacteria. ***

Effective control of these creatures involves sanitation, thorough inspections, and targeted toxic bait applications. Depriving them of food and hiding places is essential. As a non-native, potentially harmful species living indoors, the responsible reaction to German cockroaches is to try and eliminate them.


Male German Cockroach.


Female with egg case (ootheca) attached. She is coated with boric acid powder, applied by a pest control technician. The powder is puffed into roach harborages, and they ingest it when they clean it off themselves, and the powder poisons them. Boric acid is about as toxic to vertebrates as table salt.

* http://www.curioustaxonomy.net/etym/misnamed.html
** http://en.wikipedia.org/wiki/German_cockroach
*** http://www.ncbi.nlm.nih.gov/pubmed/16417714

Comments

[deathling.livejournal.com]

I'm so happy you brought back urban species!