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

[drhoz.livejournal.com]

They're a sod to eradicate, I'll tell you that.

[jilder.livejournal.com]

Tell me about it! I had a housemate bring home a microwave he found only Gods know where, and it must have had a few of the little bastards holed up in its warm interior. Lo! My tiny flat went from "ocassional flying roach" to "hey, the kitchen bench is moving" in something like two weeks. Infestations where I was- tropical Australia - tend to be ridiculously hard to deal with due to how much they love the heat and humitity, and how most Aussie houses are set up to allow free air flow between pretty much everything we can manage - i.e, lots of little cracks and crannies for them to hide in. I wound up abandoning all my electricals to prevent the accidental transportation of the little buggers to my new place.

[iheartoothecae.livejournal.com]

Yay roach! :)

If a pest animal has a common name with a country in it, you can almost be positive that it is not from there.

So, so true.

[wirrrn.livejournal.com]

All bow before our future masters!

[elainetyger.livejournal.com]

Thank you for the pictures and explanations. I learned some things.

IIRC the way the boric acid works is that it creates gas when metabolized, and insects can't burp or fart. I know that the gas thing is the reason why you have only a few ants and not much other food available (ie no animals like mine that graze instead of eating meals), you can put down some confectioner's sugar mixed with baking soda to kill them.

I see the American cockroaches often in basements in and near the sump pits. Only one time did I see a big infestation in a food area, and it was under a deli sink that had leaks and rotting wood.

The German ones I see most often in cracks in wood and under those deli platform floors when the nighttime cleaners don't bother to turn the platforms over to clean the underside. Also in the boxes holding the giant rolls of foil and plastic wrap on the deli counters, under the blade sharpener cover of deli slicers, and inside butcher and deli knife holders.

[drhoz.livejournal.com]

um, no. They most certainly can - termites for example are major producers of methane.

[deathling.livejournal.com]

I'm so happy you brought back urban species!

[agelena.livejournal.com]

I'm having flashbacks to my dorm room in college. Masses of them. You couldn't walk to the bathroom at night without stepping on one.

[weofodthignen]

Revoltin'. Thanks for the primer, which I am sure will get lots of hits. But they are so disgusting.

How come there are so few of them in England? It can't be the cold winters--winters in most of the US are far colder. Maybe the habit of building with bricks not wood? I honestly don't think I ever saw one till I came over here.

M

[urbpan.livejournal.com]

I can't imagine why you didn't see cockroaches in England. Surely there is a cultural/ecological reason, but it isn't coming to me.