The German Cockroach, Blatella germanica. Image: Alex Wild/Visuals Unlimited/Corbis. |
The german cockroach, Blatella germanica, lives almost everywhere that humans live. It lives in our homes, our hospitals and hotels, in our shops and factories and sewers and offices. In fact it lives in practically any buildings built by humans and especially heated ones with food in. But it is completely unknown in the wild and quickly dies if stranded outdoors. (It is probably all too obvious already what question I'll be asking creationists at the end of this blog.)
Quite when and where it took up with humans and evolved its complete dependence on us is unknown but it is believed to have been somewhere in Africa, probably before we were modern humans. Its ancestors might well have lived in caves like several other species of cockroach.
B. germanica has shown itself to be capable of rapidly evolving. In the 1980's the control method of choice was to use sugars laced with insecticides then, in the 1990s, this stopped being effective. Cockroaches had not, as might seem probable, evolved a resistance to, or tolerance of, insecticides; they had evolved