ABSTRACT
Cockroaches are placed in five families which belong to two major phyletic lines (Blattoidea and Bla-beroidea) separated on the basis of reproductive strategies and morphology. They can be found in almost all habitat types where insects occur, but they are most diverse in warm, humid tropical regions. Cockroaches are primitive on the family tree of insects, and as such most of the functional systems of cockroaches are fairly unspecialized compared to representatives of higher insect orders. An important characteristic of laboratory cockroaches is that they can withstand and in many cases thrive in crowded conditions. Often cockroaches in containers are literally on top of one another, and they seem quite able to carry on feeding, mating, and production of offspring under these circumstances. In addition to learning more about vertebrates through the use of cockroaches, studying model systems leads to a better understanding of the evolutionary history of biological phenomena and elucidates the general applicability of basic principles.
