Cockroaches – A Bad Reputation
Timothy J. Gibb, Dept of Entomology, Purdue University
likes cockroaches. They have a reputation as disgusting
insects that live in garbage and sewers and secretly invade our
homes during the night. There are many species of cockroaches
but scientists have estimated that 99% of them give the rest a
bad name. None more so than the American cockroach, Periplaneta
americana (Linnaeus). This is the species that people
find most repulsive. It is the largest of our common house-hold
invading cockroaches and can easily measure 2 inches in length.
It occurs throughout the world and especially in commercial buildings,
basements, sewers, steam or heat tunnels, drainage systems, compost
piles, garbage facilities, or in accumulations of organic debris.
The American cockroach is an omnivorous and opportunistic feeder.
It consumes decaying organic matter but since the cockroach is
a scavenger it will eat most anything, and seems to be most fond
of anything particularly nasty, putrid or filthy.
American cockroaches can become a public health
problem due to their association with human waste and disease,
and their ability to move from sewers into homes and commercial
establishments. Although not shown to be direct carriers of disease,
they can contaminate food and kitchen utensils with excrement and
salivary secretions and leave an unpleasant odor
The adult American cockroach is reddish brown in appearance with
a pale-brown or yellow band around the edge of the pronotum or
shield behind the head.
These have three life stages: the egg, a variable number
of nymphal instars, and adult. The life cycle from egg to adult averages
about 600 days while the adult life span may be another 400 days.
Interestingly, the American cockroach is originally
not of American descent. It was introduced to the United States
from Africa as early as 1625 and was spread throughout the world
at that time.
Unfortunately, for the global reputation of Americans,
the name American cockroach was somehow adopted and has stuck. It is not an insect
that we would choose to have as an ambassador of America, but at
this point the choice is out of our hands …… baseball,
apple pie, 4th of July and the American cockroach.