Cockroaches live in a wide range of environments around the world. Pest species adapt readily to a variety of environments, but prefer warm conditions found within buildings. Many tropical species prefer even warmer environments and do not fare well in the average household.
Cockroaches leave chemical trails in their feces, as well as emitting airborne pheromones for swarming and mating. These chemical trails transmit bacteria onto surfaces. Other cockroaches will follow these trails to discover sources of food and water, and also discover where other cockroaches are hiding. Thus, cockroaches can exhibit emergent behavior, in which group or swarm behavior emerges from a simple set of individual interactions.
Research has shown group-based decision-making is responsible for complex behaviors such as resource allocation. In a study where 50 cockroaches were placed in a dish with three shelters with a capacity for 40 insects in each, the insects arranged themselves in two shelters with 25 insects in each, leaving the third shelter empty. When the capacity of the shelters was increased to more than 50 insects per shelter, all of the cockroaches arranged themselves in one shelter. Researchers found a balance between cooperation and competition exists in the group decision-making behavior found in cockroaches.
Tree Roaches: Tree roaches, also known as wood cockroaches, come from the American cockroach species and are usually found in areas with a large tree population. They can’t bite or spray. Unlike household pests as the German, Oriental or American cockroaches, wood roaches aren’t as threatening if they happen to come indoors, but are bigger menaces outside wherever there are trees or woodpiles.
Similar to the American cockroaches, tree roaches are oval-shaped with spiny legs and long antennae. They are just under an inch long with coloring varying from light to dark brown. Adult males are tan with long wings extending beyond their abdomen, while females have shorter wings. Adults and larger nymphs have a pale white or transparent stripe running alongside the outward edges of their wings, behind their head.
Tree roaches damage trees by feeding on decaying organic materials as rotting trees or fallen logs. They also live in firewood piles where they eat wood shingles. Rather than living trees, they favor dead or dying wood and are known for killing a healthy tree, turning it into a dead one for a feast. Similar to termites, they absorb cellulose making up the tree’s cell walls. With the special microorganisms within their guts they are able to digest cellulose. Besides damaging trees, they also carry diseases and other pests, causing more harm.
American Cockroaches: American cockroaches are the largest cockroaches that invade homes. Adults can be slightly more than 2” long. Adult American cockroaches are reddish-brown or mahogany-colored. The area behind their head is outlined with a yellow band. Immature American roach nymphs are grayish brown. As they mature, their color becomes more reddish brown. Both male and female American cockroaches can fly. The wings develop when the roaches become adults.
American cockroaches normally live outdoors. They prefer warm, damp areas like flowerbeds, and under mulch. In many parts of the United States people call them “palmetto bugs” because they live on trees. American cockroaches are very common in sewer systems of many American cities.
American cockroaches enter homes to find water or food. They can easily pass under doors if the weather-stripping is damaged. Basement windows and garages are also common entryways. When American cockroaches enter homes, they often go to bathrooms, kitchens, laundry rooms, and basements.
Outdoors, American cockroaches eat leaves, tiny wood particles, fungi, and algae. They also eat small insects. Indoors, American cockroaches forage under appliances, in drains, in kitchen cabinets, and on the floor. They eat crumbs, scraps of food, and spilled food that they find. They will also eat pet food that is left out overnight.