Cockroaches in one form or another have been around for 300 million years with fossil examination indicating very little change in form and detail since that time. Cockroaches exploit a diverse range of ecologies living among decaying leaf matter, under bark, in caves and burrows on the foliage of shrubs and in the nests of social insects. While there are about 3500 species worldwide, only about ten have seriously exploited the dwellings of humans. Some species have become very successful scavengers that cohabit with people in most communities around the world. In New Zealand, there are 4 main pest cockroaches that enjoy human habitats like homes, restaurants and food preparation business'
German cockroach (Blatelle Germanic)
The relatively small German cockroach is probably the most widespread and successful cockroach that co-exists with humans in buildings. It is the most prolific breeder taking as little as 40 days to develop from hatching to adulthood. Eggs cases are usually carried by the female until just prior to hatching and these may contain 30-40 eggs. Generally, there may be 3-4 generations a year. This cockroach seeks conditions that provide warmth, moisture and food. The vast majorities of infestations are in the kitchen or other food handling areas, both domestic and commercial. If numbers of cockroaches are seen during the day it is likely there is significant infestation that will need treatment. Cockroaches carry diseases such as salmonella and spread this via contact with food and excreta
Oriental cockroach (Blatta orientalis)
The medium-sized Oriental cockroach is dark brown to black. Its preference is for relatively cool conditions where it is commonly encountered outdoors under leaf litter and bark and in damp subfloors. This is the cockroach most often found around and in compost bins and leaf piles. Egg cases are usually glued to surfaces and may contain up to 16 eggs. The adult lifespan is usually 3-6 months and a female may produce up to 14 egg cases in a lifetime.
American cockroach (Periplaneta americana)
Up to 4 cm 's long the American cockroach is the largest we come across in our homes and businesses. It prefers warm, moist dark conditions and tends to live indoors in colder regions. Because of its size, it tends not to infest dwelling parts of a building however and generally is found in wall, roof and subfloor voids and in and around sewers, drains, moist cellars grease traps and rubbish dumps. It has a preference for decaying organic material but will eat most human and animal foods and also book bindings, paper and clothing. Adults with only a water source may survive 2-3 months without food. Egg cases with up to 16 eggs are dropped or glued to surfaces within reasonable proximity to food and water. Adult lifespan is 6 -12 months females may produce up to 50 egg cases.
Brownbanded cockroach (Supella longipalpa)
The Brownbanded cockroach is relatively small and tends to live indoors infesting the dwelling parts of a building as well as offices, hospitals, restaurants, storerooms etc.
It is very active and may fly when disturbed or in warm conditions. It tends to be well dispersed within buildings, unlike the German cockroach which tends to stay close to food sources. Egg cases usually contain 10-18 eggs with a female laying 6 -13 cases in a lifetime.