According to the ecological habits of cockroaches, a biologist once came to a conclusion: if there is a global nuclear war on the earth one day, all creatures in the affected area, including humans and even fish, will disappear, and only cockroaches will continue their lives! This is because under normal circumstances, the radiation that the human body can bear is 5 rem, and once the total radiation exceeds 800 rem, it will die. Blattella germanica can tolerate 9000- 105000rems, and Periplaneta americana can tolerate 967500rems! So cockroaches can survive even if there is a nuclear explosion. At present, the U.S. government spends1500 million dollars to eliminate cockroaches every year, which is about twice the budget for AIDS prevention and control.
Most of them look the same, but if you look closely, you can still see the difference. At present, taxonomists divide the species of cockroaches into about 6,000 species, of which about 50 species are pests, such as common Asian cockroaches. In addition, Periplaneta americana, Blattella germanica, brown cockroach and Australian cockroach are also widely distributed. There are about 200 species in China, and the common indoor cockroaches are about 10, which varies from place to place. Blattella germanica and Periplaneta americana are common.
Blattella germanica is very small, about 10- 15mm long, and its adult is brownish yellow, which is a common dominant species in northern China. In addition to being distributed indoors, it is also the dominant species in restaurants, restaurants, hospitals, ships, trains and passenger planes.
Periplaneta americana is a dominant indoor species in southern China, with a large body size of about 30-40mm, which is distributed in dark and humid environments such as sewers, heating ditches, toilets, bathrooms, breweries and sauce factories.
The scientific name of cockroach is cockroach. It has a chewing mouth and can chew food. Cockroach's food is very complicated, ranging from ordinary food to brushes for shoeshine, including wire rubber, cardboard, soap, paint scraps, dead leaves, textiles, leather, hair and so on. Entomologists have found that there are 12 species of cockroaches that can live on paste for one week, while American cockroaches can live for one month only by drinking water, and for three weeks without eating or drinking. When food is short or space is crowded, cockroaches will devour each other.
Cockroaches are good at crawling, swimming and flying in times of crisis. Cockroaches are good at living in tiny cracks because of their flat bodies. As long as there is water and food, they can live almost anywhere. If the conditions are not good, you will not die if you don't eat or drink for a long time. With the appearance of the above characteristics, the number and distribution range of cockroaches are increasing day by day, and they have become the number one household pest.
Cockroaches like the dark and fear the light. They like to go out at night on their stomach during the day and occasionally see them during the day. Generally, after dusk, they start to climb out for food and return to their nests in the morning. The temperature is most active at 24-32℃ and completely inactive at 4℃. In the tropics, cockroaches can breed and move all year round. In northern China, if the indoor temperature is suitable in winter and there is heating equipment, cockroaches can move and reproduce as usual. Cockroaches are mostly oviparous, and their eggs are arranged orderly in the egg sheath, which can resist the influence of adverse environment and is not easy to be killed by chemical drugs. When conditions are suitable, they can hatch larvae.
Cockroaches have a strong reproductive ability. After the male and female cockroaches mate, the female cockroaches will grow a pod-like thing on the tail, called an egg sheath, in which the eggs are laid. A few females can produce more than 10 and more than 90 egg sheaths. In an egg sheath, at least 10 cockroaches can be hatched, and at most more than 50 small cockroaches can be hatched, which is related to the species of cockroaches. In the eastern United States, there are more than 1000 cockroaches living in an average house; And a pair of Blattella germanica can breed 100,000 offspring in just one year! It takes about 15 days for the eggs of cockroaches to hatch in the egg holder. The newly hatched cockroach is a milky nymph without wings. Like other kinds of insects, it must shed its skin during its growth. After molting for 3-4 times, wing buds can be seen. Blattella germanica needs 6-7 molts to reach the adult stage of sexual maturity, while Periplaneta americana needs 10- 12 times. The growth and molting time of cockroaches are closely related to climate factors and food acquisition. Usually this process is completed within two months.
Spiders, scorpions, ants, parasitic flies, parasitic bees, toads, lizards, birds and mice are common natural enemies of cockroaches.
Most cockroaches living in the wild feed on decaying organic matter or litter. Cockroaches living in houses like starchy food. They often leave pathogenic organisms on the food they climb and spread diseases. Cockroaches have the bad habit of eating, spitting and excreting, polluting food and spreading many diseases, such as dysentery, paracholera, hepatitis, tuberculosis, diphtheria, scarlet fever and ascariasis. No matter what kind of cockroach it is, the pathogens it spreads are typhoid Bacillus, dysentery Bacillus, Escherichia coli, tuberculosis Bacillus, anthrax Bacillus, gall fungus, tapeworm eggs, ascaris, schistosomiasis and so on. Cockroaches also secrete and excrete odorous substances, which make people feel sick and even vomit after smelling them. The Thai government has announced that it will no longer allow the sale of a "giant cockroach" originating in Madagascar in the name of a pet, and it is also prohibited for ordinary individuals to own it.
Cockroaches are moderate in size, easy to raise and have strong reproductive ability, and have long been the favorite experimental objects of biologists.