About the incredible endurance of cockroaches go the most real legends: they live for years, and radiation is not afraid, and they do not need food and water, and even without a head, cockroaches can exist just as if they did not need them at all.
Of course, with a strong radiation exposure, these parasites die, like any living thing, just to endure without harm to themselves they can dose that is 15 times more safe for humans. But whether the legend of the claim that the cockroach lives not only without water and food, but also without a head, and in general how many live cockroaches, still need to be understood ...
Stages of life of the cockroach
All cockroaches have an incomplete development cycle, i.e. without the stage of transformation of the larva into a pupa.
- The greater part of the female after fertilization lays the eggs in the ootheka (small light sac) and wears it on the stomach. Over time, the ooteka darkens and begins to swell from the eggs grown inside, which takes from two to four weeks.
- Females of some species discharge the ooteca into a secluded (warm and humid) place, most often in some hard-to-reach crevice where small tiny white nymphs (nymphs) hatch about 3 mm long. In other species, females wear ootec on themselves until hatching eggs and even take care of them for a while after this.
- Over time, the nymphs darken and their chitinous covers become firm. After passing through the stages of several lines, the nymph becomes an adult, which takes about 2 months in the warm season (at a temperature of 30 degrees and above) and for up to six months at a temperature of 22 degrees in very common red cockroaches . The life span of an adult specimen (imago) of a red cockroach is 20-30 weeks.
It turns out that since the hatching of the nymph, the cockroach theoretically lives about 9-12 months, if nothing prevents it.
There are species of cockroaches living for several years, which includes a black cockroach (can live up to two years). The total number of individuals in a colony can increase thousands of times 3-4 months after a small number of parasites enter the dwelling. This interval is explained by the longer life of females than in males, which are very prolific, and also by the long development of eggs.
Can cockroaches live without food?
These insects can actually do without food for quite some time. Red cockroaches live without food up to 40 days, and black cockroaches - up to 70 days. This is due to the fact that they are cold-blooded creatures (poikilothermic), which means that they do not need to expend energy to maintain a certain body temperature.
The metabolism of such organisms is 20 times slower than that of warm-blooded animals, and the cockroach is sufficient to take food once, after that to live a long time (even several weeks) without hunger. On the other hand, the main source of energy for poikilothermic organisms are external sources, so cockroaches live only in heated dwellings, and at subzero temperatures their numbers are dramatically reduced.
The need for cockroaches in water
Despite the fact that without food, cockroaches live for several weeks, without water, they perish within a week. This is due to the fact that water plays an exceptional role in the life of any organism, since it is a structural component of the cell, and practically all metabolic processes consisting of a chain of chemical reactions occur with the participation of water.
Cockroaches do not live long without water and prefer to eat moistened food (waste), because water is necessary for the process of digestion, for the salivary glands and circulatory system.
The remarkable thermal conductivity of water also determines its important role as a thermoregulator in living beings. So, from overheating of cockroaches, shedding excess liquid through Malpighian blood vessels on the body saves, and nightlife and waterproof chitinous cover, on the contrary, help to save water in case of low humidity and too high temperature.
Do cockroaches live without a head?
No matter how strange this question may sound, the answer "yes, the cockroach without a head lives" sounds even stranger.
American scientists to study the ability of these insects to reproduce conducted a series of experiments on their decapitation. After that the researchers came to the conclusion that not only the body of a cockroach lives without a head, but its head (placed in a cool place and fed with a special solution) may well exist without a body. In turn, deprived of heads and sealed with special wax in the neck of the body of cockroaches live in a flask a few more weeks, according to the entomologist K. Tipping.
In order to understand why this is possible, it is necessary to understand that all life support systems for insects (nervous, circulatory, digestive) are not designed in the same way as in humans. Thus, loss of a person's head is fraught with deprivation of a critical amount of blood, a drop in blood pressure and a violation of oxygen supply, and with it important nutrients to internal organs.
In insects, however, the circulatory system is not closed, it lacks thin capillaries, and pressure does not play a decisive role in it. According to the physiologist and biochemist J. Kankel, if you tear off the cockroach head, the cervical vessels are simply sealed with clotted blood, and the circulatory system will continue its work.
Of course, food does enter the digestive system of these parasites through oral organs. However, without a head, a cockroach can live 9 days or even longer, as it can do without food for quite a long time, being more likely to be killed by mold or other microorganisms than starving to death.
To perform a normal breathing process, a person is vital to the head, since it contains the mouth and nose, through which, in fact, air enters, and the brain that controls this process. In cockroaches, the respiratory process is carried out by means of special openings on the body, called "spiracles", and a network of small tubules - the trachea. In this case, the brain does not take part in breathing, and after elimination of the head the body continues to be supplied with oxygen in the previous regime.
Moreover, the brain as such is not particularly necessary for cockroaches, since on each part of the body they have nerve nodes (ganglia) responsible for the basic nerve functions at the level of reflexes.
Without head, cockroaches wiggle their paws, stand up and even move. True, as Nick Strosefeld of the University of Arizona notes, the head of these insects receives a large amount of sensory information from the body, so their brains, devoid of body, can not function properly. Thus, experiments have shown that cockroaches demonstrate memorization skills in training, when the head and body are in indissoluble unity. With the separation of the head, of course, these creatures lose their abilities.
So, cockroaches are really incredibly tenacious insects and are able to live without food, water and even without a head for a very long period. The chitinous cover is so strong that even when it is slammed with this insect with a tap, one can not be sure that after a while it will not depart after the impact and will not run away.
On the other hand, the deprivation of water threatens them with an early death, therefore those who wish not only to get rid of intruders, but also to prevent their appearance in the future, should by all possible means avoid water leaks from taps, pipes and flower pots.