Cockroach eggs and larvae: what they look like, how many hatch at a time

  • By Vil Malinoshevsky
  • About cockroaches

Cockroach larvae are the most dangerous part of the entire population of cockroaches in an apartment for people.

Firstly, there are the most of them here and they are the ones who bring the largest amount of various contaminants into the room and onto food products in the room from sewers, garbage chutes, entrances and other less clean places in the house.

Secondly, it is the larvae of domestic cockroaches that are the source of strong allergens, due to which, perhaps, some of the people living in the house constantly have a stuffy nose and develop chronic allergic rhinitis. Young children are especially sensitive to these allergens - a significant part of children's runny noses, which are not accompanied by an increase in temperature, are caused by cockroach nymphs.

What kind of allergens are these and why are cockroach larvae more dangerous as carriers of allergens than adults?

Features of the appearance of larvae

Quite interesting is the fact that some pests demonstrate a certain maternal instinct towards their offspring.
When cockroaches hatch from the eggs of a Madagascan representative, they crawl under the mother’s abdomen and remain under her direct protection for some time. The female hisses and makes threatening lunges when potential danger approaches. However, such care is only enough for 1 day. Classic Prussians practically do not care for their young. The offspring simply stays near the female for a few more hours, after which they scatter to secluded corners.

One of the interesting exceptions remains the species of relict cockroaches. In their case, after the “birth” of young individuals, they are looked after and provided with food. Upon reaching a certain degree of maturity, new members of society take their assigned place in the hierarchy of the colony. In this case, it is somewhat reminiscent of a termite mound with different ranks and its own complex hierarchy.

Types of cockroaches and their reproduction

Domestic cockroaches are rightfully considered one of the most unpleasant insects that have ever appeared in our homes. Just by their appearance they cause disgust. In addition, these insects are carriers of pathogenic bacteria, helminth eggs, spoil food and leave their poop. Among the huge number (about 4 thousand) species of insects, only 3 are adapted to life in close proximity to humans:

  • redheads;
  • black;
  • American

They differ from each other in color, size and area.

The homeland of domestic red cockroaches is southern Asia. In the 18th century, they came to Europe and quickly began to multiply. Human dwellings became the habitat. They are still more often found in our homes than others. This synanthropic organism has a body size of 1-1.5 cm. Prussians are equipped with wings, but cannot fly, and are only capable of short-term gliding. Cockroaches in an apartment usually live in dark, cluttered places, crevices, under baseboards, etc.

After mating, the female cockroach places the fertilized eggs in a special cocoon called an ooteca. There, the cockroach larvae are located in 2 rows and 2 tiers. A capsule can contain up to 40 eggs at a time, and in some cases more. The time for embryo maturation depends on the conditions in which the uterus is located - the availability of food and water, as well as the temperature in the room. Typically, cockroaches hatch 2-4 weeks after laying eggs. The process may take several months if the room temperature is below 8-10 °C.

Before eggs can be laid, the female must be fertilized. It is enough for her to meet a cockroach once, and that will be enough for the rest of her life. Over the entire period, cockroaches lay eggs 6-9 times. For some time, females carry the ootheca on themselves and only after 8-10 days they shed it. The place where the cockroaches lay the capsule must be reliably protected from daylight and be warm enough. At a certain time, the larva is born. Red insects are characterized by an incomplete development cycle. To reach sexual maturity, the nymph (larva) must undergo several molting processes.

The little Prussian is completely similar to the adult one, only it does not have wings. Nymphs hatch without chitinous cover and therefore have a white color. Already at this age they move quickly. As a rule, insects do not move far from the hatching site. For some time it serves as a shelter for them. Adults are not responsible for hatching nymphs.

Black beetle

These insects are distributed throughout Europe. With the arrival of the Prussians, black cockroaches gave up their primacy, but continue to terrorize homes. The red cockroach happily feasts on the found egg of its black fellow. The lifespan of these insects is slightly more than 6 months. Unlike red ones, black ones almost immediately shed their ootheca. Therefore, some of the eggs die even before maturity.

A black pregnant cockroach produces much fewer offspring than a black cockroach. Usually it lays up to 30 eggs, and taking into account those eaten by red insects and the eggs lost during maturation, less than half of the larvae will hatch. Just like red ones, they are born without wings and have a white color, because... There is practically no chitin in the body. Only with age do their bodies acquire a black color with a characteristic shine.

Newly born and adult cockroaches differ little from each other. These insects rarely settle on the upper floors of the house. Typically, black cockroaches live in basements and on the lower floors of buildings, as well as in garbage disposals. They tolerate cold better, and at temperatures below -10 ° C they die. The cockroaches abandon the hatched young. From this moment on, the offspring are competitors in the territory of residence of the adults. In an abandoned capsule, cockroaches may be born after several months if the external conditions are not suitable for the maturation process.

Insects differ from each other not only in the color of their chitinous coating, but also in size. Black cockroaches are almost 3 times larger than their red counterparts and reach a length of almost 5 cm. However, this does not prevent red insects from displacing competitors from the territory they like. The damage caused by black cockroaches is no less than that caused by Prussians.

Fighting cockroaches

Knowing what domestic cockroaches look like makes it much easier to deal with them. To exterminate them, not only traditional mechanical destruction is used, but also a whole arsenal of chemicals - insecticides. If the residents decide to completely get rid of these aliens, then for this it is necessary to exterminate not only the adult individuals, but also the laid eggs, and for this you need to know what cockroach eggs look like.

You need to look not for small balls less than 0.5 mm in size, but for hard brown capsules with rows of laid eggs. The ootheca must be collected and destroyed. This is the only way to get rid of the unborn cockroach offspring, otherwise many dozens more nasty insects will hatch. In places where oothecae are located, as a rule, there are no adult individuals, since they are not present at hatching.

In order to completely get rid of harmful insects, and the labor spent on these activities is not in vain, it is necessary to kill the cockroach offspring. But to do this you need to know what small cockroaches look like. Usually these are fast running insects, slightly larger than a poppy seed. Most often they can be found in the area where the trash can is located and sources of moisture.

To more effectively get rid of cockroaches, the fight against them must be carried out in adjacent apartments, and ideally - in the entire house at the same time. Otherwise, these insects will migrate through ventilation and other openings. After properly carried out disinsection, many are surprised at the number of insects eradicated from the apartment.

It is necessary to maintain cleanliness in areas where pests may appear. First of all, this is the kitchen, bathroom, storage rooms. If, a few days after disinfestation, traces of harmful insects appear, do not despair. Work on the destruction of pests must be continued, since it will give a positive result only with the integrated use of all types of control.

In addition to cockroaches, other insects may appear in the apartment. During the warm season, a beetle can fly into almost every room through an open window. But how to distinguish a cockroach from a beetle? The most important difference between them is that a beetle that gets into an apartment can fly. He can always be recognized by the absence of a long mustache. They differ in color and body shape. It is not at all necessary to know what beetle larvae look like. All alien beetles live on the street and enter the apartment completely by accident. Therefore, the offspring of these insects are not born indoors, but go through completely different stages.

Many people think that cockroaches only cause harm, but this is not entirely correct. Scientists have calculated that if all cockroaches are destroyed, about 10 thousand species of living beings inhabiting our planet will become extinct.

Are nymphs and larvae of a cockroach the same thing?

Cockroach larvae are often called nymphs.

The fact is that in entomology the term “nymph” is used for immature stages of development of insects and some other arthropods, which are similar in appearance to adults and differ primarily in their inability to reproduce.

If you remember, for example, the differences between a larva and an adult butterfly, then you will agree that these differences are radical - the caterpillar is completely different from the adult butterfly, leads a completely different lifestyle, eats different food. Similarly, in beetles, mosquitoes, fleas, ants, bees and wasps, the larvae are completely different from the adults. All these groups of species belong to insects with the so-called complete transformation.

Butterfly and caterpillar of different types

Cockroaches are insects with incomplete transformation. Their larvae are very similar in appearance to adult individuals and differ from them only in size, underdeveloped reproductive system and, in some species, the absence of wings. For example, both adults and larvae of Madagascar cockroaches do not have wings.

Accordingly, cockroach larvae lead the same lifestyle as adults, eat the same food, and live in the same places. They are sensitive to the same agents that poison adult cockroaches and die at the same temperatures. It has been shown that all red and black cockroaches - both adults and larvae - die in a few hours at a light frost of 2-3 degrees, and in less than an hour at a temperature of +45 degrees. By the way, this can be used to fight them - you can heat the kitchen with a heat gun to 45-50 degrees, maintain this temperature for 2-3 hours, kill them all and be sure that the cockroaches died here along with the larvae.

Similarly, insects with incomplete transformation are bedbugs, crickets, grasshoppers, lice, and dragonflies. In all of them, the larvae are similar to adults and are called nymphs. Dragonflies also have the name naiad for this stage, since, unlike typical nymphs, they lead an underwater lifestyle that is radically different from the lifestyle of adults, although they are similar in appearance to adults.

For example, the photo below shows nymphs of black house cockroaches. One of them has just moulted and the coverings of her body are still soft and white.

It is these cockroaches that have just changed their coats that are called white, and they can sometimes be found in an apartment, although in general such encounters are rare - cockroaches are very vulnerable during molting and prefer to experience this process in very reliable shelters.

Features of reproduction

With the onset of puberty, cockroaches look for a pair to reproduce. They use pheromones to attract partners. After transferring the spermatophore, the male leaves the female. A special feature of insects is the ability of females to store their partner’s seed material. She can use it more than once in the future.

The short ovipositor of females is hidden in the abdomen. Here are the ducts of the glands that produce fluid for the construction of the capsule. After fertilization, the female cockroach with the egg appears thicker and her abdomen increases in size. To form an egg cocoon, there is a reproductive chamber inside the insect. It is filled with a foamy protein secretion, it quickly hardens and creates a capsule shell.

Information. Not everyone knows the name of the shell in which cockroach eggs are packaged. This is ootheca, a concept formed from two Greek words “egg” and “storage”.

Not knowing the structure of the capsule and surprised by its size, people wonder how many cockroaches hatch from one egg? Each egg contains one embryo, which as it develops turns into a larva. There are more than 10 of them under the chitinous shell. The chamber protects against low temperatures (-10°) and heat (55°). In it, the offspring survive the effects of insecticides, which are harmful to adults.

Information. The chitinous shell does not save the larvae from parasites; they destroy the walls and penetrate inside.

What do cockroach eggs look like?

It is rarely possible to examine the eggs of arthropod insects; they are reliably hidden from prying eyes. The shelters of the embryos are light, transparent, with an outer and inner shell. Gas exchange occurs through tiny pores in their walls. They are vulnerable to mechanical damage, temperature fluctuations, and bacterial infection. These dangers can be avoided by placing them behind the walls of a durable shell.

One by one, the eggs are laid in 2-4 even and dense rows. Each is lubricated with a sticky liquid and tightly attached to the others. After the process is completed, the secretion of the glands stops, but the secretions are enough to seal the cocoon. The ootheca does not completely fit into the abdomen of females; part of it is clearly visible.

The shape and size of the cocoon depends on the family and species of insects. It can be from 8 to 25 mm long. Various colors: yellow, pink, brown. The capsules are oblong, embossed, and have a characteristic scallop. At this point, the larvae gnaw through the wall of the shelter and escape to freedom. The grooves and bumps on the sides indicate the egg chambers. The average number of capsules produced by a female during her life is 5-9 pieces.

How many eggs a cockroach lays at a time depends on its species. The female German cockroach leaves 30-40 pieces in the capsule, the Egyptian cockroach 14-18, the black cockroach - up to 50. On average, the incubation period is 30-90 days. The rate of embryo maturation depends on the ambient temperature. The optimal temperature is 30° and moderate humidity. In cool conditions (15-18°), the development of embryos stops.

Where do cockroaches lay their eggs?

Insects try to protect their offspring from various dangers. They leave the ootheca with mature embryos in a secluded place. For some species, it is enough to hide the capsule from enemies; for others, climatic conditions are important. There must be suitable temperature and humidity level. In tropical species, the shell may dry out. In this case, the offspring dies or is born weakened.

Many species of tropical arthropods bear their young in their own bodies. They do not shed the capsule; it remains in the genital chamber. The hatched larvae emerge from the abdomen of the female. Such insects are called ovoviviparous. They have a more developed maternal instinct than their relatives. At first, the nymphs do not leave the female, seeking refuge on her back. The mother protects the offspring, hisses and drives away enemies.

Interesting fact. During prolonged gestation of the ootheca with its offspring, the female periodically pushes it outside for ventilation.

Black cockroaches leave the egg capsule unattended for the entire period of embryo maturation. Over a period of 40-50 days, predatory representatives of other species find it and destroy the defenseless offspring. Prussians act more carefully; their cocoon remains on the female’s body almost until the larvae hatch. This species is distinguished by its fertility and high survival rate of offspring. Females leave clutches in dark and secluded corners of the apartment:

  • ventilation duct;
  • space behind the gas stove and bulky furniture;
  • under the sink;
  • behind the baseboards;
  • near the trash can.

In the process of fighting parasites, it is important to find and destroy the offspring, otherwise the population will quickly restore its numbers.

Cockroach larvae

The process of gnawing through the ootheca takes from several minutes to an hour. The offspring are born with a soft cover, without the coloring characteristic of the species. At first they stay near the shell, which serves as their first food. Nymphs are white, transparent, the only dark spots on the body are black compound eyes. Their body structure resembles that of an imago. A distinctive feature is the absence of wings, sexual characteristics, and a small number of segments on the antennae.

Nymphs darken and become covered with a chitinous shell by the end of the first day of life. Their body size is 1-2 mm. At this age, young animals arrive from a month to 2-4 years. The rate at which they reach sexual maturity depends on the species of cockroaches and their lifespan. There are several other contributing factors:

  • temperature (high indicators accelerate development, low indicators slow down);
  • quantity and quality of food;
  • humidity, which helps with shedding.

Nymphs lead a secretive lifestyle and, in natural conditions, often burrow into the soil. The diet is similar to that of adults. During the growth process, the chitinous cover becomes small, it is periodically shed and replaced with a new one. This process is called molting. Before reaching adulthood, young animals experience it 5-12 times. After the premago stage, wings appear in flying species. The transition to the adult stage means the insects are ready to reproduce.

Interesting fact. The use of edema is also typical for praying mantises. They hang structures made from frozen secretions at the bottom of tree branches.

The attitude towards cockroaches and their eggs depends on the type of insect. Exotic species that do not harm people are popular. They are kept as pets. The attitude towards red Prussians is different. Synanthropic cosmopolitans infect and spoil food, wallpaper, books, and paper. They are mercilessly destroyed.

How many cockroaches will hatch from one egg?

In 30-75 days, a larva forms from the egg. The duration is determined by external factors. Optimal conditions for rapid development are high humidity and a temperature of about +30 °C. In a less favorable microclimate, the maturation of the nymph slows down, but does not stop. The embryos grow by absorbing nutrients. If the ootheca compartment becomes crowded, they gnaw through the membrane and come out.

If we talk about how many cockroaches will hatch from one egg, then it would be correct to say that there is only one. But this question in most cases refers to the number of embryos in one protective capsule.

Nymphs of red cockroaches are located in the lower and upper parts of the ooteca, 15-24 pieces each. Thus, from 30 to 48 larvae hatch from one egg. The American, Oriental and other larger species produce fewer offspring: a maximum of 16 nymphs hatch from one egg.

At the final stage of development, the nymphs independently open the egg shell and scatter in search of food and a secluded place.

Larval stage

A fertilized female carries eggs in a special capsule, which is located at the end of the body. Embryos develop internally up to a certain point. The female red cockroaches carry the ootheca with her almost until the birth of the larvae. Leaves them in a secluded place either 2 weeks before they are born, or in case of danger. The dense shell protects the eggs from temperature changes, poison, and dry air. Inside there are food reserves in sufficient quantity for the full development of the larvae.

Larval stage

Female black cockroaches leave an ootheca 2 weeks after the eggs are formed. They are not as caring mothers as their relatives. A baby cockroach is called a nymph. Until he grows up, he has a period of 1 month to a year. Depends on living conditions, temperature, availability of food, water. Under unfavorable conditions, the development process slows down.

The cockroach nymph is practically no different from the adult; it leads a similar lifestyle, except for mating. It becomes vulnerable during molting, when, after shedding its chitinous shell, its body becomes soft for several hours.

How to destroy cockroach eggs

The main difficulty in fighting cockroaches is not to detect and destroy all the adults, but to get rid of the eggs. They are reliably protected by ootheca, which is highly resistant to insecticides, water, chemical components, and pathogenic viruses. The shell easily allows air to pass through and withstands cold down to -11°C.

Knowing the physiological and biological characteristics of red cockroaches, you can choose the best option for destroying cockroach eggs. Our goal is to get rid of not only adult individuals, but also females with ooteca. To do this, you should adhere to the following recommendations:

  1. At the first stage, it is necessary to disinfest the premises. She must destroy all adults.
  2. If there were a lot of cockroaches in the house, then there is a high probability that several females managed to form a clutch of eggs. A few days after treatment, you may encounter annoying parasites again. To completely destroy the insects, you can re-disinfest the room or try using traditional methods.

One of the popular methods of destroying larvae is freezing. If previously the larvae were protected by the ooteca, then the hatched nymphs can no longer withstand negative factors. They are detrimentally affected by the same conditions as adults. Natural frost disinfestation can only be done in winter. To do this, you will need to leave the apartment for a day, opening all the windows and the balcony wide. Cockroaches die if the temperature drops to -3°C. In some cases, the procedure must be repeated 2 times.

Among folk methods, one can also note the use of aromatic plants, their oils and various concentrated decoctions. But such methods are more suitable as auxiliary or deterrent. They will help create a protective barrier and reduce the likelihood of cockroaches reappearing, but will not be effective in killing them.

It is easier and more effective to use chemicals. In special departments of the store you can find traps, gels, crayons, baits and other types of preparations. Please read the instructions carefully before use. When applying the chemical component, gloves and respiratory protection should be used. Particular attention should be paid to cracks, holes, the space under the baseboard, bathtub, sink, cabinets and other dark and hard-to-reach places.


How to get rid of cockroaches. Ways to control cockroaches

How many cockroaches can hatch from one egg?

What instills fear, a feeling of horror and disgust in the residents of apartments and houses are swarms of cockroaches, which in an unimaginable way appear in homes and are not easily exterminated. These pests are almost invisible, as they move very quickly and “attack” food when the lights are off.

Some people have been struggling with uninvited guests for years; even calling a special service does not help. To make your task of exterminating insects easier, it is worth understanding how many cockroaches can hatch from one egg and how they reproduce. They do not live long - up to four months, but, like any insects, they multiply quickly.

They are in a mature state for half of their life, so they need to constantly maintain their strength with the help of food, this can be not only food waste, but also furniture and fresh food. During its life, the nymph molts several times and increases in size. Cockroaches can exist in any conditions, but in unfavorable conditions their development occurs more slowly. The following are considered unfavorable:

  • low temperature;
  • lack of food;
  • regular exposure to chemicals.

In apartments and houses, the temperature is optimal for the development of larvae.

Female and male cockroaches: differences

Females pose the greatest danger to residents, as they are capable of laying eggs. It is easy to distinguish a female from a male, since they are larger in size than male individuals, and there are no characteristic growths on their body. Male cockroaches have more developed wings; if necessary, they can fly short distances.

What is ootheca in cockroaches?

The fertilized female cockroach carries it on herself for some time, before the birth of the larva. When she feels that the egg is ripe and ready to be laid, she dumps it in a dark, warm place. At first glance, ootheca is a very thin protection for the larva, but in reality it is a substance that does not allow chemicals to pass through and protects the baby cockroach from external influences. The shell is quite dense, so a person can hardly destroy it.

The appearance of the eggs depends on the type of cockroach:

  1. black cockroaches lay dark-colored oothecae, they exceed 10 mm in length and 5 mm in width;
  2. female Prussians carry light-colored eggs, which reach 1 cm in length, the transverse lines on the larva are practically invisible;
  3. an exotic Madagascar insect lays a large ootheca - 2.5 cm long and 6 mm wide, light brown in color.

What is considered an egg is appropriately called a storage facility for larvae, so several cockroaches can hatch from one ootheca at once. Experts believe that it is wrong to talk about how many cockroaches hatch from one egg, since the number depends on the type of insect. From the capsules of Madagascar cockroaches, 1-2 individuals hatch, while Prussians hatch up to 50 larvae from one egg!

Ootheca of the cockroach

The red ootheca is attached to the female’s body until the very moment of hatching - this is how the mother tries to protect her offspring and, in case of danger, take them away from a dangerous place.

The capsule is formed when the insect lays eggs. In the abdomen of a female individual there is a special substance that is used to process the eggs. When the ootheca maturation process comes to an end, this substance is produced for several more days in order to protect the egg from all sides. That is why it remains attached to the female’s body for a long time.

When fighting these insects, it is worth knowing how many days it takes for cockroaches to hatch from the egg - the larvae continue to remain in the capsule for 30-65 days. Their development occurs much faster, then the room is warm and humid. Many unscrupulous owners themselves contribute to the appearance of arthropods in the apartment and their reproduction. Even if the mother, carrying the egg on her abdomen, dies, the larvae continue to grow and develop.

During her life, a female can bear up to 9 capsules, which is 200 – 450 young cockroaches. Typically, these figures are much lower; the average arthropod gives birth to up to 100 “children”.

Maturation of larvae and hatching process

The method of maturation of embryos is somewhat reminiscent of the development of a human child - an ootheca with larvae is formed inside the body of a female cockroach, where the larvae receive nutrients and juices that enter the mother’s body.

See on the topic - Peculiarities of reproduction and life cycle of cockroaches

As they grow, they begin to move, and when the capsule is fully formed, it emerges from the female's abdomen and attaches to her body. When the offspring have grown to such a size that they do not even fit in the ooteca, they tear its walls and hatch. The birth process takes several minutes, in some cases, when the capsule is very strong, up to several hours.

Newborn cockroaches do not exceed a few millimeters in size and have a white, almost transparent color that darkens as nutrients enter the body.

Some people mistakenly believe that cockroaches are viviparous creatures; in fact, they are most often called oviparous (black cockroaches) or ovoviviparous (red and Madagascar cockroaches). The process of hatching is called hatching.

Caring for offspring

Cockroaches show almost no care for their children; biologists say that the larvae hatched from the ooteca stay near the mother for only a few hours, hide under her abdomen and do not contact other individuals. After 2-3 hours they get used to it and scatter to convenient shelters and grow separately from their mother.

Even tropical species of insects do not worry too much about their larvae - for only a day, small cockroaches are under the protection of their mother, who can make frightening sounds, lunge towards the enemy and even attack, and this is where maternal care ends.

Where to find cockroach eggs in an apartment?

Most often, the female lays the ootheca in a quiet, dry, dark place where other individuals and apartment owners would not find it. In nature, masonry can be found under stones, in the bark of trees, under a layer of humus, in the ground, under fallen trees, etc. There are also many places in the house where cockroaches can lay eggs in the following places:

  • in furniture;
  • in the cracks of the floor covering;
  • between the sink and the bedside table;
  • under the baseboard;
  • in ventilation;
  • in the pantry, etc.

Where do insects live in an apartment?

Often, when cleaning, you can find an empty shell, which you can safely throw away, but if you doubt whether there is something inside, you can try to crush it - in this case, it is better to be safe.

Important: destroying several eggs will not lead to the desired result, since Prussians carry filled eggs on themselves, therefore, it is necessary to destroy living individuals, and then the eggs from which larvae can hatch.

How to get rid of cockroaches?

Each time, cockroaches become more and more resistant to chemicals. Experts advise not to fight red cockroaches on your own, but to entrust this task to exterminators, especially if you have been unable to deal with them for a long time.

When fighting pests yourself, it is necessary to choose a substance that would affect adults and larvae. The ootheca film is resistant to chemical influences, so the wrong choice of drug will make all efforts pointless. It is also recommended to repeat pest control every week to prevent new insects from hatching.

See on the topic - The most effective remedy for cockroaches - a review of popular poisons


Cockroaches are one of the most unpleasant “guests” in any human home, so you need to know the peculiarities of their behavior and where they lay eggs in order to deal with the problem as soon as possible and prevent a mass settlement of pests.

Video: The birth of cockroaches

Where do females hide their eggs?

In order to effectively combat pests, a person should know where, most likely, the female will leave her clutch. She mainly chooses secluded, inaccessible places where her offspring will not be disturbed.

These are:

  • Gaps between furniture.
  • The space under the bedside tables.
  • Along or behind baseboards.
  • In the ventilation ducts.
  • On shelves in the pantry.
  • Under the sink.

Knowing the location of the eggs, you can better fight cockroaches. If even a hint of unwanted guests appears, it is worth taking measures to eliminate them. Fortunately, at the moment there are quite a lot of different ways to destroy this type of insect.

And this is what the process of “birthing” cockroaches into the world looks like:

How do cockroaches hatch from eggs?

Cockroach embryos are constantly moving inside the egg, absorbing embryonic fluid and nutrients. When they reach such a size that they no longer fit in the egg, they tear its shell and begin to gnaw through the ridge of the ootheca.

In those species whose females lay capsules, after the larvae emerge from the ootheca, a strong outer shell remains. In those whose oedema develops inside the female’s body, its shell is very soft, and by the time the larvae are born, it completely bursts, and the offspring leaves the mother’s body in a free state, after which the female gets rid of the remains of the capsule.

In the video at the end of the article you can see how cockroaches are “born”.

In large species, up to 60 young larvae can hatch at a time, but in general the normal number of young individuals is 25-35. The same number of young cockroaches hatch from the ooteca of common domestic species.

Next in the photo you can see what the ootheca of a black cockroach and the newborn larvae around it look like:

It is also useful to read: Can cockroaches bite humans?

And one more thing: Cockroaches in an apartment are not just disgusting, but also dangerous to health. And they are dangerous not only because of the infections they carry...

As a rule, the entire process of “birth” of cockroaches lasts from several minutes to several hours. After hatching, the larvae are usually very light, almost white, but then, as the chitinous cover hardens, they darken.

Are there viviparous cockroaches?

Cockroaches are not viviparous creatures. The terms “ovoviviparous” and “oviparous” are used for these insects.

If the embryo develops in an egg and does not receive nutrition from the mother’s body during development, but is still in the female’s body, then this method of reproduction is called ovoviviparity.

Those cockroaches whose females simply leave their ootheca to the mercy of fate are typical oviparous insects. The same species in which the eggs develop inside the female’s body, and the nymphs hatch simultaneously with their exit from the brood chamber, are ovoviviparous.

Therefore, the terms “pregnant cockroach” and “viviparous cockroaches” are not entirely correct - only viviparous animals are truly pregnant.

From a scientific point of view, the expression “cockroaches give birth” is not entirely correct. This process is not called childbirth, but birth.

In the photo there is a female Madagascar cockroach with nymphs emerging from her abdomen:

Cockroach eggs and egg capsules (oothecae)

The eggs of cockroaches of almost all species, while still in the female’s body, are “packed” into a special shell, which quickly hardens in air and forms a characteristic capsule.

Such a capsule is called an ooteca (from the Greek “oo” - egg, “tekos” - storage) and serves to protect vulnerable eggs from exposure to adverse environmental factors. It is this that ensures the high survival rate of cockroaches both in nature and in human habitation.

On a note

Ootheca is also present in other species of invertebrates: in addition to cockroaches, it is, for example, characteristic of mantises and mollusks.

The ootheca of cockroaches can have different shapes, sizes and colors, depending on the type of insect. For example:

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  • Article: Where do cockroaches usually hide in an apartment and can they crawl from the sewer?
  • The ootheca of black cockroaches is dark brown in color, about 12 mm long, about 6 mm wide, and has a clearly visible ridge on the surface;
  • The red geranium ootheca is red, approximately 8 mm in length, with clearly visible transverse constrictions;
  • In the Madagascar cockroach, the ootheca is very elongated in length, has a light yellow color, and measures about 25x4 mm.

The photo below shows the appearance of the Prussian ootheca:

And the following photo clearly shows what the ootheca of the Madagascar hissing cockroach looks like:

Despite the relatively high strength and hardness of the wall, the ootheca allows the developing embryos to breathe, reminiscent of the shell of a bird's egg.

How many eggs are in each ootheca is determined by the type of cockroach. So, for example, in red cockroaches, each capsule contains an average of 20-30 eggs, rarely up to 50. They lie very close to each other in 4 even rows - two in height and two in width.

The eggs themselves are tiny - about 1 mm long and a few tenths of a millimeter wide. They are light yellow or white, translucent, and through their shell you can even see the embryo with a magnifying glass.

The photo below shows what cockroach eggs look like inside the ooteca:

Ootheca is formed during the period of cockroach laying eggs. In a special chamber in the female’s abdomen, a large amount of sticky secretion is secreted, into which the eggs coming from a special organ are literally dipped.

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When the process of egg formation ends, the secretion is released for some more time, closing the ootheca from the inside. At this point, in most species of cockroaches, the capsule extends a significant part of its length from the body of the “pregnant” female and remains attached to the end of the abdomen for some time.

In this capsule, cockroach eggs develop from 30 to 75 days. Development occurs most rapidly in conditions of high temperature (above 30°C) and humidity, but when the temperature drops below 15°C, their development stops, resuming with the return of heat. This allows the population to survive the cold.

This is interesting

An adult Prussian locust dies at temperatures below -5°C and above +45°C, while its ootheca normally tolerates short-term cooling to -10°C and overheating to +55°C. In addition, insecticides have little effect on the ootheca (and many of them have practically no effect). For example, in Prussians, whose females carry a capsule at the end of the abdomen until the end of larval development, if the mother dies from exposure to an insecticide, then the eggs in the ooteca continue to develop, and later young nymphs still hatch from them.

Different species care for their eggs and their protective capsule differently.

For example, female black cockroaches lay edema, and thus leave their eggs to fend for themselves within 3-4 days after the ootheca is fully formed. Then the capsule develops for almost two more months without any protection. If predators or parasites find such an ootheca at this time, they will destroy the eggs. This is largely why red cockroaches are replacing black cockroaches everywhere - they simply eat their eggs.

The Prussians themselves, as well as various exotic species, for example, ash and Madagascar cockroaches, show some care for their offspring. Female red cockroaches carry an ootheca at the end of their abdomen until the larvae hatch, and they can at least carry it away from danger.

And in the same Madagascars, ootheca develops in the body cavity, and only a few times a day the “pregnant” cockroach exposes it outside for ventilation. The larvae also hatch inside the mother's body, but almost at the same moment they leave the brood chamber. The observer of this process gets the feeling that the cockroach is giving birth (that it is supposedly viviparous), although in fact all cockroaches without exception lay eggs, it’s just that in some species the development of eggs to the larval stage occurs inside the mother’s abdomen.

The photos below show how a female Madagascar hissing cockroach “gives birth”:

Depending on the type of cockroach, the number of “pregnancies” and oothecas carried by the female throughout her life varies. Thus, a female German can produce up to 9 capsules during her life (of which more than 250 larvae are “born” in total), although usually the “average” female produces about 3-4 ootheca during her life.

At the same time, the ootheca is clearly visible in the female German wolf, but in large tropical species, in which the capsule is hidden in the body, it may not be clear that the female is in an interesting position.

Where and how often are egg capsules laid?

In order to get rid of parasites forever, it is recommended to know where the eggs of red cockroaches are especially often located.

Since sufficiently comfortable conditions are necessary for the development of masonry, cockroaches often lay masonry in such secluded corners of the apartment as: the joints of wallpaper, the space under them, as well as tiles, cracks between floorboards, ventilation holes, the space under the bathroom, kitchen furniture.

In order to prevent the spread of insects, it is recommended to thoroughly vacuum the places where a cockroach can lay eggs; this measure, as well as maintaining cleanliness of the home, will help to eliminate the appearance of parasite colonies as much as possible.

Possible locations of the ootheca

The presence of cockroaches in apartment buildings has remained a problem for many years. These insects have become so adapted to human habitation that they successfully find safe places to breed:

  • in ventilation compartments;
  • in the cracks behind the baseboard;
  • in the cracks present between parts of furniture;
  • under washbasins, sinks, cabinets, beds;
  • in utility rooms and storage rooms.

When cleaning an apartment, you come across dry shells of insect capsules. They must be taken out of the apartment to the trash can. If an ootheca of cockroaches is found, then it must be destroyed - there is a risk of the birth of a large number of pests.

Fighting cockroach populations on your own is a thankless task, because it is ineffective. The best way to get rid of it is to call a pest control service.

Pest Control

Having considered all the intricacies of the maturation and development of these unpleasant insects, we can determine the rules for combating them. To minimize the risks of the formation and reproduction of colonies, it is necessary to narrow the number of potential areas where cockroaches live. The ideal option would be to renovate the apartment - fill holes in the floor and seal cracks in the walls, re-glue the wallpaper, cover the ventilation compartments with a fine mesh.

You need to watch the bread crumbs very carefully. The slightest amount of them in a room will provide energy to an insect colony for almost a month. It’s not worth mentioning about the accumulation of garbage in the apartment. It is important to isolate pests from access to water, and it is better to protect yourself from guests from neighbors with special poisonous traps.

Ventilation of rooms is necessary daily. But in winter, sub-zero temperatures are detrimental to eggs. Hot steam treatment helps, but this can only be done by specialists. You should also remember that one-time cleaning of the room will not give results - several treatments are required.

Cockroach larvae as the main carriers of dirt and infections into the apartment

It is believed that the main danger posed by cockroaches is the introduction of bacteria and fungal spores from places where garbage accumulates into living quarters. That is, a cockroach that was swarming in the garbage chute in the evening or running along a sewer pipe, after a couple of hours can already crawl into the apartment and run over a piece of bread with the same paws. Which you will eat tomorrow or give to your child. And that's how it really is. How dangerous this is is not clearly known - no one has calculated what proportion of infectious diseases is associated with infection brought specifically by cockroaches. That is, this danger is assumed, although it certainly exists.

By the way…

Cockroach larvae, like adults, do not bite humans. There are reports of exceptions to this rule, but they are not confirmed and cannot be considered the norm. Therefore, if people get bites in an apartment with cockroaches, this means that blood-sucking insects, bedbugs or fleas, live here along with the cockroaches.

And it is from larvae that this danger is most pressing. There are just a lot of them. Each female produces about 30 larvae every 1-2 months. In the apartment they have practically no dangers, most of them survive safely, and during their life there are several hundred larvae for each adult female. That is, the bulk of cockroaches in the apartment are larvae. And starting from the second or third instar, these are fast running larvae.

Consequently, it is they, as the most numerous insects, that migrate in the greatest numbers from dirty locations into the apartment and it is they who bring here the largest amount of different dirt and various infectious agents.

How to prevent mass reproduction

Chemical treatment is perhaps the most reliable and fastest way to get rid of these pests in the house. In this case, the insects die almost immediately, but this does not in any way affect the larvae, which at this moment are still in the ooteca. After some time, they will quietly hatch, and the problem with cockroaches will arise again.

To avoid this, after the first disinfestation, this activity should be repeated after 2 or 3 weeks in order to “finish off” the hatched young.

In addition, it is important to maintain cleanliness in the house: do not leave food open, take out the garbage on time, monitor the humidity in the apartment, and then the chances of unwanted neighbors will become much less.

Cockroaches can release gases, and after death they continue to release gases for another 18 hours, so cockroaches can be called the stinkiest insects in the world, and not bedbugs, as many believe.

How many eggs can there be in the edema?

The number of eggs hatched in each ootheca does not always correspond to the number of eggs laid inside it. These insects are able to regulate the number of offspring depending on the availability of food and favorable living conditions.

This is what eggs look like inside the ooteca

Types of cockroaches differ in the number of eggs in each swelling and the way they are packaged:

  1. Red cockroaches - from 25 to 50 eggs, 12 clutches during life;
  2. Black cockroaches – 12-18 eggs, 22 clutches per life;
  3. American periplanets - on average 19 eggs, 10-15 ootheca during life;
  4. Madagascar cockroach – 20-50 eggs per ootheca, 6 tubs throughout life.

Female cockroaches in unfavorable conditions can shed ootheca earlier than expected. In this case, the larvae inside them do not hatch, and if they do hatch, they are underdeveloped or do not survive. This is due to exposure to unfavorable environmental factors - too dry weather, lack of food, treatment of the premises with insecticidal preparations, high levels of radiation.

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