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How Do Cockroaches Reproduce?

Last Updated: 28.05.20

 

Cockroaches are hazardous pests that do not only look unpleasant but can pose a real hazard to you, your family, and your pet’s health. If you want to know more about efficient remedies, reading reviews of cockroach killers can be a good way to start your battle against these invaders. After mating, females can lay up to 8 oothecae during their lifetimes, which means about 300 to 400 eggs that will turn into adults in a few months.

 

What do you know about cockroaches?

Cockroaches are insects, and they are part of the Blattodea order, which is the same one that includes termites, as well. Out of 4,600 species, 30 are associated with human habitats. Only four species are well-known as pests. 

These insects are ancient, dating back at least about 320 million years ago, in the Carboniferous period. However, those ancestors lacked the internal ovipositors of contemporary roaches. These creatures are generalized insects that do not have special adaptations such as the sucking mouthparts of aphids and other similar bugs. 

They possess chewing mouthparts and are some of the most primitive among living insects. Roaches are common and resistant insects that can tolerate many types of environments from tropical heat to arctic cold.  

The tropical species are often bigger than temperate ones. There are species, like the gregarious German cockroach, that have a very elaborate social structure which involves social dependence, common shelter, information transfer, and even kin recognition. 

Roaches have made their presence in the human culture since classical antiquity. They are commonly described as dirty pests, even if most species are quite harmless and live in a vast range of environments around the world.

 

 

What does a cockroach look like?

Most cockroach species are around the size of a thumbnail, but there are a few bigger ones. The heaviest cockroach in the world is the giant burrowing cockroach, native to Australia, which can reach 3.5 inches and weigh over 1.1 oz. In the Central American region, there is the giant cockroach, Blaberus giganteus, which is comparable in size with the first one. 

The longest species is the Megaloblatta longipennis, and it can reach 3.8 inches in length and 1.8 inches across. The longest wingspan of 7.3 inches is achieved by the Megaloblatta blaberoides species. The most common species have a relatively small head and a broad, flattened body, and most of them have reddish-brown or dark brown colors. 

Also, they have two ocelli, large compound eyes, and long and flexible antennae. On the underside of their head, they have the mouthparts which include salivary glands, chewing mandibles, as well as several taste and touch receptors.

The body of a cockroach is divided into a chest of three segments as well as a ten-segmented abdomen. The exterior has a hard exoskeleton that contains calcium carbonate and has the role of protecting the inner organs and also provides an attachment to the muscles. Furthermore, the body is coated with wax which repels water. 

The wings are attached to the second and third thoracic segments. The first pair of wings is called the tegmina, and they are hard and protective. They lie as a shield on the hind wings which are membranous and are used for flying. Both pairs of wings are equipped with longitudinal veins as well as several cross-veins.

These insects have three pairs of legs which are very sturdy, and each has large coxae and five claws. Every pair is attached to one of the three thoracic segments. Since the front legs are the shortest and the rear ones the longest, they provide the cockroach the main propulsive power when running. 

In the past, the spines on the legs were thought to be sensory, but recent studies revealed that they actually help the insects crawl on difficult terrain. These structures have also been used as an inspiration for robotic legs.

As previously mentioned, the abdomen of a cockroach is divided into ten segments and each has a pair of spiracles for respiration. The tenth segment has a pair of cerci, a pair of anal styles, the external genitalia, and the anus. 

Male roaches have an aedeagus through which they can secrete sperm when copulating, while females have a spermatheca in which they store sperm, and an ovipositor used to lay the ootheca. This brings us to the main topic of our article, and that is the process through which cockroaches reproduce. 

 

How do cockroaches reproduce?

In order to attract mates, these insects use pheromones. The male cockroaches practice courtship rituals like posturing and stridulation. Similar to many other insects, these ones mate facing away from each other, keeping their genitalia in contact. Thus, copulation can be prolonged. 

Only a few species are known to be parthenogenetic, which means that they can reproduce without the need of mates. Females can sometimes be observed carrying egg cases on the end of their abdomens. For example, the German cockroach can hold about 30 to 40 long and thin eggs in a case that is called an ootheca. 

Before hatching, she drops the capsule. In very rare cases, live births may occur. The egg capsule can take over five hours to lay and it is bright white initially. Due to the combined pressure of the hatchlings gulping air, the eggs finally hatch. Baby cockroaches are first bright white nymphs, and then they continue inflating themselves with air. 

Within a few hours, they become harder and darker. The development from eggs to adults can take three to four months. These insects usually live up to a year, in which time the female can produce up to eight oothecae in a lifetime. 

This means that, if the conditions are favorable, she can give birth anywhere from 300 to 400 offspring. Some species can produce even more eggs. There are even cases where the female only needs to be impregnated once in order for her to be able to lay eggs for her entire life. 

Usually, the female attaches the ootheca to a substrate, places it into a fit protective crevice, or carries it until just before the eggs begin to hatch. The ovoviviparous species keep the eggs inside their bodies, with or without an ootheca, up until they hatch. 

The Diploptera species are known to be viviparous, which means that they produce living younglings instead of eggs, similar to mammals. These insects have an incomplete metamorphosis. This means that the nymphs are very similar to adults, the exception being undeveloped genitalia and wings. 

The development is a slow process that can usually take a few months, but, in some cases, even a whole year. Some adults are also long-lived and can survive up to four years in the laboratory, as studies reveal. 

 

 

Large families

Cockroaches are social beings. If you see one cockroach, you should know that there are usually many more lurking around. If that happens in your home, you have a serious problem on your hands. A considerable number of species can be either gregarious or inclined to aggregate. 

A slightly smaller number show parental care. If earlier observations lead to the belief that these insects aggregate because they are reaching to environmental cues, recent studies reveal that pheromones are involved in these behaviors. There are species that secrete these in their feces with gut microbial symbionts. Others use the glands that are located on their mandibles. 

The pheromones that are produced by the cuticle may allow these insects to differentiate between distinct populations of cockroaches by odor. 

 

Cockroaches are pests

No matter how fascinating cockroaches might be for the insects’ fans, the fact of the matter is that these creatures are known pests. There are only a few harmful species, but that is already enough. 

Roaches pose a serious health risk, and they often invade homes in search of food, water, and shelter. Unfortunately, human habitats are also some of the roaches’ favorite places to hide as well. They are dirty on the outside because they crawl in many unsanitary places like sewers, as well as on the inside, as they carry and transmit multiple bacteria and parasites. 

They both regurgitate and defecate the food they eat, so you can imagine what would happen if they got to your food. Moreover, they can infect your belongings by crawling over them and leaving a lot of feces behind. 

Besides the fact that they transmit diseases, they worsen the condition of people with allergies.  However, the biggest problem is that they stay in large numbers. As mentioned earlier, if you see one in your home, drop everything and deal with this issue immediately.

 

 

 

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