Though cockroaches would have you believe they are immortal and indestructible, they do have a complete life cycle. Cockroaches undergo two life stages—egg and nymph—before entering adulthood. Understanding their life cycle can help you identify and eliminate an infestation. Check out the life cycle of four of the most common cockroaches found in the U.S. so that you’ll know what you’re up against.
The egg is the first stage in the cockroach life cycle. Cockroaches produce egg cases, called oothecae, which hold multiple eggs. These cases are a protein substance before hardening into a tough shell. They vary in size and color depending on the cockroach species. Oothecae act as a protective barrier and are extremely resilient.
American cockroaches produce dark brown cases that can grow up to 8mm. These cases contain about 15 eggs and females can lay between 6-14 cases in their life. They deposit their eggs in cracks and crevices a few days after being produced.
German cockroach egg cases are brown and about 7mm in length. Some cases can contain up to 35 eggs. These cockroaches carry their egg cases with them until they are ready to hatch.
Oriental cockroaches produce dark reddish-brown cases. They range in size from 8-10mm. They typically contain 16 eggs. These cockroaches only carry their oothecae for about a day before depositing it.
Brown-banded cockroach egg cases are light reddish-brown and about 1/4ʺ in length. Each case can contain up to 18 eggs. After about 1 ½ days, these cockroaches deposit their eggs on ceilings, walls, or underneath furniture.
When eggs hatch, the cockroach enters the nymph stage. Cockroach nymphs are white when they hatch. After a few hours, they begin to darken and their soft exterior hardens and forms a tough exoskeleton. After darkening, they look like smaller adult cockroaches. Cockroach nymphs go through several molts before fully developing into adults. The length of the nymph stage and their appearance varies for each cockroach species.
American cockroach nymphs emerge after 24-38 days in an egg. They darken to a grayish-brown color before developing a red hue. Nymphs don’t have wings and are smaller than adults measuring about 1/4ʺ. These cockroach nymphs will molt between 10-13 times before reaching adulthood. They take between 65-400 days to develop, which is longer than other species.
German cockroach nymphs are very small, about 3 mm when they first hatch. Over time, they darken to brown or black and are actually darker than adults. They have a tan stripe on their back. Like other cockroach nymphs, they are wingless. These cockroaches molt 6-7 times before reaching the adult stage. They are known to complete their development within 100 days.
Oriental cockroach nymphs appear similar to adults. They have a reddish-brown body and are about 6mm in length. They have light and dark bands on their body. Female nymphs are broader than male nymphs. They molt several times and development times vary. Some nymphs will molt into adults in less than 200 days while others can take up to 600 days.
Brown-banded cockroach nymphs begin this stage at about 3mm in length. They are dark brown and have two yellow bands on their abdomen. Throughout this stage, they will undergo 6-8 molts before becoming adults. The nymph stage is dependent on environmental factors and can range from 90-300 days.
By the time cockroaches reach adulthood, they are fully developed. Like during the other life stages, cockroaches will vary in size and color. They also have different habits and hiding places. The length of their life depends on the conditions of their environment and temperatures.
American cockroaches are one of the largest species of cockroaches you could encounter. They can reach 3ʺ in length. They have a reddish-brown body and a yellow band behind their head. Adults have developed wings and females are able to reproduce. American cockroaches prefer to live outdoors, but they will travel inside for food. They are often found in basements and kitchens. These cockroaches can live for about a year.
Adult German cockroaches are smaller than other species at about 1/2ʺ in length. They have a light brown body with two dark lines on their back. Though they have wings, they are rarely seen flying. These cockroaches like to live inside where it’s warm and humid. They are able to reproduce very quickly. Adult German cockroaches can live for about 200 days.
Oriental cockroaches have a shiny, dark reddish-brown to black body as an adult. Males can reach 25mm in length while females grow up to 32mm. Adult male oriental cockroaches grow wings that cover part of their body. Females do not develop wings. These cockroaches usually spend time outside, but come indoors searching for a cool, damp place to hide. Adult males have a lifespan of 110-160 days. Females usually live between 35-180 days.
Brown-banded cockroaches have light brown bands on their wings and body. They grow to be about 1/2ʺ in length and males are slightly longer than females. These cockroaches like areas that are warm and dry. They are often found in furniture and higher locations including ceilings and upper cabinets. They can live anywhere from 130-315 days.
Treating a cockroach infestation can be difficult because of how quickly they multiply. Having a plan is important to eliminate an infestation. When cockroaches are still in egg cases, they are very protected. The best thing you can do is vacuum frequently, making sure to cover as much ground as possible. This will remove the egg cases from your home. Vacuuming can also help with nymphs and adults. Make sure to place the contents in a sealed bag and then in a closed trash can outside. Since eggs are hard to eliminate, focusing treatment on nymphs and adults is key. Using a spray, like Maggie’s Farm Simply Effective Ant & Roach Killer, can help to eliminate the cockroaches you see. It will kill on contact and provide you with residual repellency. You’ll also want to use a bait like Maggie’s Farm Simply Effective Roach Killer Gel Bait. This is designed to allow cockroaches to consume the bait and return to the nest. Then, other cockroaches can consume its droppings, or the cockroach after it dies. This exposes them to the bait and helps to eliminate the source of an infestation. It’s important to remember that multiple treatments may be needed to eliminate newly hatched cockroaches. Eliminating the nymphs and adults will prevent the production of more eggs.
Understanding the cockroach life cycle will help you properly treat an infestation. Focusing on removing the source of the infestation, will help you eliminate the entire infestation. If you’re dealing with a bug problem, we want to help! Check out our Maggie’s Farm Simply Effective Pest Control products.