What is a Cockroach Nymph? A Quick Guide for Curious Minds

Cockroach nymphs are fascinating creatures that offer insight into the life cycle of these common pests. Nymphs are the stage between eggs and adults in a cockroach’s development, playing a vital role in their survival and reproduction. Understanding what a nymph is and its characteristics can help you better comprehend the life of a cockroach.

To identify a cockroach nymph, you should look for a few key features. These young insects may have a different color and appearance than their adult counterparts, often taking on a more uniform and lighter shade. Nymphs are smaller in size and have not yet developed wings, which set them apart from adult cockroaches.

As a nymph progresses through its life, it goes through several molts, shedding its exoskeleton to grow larger. This period is crucial for their development into adulthood, eventually allowing them to reproduce and continue the cockroach life cycle. By learning about cockroach nymphs, you can gain a greater understanding of these insects and their place in the world around you.

Understanding Cockroach Nymphs

Cockroach nymphs are the young, immature form of these insects. They undergo a series of molts, shedding their exoskeleton to grow and develop into adulthood. A cockroach starts its life as an egg inside an ootheca, a protective capsule. Once hatched, you’ll find that the nymph is generally smaller and wingless compared to the adult counterpart.

During their development, cockroach nymphs molt several times, shedding their exoskeleton. Each time they do, their size increases, and their appearance evolves. It’s essential to recognize that the number of molts a nymph goes through depends on the specific cockroach species.

Some of the common features of cockroach nymphs include:

• Wingless and smaller than adult cockroaches
• Brown or dark color, depending on the species
• Faster movements to find food and shelter

As nymphs grow and molt, they become more similar to adult cockroaches. However, if you’re comparing nymphs and adults, there are a few key differences:

In summary, understanding cockroach nymphs is crucial in identifying their presence and successfully controlling infestations. Keep an eye out for small, wingless insects that move fast and molt periodically. Paying attention to these details will help you quickly recognize and deal with any unwantedroach infestations in your surroundings.

Life Cycle of a Cockroach

From Eggs to Nymphs

Cockroaches have a three-stage life cycle: egg, nymph, and adult. Mature females produce 12 to 36 eggs at a time, depending on the species. The eggs are protected in a bean-shaped capsule called an ootheca. The number of oothecae females produce depends on the species. After a while, the eggs within the ootheca hatch into young cockroaches, which are known as nymphs.

Nymph to Adult Transformation

As nymphs grow, they go through a process called incomplete metamorphosis. This means they do not have a pupal stage and instead undergo a series of molts as they develop. Nymphs typically molt several times before reaching adulthood, and each molt makes them slightly bigger and more developed. They share some physical similarities with adult cockroaches, such as the presence of legs and antennae.

Some key features of nymph cockroaches:

• Smaller than adult cockroaches
• Lighter in color than adults
• Lack fully developed wings
• Grow through a series of molts

Adult Cockroaches’ Characteristics

Once a nymph molts for the final time, it becomes a fully functional, sexually active adult cockroach. Adult cockroaches typically measure 1-1/2 to 3 inches in length, have three pairs of legs, and two pairs of wings. They also have a long pair of antennae on their heads and are usually brown in color. Adult cockroaches are responsible for reproducing and laying eggs to continue the life cycle.

Some characteristics of adult cockroaches:

• Larger in size compared to nymphs
• Darker in color than nymphs
• Possess fully developed wings
• Capable of reproduction

Different Kinds of Cockroach Nymphs

German Cockroach Nymphs

German cockroach nymphs are the babies of the Blattella germanica species. They are usually small, wingless, and darker in color than adults. Here’s what you need to know:

• Start life in dark-colored egg cases with up to 50 eggs
• Develop into adults in around 1-2 months

These nymphs are fast-growing and can create large infestations if not controlled.

American Cockroach Nymphs

Moving on to the American cockroach, or Periplaneta americana, nymphs are also wingless and vary in color from light to dark brown. They have a few key differences from their German counterparts:

• Hatch from bean-shaped egg capsules with roughly 16 eggs
• Develop into adults in 6-12 months

These nymphs may be found in any room of the house. They are larger and take longer to develop compared to German cockroach nymphs.

Oriental Cockroach Nymph

Finally, there are the Oriental cockroach, or Blatta orientalis, nymphs, which are sometimes called “waterbugs.” These nymphs are unique in a few ways:

• Females deposit egg cases in sheltered places
• Development can range from 300-800 days, making them slower to mature

Oriental cockroach nymphs are larger than German and American nymphs and often found in damp areas.

Comparison Table

By knowing these characteristics, you can distinguish between different cockroach nymph species and target your pest control efforts accordingly.

Signs of Cockroach Infestation

Cockroach infestations can be an unwelcome sight in your home. To identify if you have a problem, look for the following signs:

• Droppings: Cockroaches leave behind small, dark droppings that resemble coffee grounds or black pepper. These can often be found in areas where they’ve been feeding or hiding, like kitchen cabinets or crevices.

• Feces: Similar to droppings, cockroach feces are another indication of an infestation. They may be found in the same areas as droppings or in dark, secluded corners.

• Aggregation: Cockroaches tend to gather together in groups, particularly nymphs as they are growing. Keep an eye out for clusters of cockroaches in dark, damp spaces.

• Crevices: Roaches are excellent at hiding, and they seek out narrow cracks and crevices to make their home. Inspect behind appliances and furniture, as well as the spaces underneath cabinets and countertops.

To deal with a cockroach infestation, consider taking steps like hiring a pest control professional, cleaning up food debris, sealing off potential entry points, and using roach bait or traps. By staying vigilant for these signs and acting quickly, you can help minimize the impact of an infestation in your home.

Controlling Cockroach Infestation

Prevention Measures

To keep cockroaches at bay, maintain a clean and sanitary environment. Remember, a cockroach infestation thrives in filth and unsanitary conditions. Ensure that your living space is clutter-free by:

• Regularly cleaning up food crumbs and spills
• Sealing food in tightly closed containers
• Emptying trash cans frequently
• Fixing any water leaks to eliminate unnecessary sources of water

Cockroach Traps and Insecticides

In addition to sanitation efforts, consider using traps and insecticides to manage the cockroach population. Some popular methods include:

• Sticky traps: These traps can help you monitor and catch nymphs and adult cockroaches.
• Bait stations: Replace them regularly to ensure continued effectiveness.
• Residual insecticides: Application of these chemicals can help target hiding spots and high-traffic areas where cockroaches might frequent.

However, bear in mind that insecticides should be used with caution, as they can be harmful to humans and pets. Follow the product’s instructions carefully.

Hiring a Professional Exterminator

If the infestation is severe or you’re unable to control it on your own, consider hiring a professional exterminator. They have the expertise and resources to effectively eliminate cockroach infestations. Some advantages of hiring an exterminator include:

• Customized treatment plans for your specific situation
• Access to powerful pesticides not available to the public
• Follow-up visits to ensure complete eradication of the infestation

Remember, controlling a cockroach infestation not only involves getting rid of the current problem but also taking preventive measures to minimize future infestations. By combining sanitation efforts, traps, insecticides, and, if necessary, professional help, you can reclaim your home from these unwanted pests.

Cockroaches and Public Health

Cockroaches can be a threat to public health as they consume our food and contaminate indoor environments. They are known to carry food-borne pathogens such as Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Salmonella enterica, among others. These pathogens can cause a variety of illnesses, some of which can be serious.

One major concern related to cockroaches is their potential to trigger asthma attacks. Their body parts, feces, and saliva can be allergens to sensitive individuals. Regular exposure to these allergens can worsen asthma symptoms and even cause asthma in some cases.

To protect your health, it’s crucial to prevent and control cockroach infestations in your home. Here are some tips to consider:

• Eliminate sources of food, water, and shelter for cockroaches.
• Repair leaky pipes and fix other plumbing issues.
• Regularly clean your living spaces, including kitchen appliances, floors, and countertops.
• Seal any cracks or crevices in walls, windows, and doors.
• Use cockroach traps, baits, or insecticides if needed, but always follow label instructions.

By following these steps, you can reduce the risk of cockroach-related health issues and maintain a safer living environment for you and your family.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Cockroach Nymph

what is this bug?
Dear Whats That Bug:
Hello. I love your site. Considering I don’t know what this little guy is I let him leave unharmed. I have seen a couple of these bugs around my bathroom they crawl under the cracks of the sink and inside the bathtub. I’m not sure if this has anything to do with their nature but they come out closer to nighttime. When I was trying to take a picture of this one he was running so fast I only got one shot and that was a lucky one, keep in mind he isn’t any bigger than the fingernail on my pinky. He was crawling on the wall of the bathtub and I’m not sure if he fell or jumped but nevertheless he ended up on the inside of the bathtub. Do you know what he is??
Thank you sincerly,
Kristen J.

Hi Kristen,
We have never seen an immature Cockroach with this coloration pattern. We found a match on Bugguide that listed it only by genus Periplaneta. The submitted photos were from North Carolina.

Letter 2 – German Cockroach Nymph

Subject: New apartment, new pantry protein?
Location: Orem, Utah
November 4, 2015 10:25 pm
We just moved to a new apartment and I decided I wanted to clean all the cabinets myself before putting anything in them. Imagine my surprise to find several of these crawling around the edges of my cabinets before I put anything in! I haven’t seen them eating anything, but I’ve found them on all my cabinets and the extra free standing pantry on the far side of the kitchen, so I think they’re after my food. I’ve only seen them in the evening and it has recently gotten cold, so perhaps they’re more recent invaders. I’ve combed through several pages of your site and others and can’t figure out what it is. I’d like to know so I’m not as paranoid with my 10 month old sticking everything in his mouth. I took the pictures on a sheet of lined paper with this bug in a Ziploc, so sorry if it isn’t really clear. They’re trangular in shape with a colorful band separating the black/brown head and tail. I’ve mostly seen a yellow/tan like this specimen, but I did see an orange band once as well. Thank you so much for running a great website where I hope to find answers!
Signature: Ashley B.

Dear Ashley,
This is an immature Cockroach and we are relatively certain your nymph is that of a German Cockroach based on images found on BugGuide and FlickR.  Of the 1000s of species of Cockroaches in the world, only a few species are considered household pests and the German Cockroach is probably the most pernicious.  According to BugGuide:  “Infests human dwellings and workplaces” and “Omnivorous, eats just about anything edible”.  BugGuide also states:  “Like most cockroaches, the German Cockroach is nocturnal. It is a major pest of residential and commercial structures.  Some people can develop severe allergies to cockroach parts, feces, and oils. “

Oh my goodness. Worst fears come true, but now I know for sure! Thanks for your help, I’ve got a landlord to call and food to put in plastic containers…

Letter 3 – Australian Cockroach Nymph, we believe

Another mouth to feed?
Location: St. Petersburg, FL, 33705
December 7, 2010 11:14 pm
Your site is great & the most informative I’ve founf so far. I found this guy scurrying across the living room tonight, hope you can help. The photos on your site that come closest are I.D. as immature roaches. I sure hope this isn’t the case, but I need to know in order to proceed. It is approx 3/4” long & 1/2” wide.
Thanks, Steve
Signature: Swamp Critter Steve

Dear Steve,
In our opinion, your Cockroach Nymph looks the most like the Australian Cockroach Nymph, Periplaneta australasiae, that is pictured on bugGuide. On the information page for the species, BugGuide indicates:  “Immature Australian cockroaches are considerably more ornate than nymphs of other Periplaneta species found in North America“ and “They are scavengers, they feed on almost everything” and that they are a “A nocturnal species that favours tropical and subtropical climates.” They are in the same genus as the American Cockroach, a misnomer since the species is believed to have originated in Africa and then transported to the new world on slave ships according to BugGuide. Of the Australian Cockroach, according to the Oz Animals website, in Australia  “They are pest in households. This is a common pest in homes and can transmit disease by contaminating food. The name is misleading as they are an introduced species from Asia.”  The same assessment probably holds in North America.

Letter 4 – German Cockroach Nymph

Subject: WTF is this.
Location: Lexington, KY
November 16, 2016 9:04 am
Bugs initially found in kitchen, specifically hiding in toaster, microwave, and rack of coasters. Sometimes coming out onto counter, especially when food present. Also hiding in cabinets. Range in size from a couple millimeters to a couple centimeters. Some appear gnat like, larger ones are black with red/orange/brown stripe down back. No wings/flying that we’ve seen. Saw first one in bathroom and vanity this morning.
Signature: Kari

Dear Kari,
This is a German Cockroach nymph, one of the species that is best known for infesting apartment buildings and restaurants.  They tend to feed at night and scurry away when the lights are turned on.  You can compare your image to this BugGuide image.  According to BugGuide:  “Omnivorous, eats just about anything edible.”

Letter 5 – Beautiful Cockroach Nymph from Australia

Subject: Australian Beetle
Location: East Fremantle, Australia
December 3, 2014 3:54 pm
Here’s one that’s quite distinctive — in my eyes it looks like an Aboriginal painting — but I can’t find anything like it on the web.
It’s about 12mm (1/2″) long, without the antennae. The picture was taken on Dec. 3, 2014 (beginning of summer), on an indigenous tree in an urban park rather late in the day (4:20pm).
Signature: Norm Jackson

Dear Norm,
This is not a beetle.  It is a Beautiful Cockroach nymph, Ellipsidion australe, which we identified on the Insects of Brisbane website, or it is a related species of Cockroach in the genus Ellipsidion.  This is not a species that infests homes. 

Letter 6 – Beautiful Cockroach Nymphs from Australia

Subject: Melbourne bugs in spring
Location: Melbourne
September 28, 2016 5:40 pm
These bugs seem to cluster together
They are on a fence post in a local park, late September in Melbourne
I’ve not seen this type before
Any ideas?
Signature: Bridget

Dear Bridget,
These are Beautiful Cockroach nymphs, Ellipsidion australe, or a closely related species in the genus.  This is not a Cockroach species that infests homes.  More images and information can be found on the Brisbane Insect website.

Letter 7 – Beautiful Cockroach Nymph from Australia

Subject:  What’s this insect?
Geographic location of the bug:  Outer Eastern Melbourne, Victoria, Australia
Date: 11/08/2018
Time: 06:38 PM EDT
Your letter to the bugman:  Hi bugman, just wondering what these are. They are swarming a chilli bush. I’m thinking they’re predatory, but I’m not sure.
How you want your letter signed:  Andy G

Dear Andy,
This is a Beautiful Cockroach nymph, Ellipsidion australe, and though it is not a predatory species, it is also not a species that will infest homes.  According to the Brisbane Insect site:  “Not all cockroaches are ugly. This Austral Ellipsidion Cockroach looks beautiful. Its body is orange-brown to dark brown with white patterns. Its thorax is dark brown with a good looking yellow around the edge. The cockroach adult is winged, with brown forewings covered the black and white abdomen. Male and female look almost the same. Nymphs have the similar body structure except wingless. …They are very good runners.  This Cockroach  is active at day time, running openly on the leaves and flowers. Most other cockroaches are scavengers, they feed on almost everything. We are not exactly sure what this Austral Ellipsidion Cockroach feeds on, but they are always found on plants, seldom on the ground. They are believed feeding on pollen, honeydew and mould fungus. “

Letter 8 – German Cockroach Nymph

Subject:  Changes around the house
Geographic location of the bug:  Northern New Jersey
Date: 08/26/2018
Time: 06:41 AM EDT
Your letter to the bugman:  Recently, we’ve been having a lot of construction done at our house and the house has been completely open to the outside. Over the past couple of days, we’ve seen some of these sharing our home with us. We haven’t seen them before. We live in a forested, semi-rural area.
It would be great to understand what these are so we can understand their habits.
Thank you.
How you want your letter signed:  Jim Jacobson

Dear Jim,
As you can see from this BugGuide image, you have a German Cockroach nymph, Blattella germanica.  This is one of the species of Cockroaches that will infest homes and businesses.  It is possible that they were already in your home and the construction has caused them to flee into the open, as they are generally nocturnal feeders that shun light.  It is also possible that they were somehow transported to your home with construction materials or personal belongings of the construction workers, but if you are finding them in large numbers, they are likely reproducing in your home.

Dear Daniel,
Thank you very much for this information. I truly appreciate it. I would guess that somehow they were transported into the house. We’ve lived here 6 years and this is the first time we’ve seen any. We have only seen two.
Thanks again,
Jim Jacobson