No matter where you live in New Zealand, cockroaches are an unfortunate fact of life. These pests are lurking around every corner, laying their eggs and getting ready to infest your household. Not only do they look disgusting, but they can carry some nasty diseases too. But where are they coming from? Where are they laying their eggs?
The two most common types of cockroaches in New Zealand are the American cockroach and the German cockroach. American cockroaches lay their eggs near a potential food source. German cockroaches lay their eggs a few hours before hatching and do not prefer a single area.
Cockroaches are problematic for any household, and it is vital to know where to look for possible cockroach eggs to prevent your house from having a complete infestation. This article addresses the possible places where various species of cockroaches lay their eggs, what those eggs look like, and how to stop them from infesting your house.
Where Do Cockroaches Lay Their Eggs?
Where a cockroach lays its eggs depends on the type of cockroach. However, regardless of type, if you are checking for cockroach eggs in your household, you should always look in places like the pantry and the bathroom where cockroaches might have access to food and water sources.
Cockroaches are more likely to lay their eggs inside buildings whenever possible, especially in warm environments. Although cockroaches are incredibly resistant to food and water shortages, the one thing that they cannot survive is cold temperatures. Because of that, cockroaches will often come inside to lay their eggs and make their home.
Buildings often offer food sources that are much more convenient than searching around outside, which is another benefit for cockroaches. Because they are willing to eat such a variety of things, you will have to be vigilant when checking around your house. Cockroaches will choose places near food or water sources or where it is dark and moist.
Although there are many cockroach subspecies, they have many things in common, including where they like to nest and lay their eggs. These are typically damp and dark areas since most cockroaches stay away from the light whenever possible. Cockroaches usually prefer buildings in the following categories:
- Homes
- Hotels
- Restaurants
- Nursing homes
- Food processing warehouses
American Cockroaches | German Cockroaches |
Lay oothecae high up | Lay oothecae near the ground |
Lay oothecae directly on food sources | Lay oothecae near food or water sources |
Hatch in 6-8 weeks | Hatch in less than 24 hours |
Oothecae contain approximately 15 eggs. | Oothecae contain 30-40 eggs. |
American Cockroach (Periplaneta americana)
American cockroaches are the biggest kind of cockroach known to man, although it does not lay substantially larger eggs. Instead, the cockroaches are allowed to continue to grow because they live for such an extended period. During their time as mature adults, American cockroaches lay an average of ten oothecae, each containing around fifteen to twenty eggs.
American cockroaches lay their eggs well in advance of the nymphs preparing to hatch, so if you see oothecae of American cockroaches, you have some time to kill them by freezing them or taking other precautions in your household for when they eventually hatch. They are often laid around potential food or water sources.
American cockroaches are capable of flight, which can make looking for their oothecae more challenging than the other subspecies that cannot fly. Cracks and crevasses high up, the tops of refrigerators and cupboards, or around the ceiling are all fair game for the American cockroach who can fly and maneuver into smaller spaces than you might imagine.
It is difficult to follow a single roach back to the nest because they move so quickly, but even if you could, it likely would not lead you to her eggs. Cockroaches do not have a traditional nest where they lay their eggs; instead, the eggs are attached to food sources using their incredibly sticky and long-lasting saliva.
German Cockroach (Blattella germanica)
Unlike other cockroach subspecies, the German cockroach does not lay its eggs more than twenty-four hours before they are ready to hatch. With other species, finding the oothecae might mean that you have time to call an exterminator or go out and buy some pest control, but with a German cockroach, you do not have the luxury of time.
When searching for the German cockroach’s oothecae, you should always look around the food in your house. They especially enjoy starches and sugars, although cockroaches are well-known for the fact that they are not picky about their diet. If you have secured your food in containers that they cannot penetrate, that might not dissuade the German cockroach.
With a German cockroach, you should look for places near to the ground for their egg sacs. Although they have wings, they are incapable of much in the way of flight, so you often will not find their eggs in high places. However, they will crawl up to find cracks and crevasses to hide because they prefer small spaces.
Each ootheca often contains between thirty to forty-eight eggs. Because German cockroaches are such a hardy and resilient species, they can feast on other types of items you might not have safeguarded as closely as your food. You might also find their eggs around other household items that they can eat, such as:
- Glue
- Toothpaste
- Soap
Egg Characteristics
Unlike birds and other animals, cockroaches do not lay single eggs. Instead, they lay a pod of eggs, known as an ootheca. An ootheca can contain between twenty to forty eggs inside. The ootheca is a flexible but rigid pod that protects the vulnerable eggs inside from potential predators and other risks like pesticides.
Unfortunately for you, that means that merely spraying the ootheca with your favorite pest control is not enough to kill them off before they have a chance to hatch and start the breeding cycle once again. That does not mean that you are totally helpless, however. This article addresses some possible solutions in a section below.
The first step to combating cockroaches is learning to identify their oothecae. Both American and German cockroach oothecae are very small, around eight millimeters long. They have a wrinkled appearance. German cockroach oothecae are light tan and extremely wrinkled. American cockroach oothecae are reddish-brown and not as wrinkled.
Another problem is that it is difficult to tell if the ootheca is full or empty. There is a seam along the side of the ootheca, known as the keel, which allows the cockroaches to leave the ootheca when they hatch. However, that seam reseals itself after the cockroaches hatch, so, to the human eye, it is hard to see if there is anybody home.
Lifecycle Of The Cockroach
In general terms, there are three steps to the cockroach’s lifecycle, regardless of the subspecies. The eggs laid within a leathery ootheca hatch into nymphs, the adolescent version of a cockroach. Larvae take deep breaths in order to get big enough to force the ootheca open when they hatch so that they can leave.
Nymphs then mature into adult cockroaches who then breed, and the cycle begins all over again. The amount of time it takes for eggs to develop and hatch and how long the cockroach spends in the nymph phase depends on the subspecies. The subspecies also dictates how long the cockroach is expected to live.
On average, a cockroach will live for anywhere from five months to multiple years under ideal conditions. During that time, a cockroach will lay multiple oothecae, meaning that what started as a small cockroach problem can very quickly evolve into a large colony infesting your household or office space.
A single cockroach might be scouting out your building to see if it is suitable for it to live in, but often seeing a cockroach means that there are quite a few lurking just out of view. Cockroaches breed very quickly, and many subspecies are capable of doing so without mating with another cockroach in a process called parthenogenesis.
American | German | |
Total Lifespan | 2.5 years | Around one year |
Time As An Egg | 6-8 weeks | Three days |
Time As A Nymph | 6-12 months | 2-7 months |
Number Of Moltings | 13 | 6-7 |
Time As An Adult | Up to a year | Up to 7 months |
Average Number Of Offspring | 150 | Hundreds |
American Cockroach
The American cockroach can live, on average, for a staggering 700 days. That is almost two years! Unlike their German counterparts, American cockroaches lay their oothecae well in advance of their nymphs hatching. Nymphs take between six to eight weeks to hatch from their eggs, although they emerge in the same way as other subspecies.
After hatching, a nymph might take anywhere from half a year to an entire year to finish the growing and maturing process before they become fully-fledged reproductive adults. This gives you time to exterminate their population before another round of breeding occurs, which is nice, although they eat a lot more than other types of cockroaches in the meantime.
A nymph must go through around thirteen moltings before it is considered a mature adult capable of reproduction. Usually, a female cockroach is able to reproduce for roughly two years. Although you might be imagining that there need to be at least two cockroaches in order to breed, you would be unfortunately mistaken.
American cockroaches are capable of a type of parthenogenesis. Parthenogenesis is the ability to reproduce asexually. Although usually seen in plants and not complex animals, individual animals like cockroaches do not require both a male and a female in order to generate new roaches. A female can fertilize her own eggs before laying them.
German Cockroach
Over the course of its lifetime, a German cockroach can lay around eight oothecae, meaning that a single cockroach might end up creating 320 other new cockroaches during the seven-month lifespan as a mature adult. German cockroaches are incredibly tenacious and only require a minimum of fifty to sixty days to go from living in an egg to being a reproductive adult.
After hatching from the egg, the nymphs must go through multiple instars. An instar is a stage in a process called ecdysis. Ecdysis is a process for insects where the young shed their skin in order to grow larger and mature. It is necessary because insects have exoskeletons, and therefore their skin restricts them from growing.
The process of shedding their skin is very dangerous for German cockroaches, and many nymphs perish during the process. However, you are not likely to find their corpses or the shedding skins because the other surviving larvae or adult German cockroaches will cannibalize their brethren and eat those skins and dead nymphs.
While the nymphs grow, they primarily subsist on the molted skins and excretions from the adult German cockroaches in the area. That means that the larvae will not be eating your food, but it also means that they will not enter traps or eat cockroach bait that you set out in hopes of decreasing their populations.
Cockroach Infestations
Although everyone has a different interpretation of the word infestation, it generally means that there are too many bugs in your house for a single day of crushing them to be enough. Cockroaches are surprisingly flexible, even the larger ones, and can fit through tiny cracks between floorboards and walls.
If you work or live in a building with cockroaches on one floor, it will not be long before the entire building is infested because they breed so quickly. If you see a single cockroach, you should act soon, although it may already be too late since cockroaches typically hide during the daytime and do not usually spend time with other roaches.
Unlike ants or bees, seeing a single cockroach during an infestation is not unusual. They are not social insects, although they do often sleep or nest in the same places. If you happen upon a nest, you will likely find a lot more than one, but seeing one in your kitchen or bathroom often does not mean that your house only has that one roach.
Depending on the severity of the infestation, you might be able to wipe it out quickly with your own insecticides and increasing your preventative measures. Still, most people require a professional pest control company’s services to get the cockroaches under control because they are so hardy.
Risks
Some people are allergic to cockroaches, but the typical risks that people think about when it comes to roaches of all types are the diseases that they carry. Cockroaches can eat and live among excrement and other unsanitary things, which is how they get the conditions in the first place, but they do not suffer symptoms as humans do.
They look for food in places like sewers and rubbish bins, which are known to be extremely fertile breeding grounds for bacteria that can fester in a human’s digestive system and give them unpleasant experiences with nausea, diarrhea, and other forms of digestive distress if the human comes into contact with a roach.
However, you do not have to actually touch a cockroach in order to contract a disease from them. Cockroaches who have touched food that you then consume can transmit these diseases by infecting the food they feasted upon. You should always check your food containers to look for any holes for this reason.
Some people store their cereals and other types of food products in inflexible plastic containers. Assuming these have been sealed correctly, they should be enough to stop cockroaches from touching the contents inside. If you are in the midst of an infestation, you should be cautious about your food. The most common diseases that cockroaches can carry include:
- Dysentery
- Typhoid fever
- Cholera
- Salmonella
- Other digestive disorders
Prevention
Because cockroaches dislike the cold, you have a much higher risk of attracting cockroaches if you live in a region with long and cold winters. Most cockroaches do not enjoy anything under 60 degrees Fahrenheit or about 15 degrees Celsius. However, the convenience of food and water sources does make your home appealing to them all year round.
To dissuade cockroaches from coming in, you should make sure that your home is as sanitary as possible. Use rigid plastic containers to hold cereals and other types of grain, pet food, or treats. Check on your taps and pipes to ensure that you do not leak anywhere. Toilets are more difficult because closing the lid will not stop a determined cockroach.
You should frequently wipe down your counters and vacuum your floor as well as any cushions or couches so that the crumbs are not tempting for the creepy-crawlies. You can also check your floorboards and caulk up any cracks there or along the seam of your walls, doors, and windows to stop intruders.
If you have any bowls of food or water that you leave out for your pets, you might consider not doing so. If your pet can tolerate specific feeding times, try that instead to minimise the risk of cockroaches coming in and eating your pet’s food. Besides wasting the food, the diseases they carry can also harm your pet.
Dealing With One In Progress
Sadly, cockroach oothecae of all subspecies are as tough as nails. No type of insecticide has been proven to be effective on them. Your best way to stop the nymphs from hatching, assuming that they have not already, is to collect any oothecae you find, put them in a sealed container, and then put that container in a frigid place.
Certain chemicals can be sprayed or infused into the bait that will stop the molting process entirely. This is an effective way to kill cockroaches as well as their young because, without the ability to shed their skin, cockroaches will become trapped in their decaying exoskeleton and die. It will also prevent nymphs from maturing enough to procreate.
You can also set out sticky traps in order to capture the cockroach and hold it there until it starves or dehydrates and dies. Other possible methods might include sprinkling out a bag of poisonous dust around crevasses and dark cupboards, although people with pets and small children might stay away from this method.
Another method that is more friendly to other inhabitants in your house is small bait houses. These little plastic houses are too small for other animals to get into, but they attract cockroaches with sweet smells and hold a tasty mixture that is laced with poison. You should always consult with an exterminator about the right pest control for your home.
American Cockroaches | German Cockroaches | |
Avoid | Sticky traps | Sugar-based traps |
Use | Liquid, dust, sugar-based traps | Sticky traps, liquid, dust |
Important Vacuuming Warning
Plenty of people have learned the hard way that vacuuming is not the answer to cockroaches. Because of the relatively indestructible nature of the cockroach oothecae, merely vacuuming them up is not enough to actually kill the cockroach babies inside. If you just vacuum them up, the nymphs will crawl back out of the vacuum and take over your cupboard.
If you choose to use a vacuum for oothecae, you should immediately remove the vacuum bag, seal it in a container, and put it in the freezer or some other very cold place. As noted above, the cold is something that no cockroach at any stage in its lifecycle can handle. Approximately five days in a cold place should be enough to kill them.
Vacuuming might also not be the right answer if you have been sprinkling some kind of poisonous dust around the areas where the cockroaches have been living because you can accidentally vacuum up the dust before it has a chance to work on the cockroaches that you have been targeting.
Vacuums typically only serve to hide the problem. For dealing with cockroach feces, you might be tempted to use the vacuum since nothing will hatch from them, but they often stain the floor and stick to it as well. A wet wipe or washcloth is a better method for cleaning them, and you should sterilize the area entirely after you have wiped it down.
German Cockroaches
In a fascinating example of adaptive evolution, German cockroaches have begun to avoid sugary foods in order to survive after humans started using sugar-based bait and traps. This might be less fascinating and more annoying if you are currently dealing with an infestation, but it means you will need to be more creative.
You will have to rely on liquids and other types of traps that are sticky and hold the cockroach in place until it dehydrates and dies in order to control the population of German cockroaches. Powdery poisons can also be useful if you sprinkle them on the oothecae before they hatch because the nymphs will eat some of their remaining oothecae.
Boric acid is a common remedy used for German cockroaches and other subspecies because it is very poisonous to them and can quickly kill cockroaches before they have a chance to reproduce. Because the females hold on to the oothecae for so long during the nymphs’ development, you should concentrate on killing the adults.
By focusing your efforts on the adult cockroaches, you will have a better chance of eliminating the population. However, it will necessitate that you check the adult cockroaches that you kill to see if any of them are carrying oothecae. Alternatively, you could immediately dispose of all cockroaches outside of your home without having to worry.
American Cockroaches
Unlike other subspecies, American cockroaches are capable of regrowing individual limbs like legs and wings. That is not only a horrifying thought, but it means that some types of traps will not be effective in killing them. Sticky traps typically function by catching an insect’s legs and then trapping them there until they dehydrate and die.
However, American cockroaches can simply chew off some of their legs and escape from the trap. Although the loss of those legs will slow them down for some time, their legs will eventually grow back, and it will not do anything to kill them faster or to stop them from reproducing and generating even more cockroaches in your house.
Generally, baited traps with poisonous food and dusts like boric acid work best on American cockroaches. American cockroaches enjoy eating hair and leather, in addition to things that humans recognize as food, so make sure that you think of closets and bathrooms when you are spreading traps for them.
American cockroaches take longer to mature and reproduce, so they are somewhat easier to eradicate than other subspecies of cockroaches, but they are still a tenacious species that is a force to be reckoned with.
In Summary
Most people find cockroaches to be ugly, disgusting creatures that sneak into our houses and eat our food. These freeloading insects carry some upsetting diseases, but if you know where to look for them and can recognize their egg sacs, you can take preventative measures and stop them from infesting your household.
Sources
https://cockroachfacts.com/cockroach-eggs-2/