Cockroaches are nocturnal, so you rarely see them during the day. While you may see a lone cockroach scuttling across the floor, they’re more likely lurking in large colonies somewhere dark and secluded where they’re safe from harm.
Cockroaches live in large colonies but travel around in small groups to forage food, water, and shelter. Doing so protects them from predators and other dangers. As soon as they find what they need, they release aggregation pheromones to let the rest of their colony know to join them. A group of cockroaches is called an intrusion. When they invade the home, they’re called an infestation.
A cockroach colony’s difficult to eradicate. They don’t all come out simultaneously, so you have more cockroaches inside your house than you expect. Calling in an extermination company is the best way to deal with the problem.
Are Cockroaches Social Insects?
Because cockroaches tend to emerge alone, it might surprise you to learn that cockroaches are social insects that prefer to live and travel in large groups. Doing so provides greater protection against predators and other dangers. As soon as they find an environment that provides them with what they need, they settle there as a colony.
To do this, The Chemistry of Pheromones and Other Sociochemicals describes how household roaches communicate through pheromones, which are a complex range of smells that transmit information and intent.
There are many different types used in roach communication, but aggregation pheromones gather them all into one place. This keeps the nest organized and tells cockroaches when to:
- Forage for food
- Move from one location to another
- Look for find shelter
The Proceedings of the National Academy of Sciences found that each cockroach group has its own aggregate pheromones, allowing them to communicate with members of their own colony. Scientists believe that pheromones comprise of:
- Skin. It’s thought that pheromones are made from waxy substances found on the surfaces of the cockroach’s skin.
- Poop. Other scientists believe that aggregate pheromones are found in roach poop in the form of nitrogen compounds.
- Fatty Acids. This is still up for debate, but these pheromones are made of fatty acids.
To release aggregate pheromones to talk to their colonies, cockroaches deposit their poop in various locations, alerting other cockroaches of where they are.
Similarly, foraging pheromones allow roaches to recommend food sources to each other. Once they find a suitable food source, they spread the word to the other cockroaches in the colony. This is why you’ll find multiple cockroaches feasting on the same food source.
Do Cockroaches Travel Alone?
Because cockroaches come out at night, it’s unlikely you’ve seen them moving around together. But cockroaches don’t like traveling alone. Instead, they live and travel in small family groups. Once they find a suitable place to settle, they build their colony by mating and multiplying, setting up small foraging groups.
Female cockroaches can produce as many as 30-40 cockroaches at a time, meaning their colony grows rapidly. Increasing their population has survival benefits, as it allows them to thrive as an entire group instead of being picked off by predators one by one.
However, every now and then, lone cockroaches enter houses to find shelter, also getting into them through wood, packaging, and furniture. These harmless loners rarely build colonies unless it’s a pregnant female.
Do American Cockroaches Travel in Packs?
American cockroaches live and travel in groups. Aggregate pheromones allow them to stay together and locate one another if they get separated.
When they’re in their groups, they explore their surroundings together and search for food as a foraging pack. It was previously thought that cockroaches forage individually, but this has been proven not to be true.
As soon as they find food and water, they send signals to the rest of the colony who’ve remained behind to come and join them. This method of communication and togetherness is crucial for their survival.
Unfortunately, this means if you see one American cockroach in your home, there’s likely to others hiding in a dark corner. Because they’re expert hiders, they’re hard to find.
Do German Cockroaches Travel in Packs?
German cockroaches live and travel in packs. Out of all cockroach species, they’re more likely to travel alone, but like all other species, they prefer to be in groups where there’s greater protection against dangers.
German cockroaches live in mixed-family aggregate groups of equal male and female numbers. 60% of the population are nymphs, and 40% are adults. They feed on the same food sources after getting the go-ahead from the foraging roaches.
How Many Cockroaches Live Together?
A cockroach nest can hold over 100 roaches at once. However, young colonies can contain only a handful of roaches. As mentioned, this number will quickly grow as the roaches breed and multiply.
Cockroaches won’t let the nest get too large. If the population grows too quickly and they have to compete for food, water, and shelter with one another, they’ll start to cannibalize the nymphs and weaker roaches in the colony to thin the numbers out. Cockroaches also reduce numbers to:
- Preserve the available food
- Consume energy during harsh conditions
- Replace lost nutrients
When starvation causes a colony to cannibalize, nymphs are usually the first to be eaten. That’s because, during the first through molts, they’re left with only a soft layer of skin.
Eventually, it’ll harden into a protective shell. Before this happens, adult cockroaches can penetrate their skin, tearing them apart.
Nymphs are also slow, meaning they can’t flee from larger, quicker cockroaches. Not only does this provide the surviving roaches with the nutrients they need, but culling nymphs make the population more manageable.
How Do Cockroaches Travel?
Cockroaches move through small holes, under doors, or up and down plugs and drains. They prefer gaps that are less than half an inch wide. They also travel by hitchhiking in cardboard boxes, furniture, suitcases, bags, and packaging materials. This is how lone cockroaches get into houses and buildings.
When they travel, they move along the edges of rooms, which allows them to remain undetected. However, because they usually surface when it’s dark, it’s hard to know whether they travel alone or in groups.
Both are true, especially if the colony’s small. In this case, lone cockroaches forage for food, while the rest remain out of harm’s way in a dark, quiet spot. Once the colony grows, they’ll form groups for protection and safety.
How Far Do Cockroaches Travel?
Cockroaches don’t travel far once they’ve invaded a building. Instead, they find a spot that suits them and make it their home, leaving it only to forage for food and water. If your house has an infestation upstairs and downstairs, you likely have two separate colonies in your home. That’s because the same family of cockroaches rarely split up and live apart.
Some cockroach species, including Asian, brown, and Smokybrown roaches, also fly, meaning it’s easy for them to get to difficult-to-reach places.
Cockroaches rarely live alone. If you only see one, there’s bound to be more lurking nearby. If you catch the infestation early enough, you may only have to deal with a small number of cockroaches. If the colony had time to multiply, you could be dealing with hundreds or even thousands of cockroaches.