Cannibal Cockroaches

Cannibal cockroachesFor some people, even the mention of cockroaches sends shivers down their spines. These crawling insects are synonymous with notions of dirtiness, and rightly so. Cockroaches are known for spreading diseases such as salmonella, and also triggering allergies and asthma!

But did you know on top of these unhygienic ideologies cockroaches also portray another unpleasant characteristic? Cannibalism.

Studies have shown cannibalism in six species of cockroaches and there’s a strong chance it occurs in the other 4,494 species. All three of the major pest cockroach species: German, American, and Oriental are known to show cannibalistic tendencies.

What do cockroaches eat?

Cockroaches are opportunistic and will consume a huge range of materials, this trait makes them a very successful urban pest.

Cockroaches are omnivores, which means they eat both plants and animals. Their omnivorous diet assists them in being relentless scavengers, allowing them to consume most things they come in contact with.

Although cockroaches aren’t fussy eaters, there are certain foods which they particularly love.

Cockroaches eat:

  • Sweets
  • Meats
  • Starches


cockroaches easting fruitLike rodents, cockroaches are known to have quite a sweet tooth. They are known to be particularly fond of foods such as chocolate, sweet cereals, fruits, jams, biscuits etc. It is because of this that cockroach bait features both glucose and sugar in their recipe to help attract cockroaches.

However, some research suggests that through evolution, a few individuals in the cockroach family are starting to find the taste of glucose a bit bitter and tend to avoid bait featuring this ingredient. However, these mutant cockroaches aren’t completely sugar-free and still go crazy for other sugars such as fructose.


Cockroaches love to eat the same meats as us such as beef, chicken, lamb, and fish. Don’t worry though they don’t go out hunting for live animals, these are just some of the products they find and devour when they have migrated into our kitchens, either in our homes or in restaurant or hotel kitchens.

However they are also known to consume dead insects, animal skins, and in some cases live baby mice!

The meat part of a cockroach’s diet also consists of human hair and fingernails! Due to their sideways-moving mandibles, their jaws are quite weak so they mainly pick on calluses, eyelashes and dead skin rather than living tissue.

Don’t worry, it’s extremely unlikely that a cockroach will bite you. This rarely happens, and only occurs when an infestation has reached an astronomical level, and food sources are limited.


Like us, cockroaches like to have a bit of starch with their meal. This can be anything from potatoes, bread and pasta. Their consumption of starch goes beyond the conventional norms. You may find cockroaches feasting on books, paper, clothes, and even glue!

When it comes to food, cockroaches are relentless. Their hunger, and appetite fuels their existence and they will go through any means necessary to feed it.  Cockroaches which live in sewers will turn to sewage to feed their hunger, whilst those living in rural areas will eat trees and plants.

Do cockroaches drink water?

Cockroaches are a lot like rodents with their relationship to water. They can survive without water for a week or two if the moisture content in their food is high. Alternatively, if they have access to a constant supply of water and no food they can survive months on end.

The combination of a good supply of both food and water increases their lifespan. If other conditions are favourable, such as shelter and breeding, then you could potentially have a large cockroach problem on your hands.

Why are cockroaches cannibals?

So you know by now that the range of a cockroaches diet is limitless. But what makes them switch to cannibalism?

Well, population density plays a huge part in it. The reasons behind cockroaches developing cannibalistic tendencies can be divided into two sections:

  1. Food
  2. Regulation


cockroach infestationCockroaches can breed at an exceptional rate. For example, if conditions are favourable a female german cockroach can lay 384 eggs in her lifetime. As you can imagine during an infestation the population can get quite high, which limits the amount of food available.

When food becomes scarce, cockroaches turn to cannibalism to feed their hunger. Usually, it’s the older, stronger cockroaches praying on the young and weak.

However, in terms of pest control this survival instinct sometimes doesn’t work out for them. If one cockroach has consumed some bait, and then falls victim to being cannibalised, those feeding upon it will also become infected with the effects of the bait.


Another reason behind their cannibalistic instinct is due to self-regulation. Large populations mean less food to go around. Eliminating members of the intrusion means fewer mouths to feed, resulting in more food for everyone else. Usually, this occurs with the females consuming eggs and nymphs when food is scarce.

German cockroach nymphs can sometimes avoid being cannibalised by foraging for food during the day. Adult cockroaches usually operate during the night. These nymphs have also developed a pheromone that repels adult cockroaches.

It has also been reported that female American cockroaches turn to cannibalism when mating. Just like black widow spiders, female American cockroaches can consume their male partner during copulation.

It is important to note that their cannibalistic traits are purely a survival mechanism. It allows cockroaches to continue existing when there is little to no food available.

Worried about cockroaches? Contact us now for more advice and professional solutions.


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