The one thing that could distress you more than the actual presence of cockroaches in your space is the knowledge that they are reproducing and laying eggs all over your space. Cockroaches will lay their eggs and contain all of them in a casing known an ootheca. Sometime you will see a cockroach with a load on its abdomen. This is the ootheca and that is the female cockroach carrying her offspring around. Did you know that the female cockroach needs to only mate once for her to keep reproducing eggs for her lifetime? This is because the female can store the male’s sperm and continually use it to reproduce.
When at their peak the female roaches can produce two egg oothecas a week and each case can contain up to sixteen eggs. But as they outgrow that stage they will decline and they can only produce one case a month. But don’t celebrate yet. In her lifetime the female can produce at least 150 offspring! Considering the average lifespan of a cockroach is about six months you are looking at a high number of cockroaches in your space. This may be the main reason why you have so many roaches and no matter what you do you cannot get rid of them.
At this point you need the help of a professional exterminator and slightly more sophisticated tools compared to the insecticide you are used to. Contrary to what most people believe crushing the female cockroach will not release the eggs so they die with her if unfertilized and live on to become a nuisance another day if she had stashed the ootheca away in a safe place.
In each casing the female has stashed multiple eggs and they casing they are contained in is made from a protein produced and woven by the female. For roaches that have a high reproductive rate you will find high numbers of eggs. The roaches that reproduce slower the number of eggs is significantly less.
The common American and german cockroaches that are found most in the US mate quickly infesting your home with over 30,000 roaches in just one year. Their ootheca will hold between up to 40 eggs and the female carries the eggs on her until they are ready to hatch. The brown banded roach that are native to Africa will attach her ootheca to the wall to keep it safe and each case holds 20 eggs at a time.
The Australian cockroach hide their ootheca in crevices and cracks for safekeeping and each case can have 24 eggs. The oriental cockroach has 16 eggs in their ootheca which they carry around for five days and then leave in a warm place to hatch.