Why Does a Cockroach Have Blood?
WouterThe first question you may ask is, “Why does a cockroach have blood?” This is a common question, but cockroaches don’t have red blood. They don’t produce hemoglobin, which carries oxygen, so their blood doesn’t have color. The other question you may ask is, “What is the color of cockroach blood?” The answer is that the color of cockroach blood is due to other factors. Males and larval females have blood that is colorless, while adult females who are producing eggs have slightly orange blood. The color of their blood is caused by a protein called vitellogenin that is produced in their liver and transported to their ovary. This protein contains carotenoid molecules that are essential for developing embryos.
In order to breathe, cockroaches breathe through a tube system known as a trachea. The tracheae connects each segment of the cockroach’s body, excluding the head. When CO2 levels are high, the spiracles open, allowing fresh oxygen to diffuse into the tracheae.
Cockroaches have a gland on their abdomen that releases a pheromone when they are mating. The taste of the gland stimulates the female, encouraging the male to continue mating. The male then transfers a package of sperm to the female, which uses the sperm to fertilize the female’s egg. This process is the same as in a human, except that the female cockroach does not have a ootheca.
