Cytoplasmic incompatibility is a reproductive phenomenon observed in some insects, particularly in mosquitoes. It occurs when a male insect infected with a certain bacterium (such as Wolbachia) mates with a female that is not infected, resulting in reduced fertility or death of the offspring. This phenomenon is believed to be a result of the bacteria manipulating the reproductive cells of the host insect in a way that affects their ability to produce viable offspring. Cytoplasmic incompatibility has been studied as a potential tool for controlling insect populations, particularly those that are vectors of human diseases.