Paternity assurance is the driving factor behind anti-cuckoldry behavior. Paternity is something that cannot be truly guaranteed, and as such, various behaviors have evolved to provide the highest percent of certainty with regards to offspring. These behaviors are present almost always in species with paternal investment. The necessity of this behavior varies from species to species. The majority of females are promiscuous given the opportunity, but there are some species such as the duetting fairy-wren, where females are loyal to their mate without any anti-cuckoldry tactics (Hall and Peters 2008). These behaviors are not limited to a single genus, but instead are prevalent throughout mammals, birds, lizards and insects (Komdeur et al 1999, Moreira et al 2007, Watts 1998, Wedell and Cook 1999).
Anti-cuckoldry behaviors take many forms, each developed in response to specific evolutionary pressures and situations. The most common of the anti-cuckoldry tactics is mate guarding or following, in which the male closely follows the fertile female to prevent Extra-Pair Copulations (Chuang-Dobbs et al. 2001). Second in frequency is sperm competition. This involves frequent within-pair copulations in monogamous species, and varying ejaculate composition in more promiscuous species (Wedell and Cook, 1999). A more physical behavior is demonstrated most often in insects; the mating plug (Takami et al. 2008). It is a physical block to future copulations and fertilization attempts. This is often coupled with other ejaculate fluids that can interrupt the female’s cycle or displace competitor’s sperm. Less common is the practice of bribery, where the male uses the Domestic Bliss principle to ensure his mate’s fidelity (Hall and Peters 2008).