Sex ratio

Common card · No. 299484

A sex ratio is the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is usually about equal in species which reproduce sexually. However, many species deviate from an even sex ratio, either periodically or permanently. These include parthenogenetic and androgenetic species, cyclical parthenogens such as aphids, and some eusocial wasps, bees, ants, and termites.

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