Gyne is the primary reproductive female caste of social insects (especially ants, wasps, and bees of order Hymenoptera). Gynes are those destined to become queens, whereas female workers are typically sterile and cannot become queens. A colony with multiple queens is said to be a polygyne form, whereas with only one is a monogyne form.
The fire ant Solenopsis invicta is known to have colonies in both polygyne and monogyne forms.
In species lacking morphological castes (i.e., where "workers" may not be sterile), the term "gyne" is usually reserved for those females whose entire life is spent as a reproductive or potential reproductive, as opposed to those who start life as a worker and subsequently attain reproductive status (often called a "replacement queen" or a "laying worker"). In most species with annual colony cycles, only gynes can enter diapause and overwinter, while workers - both non-reproductive and reproductive - die off. In some groups, such as paper wasps, gynes will join with other gynes at the time of nest founding, and may be relegated to subordinate reproductive roles, so being a gyne does not guarantee that a female will become a queen.