Division of labor in the ant caste system

In the same ant species, different types of individuals can be distinguished either by their external appearance (in which case they are referred to as different morphological caste) or by their function within the colony (different behavioral castes). The number of morphological castes and their function in the colony vary depending on the species. Here below are the most common ones.

The reproductive queen is responsible for reproduction in the colony. After mating in the wild the queen stores the male sperm for the rest of her life and uses it to fertilize eggs for the rest of her life. The queen never leaves the nest of a fully grown colony and survives thanks to the foraging workers that provide food and defense for the colony.

A young queen compared to small workers in C. floridanus.

The alate queen is a young individual that has the potential to be reproductive but has not left the nest yet to mate with the male. After mating in the wild the alate queen will find a suitable location to build its nest, will shed her wings and start laying eggs to produce the first generation of workers in her new colony. After this transition it will become a reproductive queen and continue to lay eggs for the rest of her life.

An alate queen of H. saltator

Males in most ant species come from unfertilized eggs, therefore carry 1⁄2 of the genomic material as the females (haploid). The only function of the males in a colony is to fly out and spread their genetic material by mating with alate queens from other colonies.

A H. saltator male

The workers are typically non-reproductive individuals that carry out all foraging and defense functions necessary to sustain the colony. In some species, such as C. floridanus smaller, (minor) and bigger (major) workers are observed. In other species (such as for example Pheidole bicarinata) a morphologically distinct type of worker is assigned defense tasks and is called a soldier.

A C. floridanus major worker is shown (center) standing
near minor workers on top of their brood of larvae.

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This project is funded by a Collaborative Innovation Award (CIA) from the Howard Hughes Medical Institute.
Collaborative awards are conferred to HHMI scientists (in this case Dr. Danny Reinberg, NYU School of Medicine)
to expand the scope of their research by recruiting collaborators outside their field of expertise.
Our team includes Dr. Shelley Berger (University of Pennsylvania) and Dr. Juergen Liebig (Arizona State University).