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How do pheromones help regulate the number of termite workers, soldiers, and reproductives?

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Learn how termites use salivary secretions to cement debris to decaying wood nests in their rainforest habitat — termite A termite nest in a tropical rainforest.

Termite colonies maintain a precise balance of workers, soldiers, and reproductives through a system of chemical inhibition. Both the reproductive and soldier castes secrete specific pheromones that act as regulatory signals.1

These chemical messages are distributed throughout the colony via grooming and food sharing, a process known as trophallaxis. Under normal conditions, these pheromones inhibit undifferentiated nymphs from developing into additional reproductives or soldiers.1

If the colony’s caste balance is disrupted—for instance, if members of a specific caste are lost—the concentration of the corresponding pheromone decreases. Nymphs that no longer receive this inhibitory "message" are then free to develop into the required caste, thereby restoring the colony's equilibrium. While the exact physiological mechanism is not fully understood, these pheromones are believed to influence caste differentiation by triggering hormonal changes, potentially involving the juvenile hormone or other glandular activities near the brain. If a caste becomes overpopulated, the colony may also use selective cannibalism to restore the necessary ratio.1