Stored excess food is sufficient for reducing protein foraging in Temnothorax longispinosus ants

In social insects, foraging behavior is shaped not only by individual physiological needs but also by the demands of the colony. While larval cues are known to initiate protein-foraging in ants, the mechanisms that terminate protein-foraging once larval demands are met remain poorly understood. Here, we experimentally tested two potential regulators of how protein-foraging can be downregulated in the ant Temnothorax longispinosus: (1) reduced larval signaling after feeding, and (2) the presence of excess protein food inside the nest. Using split-nest designs that physically separated larvae and foragers, we manipulated food access and recorded protein-foraging over time. We found that foragers reduced protein-foraging shortly after protein was introduced into the nest, regardless of whether larvae could consume it. These findings suggest that the presence of protein stores is sufficient for reducing protein-foraging in T. longispinosus. Our results align with similar findings in honey bees and support a broader model in which social insect foragers use in-nest nutrient abundance as a primary cue to downregulate foraging intensity. This strategy may allow colonies to quickly adjust foraging efforts without requiring energetically costly changes in brood-derived signals. Identifying the chemical cues mediating this response may provide key insights into the regulation of nutrient flux in insect societies.