Emergent regulation of ant foraging frequency through a computationally inexpensive forager movement rule

Abstract

Ant colonies regulate foraging in response to their collective hunger, yet the mechanism behind this distributed regulation remains unclear. Previously, by imaging food flow within ant colonies we showed that the frequency of foraging events declines linearly with colony satiation (Greenwald, Baltiansky & Feinerman, 2018). Our analysis implied that as a forager distributes food in the nest, two factors affect her decision to exit for another foraging trip: her current food load and its rate of change. Sensing these variables can be attributed to the forager's individual cognitive ability. Here, new analyses of the foragers' trajectories within the nest imply a different way to achieve the observed regulation. Instead of an explicit decision to exit, foragers merely tend toward the depth of the nest when their food load is high and toward the nest exit when it is low. Thus, the colony shapes the forager's trajectory by controlling her unloading rate, while she senses only her current food load. Using an agent-based model and mathematical analysis, we show that this simple mechanism robustly yields emergent regulation of foraging frequency. These findings demonstrate how the embedding of individuals in physical space can reduce their cognitive demands without compromising their computational role in the group.

Social interactions are impacted by food availability, food type, and group size

“…For example, changes to the level of activity of workers and their walking patterns when fed different types of food might explain changes in interaction rates (Pinter-Wollman, 2015b). Furthermore, the spatial distribution of ants within the nest might determine who interacts with whom and how frequently (Pinter-Wollman, 2015a;Pinter-Wollman et al, 2013;Pinter-Wollman et al, 2011) and can influence foraging decision and the flow of food among nestmates (Baltiansky et al, 2023;Buffin et al, 2009). It might be interesting to determine who initiates interactions, fed or hungry ants because recent work suggests that fed and hungry ants play different roles in food distribution within ant colonies (Miller and Pinter-Wollman, 2023).…”

“…Certain individuals (i.e., foragers) leave the nest to collect food and bring it back to the nest (Gordon, 1989;Gordon, 1996). Once at the nest, food is distributed and stored, and foragers decide whether or not to continue foraging based on certain types of interactions with nestmates (Miller and Pinter-Wollman, 2023), the forager's own food load (Greenwald et al, 2018;Howard and Tschinkel, 1980;Wallis, 1964), how deep a forager moves into the nest (Baltiansky et al, 2023), and the presence of larvae in the nest (Ulrich et al, 2016).…”

Ant social network structure is highly conserved across species

“…For example, we now know that increased group size and genetic heterogeneity can confer fitness benefits by enhancing division of labour [2,13] (though do not always seem to [14]), how fundamental aspects of insect biology map onto colony social networks [15,16] and how social network structure is influenced by both pathogens [17,18] and symbionts [19]. We also know more about the dynamics of individual-level behavioural change [9,20,21], foraging and food dissemination [22,23], cooperative transport [24] and other aspects of self-organization [12,25–27], all of which are important topics for scientists investigating biological and artificial collective systems, and optimization algorithms [28–30].…”