Movement, Encounter Rate, and Collective Behavior in Ant Colonies

Abstract

Spatial patterns of movement regulate many aspects of social insect behavior, because how workers move around, and how many are there, determines how often they meet and interact. Interactions are usually olfactory; for example, in ants, by means of antennal contact in which one worker assesses the cuticular hydrocarbons of another. Encounter rates may be a simple outcome of local density: a worker experiences more encounters, the more other workers there are around it. This means that encounter rate can be used as a cue for overall density even though no individual can assess global density. Encounter rate as a cue for local density regulates many aspects of social insect behavior, including collective search, task allocation, nest choice, and traffic flow. As colonies grow older and larger, encounter rates change, which leads to changes in task allocation. Nest size affects local density and movement patterns, which influences encounter rate, so that nest size and connectivity influence colony behavior. However, encounter rate is not a simple function of local density when individuals change their movement in response to encounters, thus influencing further encounter rates. Natural selection on the regulation of collective behavior can draw on variation within and among colonies in the relation of movement patterns, encounter rate, and response to encounters.

Scaling of ant colony interaction networks

“…However, and much to our surprise, the scaling of network properties with colony size was not significantly different when comparing between these two ways of determining the networks, the power-law scaling exponents for 12 metrics of social network structure were indistinguishable between these two different ways of assessing interactions. These findings support an idea that has long been reported in the cellular automata (Miramontes et al, 1993;Solé et al, 1993) and social insect literature (Boi et al, 1999;Sendova-Franks et al, 2010;Mersch et al, 2013;Razin et al, 2013;Quevillon et al, 2015;Richardsonv and Gorochowski, 2015;Davidson and Gordon, 2017;Crall et al, 2018;Gordon, 2020), that the function of complex systems like social insect colonies is strongly dependent on their spatial distributions.…”

Dynamics of cooperative excavation in ant and robot collectives

“…We assume that the gradient in the antennating field along the local normal, on the right hand side of Equation 2 , determines the rotation of the agents with being the rotational gain. In order for the agents to initiate the excavation process, they can pick the elements from the boundary and drop them in the interior of the corral only when the local concentration of the antennating field is larger than a critical threshold , consistent with observations ( Gordon, 2021 ; Gordon et al, 1993 ). Figure 3(b) shows snapshots (see Video 2 for a movie of the simulations) of the agent-based simulations following Equations 1–3 showing that the agents excavate successfully out of the corral when the gradient following behavior is strong (see Appendix 2 for details).…”

“…However, when ants move slowly relative to the time for the decay of the memory associated with antennation with other ants, the dynamics of both these processes is similar. Then the signals laid down (or transported) by ants increases locally at a rate proportional to their density ( Gordon, 2021 ), and is subject to degradation and diffusion slowly. Accounting for these effects, we arrive at the following dynamical equations for the evolution of as: …”

Editorial: Neuroethology of the colonial mind: Ecological and evolutionary context of social brains

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Editorial on the Research Topic Neuroethology of the colonial mind: Ecological and evolutionary context of social brainsCollective behavior relies on interactions among individuals who have neural substrates supporting the exchange and processing of social information (Gordon, 2021). The collective acquisition and processing of information in these advanced societies suggest that individuals form a "colonial mind."

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