Tracking Individuals Shows Spatial Fidelity Is a Key Regulator of Ant Social Organization

Abstract

Ants live in organized societies with a marked division of labor among workers, but little is known about how this division of labor is generated. We used a tracking system to continuously monitor individually tagged workers in six colonies of the ant Camponotus fellah over 41 days. Network analyses of more than 9 million interactions revealed three distinct groups that differ in behavioral repertoires. Each group represents a functional behavioral unit with workers moving from one group to the next as they age. The rate of interactions was much higher within groups than between groups. The precise information on spatial and temporal distribution of all individuals allowed us to calculate the expected rates of within- and between-group interactions. These values suggest that the network of interaction within colonies is primarily mediated by age-induced changes in the spatial location of workers.

Fungal disease dynamics in insect societies: Optimal killing rates and the ambivalent effect of high social interaction rates

“…The linear dependence on colony size K comes from our assumption that the host colony is sufficiently well mixed (see Section 2). However, nest architecture, and social and demographic structure of the colony is known to ameliorate the effect of colony size on pathogen transmission risk (Hock and Fefferman, 2012;Mersch et al, 2013;Pie et al, 2004). In realistic scenarios, the basic reproduction number (4) will not depend linearly on colony size; rather, K should be interpreted as an effective colony size that leads to cK cadaver contacts per infectious cadaver in one time unit.…”

Automated image-based tracking and its application in ecology

“…Tracking over short durations (minutes) has aided in our understanding of the genetic basis of social behavior, such as aggression or courtship [8,85], where the high throughput that automation allows provides enhanced power for uncovering patterns in behavioral data [27]. Research over longer times can uncover complex temporal linkages between social behaviors [8,28], and experiments over the order of weeks provide unique insight into the social and behavioral development of individuals in intraspecific groups [31,53,54].…”

“…Another alternative is to use computer vision technologies that detect animals even when their color pattern is statistically indistinguishable from the background, based, for example, on their shape or movement [21]. Finally, it is possible to mark individuals [53] or integrate with other tracking methods such as bio-logging -combining the robustness of bio-loggers for detecting individuals in complex habitat with the high spatiotemporal resolution of imaging [54].…”

“…Fingerprinting allows the addition of habitat structure without increasing assignment errors, as identities are recovered following occlusion [20,21] (Movie S5 in the supplementary material online). Again, use of multiple cameras (Movie S6 in the supplementary material online), marking [53], or integration with bio-logging [54] can enable tracking and identity maintenance during or after occlusions. Some imaging methods can even pass through physical structure, revealing the position of organisms either behind the structure or embedded within it, thus removing the problem of occlusions from physical habitat altogether.…”

“…Knowledge about the spatiotemporal position of organisms relative to the environmental landscape, or to each other, is sufficient for many questions in ecology [1,3,4,33,53] (Box 1). For other questions, such as those about the mechanics of locomotion or ecological interactions, it is necessary to know about the positioning of appendages or other specific points along an individual's body [8,17,19,28,29,69] (Movie S2, Movie S11, Movie S14, and Movie S22 in the supplementary material online) (Box 1).…”