Florian Hartig

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The multi-dimensional nature of information drives prioritization of private over social information in ants

Tomer J. Czaczkes, John J. Beckwith, Anna-Lena Horsch & Florian Hartig

Proceedings of the Royal Society B: Biological Sciences, 286(1909), 20191136 (2019)
Cite this
@article{czaczkes2019multi,
  author = {Tomer J. Czaczkes and John J. Beckwith and Anna-Lena Horsch and Florian Hartig},
  title = {The multi-dimensional nature of information drives prioritization of private over social information in ants},
  journal = {Proceedings of the Royal Society B: Biological Sciences},
  volume = {286},
  number = {1909},
  pages = {20191136},
  year = {2019},
  doi = {10.1098/rspb.2019.1136},
}

DOI: 10.1098/rspb.2019.1136
Citation statistics: 55 (Google Scholar) · 38 (OpenAlex), as of 29 October 2026

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Funding

This study was supported through funding by DFG (Deutsche Forschungsgemeinschaft), grant to T.J.C (CZ 237/1-1).

View article (DOI)

Abstract

When personally gathered and socially acquired information conflict, animals often prioritize private information. We propose that this is because private information often contains details that social information lacks. We test this idea in an ant model. Ants using a food source learn its location and quality rapidly (private information), whereas pheromone trails (social information) provide good directional information, but lack reliable information about food quality. If this lack is indeed responsible for the choice of memory over pheromone trails, adding information that better food is available should cause foragers to switch their priority to social information. We show it does: while ants follow memory rather than pheromones when they conflict, adding unambiguous information about a better potential food source (a 2 µl droplet of good food) reverses this pattern, from 60% of ants following their memory to 75% following the pheromone trail. Using fluorescence microscopy, we demonstrate that food (and thus information) flows from fed workers to outgoing foragers, explaining the frequent contacts of ants on trails. Ants trained to poor food that contact nest-mates fed with good food are more likely to follow a trail than ants which received information about poor food. We conclude that social information may often be ignored because it lacks certain crucial dimensions, suggesting that information content is crucial for understanding how and when animals prioritize social and private information.

What the paper shows and why it matters

(AI-generated)

When what an animal has learned itself (private information) conflicts with what other animals do or signal (social information), animals mostly follow their own information. This holds even for ants and bees, whose dedicated signals include pheromone trails. Earlier explanations point to source reliability or age, the cost of gathering new information, and the gain for a colony when workers specialise; these are reasonable and not disputed by the paper. The paper takes on what they leave out, information content: a signal can be precise about direction yet ambiguous about food quality.

The paper argues that animals neglect social information, such as an ant pheromone trail, when it lacks a kind of information their own experience supplies, such as food quality, so supplying that kind of information should make them follow the social signal. It tests this with the ant Lasius niger, whose trails show the way but say little reliably about food quality. In a Y-shaped maze, ants trained to poor food on one arm chose that arm rather than a trail on the other in about 60% of cases, not clearly different from chance. When they also met a tiny droplet of better sucrose, the pattern reversed, from about 60% following memory to 75% following the trail; neither trail nor droplet alone did this. In a second experiment, ants meeting nest-mates fed on rich sucrose followed memory less often than ants meeting nest-mates fed on poor food. A fluorescent dye in the nest-mates’ food reached the meeting ant in 21 of 30 trials, so contact with fed nest-mates can pass on food and information about food quality.

The results suggest that research on private versus social information, which has asked when to use social information and whom to copy, should also ask what type of information a source provides. The paper proposes that on a trail, an outgoing forager compares its own food with that of returning nest-mates and follows the trail only if theirs is better (“copy if better”), a rule the study did not test directly. It also notes that quality information, although it carries no direction, changed trail following; psychophysical models of trail following explain this poorly. A review of ant foraging cites the paper for the suggestion that trails may give rather inaccurate information about food quality (Kolay et al. 2020).

References

  • Kolay et al. (2020). Regulation of Ant Foraging: A Review of the Role of Information Use and Personality. Frontiers in Psychology 11, 734. doi:10.3389/fpsyg.2020.00734