Ant nest design impacts correct choices, but not how quickly they're made

Jim Crocker
20th January, 2026

Ant nest design impacts correct choices, but not how quickly they're made

Bent-spined Acorn Ant (Temnothorax curvispinosus)

Photo adapted from: Jessica / CC BY (Source)

Key Findings

  • Acorn ant colonies in eastern North America quickly choose new nests, a vital task for survival
  • Increasing the number of differences between potential nests improved the accuracy of their choice
  • Despite better accuracy with more information, the time colonies took to decide on a new nest remained constant
Choosing a new home is a critical decision for social animals like ants, directly impacting colony survival. For acorn ants, Temnothorax curvispinosus, this involves evaluating potential nest sites based on characteristics like size, shape, and light levels. The speed and accuracy of this decision-making process are therefore vital[1] – researchers at Tufts University and the University of Tennessee recently investigated how the number of factors considered affects these two aspects. Traditionally, studies of animal decision-making have often simplified choices, focusing on single attributes[2]. However, real-world scenarios are rarely so straightforward; animals frequently face options that differ in multiple ways. This is particularly true for foraging insects like bees and ants, who must weigh various qualities when selecting resources. Understanding how animals handle these complex, multi-attribute choices is a central question in behavioural ecology and psychology. The new study addressed a specific question: does increasing the number of differences between potential nest sites improve the colony’s ability to choose the better option, and does this come at a cost in terms of decision time? The researchers conducted experiments where ant colonies were presented with pairs of nests, one of which was clearly superior. These nest pairs differed in one, two, or three attributes – cavity shape, height, and brightness. By systematically varying the number of differentiating factors, the researchers could assess how colonies weighed the information available to them. The results showed a clear trend: accuracy in nest selection increased as the number of attributes differentiating the nests increased. This suggests that having more information does indeed help the colonies make better choices. Interestingly, brightness proved to be a particularly important attribute; manipulating brightness had a significant effect on the colonies’ ability to discriminate between nests. However, the study also revealed a surprising finding. Despite the increased accuracy with more attributes, the time it took colonies to reach a decision didn’t change based on the number of differences between the nests. This indicates that the colonies may be facing a time constraint during the emigration process, meaning they can’t simply spend more time evaluating options even if it would lead to a more accurate decision. These findings build on previous work exploring the rationality of decision-making in ants. Earlier research on Temnothorax albipennis showed that individual ants sometimes make irrational choices, taking longer to decide between similar nest sites than dissimilar ones[3]. However, collective decision-making, as seen in colonies, can overcome these individual biases, leading to more rational outcomes. The current study extends this understanding by showing that colonies also demonstrate a form of rationality in their time investment, not increasing decision time despite gaining more information. The observation that colonies don’t spend more time evaluating options, even when it improves accuracy, aligns with the concept of sequential sampling[4]. This model suggests that animals don’t weigh all information equally but instead gather data until a certain threshold of confidence is reached. The new study suggests that acorn ant colonies may have a pre-defined threshold for nest selection, limiting the amount of time they’re willing to spend regardless of the complexity of the choice. The researchers highlight the importance of considering context dependence in preference experiments, as noted in earlier work[2]. The specific composition of the choice set – which nests are available – can influence the decision-making process. The study’s findings also suggest that innate preferences and other non-rewarding attributes, such as brightness, play a crucial role in nest-site selection.

EcologyAnimal ScienceEvolution

References

Main Study

1) Nest attributes influence choice accuracy, but not decision latency in acorn ants

Published 16th January, 2026

https://doi.org/10.1371/journal.pone.0329528

Related Studies

2) How do insects choose flowers? A review of multi-attribute flower choice and decoy effects in flower-visiting insects.

https://doi.org/10.1111/1365-2656.13347

3) Rational time investment during collective decision making in Temnothorax ants.

https://doi.org/10.1098/rsbl.2019.0542

4) Cognitive and Neural Bases of Multi-Attribute, Multi-Alternative, Value-based Decisions.

https://doi.org/10.1016/j.tics.2018.12.003


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