Quantification acuity in spontaneous shoaling decisions of three-spined sticklebacks

Abstract

The ability to discriminate between different quantities is widespread throughout the animal kingdom, and the underlying mechanisms of quantity discrimination are currently intensely discussed. In contrast, questions elucidating the limits of quantity estimation received rather little attention so far. Here, we examined fine-tuned quantity estimation in the three-spined stickleback (Gasterosteus aculeatus) in a natural context, i.e. during shoaling decisions. Wild-caught focal fish were given the spontaneous choice between two shoals which differed in group size by 1 fish (0 vs. 1, 1 vs. 2, 2 vs. 3, 3 vs. 4, 4 vs. 5, 5 vs. 6 and 6 vs. 7), based on visual assessment. The results show that sticklebacks generally prefer to shoal with the larger group. They discriminated numerical contrasts up to 6 versus 7, equalling a numerical ratio of 0.86. Preference patterns followed Weber's law, i.e. decreased with increasing numerical ratio. This pattern was found across all numerical conditions as well as within the small number range (ranging from 1 vs. 2 to 3 vs. 4). The results suggest that wild-caught three-spined sticklebacks are spontaneously able (i.e. without prior learning) to detect subtle differences in shoal sizes. Further, they confirm findings of previous studies highlighting the contribution of the analogue magnitude system to quantity estimation in fishes.

Does the Approximate Number System Serve as a Foundation for Symbolic Mathematics?

“…Numerical representations allow North Island robins to determine successful caching strategies, mosquito and stickleback fish to determine the more numerous social group, and elephants to choose the larger amount of food (Agrillo, Dadda, Serena, & Bisazza, 2008; Garland, Low, & Burns, 2012; Mehlis, Thünken, Bakker, & Frommen, 2015; Perdue, Talbot, Stone, & Beran, 2012). This widespread use of quantity discrimination throughout the animal kingdom is evidence of either the emergence of numerical abilities in a very early common ancestor, or of convergent evolution.…”

Quantity discrimination in angelfish, Pterophyllum scalare: a novel approach with food as the discriminant

“…As in other vertebrates, a controversy exists, however, over the representational mechanism(s) underlying discrimination in fishes. Some of the studies support the existence of two distinct mechanisms Agrillo, Piffer, Bisazza, & Butterworth, 2012;Piffer et al, 2012), whereas other studies support the idea of a single mechanism operating over the entire numerical range (Mehlis, Thünken, Bakker, & Frommen, 2015;Potrich et al, 2015).…”

Individual guppies differ in quantity discrimination performance across antipredator and foraging contexts

“…In standardised laboratory experiments, primates (Hanus and Call 2007;Beran 2008a), other mammals (Vonk and Beran 2012), birds (Bogale et al 2014), amphibians (Uller et al 2003), and fish (Agrillo et al 2012;Gómez-Laplaza and Gerlai 2013;Mehlis et al 2015), and even some invertebrates (Nelson and Jackson 2012), can discriminate between sets of objects with different numerosity. For example, monkeys presented with two dishes containing different numbers of food pellets reliably choose to feed on the largest (Hanus and Call 2007).…”