Evol Ecol Res 19: 477-486 (2018)     Full PDF if your library subscribes.

Cerebral lateralization and quantity discrimination abilities
in the threespine stickleback (Gasterosteus aculeatus)

Marion Mehlis-Rick, Timo Thünken, Markus Krings*, Simon Käfer# and Ingolf P. Rick

Institute for Evolutionary Biology and Ecology, University of Bonn, Bonn, Germany

Correspondence: I.P. Rick, Institute for Evolutionary Biology and Ecology, University of Bonn, An der Immenburg 1, 53121 Bonn, Germany. email: irick@evolution.uni-bonn.de


Background: The preferential use of one side of the body during behavioural activities (i.e. behavioural lateralization) is a consequence of functional cerebral asymmetries and can be found throughout the animal kingdom.

Hypothesis: Lateralization provides a selective advantage by conferring greater cognitive abilities on the organism.

Organism: Threespine stickleback (Gasterosteus aculeatus).

Methods: We gave individual fish the choice between two shoals differing in group size. We used the following numerical contrasts: 1 vs. 2 (small number/small ratio), 1 vs. 3 (small number/large ratio), 5 vs. 10 (large number/small ratio), and 5 vs. 15 (large number/large ratio). We manipulated eye availability by covering the fish’s right eye (left-monocular), covering the fish’s left eye (right-monocular), or leaving both eyes uncovered (binocular) during the choice trials. We measured the proportion of time the test fish spent in front of each of the two stimulus shoals.

Results: Sticklebacks generally preferred to shoal with the larger group. This preference was stronger at larger ratios. Quantity discrimination was not significantly restricted by monocular vision. In fact, left-monocular fish even tended to perform better than binocular conspecifics independent of contrast. Furthermore, when we separated the data by contrast, we found a significant effect of eye availability on shoaling preferences for the 5 vs. 10 contrast, i.e. fish with monocular vision performed similarly (right-monocular) or again better (left-monocular) at quantity discrimination compared with individuals that had both eyes uncovered. In comparison, eye occlusion had no significant effect on quantity discrimination in the other three contrasts (1 vs. 2, 1 vs. 3, and 5 vs. 15).

Conclusion: We found that cerebral lateralization is linked to certain numerical skills, which are of adaptive significance in different contexts, including shoaling, foraging, and predator avoidance.

Keywords: cerebral lateralization, cognitive abilities, Gasterosteus aculeatus, numerical contrasts, quantity discrimination, shoaling behaviour, threespine stickleback.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2018 Ingolf P. Rick. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.