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A larger brain confers a benefit in a spatial mate search learning task in male guppies.

Kotrschal A, Corral-Lopez A, Amcoff M, Kolm N - Behav. Ecol. (2014)

Bottom Line: However, experimental evidence for the link between relative brain size and cognitive ability is surprisingly scarce and to date stems from a single study on brain size selected guppies (Poecilia reticulata), where large-brained females were shown to outperform small-brained females in a numerical learning assay.Because the results were inconclusive for males in that study, we here use a more ecologically relevant test of male cognitive ability to investigate whether or not a relatively larger brain increases cognitive ability also in males.Our results support that relatively larger brains are better also for males in some contexts, which further substantiates that variation in vertebrate brain size is generated through the balance between energetic costs and cognitive benefits.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University , Norbyvägen 18D, SE-75236 Uppsala , Sweden and ; Department of Zoology/Ethology, Stockholm University , Svante Arrheniusväg 18 B, SE-10691 Stockholm , Sweden.

ABSTRACT

Brain size varies dramatically among vertebrates, and selection for increased cognitive abilities is thought to be the key force underlying the evolution of a large brain. Indeed, numerous comparative studies suggest positive relationships between cognitively demanding aspects of behavior and brain size controlled for body size. However, experimental evidence for the link between relative brain size and cognitive ability is surprisingly scarce and to date stems from a single study on brain size selected guppies (Poecilia reticulata), where large-brained females were shown to outperform small-brained females in a numerical learning assay. Because the results were inconclusive for males in that study, we here use a more ecologically relevant test of male cognitive ability to investigate whether or not a relatively larger brain increases cognitive ability also in males. We compared mate search ability of these artificially selected large- and small-brained males in a maze and found that large-brained males were faster at learning to find a female in a maze. Large-brained males decreased the time spent navigating the maze faster than small-brained males and were nearly twice as fast through the maze after 2 weeks of training. Our results support that relatively larger brains are better also for males in some contexts, which further substantiates that variation in vertebrate brain size is generated through the balance between energetic costs and cognitive benefits.

No MeSH data available.


Related in: MedlinePlus

F3 male guppies (Poecilia reticulata) selected for large relative brain size showed 13.8% heavier brains than males selected for small relative brain size. Shown are the estimated marginal means (mg ± SE) of a GLMM calculating brain weights of the fish used in this experiment corrected for body size and replicate. ***P < 0.001.
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Figure 2: F3 male guppies (Poecilia reticulata) selected for large relative brain size showed 13.8% heavier brains than males selected for small relative brain size. Shown are the estimated marginal means (mg ± SE) of a GLMM calculating brain weights of the fish used in this experiment corrected for body size and replicate. ***P < 0.001.

Mentions: The subsample of animals chosen for this experiment from the large- and small-brained selection lines differed by 13.8% in relative brain size (GLMM: brain size selection line: F1,28 = 26.9, P < 0.001; body size: F1,28 = 51.1, P < 0.001, Figure 2).


A larger brain confers a benefit in a spatial mate search learning task in male guppies.

Kotrschal A, Corral-Lopez A, Amcoff M, Kolm N - Behav. Ecol. (2014)

F3 male guppies (Poecilia reticulata) selected for large relative brain size showed 13.8% heavier brains than males selected for small relative brain size. Shown are the estimated marginal means (mg ± SE) of a GLMM calculating brain weights of the fish used in this experiment corrected for body size and replicate. ***P < 0.001.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4374130&req=5

Figure 2: F3 male guppies (Poecilia reticulata) selected for large relative brain size showed 13.8% heavier brains than males selected for small relative brain size. Shown are the estimated marginal means (mg ± SE) of a GLMM calculating brain weights of the fish used in this experiment corrected for body size and replicate. ***P < 0.001.
Mentions: The subsample of animals chosen for this experiment from the large- and small-brained selection lines differed by 13.8% in relative brain size (GLMM: brain size selection line: F1,28 = 26.9, P < 0.001; body size: F1,28 = 51.1, P < 0.001, Figure 2).

Bottom Line: However, experimental evidence for the link between relative brain size and cognitive ability is surprisingly scarce and to date stems from a single study on brain size selected guppies (Poecilia reticulata), where large-brained females were shown to outperform small-brained females in a numerical learning assay.Because the results were inconclusive for males in that study, we here use a more ecologically relevant test of male cognitive ability to investigate whether or not a relatively larger brain increases cognitive ability also in males.Our results support that relatively larger brains are better also for males in some contexts, which further substantiates that variation in vertebrate brain size is generated through the balance between energetic costs and cognitive benefits.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University , Norbyvägen 18D, SE-75236 Uppsala , Sweden and ; Department of Zoology/Ethology, Stockholm University , Svante Arrheniusväg 18 B, SE-10691 Stockholm , Sweden.

ABSTRACT

Brain size varies dramatically among vertebrates, and selection for increased cognitive abilities is thought to be the key force underlying the evolution of a large brain. Indeed, numerous comparative studies suggest positive relationships between cognitively demanding aspects of behavior and brain size controlled for body size. However, experimental evidence for the link between relative brain size and cognitive ability is surprisingly scarce and to date stems from a single study on brain size selected guppies (Poecilia reticulata), where large-brained females were shown to outperform small-brained females in a numerical learning assay. Because the results were inconclusive for males in that study, we here use a more ecologically relevant test of male cognitive ability to investigate whether or not a relatively larger brain increases cognitive ability also in males. We compared mate search ability of these artificially selected large- and small-brained males in a maze and found that large-brained males were faster at learning to find a female in a maze. Large-brained males decreased the time spent navigating the maze faster than small-brained males and were nearly twice as fast through the maze after 2 weeks of training. Our results support that relatively larger brains are better also for males in some contexts, which further substantiates that variation in vertebrate brain size is generated through the balance between energetic costs and cognitive benefits.

No MeSH data available.


Related in: MedlinePlus