Animals with large brains are generally considered to be more intelligent and more successful than those with smaller brains. Researchers from the Vetmeduni Vienna and Stockholm University have now provided the first experimental evidence that large brains provide an evolutionary advantage. In their study, large-brained female fish had a higher survival rate than those with small brains when faced with a predator, although brain size surprisingly did not influence male survival. The results were published in the prestigious journal Ecology Letters.
A larger brain brings better cognitive performance. And so it seems only logical that a larger brain would offer a higher survival potential. In the course of evolution, large brains should therefore win out over smaller ones.
Previous tests of this hypothesis had relied on comparison studies looking at the intelligence and survival potential of species with large brains versus species with smaller brains. And species with larger brains do appear to have an advantage. But such studies are unable to show a causal relationship.
Alexander Kotrschal, Sarah Zala, Séverine Büchel and Dustin Penn from the Konrad Lorenz Institute of Ethology at the Vetmeduni Vienna studied fish to answer why investing in a larger brain might provide an evolutionary advantage to compensate for the fact that brain mass is very expensive to develop and maintain.
Research on guppies with large and small brains in semi-natural streams
Guppies are a species of freshwater aquarium fish whose natural range is in the Caribbean region. Kotrschal and his colleagues previously conducted an artificial selection experiment and successfully generated large- and small-brained guppies. In this study, they aimed to test whether brain size influences survival.
Therefore, they released 4,800 guppies from these selection lines into large semi-natural streams, which also contained a natural predator, the pike cichlid. About half a year later, significantly more guppies with large brains had survived. The researchers suggest that large-brained fish have an advantage that allows them to better evade predation. “We have provided the first experimental proof that a large brain offers an evolutionary advantage,” explains first author Kotrschal, who has since moved on to Stockholm University.
Large brains an advantage for females
Large-brained females, whose brains were about 12 percent larger than that of the small-brained females, evaded their predators more often and so had a higher rate of survival. Larger brains did not provide any survival benefit for males. Ethologist Sarah Zala explains: “Male guppies are more colourful and more conspicuous than females and are therefore more easily caught by a predator. A larger brain does not appear to compensate this disadvantage.”
Confirmation of hypothesis on evolution of brain size
“Our findings support the hypothesis that large brains provide a survival benefit under predation pressure,” says co-author Dustin Penn. The first results also suggest that groups of fish with large or small brains behave differently in the presence of the predatory cichlid. This behaviour merits further study. The researchers also want to know whether surviving fish produce more offspring. Genetic analysis should help provide clarity in this regard.
The article „Brain size affects female but not male survival under predation threat”, by Alexander Kotrschal, Séverine Büchel, Sarah M. Zala, Alberto Corral, Dustin J. Penn and Niclas Kolm was published in Ecology Letters veröffentlicht. doi: 10.1111/ele.12441
About the University of Veterinary Medicine, Vienna
The University of Veterinary Medicine, Vienna in Austria is one of the leading academic and research institutions in the field of Veterinary Sciences in Europe. About 1,300 employees and 2,300 students work on the campus in the north of Vienna which also houses five university clinics and various research sites. Outside of Vienna the university operates Teaching and Research Farms. http://www.vetmeduni.ac.at
Dr. Alexander Kotrschal
Science Communication / Public Relations
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-1153
Dr. Susanna Kautschitsch | idw - Informationsdienst Wissenschaft
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy