Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Competition favors shy tits

10.03.2016

Different personalities are maintained in the wild mainly because of changes in density. This is what researchers of the Max Planck Institute for Ornithology in Seewiesen and colleagues of the University Groningen found out for great tits. During four years, they observed that slow explorers are more likely to survive if intraspecific competition increases due to an increase of density in a population. But although individuals are able to anticipate future breeding densities, they are amazingly bad in adjusting their exploratory behavior and therefore their chance to survive: Instead of slowing down, birds increased their speed of exploration when facing increases in density between years.

Exploratory behavior is a repeatable and heritable trait in West-European great tit populations and therefore underlies selection pressures in nature like all heritable differences in personality. Explorative individuals are more likely to take risks and to obtain higher social dominance ranks among territorial adults in the wild.


Great Tits have personality: They come as fast- and slow-explorers. Which type is more successful depends on the population density.

Richard Ubels

It might seem that those birds are doing better in competitive environments, such as in high densities, as they are better in defeating limited resources when intraspecific competition increases in a population. When competition is relaxed, net benefits may instead decrease because risky behaviors require more energy.

Researchers of the Max Planck Institute for Ornithology Seewiesen and the University of Groningen, however, followed another prediction: Fast-exploring, aggressive phenotypes may survive less well when facing high densities as they are less able to anticipate and buffer changes in their social environment.

For their study, the researchers regularly controlled 600 nest-boxes in 12 woodlots over four years and calculated the densities within and between the populations. Fitness was calculated as survival probability and number of recruits. Exploratory behavior was assayed in a “novel environment room” where the total number of flights and hops within the first two minutes after arrival of an animal was counted.

“The density effect on the different personality types was amazingly strong”, says Niels Dingemanse, research group leader in Seewiesen. Survival rates of fast explorers decreased with increasing density equally strongly as survival rates increased for slow explorers. These fluctuating selection pressures were mostly explained by year-to-year variation in density within rather than spatial variation among the 12 study plots.

Predicting the competition of next year

The design of the study did not only allow the researchers to understand how the different personality types underlie density dependent selection, but also if an individual is able do adjust its exploration behavior depending on the population density. „Our data show that great tits are able to anticipate future breeding densities as they are able to change their exploratory behavior between years“, says Marion Nicolaus, first author of the study.

In autumn, great tits may calculate the competition for breeding space in spring by the amount of beech seeds available: If there is a lot of food, chances to survive the winter are better. However, the birds were unable to appropriately adjust their exploratory behavior as they did not adaptively down-regulate their exploratory tendency with increasing density. According to the scientists, this explains why selection favors a mix of personality types rather than one single flexible type of individual.

Interestingly, psychologists also predict for human populations that competitive environments should favor sociable, shy, and non-aggressive individuals. In contrast, individuals with high levels of exploratory activity or aggression should perform relatively better in declining populations (e.g. because of habitat loss). “Whether this potential loss of personality variation affects the adaptive capacity of populations is currently unknown but represents an important question in both the social and natural sciences”, says Niels Dingemanse.

Publication:
Density fluctuations represent a key process maintaining personality variation in a wild passerine bird. Marion Nicolaus, Joost M. Tinbergen, Richard Ubels, Christiaan Both and Niels J. Dingemanse. Ecology Letters, Article first published online: 29 Feb 2016. DOI: 10.1111/ele.12584

Contakt:
Dr. Marion Nicolaus
Max Planck Institute for Ornithology
Research Group „Evolutionary Ecology of Variation“
E-Mail: mnicolaus@orn.mpg.de

Prof. Dr. Niels J. Dingemanse
Max Planck Institute for Ornithology
Research Group „Evolutionary Ecology of Variation“
E-Mail: ndingemanse@orn.mpg.de

Dr. Sabine Spehn | Max-Planck-Institut für Ornithologie
Further information:
http://www.orn.mpg.de

Further reports about: Competition Max-Planck-Institut Ornithology shy tits

More articles from Life Sciences:

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

nachricht Pollen taxi for bacteria
18.07.2018 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>