Travel bug is in the genes

Some great tits breed close to the nest where they hatched while others look for a breeding place several kilometres away. In a study carried out at the University of Antwerp, Peter Korsten, who currently works at the University of Groningen, discovered that this distance is heritable. Furthermore, the heritable differences in travel distance are genetically related to heritable differences in exploratory behaviour, the pace at which a great tit explores new surroundings.

The results of the study are published today in Nature Communications. Korsten: ‘This is a piece of fundamental research. Having said this, any information about factors that affect the distribution of birds and other animals is important for keeping tabs on the consequences of the fragmentation of their natural habitats.’

For the purposes of this study, Korsten and his Flemish colleagues used a data set from the University of Antwerp, containing information collected since 1994 about hundreds of great tits in an area near Antwerp. Led by Professor Erik Matthysen, the researchers analysed the distance travelled by hundreds of great tits between the place where they hatched and their chosen breeding place, the extent to which they explored their surroundings (exploratory behaviour), as well as the known family relationships between hundreds of individuals in the population.

Travel bug

Korsten used information from the Antwerp data set to study the distances travelled by the great tits. ‘We found huge differences. Some birds breed in a nest box within ten metres of where they hatched, while others breed three kilometres away.’ In fact some great tits probably fly even further and end up outside the boundaries of the study site, but the data set has no information on these birds.
Using genealogical information about the great tits, Korsten worked out that genetic predisposition accounts for 15% of the individual differences in travel distances. Moreover, Korsten noted differences in the urge to travel between male and female birds: ‘On average, female great tits travel further than males.’

Personality

The Flemish researchers also studied the exploratory behaviour of the great tits and added the results to the database. There are huge individual differences in the way birds explore new surroundings. It has been known for some time that animals show individual differences in behaviour, comparable to personality differences in humans.

Previous research showed that differences in exploratory behaviour are linked to other behaviours. Fast explorers are more aggressive, for example, and tend to take more risks. Korsten’s research shows that in great tits, these differences are 30% genetically determined. ‘What’s more, the genetic predisposition for exploratory behaviour is linked to the genetic predisposition for the travel bug. This would seem to indicate that heritable “personality” differences in great tits may have a direct influence on their dispersal.’

Inbreeding

The dispersal distance (the distance that animals travel between place of birth and breeding place) is an important ecological variable, which can determine the viability of small populations. The dispersal distance influences the variation in numbers and genetic composition of a population, and therefore the degree of inbreeding and local adaptation as a result of natural selection. Up until now, little was known about the internal factors (such as heredity) that affect the distance birds fly between the place where they hatched and their breeding place. Information about factors that influence the dispersal of animals in the wild can also contribute to the protection of fragmented and endangered species.

Curriculum Vitae

Peter Korsten (1973) studied biology at the University of Groningen, where he also conducted PhD research at the Animal Ecology Department. He then embarked on a study of genetics and personality in great tits at the Max Planck Institute for Ornithology in Germany, before working at the University of Edinburgh in Scotland. Korsten started his latest study in Edinburgh in association with the University of Antwerp, where all the practical work was carried out. He completed the research at the University of Groningen, his current place of work.

More information: Dr Peter Korsten .

Genetic integration of local dispersal and exploratory behaviour in a wild bird, Nature Communications , 23 augustus 2013