In relationships based on mutuality, number of individuals involved can determine rate at which species evolve

Sep 24, 2012
The beginning of a beautiful friendship? In some interspecies relationships, ants "tend" to a single caterpillar, preventing it from being attacked by predators. In return for such protection services, they are rewarded with the larva's sugary secretions. New research has now shown that the rate of evolution in a mutualistic relationship does not depend only on the type of interactions, but also on the number of individuals involved. Credit: MPI for Chemical Ecology/ Ian Baldwin / Alexander Weinhold

(Phys.org)—The relationship between species determines how rapidly they evolve. Parasites and their hosts coevolve more rapidly, and partners in a mutualistic relationship can evolve more slowly. But this view is obviously too simplistic. The rate of evolution in a mutualistic relationship does not depend only on the type of interactions, but also on the number of individuals involved, according to a model developed by researchers of the Max Planck Institute for Evolutionary Biology in Plön, Germany. Therefore, while partners can benefit from slow evolution if only two individuals interact, a higher rate of evolution may be favoured if several individuals are involved.

and hosts conduct an arms race with one another in which the parasite must constantly find new ways to circumvent the defensive measures of the host. As a result, they both constantly evolve. This is similar to the situation of the Red Queen in the book "Through the Looking Glass, and What Alice Found There" by British author Lewis Carroll, and is therefore labelled the . The counterpart to it is the Red King's Hypothesis, first posited in 2003: in , evolving more slowly can be favoured. This occurs, namely, when the partners behave egotistically in the beginning and then attempt to become more altruistic. The partner holding back and evolving more slowly benefits, as it does not have to invest anything in improving the partnership.

Up to now, researchers have explored the Red King Hypothesis only in models for which two individuals come into contact with one another. However, this does not reflect reality for the most part. It is much more often the case in nature that several individuals are in a relationship with one another. Thus, several protect a single butterfly larva in order to be rewarded with its honeydew. For the ant, the relationship is therefore between two individuals; however, from the perspective of the caterpillar, there are multiple partners interacting.

The scientists in Plön have therefore tested the Red King's Hypothesis in a multiplayer model. According to this, it was confirmed that the Red King's Hypothesis is only valid in pairwise mutualistic relationships. As soon as several parties are involved, it becomes considerably more complicated. "Then more rapid evolution can be favoured for a party as well," explains Chaitanya Gokhale from the Max Planck Institute for .

Explore further: Blacklegged tick populations have expanded via migration, biologists show

More information: Chaitanya S. Gokhale and Arne Traulsen, Mutualism and evolutionary multiplayer games: revisiting the Red King, Proc. R. Soc. B published online 12 September 2012 (doi: 10. 1098/rspb. 2012. 1697

Related Stories

Scientists reveal driving force behind evolution

Feb 25, 2010

Scientists at the University of Liverpool have provided the first experimental evidence that shows that evolution is driven most powerfully by interactions between species, rather than adaptation to the environment.

Evolution may take giant leaps

Dec 11, 2009

(PhysOrg.com) -- A new study of thousands of species of plants and animals suggests new species may arise from rare events instead of through an accumulation of small changes made in response to changes in ...

Recommended for you

The role of species competition in biodiversity

14 hours ago

(Phys.org)—Over long spans, biodiversity is a fluid and shifting balance of species and influences. Species diversification occurs in response to a host of complex factors, both biotic and abiotic, and ...

'Map of life' predicts ET. (So where is he?)

Jul 02, 2015

Extra-terrestrials that resemble humans should have evolved on other, Earth-like planets, making it increasingly paradoxical that we still appear to be alone in the universe, the author of a new study on ...

Single-celled predator evolves tiny, human-like 'eye'

Jul 01, 2015

A single-celled marine plankton evolved a miniature version of a multi-cellular eye, possibly to help see its prey better, according to University of British Columbia (UBC) research published today in Nature.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.