When David beats Goliath

September 24, 2014 by Anne Craig, Queen's University
The Sparkling Violetear Mulauco was one of the bird species biologist Paul Martin studied for his research into understanding why species live where they do.

Body size has long been recognized to play a key role in shaping species interactions, with larger species usually winning conflicts with their smaller counterparts. But Queen's University biologist Paul Martin has found that occasionally, small species of birds can dominate larger species during aggressive interactions, particularly when they interact with distantly related species.

The new findings provide evidence that the evolution of certain traits can allow species to overcome the disadvantage of a smaller size.

"We want to understand why species live where they do, and how different species partition resources, like food, in nature," Dr. Martin explains. "This research feeds into that. The 'larger animal wins' rule that usually governs , and often influences where smaller species can live, is more likely to break down when the interacting species are distantly related."

For his research, Dr. Martin examined the outcome of 23,362 aggressive interactions among 246 bird species pairs including vultures at carcasses, hummingbirds at nectar sources and antbirds and woodcreepers at army ant swarms. The research looked at the outcome of aggressive contests for food among species as a function of their and evolutionary distance.

The research found that the advantages of large size declined with increased evolutionary distance between species—a pattern explained by the evolution of certain traits in smaller birds that enhanced their abilities in aggressive contests.

Specific traits that may provide advantages to small species in aggressive interactions included well-developed leg musculature and talons, enhanced flight acceleration and maneuverability and traits associated with aggression including testosterone and muscle development.

"This study examines broad patterns across many species, and now we would like to understand the details of these interactions by studying specific groups," says Dr. Martin. "We really want to understand why some species can overcome the disadvantages of small size, while other cannot."

The research was published in the latest issue of PLOS ONE.

Explore further: New study refines biological evolution model

More information: www.plosone.org/article/info%3 … journal.pone.0108741

Related Stories

New study refines biological evolution model

July 21, 2014

Models for the evolution of life are now being developed to try and clarify the long term dynamics of an evolving system of species. Specifically, a recent model proposed by Petri Kärenlampi from the University of Eastern ...

Sloths are no slouches when it comes to evolution

September 10, 2014

Today's sloths might be known as slow, small animals, but their ancestors developed large body sizes at an amazing rate, according to an evolutionary reconstruction published today in the open access journal BMC Evolutionary ...

Researchers revise Darwin's thinking on invasive species

December 2, 2013

For more than a century and a half, researchers interested in invasive species have looked to Charles Darwin and what has come to be called his "naturalization conundrum." If an invader is closely related to species in a ...

New parasitoid wasp species found in China

September 8, 2014

For the first time, wasps in the genus Spasskia (family: Braconidae) have been found in China, according to an article in the open-access Journal of Insect Science. In addition, a species in that genus which is totally new ...

Recommended for you

Why do Hydra end up with just a single head?

January 18, 2019

Often considered immortal, the freshwater Hydra can regenerate any part of its body, a trait discovered by the Geneva naturalist Abraham Trembley nearly 300 years ago. Any fragment of its body containing a few thousands cells ...

How our cellular antennas are formed

January 17, 2019

Most of our cells contain an immobile primary cilium, an antenna used to transfer information from the surrounding environment. Some cells also have many mobile cilia that are used to generate movement. The 'skeleton' of ...

0 comments

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.