[ Back to EurekAlert! ]

PUBLIC RELEASE DATE:
20-Mar-2014

[ | E-mail ] Share Share

Contact: Ben Norman
Sciencenewsroom@wiley.com
44-012-437-70375
Wiley

First evidence of plants evolving weaponry to compete in the struggle for selection

IMAGE: This is an example of the horned pollinaria found in South American milkweed.

Click here for more information.

Rutting stags and clawing bears are but two examples of male animals fighting over a mate, but research in New Phytologist has uncovered the first evidence of similar male struggles leading to the evolution of weaponry in plants.

The team, led by Dr. Andrea Cocucci from the Instituto Multidisciplinario de Biologia Vegetal of Argentina, studied a species of milkweed (Apocynaceae), found in tropical climates. While plants do not mate like animals, but rather reproduce via pollinators such as insects or birds, competition between individuals to exploit those pollinators can result in confrontation between the plants.

Milkweed reproduce by hooking sacs of pollen grains, known as pollinia, to the bodies of birds and other pollinators, which can be unwittingly dropped into another flower to complete pollination.

It is possible for multiple pollinarium to become entangled together due to the limited number of attachment points on the pollinator, and this Dr. Cocucci's team believe, is the source of confrontation.

The team studied the South America milkweed genus Oxypetalum and found horn-like structures on the pollinia sacs which have no obvious biological use. The paper suggests that these horns are used to prevent the sacs from being hooked together with pollinia from other parent plants.

"Our results suggest that neither self-propulsion nor well-developed sensory perception are required for sexual selection to take place through intrasexual struggles," said Dr. Cocucci. "Apparently, only physical contact is enough to influence the mating success of competitors and to promote the evolution of defensive and attack weaponry."

###



[ Back to EurekAlert! ] [ | E-mail Share Share ]

 


AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.