[Pollinator] USA Today: Plants know how to woo a pollinator

[Jennifer Tsang]

http://www.usatoday.com/tech/science/discoveries/2007-10-04-plant-sex-perfum
e_N.htm

 


Plants know how to woo a pollinator

By Randolph E. Schmid, Associated Press

WASHINGTON - Think about strong perfume and a threesome, and what do you
get?

No, try again.

The correct answer is - reproduction by an ancient type of plants called
cycads.

Sure, lots of plants use a third party in reproduction to carry their
pollen: Think the birds and the bees.

But cycads have put their own special spin on the process, scientists report
in Friday's issue of the journal Science <http://www.sciencemag.org> .

Male cycads produce cones that open and emit a fragrance that attracts
insects called thrips, which enter the cones and become covered with pollen,
according to the research team led by Irene Terry of the University of Utah.

Then the male cycads heat up - raising the temperature as much as 25 degrees
Fahrenheit - and produce a much stronger odor, driving the thrips out.

The thrips, looking for more cycads, notice the attractive scent of female
cycads and enter their cones, bringing the male pollen to the female plants.

The scientists call this "push-pull pollination."

"People think of plants as just sitting there and looking pretty and sending
out some odors to attract pollinators, but these cycads have a specific
sexual behavior tuned to repel, attract and deceive the thrips that
pollinate them," Terry said in a statement.

"These cycads heat up, and associated with that heating is a huge increase
in volatile fragrances emitted by the cone," Terry said. "It takes your
breath away. It's a harsh, overwhelming odor like nothing you ever smelled
before."

Cycads have been around at least 250 million years. They are gymnosperms, a
group that also includes firs and pines. The ones studied by Terry and
colleagues were in Australia.

The male cycads increase their temperature between 11 a.m. and 3 p.m. daily
during their annual coning season lasting a few weeks. They generate heat
using sugars, starch and fats that normally power everyday cell functions.

Robert Roemer, Terry's husband and a professor of mechanical engineering at
the University of Utah, studied heat transfer within the cycad cones.

The research was funded by the National Geographic Society, the University
of Utah and the University of Queensland, Australia.

Copyright 2007 The Associated Press. All rights reserved. This material may
not be published, broadcast, rewritten or redistributed.

 

 

Jennifer Tsang
Coevolution Institute <http://coevolution.org> 
423 Washington St. 5th Fl.
San Francisco, CA 94111-2339
T: 415.362.1137

F: 415.362.3070

www.nappc.org

www.pollinator.org

 

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