Plants and fungi reciprocate favors
rewards for rewards stabilize underground biological market
NEWS BRIEFS
By Susan Milius
Arbuscular mycorrhizal fungi (green)
and Medicago truncatula (roots in
yellow) reciprocate in nutrient trading.
with a heavier than normal isotope.
Analyzing RNA molecules from the
fungi revealed where more of the heavy
carbon had gone. The plant had indeed
given more carbon to the more generous
fungus species.
To see if fungi would respond likewise, researchers set up lab dishes
with compartments that forced some
plant roots to cheat by restricting the
amount of carbon they passed on. Other
roots acted as good-guy partners for the
fungi. “I think we were all rooting for the
underdog, hoping the world has thus far
underestimated the bargaining power of
fungi,” Kiers says. And yes, the fungi did
pass along more of their phosphorus to
the generous suppliers.
Major steps in evolution often depend
on the rise of ways to stabilize cooperation between organisms, says Ronald
Noë of the University of Strasbourg in
France, who studies biological markets.
“You wouldn’t exist without mutualisms,
and you would have little to eat without
the arbuscular mycorrhizal fungi.”
Fruit of the loo
one of nature’s toilets uses fruity
odors to lure furry critters to its
dangerous rims. in Borneo, the car-
nivorous pitcher plant Nepenthes
rajah is a favorite throne for tree
shrews and rats. While perched on
the pot, animals simultaneously
lick the plant’s lid and deliver a
nutrient-rich poopy present. and
animals occasionally drown in the
bowl, which is filled with soupy
digestive juices, insects and
fecal matter. now, scientists from
germany and malaysia think they
know what keeps small mammals
coming back to these toilets: the
lid exudes hydrocarbons, esters,
ketones and alcohols — com-
pounds that produce a tempting
fruity or flowery fragrance, the
team reports in July’s Journal of
Tropical Ecology. — Nadia Drake
Leafy beacons beckon bats
even though they’re not as flashy
as their floral neighbors, plain old
leaves can attract pollinators, too.
Bats bounce echolocation signals
off leaves growing on the bat-
pollinated Cuban rain forest vine
Marcgravia evenia, scientists from
germany and Britain report July 29
in Science. an odd, dish-shaped
leaf hangs above the vine’s ring
of flowers. shooting simulated
echolocation calls at the leaf pro-
duced a strong, multidirectional
and invariant reflection. removing
the leaf doubled the foraging time
of nectar-feeding bats. the leaf’s
strange shape and orientation
affect its photosynthetic efficiency,
but scientists think that the cost
is balanced by the benefits of
aiding bat pollination.
— Nadia Drake
www.sciencenews.org
september 10, 2011 | SCIENCE NEWS | 15
