nobody had expected it.” — Wolf hanke
Wasps have a
mind for mugs
Like humans, insect has a
special gift for learning faces
By Susan milius
A wasp may be the first invertebrate
shown to have a special talent for learning faces of its own kind.
Like people, Polistes fuscatus wasps
can tell individuals of their species apart.
And like people, these northern paper
wasps have a special talent for recognizing faces in particular, Michael Sheehan
of the University of Michigan reported
July 28 at the Behavior 2011 conference.
“To my knowledge, no other insect has
yet been shown to have such specialized
face learning for individual recognition,”
said Emilie Snell-Rood, an evolutionary
biologist at the University of Minnesota.
Studying how individuals of any species recognize each other enriches the
understanding of a species’ social scene.
Biologists have debated whether certain species — including people and some
other primates, as well as sheep — have
some specialized cognitive power for
the northern paper wasp turns out to
be exceptionally good at learning the
faces of others of its kind.
interpreting faces. Now, it seems, the
discussion will spread to wasps.
In P. fuscatus colonies, wasps sport
irregular patterns of yellow, brown and
black markings. Recognizing each other’s
quirky face markings seems to minimize
aggression as queens clash for dominance when establishing joint nests.
Sheehan and colleagues experimented
with the wasps’ ability to learn by put-
ting them into a T-shaped setup with
an image at either end. Annoying elec-
tric tingles stopped when wasps moved
toward the correct one of a pair of wasp
faces, one of t wo abstract patterns or one
of two caterpillar portraits. Researchers
tested multiple pairs in each category.
good mother rattlesnake
Arizona black rattlesnakes may be
more caring moms than researchers
have given them credit for. rattle-
snakes give live birth to babies that
are naïve but mobile and not in need
of feeding. Females and babies linger
near each other after birth, but how
they interact has been a matter of
discussion. Melissa Amarello of Ari-
zona state University and two citizen
scientists monitored new Crotalus
cerberus moms and found a burst of
defensiveness. Females that once
tolerated people coming within a few
yards began rattling at intruders from
inside their dens, Amarello reported
July 27. she even saw one female
herding another mother’s straying baby
back to the den. — Susan Milius
up the former duds, bees returning to
a previously lucky flower, now empty,
were more likely to keep visiting if it
had nectar guides. — Susan Milius
deviously helpful flowers
nectar guides, the stripes and blobs
on petals that tell pollinators where
to sip, may help plants cheat insects.
Anne Leonard and daniel Papaj of the
University of Arizona created a garden
of fake flowers, some offering a sip of
sugar solution and some not. bumblebees lighting on a sugar-stocked flower
found the reward faster if there were
nectar guides. When researchers emptied the rewarding flowers and sugared
iSo well-spotted guy
Abdominal spots turn out to be the
waspy version of a peacock’s train.
Marks on male Polistes dominulus
paper wasps vary, and females prefer
fellows with smaller, more elliptical
ornaments, Amanda izzo of the University of Michigan reported July 27. such
males are also more likely to win fights.
Wasps raised on high-protein diets
developed the more appealing look, the
researchers found. — Susan Milius
www.sciencenews.org
August 27, 2011 | SCIENCE NEWS | 13
