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Science Notes / Entomology, zoology

Weather linked to butterfly mating

The way male and female butterflies relate to one another as adults may depend on how they grew up -- sort of like people. Except for butterflies, it's not whether they had a happy youth. It's the weather.

When certain caterpillars are raised in warm, moist conditions they grow into what some would consider traditional roles -- males pursuing demure females. But new research has found that when they are raised in dry, cool conditions, it's the ladies that become aggressive adults, actively courting the guys.

Researchers led by Kathleen L. Prudic of Yale University reported their findings in the journal Science. They studied Bicyclus anynana, known as the squinting bush brown butterfly because of the eye-like patterns on its wings.

While not visible to humans, pattern reflections make the ones doing the courting appear brighter in the eyes of those being courted, Prudic explained.

Insects have a short amount of time to mate and lay eggs, she said, so they "hit the ground running." When these butterflies mate, males deliver nutrients to the females in addition to sperm. Since cool, dry weather provides fewer resources for butterflies, these extra nutrients can be important to the females, who display to as many males as possible to obtain the extra resources.

-- Associated Press


Female chimps play dolls with sticks

Young female chimps carry sticks as a form of "play-mothering," much in the same way girls cradle their dolls, scientists said. The findings, published online in the journal Current Biology, imply that gender roles might be more biologically rooted than some people think -- and that might hold for human beings, too.

Lead author Sonya Kahlenberg, a biological anthropologist at Bates College in Lewiston, Maine, looked at incidences of stick-carrying in chimps in a community in Kibale National Park in Uganda over 14 years. After examining more than 100 cases, she and co-author Richard Wrangham, a biological anthropologist at Harvard University, noticed a distinct gender difference. Of the young females, 67 percent carried sticks, as opposed to just 31 percent of males.

Aside from their other stick-related activities -- using them to probe holes that might hold honey or water, or brandishing them like weapons -- the young chimps would also occasionally cradle a longer, thicker stick as they went about their business, almost as if it were a baby.

They would even bring the sticks into their nests -- which never happened with the sticks used for honey-hunting or play-fighting. The authors argue that the stick-carrying demonstrates a type of "play-mothering." Those males who did carry sticks stopped doing so as they grew older.

-- Los Angeles Times

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