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Time To Eat
Hummingbirds dart from flower to flower, draining each blossom of its nectar. But new research suggests they’re not just zooming around recklessly—they’re on a tight schedule. Flowers refill with nectar every few hours, so hummingbirds would be smart to remember where and when they’ve already eaten. Researchers working at a field station in Alberta, Canada, filled eight flower-shaped feeders with a shot of sugar water every 10 or 20 minutes. Rufous hummingbirds bellied up to each feeder at about the time it was refilled, showing they could keep track of eight different food sources—a useful skill for fueling such buzzing exuberance.
Observed
Name: Daphnia pulex, or water flea.
Once Noted For: Reproducing both sexually and asexually.
Now Noted For: Providing evidence that sex is better.
This Was In Doubt? Yes. Sexual reproduction costs lots of energy, and an individual that engages in it—unlike one that clones itself—passes along only half of its genes. Scientists have long wondered why organisms bother. A new study by Indiana University biologists shows that asexual D. pulex populations accumulate harmful genetic mutations four times faster than their sexual counterparts—strongly suggesting that combining one’s DNA with a partner’s, rather than simply replicating it, is a more efficient way to clean the gene pool.


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