13 de gener 2018

YOU SHOULD THINK OF HUMMINGBIRDS AS BEES WITH FEATHERS

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What’s small, buzzes here and there and visits flowers?

If you said bees or hummingbirds, you got it. And you wouldn’t be the first if you mixed the two up. In Medieval Europe, some called bees the smallest birds. In Chinese and Japanese, the words for hummingbird translate into “bee bird.” Today we call the smallest hummingbird — weighing less than a penny and only a bit larger than the biggest bee — the bee hummingbird.

And now a group of researchers say we should embrace our history of lumping the two together. The way scientists study bees could help them study hummingbird behavior, too, they argue in a review published Tuesday in Biology Letters.

Scientists first compared the two back in the 1970s when studying how animals forage. The idea is that animals use a kind of internal math to make choices in order to minimize the work it takes to earn maximum rewards. Researchers at the time focused on movement rules, like the order in which they visited flowers, and where flowers were located relative to others. It was “almost like an algorithm” for efficient foraging, said David Pritchard, a biologist at the University of St. Andrews in Scotland who led the review. Hummingbirds and bees had similar solutions.

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But the study of optimal foraging, as it was called, overlooked what animals learned about their environments. Bees decipher which flowers are more rewarding than others. They learn about color and how to manipulate a flower among other information. Decades before the concept of optimal foraging, Frank Bené, an American ornithologist, discovered that hummingbirds learned about color too, contrary to the belief that they were innately attracted to red. Hummingbirds also remembered locations of feeders that he moved in his garden.

As the field of animal cognition emerged, hummingbird and bee research diverged. Neuroscientists and behavioral ecologists developed ways to study bee behavior in naturalistic settings. Hummingbird researchers compared hummingbirds to other birds and borrowed methods from psychology to study their capacity to learn in the lab.


To be fair, hummingbirds and bees differ. Hummingbirds have more advanced eyes and brains than bees. Olfaction, while important for bee memory, has historically been ignored in hummingbirds. Honeybees and bumblebees are social; hummingbirds typically aren’t. Bees rely solely on flowers for nectar and pollen; hummingbirds also eat insects, which may require that their brains work differently, Beth Nichols who studies bee behavior at the University of Sussex in Britain wrote in an email.

But however they perceive or process information, they both experience similar information, Dr. Pritchard said. Bees and hummingbirds approach flowers that distribute food predictably in time in space, so he and his colleagues have turned to these animals’ commonalities.

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In day-to-day foraging, for instance, hummingbirds may rely on more of a bee’s-eye view than a bird’s-eye view. Like other birds, they rely on landmarks, distances and directions to make maps when migrating long distances, but they don’t use these cues to find flowers. Move a flower just an inch or so away from where a hummingbird thought it was and it will hover over the flower’s original location. Dr. Pritchard is investigating if, like bees, hummingbirds engage in view matching — hovering, scanning snapshots of a place to its memory and using those as references later.

Like bees, hummingbirds also create repeated routes between flowers during feeding, as a trapper might check traps. In the lab they learn arbitrary sequences, following one flower to the next over hundreds of trials. But they won’t do it in nature. Taking methods from bee work, however, researchers put hummingbirds in an arena of artificial flowers that refilled with nectar like flowers in the wild. Like bees that find the fastest way to nectar-rich flowers on their own, hummingbirds also found the most efficient paths, rather than following the order in which researchers had presented flowers

Ultimately, Dr. Pritchard said, advances in our understanding of an animal can come from unexpected places.


“The idea of getting inspiration from insects to study birds and mammals is something that doesn’t happen very often.”

By  - THE NEW YORK TIMES