Research by European scientists raised fresh questions about the impact on bees of neonicotinoids, a ubiquitous and controversial class of pesticides whose future use was restricted by the Environmental Protection Agency.

In a study published in the journal Nature, Swedish researchers reported that wild bees and bumblebees foraging in crops treated with that type of pesticide were less likely to reproduce than bees in untreated fields, and that bumblebee colonies in treated fields gained less weight. Ordinary honeybees appeared unaffected, perhaps, the researchers said, because they were better able to rid themselves of neonicotinoid contamination than were their wild cousins.

A second study by British and Irish researchers concluded that honeybees and bumblebees actually preferred to drink sugar solutions containing two kinds of neonicotinoid pesticides over plain sugar solutions, even though they ate less — and even when they were more likely to die. That finding was a complete surprise, said one author, Geraldine Wright of the University of Oxford.

The researchers said the results cast doubt on theories that bees would avoid treated plants because neonicotinoids tasted bad. To the contrary, the study showed the bees were unable to taste the compound but apparently preferred to consume it anyway because the nicotine-like substance affected their brains.

How to clear an earworm

A study suggests that if you want to get an annoying song out of your head, chewing a piece of gum might help.

It turns out that just the mechanical act of moving one's jaw up and down can reduce the number of times people think about a catchy song, as well as how often they "hear" that song playing in their minds.

To be clear, this method is not a silver bullet. The researchers found that volunteers who were given chewing gum and instructions to "chew vigorously" after hearing particularly "sticky" music, such as the chorus of David Guetta's "Play Hard" or "Payphone" by Maroon 5, experienced fewer phantom memories of the songs, but not zero. Still, the researchers say chewing gum is a tactic worth trying.

Only 3 Isle Royale wolves are left

Only three wolves — a male, a female and a 9-month-old pup — remain in Isle Royale National Park in Michigan, where wolves have been studied for nearly 60 years. The population will probably not recover naturally, biologists have concluded. The pup appears to be sickly, with a constricted waistline, hunched posture and a deformed tail. The wolves prey on moose, whose population is on the rise. More than 1,000 have been spotted on the island.

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