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You've probably seen clouds of insects swirling¹ round a streetlamp at night. But something you may not have noticed is that streetlights attract bugs³ to the ground below them, too—especially carnivorous bugs, like beetles⁴. So says a study in the journal Biology Letters by researchers at the University of Exeter. Thomas W. Davies, Jonathan Bennie and Kevin J. Gaston,"Street lighting⁵ changes the composition of invertebrate⁶ communities"]

 

The researchers set up 28 traps in the grass below and between streetlamps in the English town of Helston, in Cornwall. They collected captured insects at dawn and dusk over three days, and ended up with nearly 1,200 specimens⁷. Turns out, more bugs hung out under the lights than between them. And that was true at night and day—suggesting that streetlights permanently⁸ upped the value of the buggy real estate below them.

 

The researchers also found greater numbers of predators⁹ and scavengers under the lamps—like ground beetles, harvestmen and ants—because it may be easier to hunt for prey¹⁰ with the help of a spotlight¹¹.

 

With artificial lighting increasing globally at 6 percent a year, the authors say there's a chance light pollution could shake up food webs in unforeseen ways. Call it a bug² in the system.

 

Thanks for the minute, for Scientific Americans 60 second science, I am Christopher Intagliata.

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