Happy Sunday − and welcome to the best of The Conversation U.S. Here are a few of our recently published stories:

• US launches retaliatory strikes in Iraq and Syria − a national security expert explains the message they send
• How retaliatory airstrikes affect network of Iran-backed militias
• Billy Joel is back for an encore − but why did he wait so long to turn the lights back on?

If you’ve ever sat by a campfire or on your front porch after dark, you’ve likely seen moths and other insects erratically circle the source of light. I’ve often wondered what draws them in – imagining something akin to getting caught in a spaceship’s “tractor beam.” Other less sci-fi-oriented explanations for this hypnotic behavior include that insects are simply drawn to the heat or are trying to perform celestial navigation, mistaking the light for the Moon.

But the actual reason is even more surprising, as senior environment and cities editor Jennifer Weeks learned after spotting a journal article on the topic. A team of researchers from the U.K. and the U.S. used high-speed cameras to record insects flying around several light sources in labs and outdoors to determine precise flight paths and body postures. Normally, insects point their backs toward the night sky – which is lighter than the ground – to orient themselves as they fly; the researchers found that artificial light at night alters insects' flight paths, cuing them to orbit the light source.

“Although insects circling around a light are a fascinating spectacle, it is certainly better for the insects and the benefits they provide to humans when we leave the night unlit and let them go about the activities they so masterfully perform under the night sky,” they write in one of last week’s most popular stories.