Army ants make a habit of killing organisms, often much larger than themselves, breaking them into pieces and dragging them back to their bases. They don’t eat everything. Waste full with discarded bits of prey is a feature of army ant bases. But little is known about which animals make use of army ant leavings.

As recounted in a paper in Ecology &. Evolution, Christoph von Beer en at the Technical University of Darmstadt and Daniel Kronauer at the Rockefeller University in New York, went to the rainforests of Costa Rica to find out. They found an entire ecosystem thriving among the leftovers.

Monitoring tiny insects in a rainforest is tricky. But the researchers hoped modern DNA analysis techniques might make the job manageable. Working with a team of colleagues, they followed ant trails back to their bases, finding 34 sites in total.

The researchers used a handheld vacuum cleaner to suck up all the bugs at waste and brought the samples back to a field laboratory. To keep the task manageable, the team confined themselves to examining only the beetles they had collected. They identified the beetles they could and ran DNA analyses on those they could not.

In total, they collected 8, 364 adult beetles, 511 beetle larvae and 24 beetle eggs. Those were spread across 91 species, several of which were entirely new to science. Aside from that being far more than anyone had expected, the presence of the larvae and eggs indicates that the leftovers are not so much convenient restaurants as full-on homes, where the beetles live out their entire lives.

Precisely how these species manage to avoid being eaten themselves by their army-ant hosts remains to be determined. Dr. von Beeren speculates that a hygiene instinct that keeps the ants from eating material that has been taken to their waste is partially responsible. And many species of beetles are able to produce compounds that smell disgusting to ants. The chances are high that among these insects are some predators too, seeking to feed on unsuspecting scavengers (食腐动物) in turn.

An American buffalo (水牛) that escaped from a Wauconda farm is making a name for herself, with citizens posting photos and videos of her on social media. A local artist has painted a picture of the clever animal — called Billy by her fans.

Fans were amazed at her achievement — she appears to have crossed the Fox River — as well as her outstanding spirit, and her love of freedom. “I never thought in a million years there would be some big animals running around the suburbs like this", said the local artist who painted Billy.

Billy escaped in September, when she and her sister, both under a year old, were delivered to a farm. Billy escaped when she was released from the truck, Kryscha said. Billy's sister was unloaded successfully and has adjusted well to life on the farm, he said. The second buffalo has enthusiastically bonded with a group of cows, even trying to copy some of their behaviors, such as rolling on the ground.

Police aided in the search, even using a drone (无人机) . But once again, Billy avoided being caught. Part of the problem, Kryscha said, is that buffaloes, a native species in Illinois, match so well with local grasses and trees. Others have cheered the buffalo on — “Go Billy!” — or debated her sex. She is definitely female, her owners say, but she doesn't have a name yet.

Buffalos are herd animals, so Billy is probably lonely on her own, Kryscha said. Her sister is already copying the behavior of her new friends: She's been seen trying to roll on the ground to get dirt on her back, which doesn't really work for a buffalo. Billy's sister has had more success in her attempts to jump like a horse.

Billy's fans are divided as winter approaches, with some hoping she escapes forever and others saying maybe it's time to come in from the cold.