Some welcome news came late Friday amid the recent rash of robberies around town. Police arrested an 18-year-old Aiea man for allegedly robbing two Leeward 7-Eleven stores late Thursday and early Friday. He was allegedly armed with dangerous instruments in both incidents, but thankfully, no one was injured.

Still, other recent armed robberies remain unsolved, including six bank crimes in the first 12 days of December. That contributed to a worrying statistic: a 77 percent rise in bank hold-ups on Oahu — 23 this year, compared with 13 last year.

Police suspect the same two or three men in some of this month’s robberies. Surely, someone has a line on one of them: a man in his 50s, with white hair and white mustache, who walks with a distinct waddle.

Invasive species survive by eating each other

There are lots of studies that fall into the “Interesting Fact” category; this case has a subtitle: “But What Do We Do About It Now?”

University of Georgia researchers have discovered that many invasive creatures are so well established in Hawaii because there is a ready food source: the carcasses of other invasive species.

The mongoose, for example, consumed 55 percent of the carcasses the researchers were watching. Nice cleanup job. The only problem: How do we then get rid of the mongoose?