Don't call them ladybugs, says naturalist Brian Keating
Hill-topping is the Tinder for lady beetles, but it’s more than just hookups
Brian Keating was recently enjoying a stunning view of southeastern B.C.'s Creston Valley from the Thompson Rim Trail when he stumbled across what he thought were ladybugs. Hundreds of them.
"The ridge gave us some expansive views all around, and to the north, with binoculars, we could see Kootenay Lake and the glaciers of Kokanee Park," Keating — a Calgary-based naturalist — told The Homestretch.
"After stashing our bikes, we hiked about three kilometres along the ridge. At our turn-around point, around 4 p.m., we found hundreds of ladybugs congregating on and around several old fallen logs."
He said the weather was perfect. It was warm but with little wind, given the altitude.
"One doesn't usually associate ladybugs with mountaintops, so I got curious. On the weekend, I contacted two of my favourite bug people to see if I could get any answers."
And it was an entomologist, Keating's brother-in-law, to be specific, who put Keating on the right path.
"He quickly corrected me. They should not be called ladybugs but rather lady beetles. He reminded me that true bugs have sucking mouthparts for ingesting plant juices, while beetles do not. Lady beetles do not suck plant juices, they are predators," he explained.
Like many other insects, lady beetles employ a behaviour called hill-topping.
"When they need to find each other, their genetic coding tells them to go uphill to the top, and others will likely be there, too. It's easier to find each other in an area of a few cubic metres than on a big landscape."
Hill-topping is more than just a way to find love — or, more likely, procreation opportunities. It's also used to find new feeding locations and places to settle in for the winter.
There are about 150 lady beetle species in Canada, more than 500 in North America and around 6,000 around the world.
Overwintering, life cycles
Lady beetles don't generally overwinter on a mountain top, Keating said.
"All they need to overwinter is a place where hundreds or thousands of them can huddle together, in a crack, crevice, in tree bark and even in your house or roof."
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Lady beetles, like many other insects, have four life stages. They lay eggs that hatch into larvae, that change into pupae and finally into adults, where it all starts again.
"It's the larvae which do much of the dirty work," Keating said.
"They are the hungry predators which most often feed on aphids. They are so voracious that they will even eat each other. But the adults apparently continue to hunt and kill other insects, although the adults eat only about 10 per cent as much as the growing larvae."
For more fascinating stories about Alberta's wildlife from naturalist Brian Keating, visit his website and check out these stories:
With files from The Homestretch