The Big Woods were covered after an overnight snowfall; it wasn’t much, about two inches, but it was the most we had thus far in this winter. The temperature was in the mid 20s (F) and it was a dandy day for a walk in the woods.
I’d already taken a few photographs when I noticed a large dead white oak with loose bark. Loose bark on a large dead tree is too tempting to pass by, so I stopped and pulled off some of the bark since there’s often something interesting between bark and wood. Those interesting things are usually insects or spiders. Winter is a poor time to find insects, but it can be done.
Most insects spend the winter as eggs, larvae or pupae, a smaller number overwinter as adults. When I pulled the bark from the dead oak what was there but six adult red flat bark beetles –
Few insects can tolerate temperatures below -40° Fahrenheit (which just happens to be -40° Celsius) but the red flat bark beetle can tolerate that and lower – down to -70°F in northern Alaska.
This beetle is certainly flat –
Which enables them to move about beneath the bark and in small nooks and crannies –
Their larvae are even flatter than the adults and also live beneath the bark of dead trees and fallen logs –
The larvae spend two years under the bark feeding on small insects, spiders and mites and then pupate in the fall. Adults, which emerge late the following summer or fall and also eat small insects, spend the winter beneath the bark. After the adults mate in the spring the females lay their eggs under tree bark.
Both adults and larvae can survive extremely cold temperatures, not just -70°F in the arctic, but reportedly -148°F in experiments to test their tolerance of cold. They’re freeze-proofed by depositing glycerol and certain proteins in their bodily fluids.
Red flat bark beetles are certainly red, they're entirely red except for the black lower legs, antennae and, despite what some websites say, the eyes –
Red flat bark beetles aren’t uncommon but are not frequently seen unless you’re looking for them. But if you burn firewood you may find one in the house, brought in with the firewood.