In addition, at least some geometrid caterpillars have the same ability to change their color in order to match their background.
A pink geometrid caterpillar on a pink rose blossom.
Although many geometrid species feed on other parts of plants (and mimic those instead), there are well over a thousand species of geometrid moths in North America -- including plenty of ones with colorful, flower-eating caterpillars. See a few more of them here: Geometrid larvae on flowers
Lichens are a classic example of symbiosis -- the close association of two or more species. In fact, the word "symbiosis" (literally, "together living") was coined in order to describe lichens. The structure of a lichen is formed by a fungus. Meanwhile, cells of algae and/or cyanobacteria are embedded within the fungus and perform photosynthesis to capture energy. Although symbioses are not always harmonious relationships, the lichens pictured below appear to be the symbol of affection.
I can't think about Groundhog Day without recalling our backyard groundhogs, and today I have been imagining them snug in their burrows deep under the snow.
A surprise encounter with a groundhog when I went to photograph its burrow entrance.
Last summer we had two frequent groundhog visitors -- or rather, at least two, since I'm not very confident in my ability to distinguish between individual groundhogs. However, I was sure it had to be at least two. Though we only ever saw one groundhog at a time, the conspicuous difference and rapid alternation between big...
The big groundhog.
...and small groundhogs was enough to convince me that there was more than one.