This cool design was "tattooed" on this leaf.
I found it on the windshield of my car.
What's up with it?
Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It only takes a minute to sign up.Sign up to join this community
That is the work of a leaf miner. A leaf miner is the larval stage of an insect that feeds on the inside layer of leaves. Notice how the galleries (tunnels) start small and then get larger as the larva matures? Most leaf miners are moth larvae (Lepidoptera) https://en.wikipedia.org/wiki/Leaf_miner
This leafminer is a moth in the genus Phyllocnistis (Gracillariidae). If you knew what plant the leaf came from, the moth could probably be identified to species. The marginal leaf fold at lower right is where the mature larva has spun its cocoon.
Incidentally, I'm just finishing a complete guide to the known leafminers of North America. There are many species left to be discovered though!