And judging by the darkened color, it's fixing to pupate.
I'd like to see how large it is, it certainly has the look of a caterpillar about to shed its skin and pupate, but looks small and stunted.
Happens quite a lot, ones that are harboring parasitic wasp or fly larvae or have some sort of bacterial or fungal disease, these stunted guys sometimes try to do their pupation thing but don't make it.
At one point in my college career I was collecting in the field and raising to maturity hundreds of corn earworm larvae to measure parasitism and disease rates.
Here's one of them outstanding nature videos of one sort (there's a bunch)...
I can state with authority that after you have looked at a few hundred of these things up close through a dissecting scope, caterpillars are a totally alien and repulsive life form; segmented worms with legs and multiple eyes scattered in strange places on their heads. Even the cute little ones are just as repulsive as the big ones when you crank the magnification up.
Hit 'em with the right hormone at any size and they'll go through the skin-shedding thing, sorta like Jeff Goldblum in "The Fly".
The worst thing is when you're looking at a pupa under the scope and suddenly the top pops off and you're looking at a huge pair of compound eyes looking back, sticking out the top of the pupa, then this worm-looking thing with big eyes and legs quickly squeezes out (to later do the hardening and rearranging thing into the familiar moth).
And the stench; keep hundreds in a confined space and there's a smell, something resembling chicken house crap, from all the nitrogenous wastes. This goes in spades for the emerging from the pupa stage, it stinks.
..or a college work-study job to help pay one's tuition. Gross but not as menial as some such jobs.
The other thing IIRC which will produce a stunted caterpillar like that is starvation if they get separated from the host plant or if the food runs out. If I'm recalling right that can trigger an attempt to pupate with such reserves as they might have.
If they pull it off IIRC they emerge as a smaller than usual adult with fewer reserves to engage in the strenuous dispersing/host plant locating/egg laying processes of reproduction. Or else if weaker they get stuck in mid-transformation like that one appears to be.
..or a college work-study job to help pay one's tuition. Gross but not as menial as some such jobs.
The other thing IIRC which will produce a stunted caterpillar like that is starvation if they get separated from the host plant or if the food runs out. If I'm recalling right that can trigger an attempt to pupate with such reserves as they might have.
If they pull it off IIRC they emerge as a smaller than usual adult with fewer reserves to engage in the strenuous dispersing/host plant locating/egg laying processes of reproduction. Or else if weaker they get stuck in mid-transformation like that one appears to be.
Birdwatcher
mike if i'd of been doing that research, i'd be able to tell which ones worked best on bluegills.
Weird Caterpillar, Looks like the one in Alice in Wonderland. Just took the photo an hour ago.
Cool. Those big fake eyes are to deter predators. Those with random patterns that tended to look more like eyes tended to be passed up by them, so they lived to pass on that trait.