since you raised io moths, have you noticed the caterpillars only eating at night?
I believe I have noticed them eating throughout the day (but they definitely did have periods of inactivity). Although, it’s hard to say for certain because I work a full time job with a LONG commute M-F, and volunteer with a LONG commute on weekends, so I’d usually only be around at night/early morning. I think I’ve noticed caterpillars being more active during the day for some species (warmer = less energy to move around?) and the more mature io caterpillars don’t need to worry about getting eaten since they have venomous spines.
Some caterpillars, typically the smallest ones, come out only at night and hide during the day (especially in Texas, they could easily dry up in the sun!). And I went out into my yard every day and every night so I noticed different species different times of the day. Most of my caterpillars I found as eggs, and it is easier to find them at night because flashlights = shadows and that ruins their camouflage techniques.