Yup, the insect was just visiting. I could only see one picture. It's possible you've got a gopher, however gopher holes generally aren't this wide and the opening is better defined. Definitely not a snake. The soil looks very dry which makes me suspect that a contributing factor here may be a critter that did a little digging combined with native soil pulling back from the smaller hole that the tree was planted in. Be interesting to put a hose down and see how long it takes to fill up with water! Either way, I'd fill it up with dirt and see if it gets redug. If you've got a gopher you'll see another hole, too. They always have an entry and exit. Keep us posted!

Vine weevil mouth parts work in such a fashion that they are only able to feed on leaf margins - you will see telltale notching of the leaf edges but never holes in the center of the leaf. Vine weevil larvae are much more likely to bother heucheras by feeding on the roots. Holes in the center of the leaf sounds more like slugs or snails. Or possibly some sort of caterpillar-type larvae. I'd bait for slugs first but if you use Sluggo Plus, you can kill two birds (or multiple leaf snacking insects :-)) with one stone.

Skunks and racoons do did for food. The racoons practically plough the ground under my bird feeders. Your holes are sized typically of those that squirrels make at this time of the year for burying tree nuts. However, I did not see nay evidence that anything was "buried" in your lwan. During dry times, earthworms and night crawlers retreat deeper in the soil in search of moisture. Also, earthworms prepare for winter at this time of year and are not available for anumal food.

I'm also from MS. Definitely cicadas. It is a brood year and they are every where. My yard is filled with these holes and the surrounding plant life is littered with the shed exoskeletons. If you live in the country there is a low drone 24/7 from the millions of these guys that popped out of the ground this year. Interestingly enough it doesnt appear to be state wide. I work on the gulf coast during the week and havent heard the first peep out of them. But back home in Lincoln Co, its enough to drive you mad. http://www.cicadamania.com