Sounds like cutworms but the "black insects" terms you used make be wonder.

I just noticed teeny tiny black aphids on a little yellow blooming succulent so those may be your black insects. A spray of neem oil will take care of the little suckers. A solution of soapy water will also.

The cut worms are a little harder to manage as they come out at night from under the soil. Look at the base of the wilted pansy stem and if cutworms did the damage you should be able to see where they have chewed it off. I've not had a problem with them so can't suggest a solution, but found the below information on the internet.

Happy gardening, aphids, cutworms, and all!

Here is a link that might be useful: Controlling cut worms ...