HELP Fast! Something Eating my 'Yotes!

It took the top off that one, and I have noticed a little bit of marks off the top of another one. I thought peyote was suppose to be very pest resistant. These guys are about a year and a half old, I'm really worried about the one that was attacked and would LOVE to save the rest of them... they were started from seed...

The only thing I've noticed is some very small misquito/fly looking bugs that have taken a bit of interest in the soil, but they've been all over my house since winter ended.

Sorry for the huge/upside down picture, for some reason I have difficulties putting pictures on here and I believe time is of the essence.




This is the other one with marks on the top.
Nothing has changed in the way of watering/sunlight, and no extra fertilizer/nutrients have been given in case this looks like a case of over-feeding as I've heard it can cause the heads to "explode"