If you have pets or if you touch someone's dog that has Advantage or other tick killer on it's body, be aware that this will kill/poison your larvae. I learned this the hard way last year.
The stuff does not wash off. Do not handle animals during butterfly season - then wear gloves. It's something I learned the hard way as I said, but Dale pointed this out to me once and I found it to be true.
I've had butterflies land on my rug were the dogs lie and then they die .... the story goes on and on - it's toxic stuff.