Having seen the first monarch in our butterfly garden a while ago, we went out in search of caterpillars this afternoon. We were well rewarded.
After careful searching we found eight cats and brought them in. Why did we bring them all inside? Of course one or two would do for Calvin to observe, but monarchs cats are prone to a high fatality rate in the wild. Wasps, spiders, and flies are predators or parasites, and they are susceptible to a variety of fungal and other infections. Most of these are natural killers (although many pesticides are culprits as well) and as with all wild animals, this is a natural form of population control. But the flip side of the coin is that monarchs are also threatened in other, not so natural ways, in their adult form, and the more cats we can bring to butterfly stage the better. So we brought them in to see if can help them get there safely.
Number 8 is the tiniest, and number 1 we're already calling fatso. Unfortunately, even though we now have them safely away from natural predators, they may still be infected by bacterial or fungal infections and we may not see them all reach the pupal stage. I've read many horror stories and I'm already concerned about one of our little guys, but all we can do is our best.
On the recommendation of a helpful friend, we are keeping them in Glad reusable containers (BPA free!) right now. I line the bottom with moist paper towel to help keep the leaves fresh. At least once daily we prepare a second set of containers and use a soft paint brush to transfer them to the clean home, then disinfect the used container with bleach wipes and wash it to prepare it for the next change. The moist towels keep the leaves fresh longer (keeping the lid on, punched with tack holes, helps with this also), and the bleach is the only thing that will kill some of the threats.
Wish us luck! We'll keep you posted.