It all started with one caterpillar. We found a monarch caterpillar on one of the milkweed plants near our pasture. I'd heard that monarch caterpillars were really easy to rear indoors, so we brought the caterpillar back to the house with us. I figured it would be a fun little summer project.
While trying to figure out how best to take care of this caterpillar, I read that rearing can significantly increase a caterpillar's chances of making it to adulthood. So we brought a few more caterpillars in and then a few more. Our caterpillar count is now at 40 (but not all at the same time).
We've had very good success with our not-so-little project. Most of the caterpillars have pupated. So far, butterflies have emerged from all of the chrysalides.
Throughout our monarch project, which isn't quite over yet, I've noticed several parallels between rearing monarchs and rearing dairy cattle:
Proper housing. Monarch caterpillars need well-ventilated housing with good lighting. They need to be separated by size, so that the bigger caterpillars don't bully the smaller caterpillars. And they can't be overcrowded; the bigger they get, the more space they need.
Daily care. Monarch caterpillars need fresh milkweed leaves daily. Milkweed is the only kind of plant they can eat. The bigger caterpillars can devour a large leaf in hours. The more they eat, the more they poop. Their droppings, called frass, must be removed from their housing daily. Since they need daily care, you need to find someone to babysit your caterpillars if you want to be gone for more than a day. (Thanks, Emily!)
Temperament. Just as all people and cattle come with different attitudes, so do caterpillars. I had to move one caterpillar into solitary housing because it kept harassing the other caterpillars. This same caterpillar then tried to anchor its chrysalis to the side of the container, instead of the top. I'm guessing it would have failed to pupate in the wild, but I just turned the container on its side. That bully caterpillar is now a butterfly.
Quality feed. Forage quality is as important to caterpillars as it is to dairy cattle. They need fresh leaves from unstressed milkweed. (Interestingly, butterflies won't lay their eggs on stressed milkweed.) Leaves also need to come from plants that haven't been sprayed. I unknowingly fed contaminated leaves to several groups of caterpillars, some that I had reared from eggs. They all stopped eating, started vomiting, and having seizures. I had to euthanize all of them. If I didn't know that only about 10 percent of all monarch eggs survive to adulthood in the wild, I would have cried. We learned a tough lesson, though. I went back to harvesting milkweed from areas that I was certain hadn't been sprayed and haven't had any problems since.
They die. Caterpillars die for other reasons, too, both in rearing environments and in the wild - usually from viral or bacterial infections or parasites. We had one caterpillar die from an infection. I found one dead caterpillar stuck to a milkweed plant in a road ditch, too. Not all of the butterflies make it, either. We had a perfectly formed butterfly emerge from its chrysalis. But it had problems. It couldn't hang on properly and never tried to fly. I opted to euthanize that butterfly, too, rather than watch it waste away. It's disheartening when they die, but it's even more disheartening to euthanize them.
Learning opportunity. Raising kids on a dairy farm provides endless learning opportunities. Rearing monarchs provided a great learning opportunity for Dan and Monika, too. We watched together as one caterpillar pupated. (It happens really fast, so it's easy to miss; one minute it's a caterpillar, the next it's a chrysalis.) Before it started to pupate, we hypothesized about how monarchs pupate. It didn't happen the way the kids thought it would. Dan and Monika came up with lots of good questions, like, "How do the caterpillars know when it's time to make their chrysalises?"
They learned a lot about monarch habitat, too. We spent lots of time inspecting milkweed plants. They learned how to slow down and look carefully for caterpillars. Dan and Monika can now spot a milkweed plant from a mile away. Even Glen has taken to checking the patch of milkweed in the grassed waterway by our silage bags.
We would have been done with our monarch project before our trip, but then I found a weeded out milkweed plant by a neighbor's field with a dozen eggs on it. Those caterpillars would have perished shortly after hatching, so we collected the eggs. We decided that those caterpillars' chrysalides should go to Dan and Monika's classrooms so their classmates could watch butterflies emerge. Since school starts a full week earlier this year, those butterflies that emerge will still have good conditions for migrating to Mexico.
They're captivating. A lot of dairy farmers express emotional connections to their dairy cattle. It's hard not to fall in love with monarchs, too. We didn't name them - they're too hard to tell apart. But we were completely fascinated with watching them transform from caterpillars to chrysalides to butterflies. They're simply beautiful at all stages. When the first eggs that we brought in hatched, we couldn't believe how tiny those little caterpillars were. Now that the monarch season is almost over, we're seeing lots of mature caterpillars in the wild. Are they the offspring of some of the butterflies we released earlier this summer? It's hard not to wonder. Even after living with caterpillars for most of the summer, we still get excited when we find one in the wild.
Next summer, however, we'll focus more on improving butterfly habitat around our farm and less on rearing caterpillars in our kitchen. It takes far too long for me to get cows in from the pasture when I'm always stopping to pick fresh leaves and collect caterpillars.
You can find pictures from our monarch project on my blog.