Cuddly, Crawly Caterpillars
When it comes to the beauty and grace of a butterfly floating through the garden we often forget what it looked like when it was more closely tethered to the earth.
How many “inchworms” did I find burrowed into my Calendula last year that I didn’t give a second thought to?
Kind of like when all small brown birds were sparrows spp. until I realized there were 15 or more different types of sparrows that could be seen in Ontario.
It’s not just the number of caterpillars that can be seen in your average backyard when you’re really looking - it’s the fact that each caterpillar can have multiple instars.
What’s an instar?
You know how caterpillars just eat and eat and eat. Their skin doesn’t grow with them. So when they reach a certain overstuffed size they have to shed their old, too-tight skin. This can happen five times before they reach their final instar just before they turn into a pupa. This article shows pictures of the life stages of a Black Swallowtail butterfly.
Here you can see the development of the Monarch. When it first hatches out of the egg it doesn’t look very exciting and could be easily mistaken for something squishable.
If you would like to watch the entire process at home there are kits available (this one is for the Painted Lady Butterfly) that only take about three weeks to transform from egg to butterfly. I’ve never tried a kit before but we have collected Monarch and Swallowtail caterpillars and brought them inside to watch them eat and form their chrysalis.
I’m going to have to pay more attention to all the little “inchworms” this year and see if I can separate the tangle of instars that I might be confusing. I’m going to keep an eye out for Painted Lady instars on thistles. We’ve had Eastern Black Swallowtail caterpillars on our dill and fennel before but I’m going to look specially for the eggs and earlier instars to familiarize myself with what they look like. It amazes me how ugly some caterpillars can be compared to the butterfly they become. I have seen one Red Spotted Purple butterfly in my life, when I was a teenager, and I thought it the most beautiful thing ever. But seriously would you think this caterpillar would become that butterfly? One was seen in Clearview Township in 2019 and reported. Maybe you’ll see one this summer.
Food Webs
Strangely enough the beauty of these caterpillars is not foremost in their butterflies, it’s actually in their contribution to the local food web. Remember last week: Caterpillars transfer more energy from plants to other animals than all other herbivores combined. They are eaten by birds, bats, frogs, mice, squirrels, even Black bears have been found with caterpillars in their poop. Some insects parasitize caterpillars by laying their eggs in them like the Friendly Fly. All of these interactions aren’t solitary, they’re exponential.
Food chains and food webs play a huge role in the biological viability of a site. You can plant the most beautiful garden in the world but none of it will function properly without the ecosystem it is planted in running smoothly. When we interfere, or mess with the balance, all sorts of negative side effects develop. Much like the hunting that destroyed wolf populations in Yellowstone saw widespread damage to the whole habitat, their reintroduction caused trophic cascades that continue to benefit the entire ecosystem. Would you have imagined that reintroducing wolves would have healed a river, or supported tree populations, or improved the quality of the soil? And yet they have.
So much of the time we as humans focus on one, perceived as isolated, thing. We want a larger showier flower, forgetting that the changes may mean it no longer tastes good to the bugs that eat it. Ask a gardener how many bees enjoy their easy-to-maintain Knockout roses? Have they ever even seen a bee on their Knockout roses?
When it comes to bugs or animals our focus can be only on the negative. Carpenter bees are making holes in our shed. That ugly crawly thing is eating my plant. Wolves are “scary”. So we do battle against the beast. And lose pollinators, and butterflies and river systems. Which in turn loses food sources and joy and water quality. Which in turn leaves us hungry and grumpy and thirsty. An oversimplified view? Yes, of course, but true nonetheless.
Food chains and food webs don’t have to end with us to affect us. Seeing a picture of a food chain that ends with a bald eagle or a fish doesn’t mean that we are not involved or affected by the quality and continuance of that food chain.
So how do backyard food chains involve us? How can we support them?
See you tomorrow.
