Would you like to further expand your natural-world knowledge at this time of staying close to home? We have offered you amphibians and birds over the last couple of weeks, but wondered if you've ever considered learning more about native butterflies? This series of blog postings will focus on four species a month, one per week over the next three months. By the end of this mini online 'course', you should be able to identify 12 species of butterflies, which plants to incorporate into your future garden to attract and support them, and how to create features that will provide important nutrients and overwintering habitat for some species.
You see, butterflies are challenged by loss of habitat, declines in diversity of native plants and human impacts, like the use of pesticides and automobiles. However, they are also highly adaptable and easily find refuge in urban and rural landscapes if they can find enough of the plants that sustain them. Farmers and gardeners know only too well, if you plant it, they will come. So what are you waiting for? Climb aboard for Central Lake Ontario’s Butterflies 101 journey! We promise it to be light on the science and technical aspects, and heavy on the story of each butterfly.
Let’s start with one of our favourite butterflies, because for us it signals the beginning of spring: it is the mourning cloak (Nymphalis antiopa). We use the Latin name only to categorize this species into what is commonly known as the tortoiseshells or anglewing butterflies of the genus brush-footed butterflies. That is the end of the Latin lesson today, we promise. Only remember this if you have the desire.
The mourning cloak emerges first because it already went through its metamorphosis in 2019. Remember that word from your elementary science studies? It simply means the process of an insect’s life cycle: egg, larva (caterpillar), pupa (chrysalis) and adult. Ask your kids what metamorphosis means tonight at dinner. Or, better yet, ask them to spell the word. Okay, now that is the end of the science lesson for today, we promise.
As an adult in late October 2019, the mourning cloaks we have seen emerging in spring 2020 sought out a crevice in tree bark or crawled into a small space between logs in a brush pile or firewood stack. Safely tucked in, it overwinters as an adult butterfly, which scientists call aestivating (okay, we promise that is absolutely the last of our scientific references). Oh, and one more technical detail, you'll likely remember this, but butterflies are cold-blooded, so they need the sun’s warmth to get their fluids pumping so they can mate, fly and eat—not necessarily in that order.
With the first hint of warmth in April, even if there is still snow on the ground, the mourning cloak finds its way to a food source that is not typical of a butterfly. You are thinking nectar, but hmmm…there is not a lot of flowering going on in April to provide that food source.
So instead, the mourning cloak has adapted and simply takes advantage of the sap flowing from the native maple, oak, birch and poplar trees around us. Often this drips from the branches or down the trunk and is very appealing to the average mourning cloak. If you don’t see this species on and about trees, you might find them on the ground. They are referred to as “mudpuddlers.” Quite simply, they seek out standing water that looks murky to you and me, but is full of minerals extracted from the sand or soils upon which the small puddle of water sits. Think of it as a mineral 'tea'. I, personally, will stick to my vitamins, but this has worked for several butterfly species around the world for thousands of years. So more mudpuddles in the garden, please!
Every butterfly needs a host species upon which to lay its eggs. For the mourning cloak, it’s obviously going to be a tree of some sort, but which ones? And how can I plant those trees in my small postage stamp garden or on my balcony? No worries! If you have elms, willows, hackberries, birch and poplar in local natural areas, parks or in neighbouring yards, you will simply be the observer of mourning cloaks and not a host. You will benefit from seeing this early arrival in early spring and later in the fall when the next generation prepares for the following year. If you have these trees on your property, you may end up providing a bit of a nursery and winter escape for this species. Coincidentally, the very trees that provide the adults with sap, are the same trees that host the eggs of the mourning cloak. The eggs are typically laid on these same trees, where they finish out their metamorphosis or life cycle and become the adult butterfly. The larvae or caterpillar is black with a line of eight reddish-orange dots along its back, lots of small hairs, black spines and white spots, and may live high in the tree-tops, so not often observed at the human level, two metres above ground, until it becomes an actual butterfly.
We know we must inform you of the tragedy that incurrs after the female lays her eggs and the male fertilizes them. They die. After living their best life, about six months of it under the 'cloak' of darkness, they have done their duty to sustain or increase the population of mourning cloaks in your neck of the woods.
Like all our native species, the mourning cloak does face some challenges during its life cycle. An extremely cold winter could result in adults dying before they mate and the lack of suitable overwintering habitat or loss of their host tree species in and around preferred habitat could result in a seasonal population decline. When these patterns repeat themselves on a regular basis, as can be expected with climate change, these things will contribute to severe long-term decline and possibly extirpation (extirpation is another word for extinction of a species at a local level). Mourning cloaks live around the world, so a full extinction is less likely.
So not to leave you on a negative note, we have observed lots of mourning cloaks around our watershed already this spring. We hope that now that you know what to look for, you may experience this harbinger of spring close to home. If you would like some additional reading and visual resources, check out the Canadian Wildlife Federation website.