Mourning Cloak Caterpillars to Butterflies: The Butterfly Lifecycle

My kids and I love to search for butterflies, or more specifically the eggs and caterpillars, so that we can "raise" them and watch the amazing transformations. True you can just buy a kit, but we find something very satisfying about finding them ourselves. Not to mention that you learn so much more like, where and when to find them as well as what their natural behaviors might be. I'd like to share some of these observations so that maybe you or your kids might enjoy and learn as well.

The Mourning Cloak Butterfly

The Mourning Cloak or Species: Antiopa (Family: Brushfoot, Sub-fam: Nymphalinae, Genius:Nymphalis) has one of the longest lifespans of all butterflies as it estivates (a period of dormancy during the summer) and also hibernates all winter in the adult phase. This is uncommon for butterflies. Most overwinter as an egg or pupa (such as the Swallowtails) or they migrate as adults (like the Monarch.) Just imagine this seemingly fragile creature surviving temperatures of -35°F and colder while just huddled in the crack of a tree branch!

Often, adults spotted in the spring will have tattered wings from their long winter experience. In the early spring the adults will emerge to mate and lay eggs. The females will lay the eggs on the caterpillers' favorite host plants: Willow, Aspen and Cottonwood.

It is really fun, especially with kids, to find the females laying eggs on these host plants; look in moist areas such as river valleys or wet meadows. Don't look too early in the season because the females may not have mated yet; wait until the leaves on the host trees are mature. You can tell a female from a male usually by the way they are acting. The females are shy and less active than the males. The males are more aggressive and may be "hassling" the females.

Also, if a butterfly is "puddling," or drinking from shallow puddles, this is almost always a male. The female will lay clutches of eggs usually at the base of a tree branch. To collect the eggs, I usually use a small paintbrush and just collect them into a Tupperware container with a lid (and a few small holes for air.)

As soon as they hatch, move them with your paintbrush (they will be very tiny) to a cut branch of the host plant with the cut end in a bottle of water. Wrap foil or plastic wrap around the neck of the bottle so that the caterpillars cannot get into the water and drown. I keep the whole thing: plant, bottle, caterpillar and all in an old aquarium. You could also use a screened cage or even make a container out of a net. Then again, there are some great websites where a pop-up enclosure can be purchased for relatively inexpensively.

Your tiny caterpillar is in it's first stage or "instar" and is not likely to try to go anywhere. They just eat and grow and make "frass" (caterpillar poo) and then eat some more. The Mourning Cloak, like most caterpillars, has 5 stages or "instars," growing bigger and shedding their outer skin with each one. The entire larval stage is about 2-3 weeks (depending on the weather and food availability.)

If you miss the chance to collect them as eggs, then just look for the caterpillars. When the eggs hatch, the caterpillars will stay together in groups feeding on the favorite host plants (Willow, Aspen and Cottonwood) until they are close to pupating. (Because of this "social" behavior, people often confuse them with the larva of Gypsy moths or Tent worms which are fuzzy with red spots and cluster together similarly.) When they have reached the fifth and final instar, they set out individually in search of a good location to make their chrysalis.

Just FYI, if you find a caterpillar crawling on anything other than its host plant...your house, the driveway, the sidewalk, etc., chances are good that it is in what I call "the wandering stage." Most caterpillars do this just before pupating. (They are otherwise fairly sedentary creatures.) They will suddenly become very active and, if you have some at home, they will make trip after trip around the inside of their enclosure. Once they have started this behavior, they will usually pupate within 24-48 hours. They just like a safe place where they can hang upside-down. They will assume what I call the "prayer position" which looks like this:

They will hang from a stick or even just the top of a jar. I usually move them into a glass jar (like a mason or canning jar) and cover the jar with a paper towel. Then I secure it with a rubber band. They almost always choose the paper to hang from. Don't worry about trying to feed them in this stage...they won't eat.

Try not to disturb them once they are "praying." But, if at all possible, don't miss the actual transformation. It only takes a minute or two and is incredible. If you notice them sort of pulsing...it's going to happen soon!

In early August (in Montana), the Mourning Cloak caterpillars will pupate. If you have given yours a stick or paper to hang from, than it is easy to move them back into the larger container after the chrysalis has had several hours to harden. Maybe even wait a day or so, you have plenty of time. Then just pin the paper or stick to the inside of the enclosure.

It is important that they have plenty of room when they "eclose" or emerge. If they are crowded, the result will be misshapen wings. After 10-14 days, the beautiful adult will emerge. Hopefully, you will get to witness this wonder! A crumpled, damp adult will pull itself out of the chrysalis shell, then it will begin to pump its wings bigger and bigger until they are fully formed and then they dry. Don't be alarmed if your butterfly has some bright red or orange discharge; it is not bleeding. It is just the left over pigment that they don't need.

The underside of the Mourning Cloak's wings are brown with a cream colored band along the irregular edges. The tops of the wings are more colorful with yellow, blue and purple.

Adult Mourning Cloak Butterflies have some strange eating habits. They enjoy rotten fruit, tree sap and even animal droppings. It is possible to hand feed any adult butterfly, follow the link above for more information about feeding adult butterflies.

The Mourning Cloak is the Montana State butterfly.