Activities for Children
Observing the caterpillars
With the new method, it's easier to see the caterpillars, and there's much to observe. Good illumination is important, so keep a small lamp or flashlight nearby.
- Feeding behavior: Tiny caterpillars shave the hairs off the leaf before they begin to feed. They may resort to cannibalism; signs of this are missing caterpillars, plus one much larger than others. Small caterpillars eat a crescent-shaped moat around their position. This cuts down on sap flow to the leaf where they are eating (sap is both toxic and dangerously sticky).
- Social behavior: Usually, a female lays only one egg per plant. But caterpillars do show social behavior--"threats." They rise up and "butt" another caterpillar that is approaching too closely, and also make a hostile shaking motion that can be felt by others through the stem. Personalities vary--some are more aggressive than others.
- Anti-predator behavior: Small caterpillars can escape by descending on a barely visible thread of silk. Larger ones may simply drop off or even roll off the leaf. You may notice that when you enter a quiet room, all the caterpillars may stop moving. They respond to the vibrations from your footsteps, or to sounds. Recent research shows that they can hear, and that this is a defense against one of their predators, paper wasps. Positioning themselves under a leaf hides them from predators, but also protects them from rain and overheating. Large caterpillars, when they first arrive on fresh food, will chew a notch in the leaf's main stem or vein, causing the leaf to hang down so they are hidden (it also may prevent sap flow).
- Learning: If you make a loud noise when caterpillars are undisturbed, most will show a "startle and freeze" response. But if you repeat the noise several times, they will quickly stop responding. This is called "habituation," which is a basic form of learning. Recently eclosed butterflies also rapidly learn to feed from artificial sources like a q-tip or plastic scrub pad soaked with honey water.
- Activity cycles: While caterpillars spend most of their time eating, they do rest occasionally. And while preparing to molt (and after), they are inactive for up to 24 hours, often leaving their feeding location by up to a foot. Don't disturb them when molting. Some people mistake this inactivity for sickness.
- Preparing for the J: When the caterpillar is fully grown, it stops eating and starts to wander from its food, looking for a darker place to form the J. When they find a good spot, they slowly spin a pad of silk, then turn around to attach their rear legs to it. Finally, they drop down headfirst, attached only by their hind legs, forming the J. The forward half of the J turns greenish as the chrysalid starts to show through the skin. After about 12 hours, when the antennae are thoroughly shriveled and twisted, the caterpillar's skin splits along the back, and the chrysalid emerges. As the skin comes completely off, the caterpillar--in a deft acrobatic move--thrusts its barbed "cremaster" into the silk pad and squirms until the cremaster is firmly entangled in the silk pad. The cremaster is the hard stalk of the chrysalid. This transition of J to chrysalid--lasting 1-2 minutes--is as amazing as emergence of the butterfly--don't miss it! More caterpillar behavior.
Harvest and Grow Milkweed Seeds
Find seeds. Collect milkweed pods in September while the pods are still closed. Split
the pods open along the seam. Make sure the seeds are in good shape. Viable seeds
are brown and a little plump. Strip off the seeds from the silk with your thumb.
bottom. Also drill 3 on each side, about ½ inch from the bottom. Turn the jug so the handle faces you. With a bread knife, make a horizontal cut halfway down. On the side with the handle, leave about 1 inch uncut so that it makes a “hinge.” This way you can open and close the jug. Add 3 inches of potting soil. Dampen it.
Plant the seeds. Sprinkle 12 to 15 seeds on top of the soil. Cover the seeds with
about 1/8 inch of topsoil and thoroughly moisten it again. Seal the cut in the
jug with duct tape. Loosely place the jug on top of snow on the south side of
your house. (The seeds require a cold shock of at least 6 weeks.) Throw away the cap so some rain will enter. But watch out for too
much moisture as mildew is a danger. Brace the jug so it stays upright.
Grow the seedlings. After seeds sprout in April or May, bring the jug indoors at
night if there is a danger of hard frost. When the seedlings are 2 to 3 inches tall,
cut open the jug and take them out. If there is a mass of tiny seedlings, separate them by jiggling the mass of soil and seedlings underwater. Then transplant the small seedlings to plastic plug pots, one per pot. When the seedlings have grown to 4-5 inches, you can transplant them to your garden. Water frequently for two weeks or during dry spells.
How to test your monarchs for the OE parasite
If your adults die during eclosure, or are weak or deformed, they might have the OE parasite.
You can test for OE yourself if you have access to a compound microscope with 100X magnification.
Steps in the process are (1) taking a sample by pressing scotch tape to the abdomen of an adult monarch,
and (2) looking for spores of OE on the sample using the microscope. I can show you how.
You can find out more about it here, or by sending your sample to the project shown in the link. I taught my 9 year old granddaughter how to do it. Video.
Pollinator Activities
On a warm and sunny day, find a native plant with a lot of flowers. In late August, blazing star (Liatris) is good, or in September, New England aster. Observe whatever is attracting a lot of insects, preferably pollinators.
The goal of this study is to appreciate biodiversity and sharpen powers of observation. Spread the children out, perhaps one or two per plant. Their task is to identify (and count) as many different kinds of insect as they can. By identify, I don't mean give it the name known to people or scientists, like domestic honeybee (Apis mellifera). They can give it their own descriptive name, like "little shiny green bee." They will quickly see that some insects are coming in droves, while others are less common.
If you know some biology, you might help students identify them as to general type of insect (taxonomic order), such butterfly, moth, bee, wasp, fly, beetle, bug, or spider (actually not an insect). But even identification to this level isn't necessary. Insects have 6 legs, while spiders have eight. Most insects have two pairs of wings (the front often loosely attached to the rear), but flies have only one pair.
There are often numerous domestic honeybees or wild bees. The children need not be afraid of stings if they don't harass the insects, as visiting flowers is strictly business for the bees.
To make observation and sorting easier, ask the children to bring some digital cameras that can take fairly close up photos. Afterwards, they can crop the photos on a computer and sort them into groups of different types or species.
You could use a butterfly net to catch some of the pollinators. Here's how you can immobilize the insects for close-up inspection. Get shallow plastic bin with a lid, such as used to store sweaters. Also get some chips of dry ice (available at Hy-Vee), stored in a cooler. Put a thermometer on the bottom of the bin and throw in a few chips of dry ice. The carbon dioxide should anesthetize the insects. But make sure the temperature at the bottom is not below freezing, since this would kill the insects. Inspecting them with a magnifier and flashlight, or a binocular microscope is ideal.
Some of things students might notice:
- Some insects come for nectar, while others may be gathering pollen.
- Crab spiders (camouflaged the same color as flowers) lie in wait to ambush visiting insects.
- Still others might be sucking juices from stems (aphids) or eating fruits (orange milk weed bugs).
- Some of the insects or spiders are quite beautiful. The iridescent green of some wild bees is a "structural color," meaning the bees have tiny structures on their exoskeleton, about the same size as the wavelength of light, which act rather like a prism.
- Besides honeybees, there are many, many wild bees and other pollinators which together, are quite important to agriculture and to maintaining health of the ecosystem.
- The amount of activity is very dependent on both temperature and time of day. Different species will be visible at different time.
Experiments with wild honeybees
If you put out some diluted honey in your garden near flowers, domestic or wild honeybees will find it. Once they start to come to your source regularly, you can do a variety of simple experiments with them. Some of these experiments will blow you away! They are relatively simple, easy to do, and easy to understand. This wonderful book for lay readers gives the background: The Dancing Bees, by Karl von Frisch. Some of the experiments can be modified to work with butterflies.
The honey source: Put it up on a small portable stable, stand, or tripod, where it's easy to see. You want to make something that the honeybees can lap with their tongues but not fall into. You could use a small jar, upside down with a loose lid that seeps honey around the lid. Or a floral tube filled with honey water with a wick in it. Best to surround the honey source with a moat of water in a saucer, to exclude ants. If the bees are slow to find it, you might place the source right among the flowers. Or dribble a small amount of the honey water on the flowers. This will recruit more bees who are looking for the scent of honey.
Once you have a steady stream of bees coming to your source, you can do a variety of interesting things. For example, you can put a tiny dot of "white out" on a bee, using a code so you can distinguish individual bees. Then you can "time" the bees, to see how long it takes to make a round trip between the flower and the hive. By noting the direction the bees go when returning to the hive, you can move your source in that direction, and eventually find the hive.
Notice that when the bees leave your source, they circle upward as they leave. They are remembering the location and landmarks that will direct them back. You can place a blue colored poster board under your honey source, and a white board 8 feet away. The backgrounds should be similar, such as on the lawn. After the bees get used to the blue and use it as a landmark, you can switch the two boards, with the honey now on the white one. (Of course, you put a similar jar but without honey on the blue board.) You will observe that the bees at first continue to come to the blue board, even though there's no honey there. This proves they can both distinguish and learn colors.
Experiments with monarch vision
Link to background reading on monarch senses.
With monarch butterflies, you can train them in about 2 days to feed from "artificial flowers." Then you can put out artificial flowers of different colors. You can test to see if they have a native preference for one color over another (they prefer red most, green least), or if they learn to use color as a cue, when they have been trained on a certain color.