October 13, 2011 | 3
Watching a Monarch butterfly flit past the 9th floor windows of our Manhattan offices the other day reminded me that the annual fall migration is in full swing. And with that thought came another: the end of summer need not spell the end of outdoor entomology projects.
On a recent trip to Western Massachusetts, I stopped by the Pleasant Valley Wildlife Sanctuary in Lenox to stock up on bug activities for fall. Rene Laubach, the sanctuary director, had plenty of advice, starting with the best equipment.
Tools: Laubach recommends two pieces of equipment for those who regularly observe insects: binoculars that focus within 10 feet, and a digital camera with a good zoom lens. On a walk around the sanctuary, he snapped a picture of a butterfly sitting in the middle of a dirt path. When Laubach zoomed in on the captured image, we clearly saw the butterfly’s unfurled tongue scooping up moisture and minerals from the ground. See this helpful review for how to select close-focus binoculars: http://www.naba.org/binocs.html
Now on to the projects.
Monarch migration: Each September through November, Monarch butterflies travel south to their winter homes. Monarchs West of the Rockies head for the California coast, and those East of the Rockies head for Mexico. The Monarch Watch Web site has a detailed list of peak migration and abundance dates by latitude. According to the site, New York City is just past its peak in Monarch abundance, while towns in Florida won’t see a peak until late October. My fellow blogger Amy Maxmen has a nice piece about Monarchs in the big city, their biology and migration habits here.
Butterfly licks: Now that you’ve noticed the Monarchs, what else can you do? Laubach, who leads regular bug safaris for kids and parents, suggested capturing one with a net and transferring it to a small jam jar with a lid. (There will be enough oxygen in there for the butterfly to survive for the duration of this project). Next, wipe your finger across your brow to collect perspiration, which is salty, open the jar slightly and stick your finger inside. Very likely, the butterfly will climb on your finger and lick it, before flying away.
We actually tried this with a pretty yellow butterfly we caught and, while it did not lick my daughter’s hand, it lingered on her finger just long enough for us to observe it up close.
For next year: Tagging. It’s too late in the season for this activity, but keep it in mind for next year. Laubach and his wife have tagged Monarchs, and he recommended it as a family activity. The Monarch Watch Web site sells tagging kits, which help experts track the butterflies and their survival rates. Detailed instructions are here: http://www.monarchwatch.org/tagmig/tag.htm
Woolly bear races. Gayle Tardif-Raser is the education coordinator for Pleasant Valley, and she sent me lesson plans for two activities she does with school children at this time of year. The first, which she does in October, involves catching the furry, orange-and-black-banded woolly bear caterpillars and racing them. “Woolly bears are among the fastest and smartest of all the caterpillars. (They can be trained to run through a maze),” she writes in the plan. You’ll need these supplies, in addition to the caterpillars themselves:
1) a wooden ruler
2) a stopwatch
3) some caterpillar food for encouragement, such as bits of apple, pumpkin, or maple leaves
4) wet paper towels
Once you’re set, place your woolly bear at one end of the ruler, and encourage it — “by tush push, dragging food in front, or turning the ruler” — to crawl to the other end. Record the caterpillar’s time on a stopwatch. Ideally, you’d catch two or three caterpillars, pit them against each other, and crown a winner at the end. Like all athletes, though, the woolly bears need to stay hydrated, so check their condition and put them on a wet paper towel if they appear lethargic or are curled up.
One caveat: if your kids are like mine, they will want to keep the caterpillars. Woolly bears will sleep at your house through the winter, pupate in the spring, and transform into Tiger moths. Find detailed advice is here:
Ball Galls. You might have noticed that some goldenrod plants, hardy weeds found throughout the United States, even in vacant urban lots, have tumor-like growths on their stalks. These “galls” are the homes of tiny insects called goldenrod gall flies (Eurosta solidaginis) that inhabit a particular type of goldenrod plant known as tall goldenrod, or Solidago altissima. In the spring and early summer, adult flies lay eggs on the stems of these plants. “The egg,” says Tardif-Raser, “has a chemical that causes a reaction in goldenrod so it starts to grow over the egg and completely encapsulates it. Then the larva hatches and spends the whole summer in there eating.” In fact, the larva digs a small tunnel out to the edge of the plant, and then crawls back inside. The adult fly will use that tunnel to escape. Now, here comes the experiment: “At the end of October/early November you can find goldenrod ball galls that could have larvae or they could have pupa,” says Tardif-Raser. “It’s a great exercise for kids to predict what stage, based on their observations.” Some other possibilities: the ball could have been pecked open by a woodpecker or chickadee or parasitized by a wasp. For visual evidence of each of these scenarios, click on this amazing key.
What you’ll need:
1) a ball gall or two or three
2) a knife, ideally a Swiss Army knife
3) paper masking tape
Ask your child to predict what you’ll find inside: a larvae, a pupa, or perhaps nothing if the pod looks like it’s been pecked open. Next, place your gall on a table, slice one-third to halfway into it, and turn the knife so the gall cracks open. “The larva looks like a white chocolate chip,” says Tardif-Raser. “As it warms up, especially in a classroom, it starts moving around which is kind of a cool thing. Kids go a little crazy when they see them moving. Then, they stop moving around so much and start to turn a yellowish color and get more tan, and that’s the pupa forming. It takes 30 hours for that to happen, but you’ll see it start.”
Next, place your pupa or larva back inside the plant, tape it up and stick it back in the field where you found it. (The plant will die anyway with the first frost, and the flies can dig their way through masking tape but not through Scotch tape).
More to explore on ball galls:
(All of these resources come from Bucknell University)
Detailed instructions on identifying the right species of goldenrod: http://www.facstaff.bucknell.edu/abrahmsn/solidago/plantid.html
“The Goldenrod and the Gallfly,” an incredible educational video: http://www.facstaff.bucknell.edu/abrahmsn/solidago/gallfly_lowspeed.asx
For more on ball galls, read about the fascinating work of Bucknell biologist Warren Abrahamson: http://www.bucknell.edu/x47371.xml
Photo credits, top to bottom: KoolPix via Flickr; amberlgrunden via Flickr; stevemd via Flickr.