Spotted Tussock Moth |
There are many rituals that teachers perform as they prepare
to return to the classroom, and this year, one of those rituals is going to be
especially challenging: searching the local milkweed patch for Monarch
caterpillars. For decades, teachers have
raised Monarchs in the classroom with their students, but with declines of over
90% this year, Monarchs are currently absent from much of Vermont. So what is a teacher to do?
The good news is that Monarchs are one species out of
hundreds of native caterpillars that can easily be raised in the
classroom. Unlike Monarchs, most other
caterpillars won’t emerge as moths or butterflies in the fall, but hold on to
the cocoons and your caterpillar will eclose
(emerge from its cocoon) in the spring, reinvigorating students months after
they’ve forgotten about their caterpillar friends. Many of the same lessons that we learn from
the Monarch can apply to other species: life, death, adaptation and
transformation. This short tutorial will
give teachers some of the tools they need to raise caterpillars in the
classroom this fall.
Finding Caterpillars
Beautiful Wood-nymph caterpillar |
Caterpillars spend their lives doing two things: eating and
trying not to be eaten. This can make finding
caterpillars challenging. But fear
not! If you spend time outdoors doing some
targeted searching, you are likely to stumble upon a caterpillar sooner than
later. Here are a few methods for
finding caterpillars:
- Examine foliage for signs of caterpillar feeding, including damaged leaves and frass (caterpillar poop). The fresher the damage to foliage, the more likely a caterpillar is still nearby.
- Use a beating sheet. Place a white bed sheet beneath vegetation, and then shake the vegetation to dislodge any caterpillars. If all goes well, a caterpillar will fall onto the bed sheet and be easy to spot against the white background.
- Look for caterpillars at night. Many species of caterpillars hide by day and become active after dark, when fewer predators are out hunting for them.
- Search with your students. Having a few dozen eyes helping you search will increase your chances of success, and your students will enjoy the hunt!
Raising Caterpillars
Our Promethea caterpillar doesn't even have a tank! We feed it lilac, white ash, and black cherry. |
Before bringing a caterpillar back to the classroom to
raise, it is essential to know what that caterpillar eats. Many species will feed on just one or a
handful of host plants (such as the Monarch, which feeds only on
milkweeds). If you find the caterpillar
on a plant, it is likely that that plant is a host. You can collect some branches of the host
plant along with the caterpillar, so it has something to feed on. If you find the caterpillar away from plants,
you must identify it in order to determine what it eats. Keeping a steady supply of host plant
available to your caterpillars may be the most challenging part of raising
them.
Next, you should try to identify your caterpillar. There are some great resources on the web to
help identify mystery insects, such as the Vermont Atlas of Life. You can also email a picture to NBNC and
we’ll do our best to help with identification.
Knowing what kind of caterpillar you have will shed light on its life
history, what special adaptations it has, and what moth or butterfly it will
become.
Our Variable Oakleaf caterpillars have almost doubled in size since we found them a week ago |
Terrariums that hold caterpillars should be kept clean and
well-ventilated. Provide a constant
supply of fresh food to the growing caterpillar. Research your caterpillar, as there may be
tips specific to each species that help ensure successful rearing. For example, some caterpillars burrow
underground to create cocoons and will need a substrate of soil in their
terrarium. NBNC can help, so don’t be
shy about letting us know what caterpillars you are raising.
If you have questions about raising caterpillars, please see
the resources below or get in touch and we’ll see if we can help!
Involve Your Students
Be sure to involve your students every step of the way. Caterpillars grow fast and your students will
be excited to see their caterpillars change from day-to-day. Countless lessons on adaptation, evolution, growth,
and change can spur from the raising of caterpillars. Their progress can be documented with
students through art or writing. Their
growth can be measured and graphed, as can the quantity of leaves they consume
or frass they excrete. Our migratory
species can even offer opportunities to learn about geography or to find pen
pals in other states/countries who share our experience with these delicate
creatures.
In Conclusion
This tutorial just scratches the surface of what can be done
with caterpillars in the classroom. The
resources listed below provide more tips on identifying and raising
caterpillars. Since much of the school
year takes place during the winter months, the window for working with insects
is narrow. The start of the school year
offers the best opportunity to raise your “class pet” caterpillars and we look
forward to hearing about your experiences in the classroom!
Silver-spotted Skipper caterpillar flaunting its impressive fake orange eyes |
Additional Resources
Champagne, C. 2012. Finding
Slug Caterpillars. Retrieved from http://bugguide.net/node/view/668155
Jaffe, S. 2013. The Caterpillar Lab. https://www.facebook.com/TheCaterpillarLab
Wagner, D. 2005. Caterpillars of Eastern North America. Princeton, N.J. : Princeton University Press
Wagner, D. 2005. Caterpillars of Eastern North America. Princeton, N.J. : Princeton University Press
Wagner, D. 2011. Owlet
caterpillars of eastern North America. Princeton,
N.J. : Princeton University Press
Wagner, David L., Valerie Giles, Richard C. Reardon, and
Michael L. McManus. 1997. Caterpillars
of Eastern Forests. U.S. Department of
Agriculture, Forest Service, Forest Health Technology Enterprise Team,
Morgantown, West Virginia. FHTET-96-34. 113 pp.
Jamestown, ND: Northern Prairie Wildlife Research Center Online. http://www.npwrc.usgs.gov/resource/insects/cateast/index.htm
(Version 11APR2001).
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