The bright afternoon sunshine made me blink as I headed out
the back doors of Retzer Nature Center in Waukesha County, Wisconsin, near
Milwaukee. A few minutes before, I’d ended the slide show portion of my
“Finding the Stories in Nature” workshop, and sent the students—a delightful
mix of staff and volunteers from Retzer and other nearby nature centers—out to
the blooming rain gardens to “find stories.” After gathering props to use
later, I headed outside, too.
Look at all of these fantastic naturalists who hung out with me at Retzer Nature Center. Thanks ladies! |
The naturalists had already dispersed into small groups, and
in one of those little pods, my friend, Janet Barthel, was exclaiming about
something. Janet has attended several Wisconsin Master Naturalist trainings in
Cable, and with her boundless enthusiasm for both nature and being organized,
recently became the Nature Center Supervisor here.
Maybe it was one of the shiny black beetles scurrying around
the brown goblet of a Queen Anne’s lace seed head that had sparked Janet’s
curiosity.
A goblet shaped seed head of Queen Anne's lace, also known as wild carrot. |
I could relate. Growing up in Iowa, Queen Anne’s lace sparked many a
fanciful daydream in my curly little head. As the story goes, while Queen Anne
sat tatting white lace, she pricked her finger and a drop of blood stained the
center. The lace then became the frilly white flower, complete with a tiny
patch of dark red petals in the center. Obviously, I’m not the first person to
look for stories in nature.
This Queen Anne's lace flower head has a goldenrod soldier beetle in the center instead of the patch of dark red petals. Not ever flower has the drop of "blood." |
Anyway, when Janet’s curiosity caused her to pry open the
seed head, she found quite a surprise. Hidden inside were several little
caterpillars. Light tan with black spots surrounded by yellow halos, they
squirmed away from the unexpected light suddenly invading their secret
hideaway. This was new and unexpected. The naturalists all got a little smile
and a chuckle from the discovery, since discovering something new about nature
is precisely what makes people like us tick.
Later that evening, I Googled our find. “Caterpillar in Queen
Anne’s lace seed head,” quickly turned up information about carrot seed moths, Sitochroa palealis.
Carrot Seed Moth adult, photo by Mark Rosenstein, iNaturalist |
While these little white moths are native to eastern Russian,
Portugal, Greece, North Africa, and China, they are a new arrival to North
America. Probably arriving by boat, they have been reported from states along
Great Lakes shipping routes since 2002. They were caught in traps intended for
other pest insects, photographed and posted to bugguide.net, brought to the
Ohio Lepidopterist Society’s “ID day,” and were now exposed in their feeding
goblet by a naturalist looking for stories.
See the little hairs surrounding each seed? If some survive the caterpillar's incessant chewing, they'll try to hitch a ride like Velcro on some fluffy mammal fur. |
While all of the caterpillars we saw were feeding on Queen
Anne’s lace (also known as wild carrot), they may also attack the seeds of
other members of the Apiaceae family, like carrots, caraway, celery, coriander,
cumin, and dill. In agricultural settings they are easily controlled with
pesticides, though, so the scholarly articles describing their arrival were not
overly alarmed.
As non-native invasive species, the story of these
caterpillars is not anything new. Queen Anne’s lace itself is not native to
this continent. It’s been here a bit longer, though, having been introduced in
the soil used as ballast in ships by the first European settlers.
Old change. New change. While humans are changing the
distribution of carrot seed moths in the New World, climate is changing their
distribution in the old world. Migratory moths and butterflies are being
monitored at a site in the southern United Kingdom, and researchers estimate
that for every 1°C increase in temperatures in SW Europe, there is an increase
of 14 species of Lepidopterans (butterflies and moths). The carrot seed moth is
on their list of newcomers, having made the open water crossing toward cooler
temperatures in about half of the study years since 1982.
While scientists worry about the impacts of newcomers, there
may be some benefits, too. As the original native species decline due to
habitat change, these invaders just might fill some vacant niches. That’s
happened in the Namekagon River, as non-native brown trout take over the niche
from native brook trout when the water warms.
Likewise, the carrot seed moth may have surprising benefits.
Queen Anne’s lace can be a weed as we try to restore native prairies, and the
juice from its leaves may cause blisters when combined with bare skin and
sunshine. In Milwaukee’s Lakeshore State Park, an entomologist observed the
carrot seed moth larvae helping to keep Queen Anne’s lace under control.
Stories like these about the arrival of new invasive species
and the shifts in ranges due to a warming climate aren’t going to go away. But
then, neither will the stories about people hungry for a connection to nature, the
benefits of boundless curiosity, and the joy of discovering something new. I’d
say that the workshop was a success, wouldn’t you?
Emily’s second book, Natural
Connections:
Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.
For more than 50 years, the Cable Natural History Museum has
served to connect you to the Northwoods. Come visit us in Cable, WI! Our new
Curiosity Center kids’ exhibit and Pollinator Power annual exhibit are now
open! Call us at 715-798-3890 or email emily@cablemuseum.org.