On March 16, 2022

Cozy cattails feed bugs and birds

By Rachel Sargent Mirus

On a winter day, I drove down to a nearby wetland bisected by a town road and walked carefully onto the ice. I was looking for cattail heads to dissect so I could meet the caterpillars who overwinter inside the seed fluff. Many of the cattails I found that day had blown over during the previous week’s windstorm, but there were enough still standing for me to collect two from each side of the road.

Submitted

Once home with my prizes, I began pulling the cattails into pieces, picking off clumps and teasing them apart into fleecy clouds with my fingers. The two heads from the bigger, more open side of the wetland were frayed and wet, with a patina of algae. But the seeds and fluff inside were still dry. I expected to find lots of caterpillars, like the cabbage worms that plague our Brussels sprouts during summer, but these first two cattails yielded only three pale, striped larvae and seven dry husks, which could be dead caterpillars or shed skins.

The cattail heads from the smaller side of the wetland, which is nestled into a hill and sheltered by trees, were in better condition, their sausage-like shapes intact and free of algae. I pulled one apart and found several sluggish caterpillars. In total, my exploration yielded 20 caterpillars, ranging in length from about 3 millimeters to 10 millimeters – less than half an inch! And after all of that, I was left with a pile of downy fluff 8 inches high.

I saved the last cattail head in a terrarium outside. If I’m lucky, it too has caterpillars hidden inside, and in the spring, I’ll see the moths emerge.

My interest in cattail winter ecology was sparked by accounts of red-winged blackbirds and chickadees foraging larvae from cattail heads. Pulling apart a cattail head was a lot of work, all to find a handful of tiny caterpillars. The littlest larvae hardly seemed worth the effort. But for a hungry chickadee or a red-winged blackbird returning to breeding grounds while winter persists, the fattest caterpillars might make a tasty morsel, especially at a time of year when insect prey is difficult to find.

I had asked Sam Jaffe, executive director of The Caterpillar Lab, a caterpillar zoo based in Marlborough, New Hampshire, if he knew of caterpillars living in cattails.

“I have collected a number to explore with guests at our winter open-hours and observed the insects within. Small Hemiptera (order of ‘true bugs’) were common as were the shy cosmet moth (Limnaecia phragmitella) caterpillars,” he said.

It was Jaffe who recommended I collect and dissect some cattails myself.

Shy cosmet moth caterpillars have brown heads and beige bodies with patchy brown stripes running along their length, a description which matches the appearance of my cattail larvae. They live inside the cattail heads all winter, feeding on the cattails’ prolific seeds – about 220,000 per head – and emerge as adults in the spring. Less than an inch in length, the adult is a demure yellow-tan moth with white-ringed brown spots.

These caterpillars spin silk threads through the cattail head to prevent the fluff from blowing away before winter ends, allowing the caterpillars to use its insulation to stay warm all season long. Bursts of un-blown fluff on a head may indicate that the caterpillars are active inside. I didn’t see any silk threads in the fluff I pulled apart, but several of the larvae dropped and dangled – inchworm style – from invisible threads while I was handling them.

After dissecting a few cattail heads, I’m not surprised these caterpillars have turned them into cozy winter nests. The fluff is as soft and light as down – I had a hard time preventing it from billowing all over my kitchen, especially after my 3-year-old decided to “help” me clean up. Even though the heads were cold and wet on the outside, all the inner fluff was dry, perfect for staying warm through cold, blustery days.

I’ve often seen cattail heads described as resembling sausages on sticks. Now that I’ve found the caterpillars tucked inside, however, cattails seem to me more like down comforters wrapped up against winter’s cold.

Rachel Sargent Mirus lives in Duxbury, Vermont. Illustration by Adelaide Murphy Tyrol. The Outside Story is assigned and edited by Northern Woodlands magazine and sponsored by the Wellborn Ecology Fund of the New Hampshire Charitable Foundation: nhcf.org.

Do you want to submit feedback to the editor?

Send Us An Email!

Related Posts

Moving sticks and rocks

May 22, 2024
By Merisa Sherman Then the tough choice of how to play today:ski, bike, paddle, fish, hike, run?  The bug went down my throat. Literally, flew down my throat and landed in the back at such speed that I had no choice but to just swallow. Mmmmm, gotta love that extra protein that Vermont provides during…

What are the chances?

May 22, 2024
Vesna Vulovic is a name etched in the annals of miraculous survival — perhaps the most unlikely survival story of all time. She was thrust into the spotlight on Jan. 26, 1972, when she unwittingly became a symbol of human resilience.  A native of Belgrade, Yugoslavia, Vesna’s journey to that fateful day began like that…

The Outside Story: Jesup’s milk-vetch: A rare beauty

May 22, 2024
A few ledges along the Connecticut River are home to a rare plant commonly known as Jesup’s milk-vetch (Astragalus robbinsii var. jesupii). In fact, this species, which has been listed as federally endangered since 1987, only grows at six sites along a 16-mile stretch of the river in New Hampshire and Vermont. But conservationists are working…

Boys, brothers, dad, Vermont

May 22, 2024
Building a Killington Dream Lodge: part 14 By Marguerite Jill Dye Dad made progress and forged ahead on our Killington ski lodge while Mom, Billie, and I toured Europe. Our extensive European whirlwind trip was the very beginning of my awakening to understand the world and how I fit in. I had no idea what…