Trichoceridae | Bugging You From San Juan Island

Tag Archives: Trichoceridae

Hang On…

Posted on March 13, 2026 by BUGGING YOU FROM San Juan Island Leave a comment

Aren’t we all? Hanging on for dear life? Whether it is financial, emotional, or health-related, it sure seems like folks in the world are facing a crisis of one sort or another. Some are facing outright catastrophic ones. We need a global re-set for the chaos. To calm my mind, I ponder bugs. How do you cope?

If you are just seeing my blog, it’s Fantasic Fly Friday. Flies are so varied and amazing. They literally fuel the world as we know it.

I photographed this one last night at my moth light. It was raining on San Juan Island, so there were more than a few bugs enjoying the refugia beneath our covered deck. Some nights it’s quite a party. A bug disco!

This is one of the more primitive flies in the family Trichoceridae (the Winter Gnats or Winter Crane Flies). Sometimes people call them hanging flies. I believe this one here is in the Genus Trichocera. However, I didn’t pluck my specimen off and take his or her life to determine that for certain under the microscope. I rather enjoy watching them alive because they all have quirky behaviors that are far more interesting to observe than counting wing veins on a dead bug.

The Trichoceridae are a family of Nematoceran flies grouped in the overarching infraorder Tipulomorpha (Crane Flies). There are approximately twenty-seven to thirty species of winter crane flies in the family Trichoceridae found in North America north of Mexico, depending on what source you use (Bugguide, 2021; Pratt, 2003). These are small to medium sized flies (wing up to 12mm), with a slender body and long, slender legs are distinguished from other families of crane flies by the presence of three ocelli (the primitive light detecting “eyes” found on the top of the head. Other identifying features include a V-shaped suture on the mesonotum that is incomplete in the middle, and long, hairlike 16-segmented antennae.

The larvae of Trichoceridae develop in moist or wet terrestrial biotopes. They can be found in decaying leaves, manure, fungi, stored roots/tubers, and rodent burrows (Bugguide, 2021). Adults are able to tolerate cool temperatures and sometimes, like I have seen, you may find them out walking on the surface in snow. Being active in winter, means there is little food available, but adults may feed on sap, or other carbohydrate sources. According to The Bug Lady (2015), they have been collected in molasses traps, and I have found them in our hummingbird feeder in winter when I take it down to change the sugar water and they are often on the sides of our seed and suet bird feeders as well. Perhaps taking nutrients in small amounts from the fruit in the bird feed mixes.

Winter Crane Fly in Snow, 2017 – San Juan Island, WA

Even though they are small (perhaps you have never even noticed them), these flies are significant in ecosystems, with the short-lived adults providing a winter protein source for birds and even bats. The larvae feed other organisms that go unseen in the winter (beetles, spiders, millipedes and such) that wake up hungry on warmer days. They are important decomposers, nutrient recyclers, and a wonderful bioindicator of ecosystem health. They do not bite, nor do they transmit disease.

Remember the behaviors I mentioned? Well, these flies dance like the world is ending. At least the males do. They can be find swarming on cool winter afternoons, bobbing up and down in what are known as ghosts (Burton-Hargreaves, 2026). Friendly ones! When I read that, it reminded me of a book by Robert Bright my mother read to me often as a child, Georgie and the Noisy Ghost. Just like the ghost in this childrens’ book, I find these little flies dancing about at my moth light to be delightful.

Winter Crane Flies may have a brief existence, but they make the most of it. We can too. Live in the moment. Read to your child. Be present and helpful. Check on your neighbor. Maybe Clang and Rattle a Bit about the state of our country to your representatives (in a polite email, of course). Stay connected, and hang on for the wild ride that is LIFE.

References

Brast, C. 2017. Winter Crane Fly. Bugging You From San Juan Island. https://buggingyoufromsanjuanisland.com/2017/02/09/winter-crane-fly/

Bugguide.net. 2021. Trichocera. Bugguide.net. Iowa State University. https://www.bugguide.net/node/view/31296

Burton-Hargreaves, A. 2026. Winter Gnats. Northwest Nature and History, All about the Natural History and History of the Northwest of England. https://northwestnatureandhistory.co.uk/2026/02/18/winter-gnats/

Pratt, Harry D. (2003). The winter crane flies of North America north of Mexico (Diptera: Trichoceridae). Proceedings of the Entomological Society of Washington, 105, 901–914. https://www.biodiversitylibrary.org/part/55628

Redmond, K. 2015. Winter Crane Fly (Family Trichoceridae). The Bug Lady. University of Milwaukee. https://uwm.edu/field-station/bug-of-the-week/winter-crane-fly/

Winter Crane Fly

Posted on February 9, 2017 by BUGGING YOU FROM San Juan Island One comment

It snowed on San Juan Island this week. We were forecast to have LOTS of rain yesterday, but instead we got more snow. So much snow that this former Texas gal just had to get out and experience the magic of our wooded, winter wonderland.

I got my coat, hat, and boots on, grabbed my iPhone and a pair of gloves, wrapped a scarf around my neck and set off to walk down our lonely country road.

Hoping to photograph some of our year-round feathered residents, I had my camera phone in hand. It was really cold outside and yet I couldn’t use the touchscreen wearing my glove. Off it came. I could sacrifice cold fingers if I could get a shot of one of the woodpeckers or maybe a Varied Thrush.

Heading down the driveway, I noted the way the limbs of the cedars and firs bowed down under the weight of the snow. Beneath them, little birds scurried, scratching about in the damp humus or flitting about on lower branches, enjoying a protected shelter from the cold. It took only a moment to spy a Dark-eyed Junco near the house on a leafless limb of our cherry tree and the Varied Thrush perched just above my head…perhaps waiting to see if I brought more seed out for them.

Dark-eyed Junco (Junco hyemalis)

Varied Thrush

A bit further down the driveway, I smiled when I saw our little carved bear. He’s not long for this world. The carpenter ants and the damp weather are slowly turning him into sawdust….but he rallied under his snow blanket today even though his little black nose was about all you could see.

Snow Bear

Wait…isn’t this post about a Winter Crane Fly? Well, I’m getting to that part. I certainly wasn’t anticipating seeing any invertebrates out on a day like this. While I’ve heard of snow fleas (not really fleas, but tiny invertebrates known as collembolans or springtails) or snow scorpionflies (Boreus spp.) found in winter in our forested area, I’ve yet to see them. It’s really a mystery how so many of these tiny creatures survive the extreme temperatures, but that’s also what makes them so interesting.

I came across the first of about ten of these tiny, winged “cranes” before I’d made it far down the road.

Winter “Crane”

We live in a somewhat densely forested area. Not many houses or development to interfere with the important ecological processes going on in the natural world. At first, it appeared to be a mosquito. Go figure. Somehow they thrive in Alaska, Minnesota, even the Arctic…in spite of frigid temperatures!

Looking closer, I speculated it was in the family Tipulidae, a common, but harmless, mosquito-looking, awkward flying, long-legged fly! I had to do some research to figure it out. The Tipulids are a genus in the insect order (Diptera) and commonly called “Crane Flies.” However, a bit of digging into the literature proved I was close to my ID of this creature, but not quite there.

What I discovered is that this is indeed a Crane Fly, but not a Tipulid. It’s a WINTER Crane Fly in the genus Trichoceridae. They are found flying on “warm sunny afternoons in fall, winter, and spring in the contiguous U.S., including Alaska and Canada” (Pratt 2003). In his study, Pratt (2003) observed specimens “swarming above or on the snow in temperatures between 0℃ and 10℃.” Maybe “warm” is subjective here!

This tiny Winter Crane Fly is very similar to the Tipulids or True Crane Flies with its long slender legs, but it differs in classification because the Winter Crane Fly has three ocelli (https://www.amentsoc.org/insects/glossary/terms/ocelli) or simple eyes that act as light sensors and are found on top of the head. The larvae of Trichocerid flies develop in the moist humus and decay of the forest floor and undoubtedly play some ecological role in this environment i.e. in decomposition or nutrient recycling. At a minimum, they are a nice protein-rich winter meal supplement for the little birds I’ve seen on my walk today.

While I’m not certain of the exact species, in the article by Pratt (2003), adults of one species, Paracladura trichopera, are found flying even in winter in British Columbia, Washington, Oregon, and California. Perhaps it will suffice to say that I was intrigued at the cold-hardiness of such a tiny creature. And I DO like the name, Winter Crane Fly!

Winter Crane Fly Trichocerid spp.

References:

1. The winter crane flies of North America north of Mexico (Diptera: Trichoceridae)
Pratt H.D. 2003. Proc. Entomol. Soc. Wash. 105: 901-914. http://www.biodiversitylibrary.org/page/16212448