A caddisfly species

Glyphopsyche irrorata


The insect above is a caddisfly and one of many caddisfly species that live in northern Minnesota. Caddisflies (Order Trichoptera) are typically active during the warm months of summer and early fall but this caddisfly was active on the evening of April 25 when air temperatures were in the low 40s. It took me about a couple of days to figure out the species after searching Bug Guide and comparing photos (compare the pattern on the ends of the wings with this) and then doing a literature search. This caddisfly is Glyphopsyche irrorata which is in the Family Limnephilidae and is interesting for a few reasons the first of which is its mode of surviving the winter. Larval Girrorata live in small ponds such as vernal pools and peatland ponds, shallow marshes, and slow moving streams that may dry up by the end of summer. Many caddisfly species in similar habits lay eggs in gelatinous masses under moist objects in the drying water body where the larvae remain until favorable conditions return. Girrorata has a different survival strategy. It goes through a rapid larval development after the eggs are laid in May, pupates in August, and emerges as an adult in September. Mating takes place in the autumn and then the adults go into hibernation until the following spring (more mating may take place then) when the females lay eggs in small ponds and slow moving streams. The larvae build cases from bits of organic material and mineral material and are detrivorius shredders feeding on decaying wood and other organic matter.

Another reason Girrorata is interesting, at least from the standpoint of where this one was found, is that this species has been recorded only twice in Minnesota in 41 years. The first time was in 1977 in Clearwater County and the second was in 2000 in Cook County. This sighting makes the third time and in a new county. Although not on Minnesota’s rare species list it must be uncommon to have only two previous records in the state. This is in spite of several caddisfly surveys conducted in the state in the last 20 years. The range of Girrorata is Nearctic extending from Newfoundland to Alaska and south to California, in the Great Lakes Region and then east to New Hampshire and Maine. The number of known sites where Girrorata occurs in Wisconsin, Michigan, New Hampshire, and Maine are few.

Girrorata is attracted to lights as are many caddisflies. It is also attracted to sweet liquids like maple sap in tapping buckets. Many caddisfly species that fly during the summer are nectar and sap feeders, too. Using a combination of lights and sweet liquids might be a way to attract this species.


The forewings are grayish chocolate-brown with small spots and many larger translucent patches. Length is about 16 mm.


Order: Trichoptera

Superfamily: Limnephiloidea

Family: Limnephilidae (Northern Caddisflies)

Subfamily: Limnephilinae

Tribe: Chilostigmini

Species: Glyphopsyche irrorata


Berté, Stephen B., and Gordon Pritchard (1983). The Life History of Glyphopsyche Irrorata (Trichoptera, Limnephilidae): A Caddisfly That Overwinters as an Adult. Holarctic Ecology, Vol. 6, No. 1: 69-73. JSTOR, http://www.jstor.org/stable/3682718.

Betten, Cornelius. (1934). The caddis flies or Trichoptera of New York State, Bulletin of the New York State Museum No. 292:1-576.

Casey Scott and Jeffrey Dimick. A Distributional Atlas of Riffle Insects from Wisconsin Streams. Aquatic Biomonitoring Laboratory, University of Wisconsin-Stevens Point. 437 pp. © 2010.

Chadde, Steve W., Shelly, J. Stephen, Bursik, Robert J., Moseley, Robert K., Evenden, Angela G., Mantas, Maria, Rabe, Fred, and Heide, Bonnie. Peatlands on National Forests of the Northern Rocky Mountains: Ecology and Conservation. 80 pages. United States Department of Agriculture, Forest Service, Rocky Mountain Research Station. General Technical Report. RMRS-GTR-11 July 1998.

Houghton, David C. (2012). Biological diversity of the Minnesota caddisflies (Insecta, Trichoptera). ZooKeys, Vol. 189:1-389. doi: 10.3897/zookeys.189.2043.

Houghton, David C., DeWalt, R. Edward, Pytel, Angelica J., Brandin, Constance M., Rogers, Sarah E., Ruiter, David E., Bright, Ethan, Hudson, Patrick L., and Armitage, Brian J. (2017). Updated checklist of the Michigan (USA) caddisflies, with regional and habitat affinities. ZooKeys Vol. 730: 57–74. doi: 10.3897/zookeys.730.21776 http://zookeys.pensoft.net

Majka, Christopher G. (2010). Insects attracted to Maple Sap: Observations from Prince Edward Island, Canada. ZooKeys Vol. 51:73– 83. doi: 10.3897/zookeys.51.478.

Nimmo, Andrew P. ( 1971). The adult Rhyacophilidae and Limnephilidae (Trichoptera) of Alberta and eastern British Columbia and their post–glacial origin. Quaestiones entomologicae, Vol. 7:3-234.

Species Glyphopsyche irrorata at BugGuide.Net.

UNH Insect and Arachnid Collections – Record Detail Glyphopsyche irroata. University of New Hampshire Department of Biological Sciences.

Wiggins, Glenn C. and Parker, Charles R. Caddisflies (Trichoptera) of the Yukon, with Analysis of the Beringian and Holarctic Species of North America, pp. 787-866 in Danks, H. V. and Downes, John A. (Eds.), Insects of the Yukon. Biological Survey of Canada (Terrestrial Arthropods), Ottawa. 1034 pp. © 1997.

Some new moths

Agonopterix argillacea


The tiny gray moth in the photo above is one of the latest moth finds here this month. I’ve seen several of these moths in the last week flying just above the ground or walking on the snow. Some even came to my porch light one warm night (April 22) with an air temperature of 46° F and also my kitchen so I was able to photograph them. They are Agonopterix argillacea. Adult moths in this genus aestivate during the winter and emerge in the early spring to lay eggs. The larvae of A. argillacea feed on willows (Salix spp.) which are abundant in the wetlands around here.

Besides A. argillacea other species of moths are showing up as the temperatures get warmer. By “warmer” I mean between 32° F and 40° F.  The three moths shown below were found flying just above the snow when air temperatures were almost 40° F in the early morning (April 18 and 22) and late afternoon (April 22) as the sun was setting. I have not been able to identify them despite going through hundreds of photos at the Moth Photographers Group and Bug Guide websites. One may be in the genus Apotomis.



On Sunday night (April 22) when the air temperature was 46° F (after almost reaching 70° F during the day) I turned on my porch light and two individuals of this large moth came to the light. I am not certain of the species but it looks like an Orthosia. I’m going to take a break from trying to figure this one out.



Ctenucha Moth (Ctenucha virginica) and other caterpillars are also coming out of hibernation venturing out onto the snow it seems not wanting to wait for the really warm weather. I found this Ctenucha Moth caterpillar (below) and several others in the late afternoon (April 22) on some icy snow floating in a flooded field. They were soaked and looked dead but after a few minutes in my hands perked up so I moved them to some higher and drier ground. Ctenucha Moth caterpillars overwinter as immature larvae. When warm spring weather comes back they emerge from hiding and begin to eat grasses and sedges their primary food plants. In a few weeks they are fully grown and pupate. By early summer the Ctenucha Moths hatch from their pupa to start the process over. Ctenucha Moths are in the Subfamily Arctiinae which includes the familiar Woolly Bear (Pyrrharctia isabella).



This next fuzzy caterpillar was found on April 19th crawling across the snow in a sedge marsh. The caterpillar, whose species identification is unknown but may be related to the Ctenucha, seemed to have no problem with the cold. I watched it for a little while until it reached a clump of exposed sedge and then went inside. It is fascinating to me that these cold-blooded animals can function just fine when ambient temperatures are only a few degrees above freezing and snow is still on the ground.



Now that most of the snow is gone it is becoming harder to find these tiny moths. But soon other species will emerge as the days get warmer and plants start to grow.

A hundred times wider in one day


Temperatures rose rapidly over the weekend melting three feet of snow in our watershed. The result is a huge flood and the little stream (West Fork of the Moose Horn River) that flows through my property has gone from 16 feet wide to almost 1,600 feet wide. Water depths have increased from 3 feet to about 6 or 7 feet depending on where you measure. And the speed of the stream’s flow has also increased although I have no measurements for that other than sore muscles from trying to paddle upstream so as not become part of the flotsam.

The rising and spreading waters clean out the stream and refresh it. They also flatten out the grasses and sedges in the shrub carr/sedge meadow making them less prone to fire. And for me they make it easier to visit the western sections of my property as I can canoe within 100 feet of the uplands. When the stream is at normal levels the walk is 1,300 feet through willow thickets and sedge tussocks.


The edge of the flood comes up to my backyard and is just three hundred feet from the stream and deep enough for the canoe.


The flood waters are stirring up many small aquatic animals which can be collected in simple traps like minnow traps. It is encouraging to find larvae of damselflies and caddisflies in the traps as most species from these insect orders require oxygen-rich waters to survive. Their presence and abundance indicates a good level of stream health. But not everything in my traps is an indicator of  oxygen-rich water. Mudminnows (Umbra limi), Brook Sticklebacks (Culaea inconstans), and isopods (most seem to be Caecidotea) are tolerant of oxygen-poor water. When rainfall is abundant and regular the stream is full and the water fresh. But if rainfall is scarce or sporadic the stream’s water levels drop and the flow slows down. During drought years the stream will nearly dry up. This can be especially problematic in the winter when what little water there is freezes solidly to the stream bed. These conditions put a lot of stress on aquatic life and species that can tolerate that stress have a better chance of surviving. In recent years rainfall has been more consistent. The arrival of beavers, which had been gone for two decades, is also helping to keep water levels higher and creating new aquatic habitats where other animals and plants can live.



While the water is high many migratory waterfowl have arrived. Trumpeter Swans (Cygnus buccinator) and Hooded Mergansers (Lophodytes cucullatus) are two species that arrived this week. They will rest here for a short while and continue northward to their preferred nesting habitats.  A pair of Canada Geese (Branta canadensis) and Sandhill Cranes (Antigone canadensis) have come back as have several pairs of Mallard Ducks (Anas platyrhynchos). These birds will stay here all summer tending their young. Redwing Blackbirds are back, too, fussing at intruders into their territory like me. Other songbirds, mainly warblers and sparrows, will being showing up soon to build nests in the willows and sedge. The flood will continue for several more days and eventually the shrub carr/sedge meadow will drain a little. Then the willows, grasses and sedges will start leafing out transforming the scene from one of bare twigs and brown thatch to green dotted with patches of aster and goldenrod flowers.



The flood at sunset.















An Afternoon in the Woods

Hardwood swamp still frozen but not for long.


On Saturday I took a canoe trip down the little stream with the big name (West Fork of the Moose Horn River) that passes through my property to visit the western section. This area is approximately 56 acres and forested. Most of it is upland aspen and spruce forest but there is a large hardwood swamp near the southern property line.


Another part of the swamp (finally) thawing out. Soon this will be a flowing stream.


The ground was still snow covered but it was melting fast in the warm sun. I spent most of my time in a portion of a hardwood swamp looking at tree trunks for lichens and fungi. I found several lichen species previously documented from here and possibly one new species for the list. There are also a number of unknown lichen specimens to figure out.



There were two fungi that interested me. One is Phellinus igniarius, a polypore bracket fungus, that was growing on the trunk of an old quaking aspen. This fungus decays the lignin in the wood leaving behind the lighter colored cellulose and is one of the causes of white-rot in hardwood trees. The other fungus looks like P. igniarius and like it causes decay in living hardwoods. This one seems to only grow on black ash trees. It is a polypore but the pore surface looks shaggy rather than smooth. So far no luck in figuring it out.



Most of the trees in the hardwood swamp are black ash (Fraxinus nigra) with some green ash (F. pensylvanica), yellow birch (Betula allegheniensis), paper birch (B. papyrifera), American elm (Ulmus americana), quaking aspen (Populus tremuloides), and red maple (Acer rubrum). A year ago I measured the trees in the lower two-thirds of the swamp to get a population count by species and to calculate basal area. Some of the black ash trees are huge (for this part of Minnesota anyway). Of the 64 black ash measured 14 were between 28 cm and 44 cm in diameter. There were also 12 yellow birch in this size range. Black ash and yellow birch are slow growing trees even on good sites like this one so it is possible that the largest trees are at the century mark.