Hex Mayflies
Hexagenia limbata
The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
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This is an interesting one. Following the keys in Merritt R.W., Cummins, K.W., and Berg, M.B. (2019) and Jacobus et al. (2014), it keys clearly to Ephemerella. Jacobus et al provide a key to species, but some of the characteristics are tricky to interpret without illustrations. If I didn't make any mistakes, this one keys to Ephemerella mucronata, which has not previously been reported any closer to here than Montana and Alberta. The main character seems to fit well: "Abdominal terga with prominent, paired, subparallel, spiculate ridges." Several illustrations or descriptions of this holarctic species from the US and Europe seem to match, including the body length, tarsal claws and denticles, labial palp, and gill shapes. These sources include including Richard Allen's original description of this species in North America under the now-defunct name E. moffatae in Allen RK (1977) and the figures in this description of the species in Italy.
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Caddisfly Genus Lepidostoma (Little Brown Sedges)
This genus is important for trout anglers. Many species of Lepidostoma produce excellent hatches, especially in the West. Lepidostoma can be very prolific in spring creek environments or smaller runoff streams with springs. Lepidostoma togatum is the most important species of this genus in the East and Midwest. The West has several species that are important.
Where & when
This genus is widely distributed with important species nationwide in all types of water. Some are especially prolific in small streams, and Gary LaFontaine had interesting comments on that in Caddisflies:I know many fly fishermen, some in the East and some in the Midwest, who have fallen in love with a certain type of trout stream. The big brawling rivers are not for them; no, they stalk the overgrown tributaries of these heavily fished waters instead. ... For these fly-fishing cronies I once had a picture postcard custom made showing an adult of Lepidostoma.
In 552 records from GBIF, adults of this genus have mostly been collected during July (27%), August (24%), June (23%), May (10%), and September (9%).
In 209 records from GBIF, this genus has been collected at elevations ranging from 7 to 19701 ft, with an average (median) of 4321 ft.
Genus Range
Egg-Laying behavior
Lepidostoma adults lay their eggs on or near the surface, but I haven't found the specifics and they probably vary by species.Larva & pupa biology
Diet: Leaves or pine needles
Shelter type: Four-sided case of bark or leaf pieces, sand case in a round tube shape, or case of tiny twigs "log cabin" style
Lepidostoma Fly Fishing Tips
In spite of the common names for this genus, the two most important species (Lepidostoma togatum and Lepidostoma pluviale) have green bodies.Specimens of the Caddisfly Genus Lepidostoma
3 Male Adults
On an evening filled with millions of caddisflies, this one stood out as the only one of its kind that found its way into my net. Dave Ruiter identified it from the photos as a Lepidostoma specimen in the pluviale species group.
1 Female Adult
These specimens are still alive, just very cold, so the colors are accurate. I put them in the freezer for a bit to settle them down and overdid it a little:)
5 Larvae
This one got a little bit damaged in the abdomen when I extracted it from its case. That's a delicate job.
The photo of the specimen cased is alive. The photo of the uncased larva is the same specimen taken after it was preserved in its case. Unfortunately, there was a lot of pigment transfer making the specimen look olivaceous. In life it was grayish white as shown in the first photo.
Start a Discussion of Lepidostoma
References
- Jacobus, L. M., Wiersema, N.A., and Webb, J.M. 2014. Identification of Far Northern and Western North American Mayfly Larvae (Insecta: Ephemeroptera), North of Mexico; Version 2. Joint Aquatic Science meeting, Portland, OR. Unpublished workshop manual. 1-176.
- LaFontaine, Gary. 1981. Caddisflies. The Lyons Press.
- Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.
- Swisher, Doug and Carl Richards. 2000. Selective Trout. The Lyons Press.
Caddisfly Genus Lepidostoma (Little Brown Sedges)
Taxonomy
Species in Lepidostoma
Lepidostoma bryanti
0
0
Lepidostoma cascadense
0
0
Lepidostoma cinereum
0
0
Lepidostoma costalis
0
0
Lepidostoma griseum
0
0
Lepidostoma pluvialeLittle Brown Sedges
0
0
Lepidostoma podagrumLittle Brown Sedges
4
9
Lepidostoma quercina
0
0
Lepidostoma rayneri
0
0
Lepidostoma roafi
0
0
Lepidostoma stigma
0
0
Lepidostoma togatum
0
0
Lepidostoma unicolor
0
0
Lepidostoma vernalis
0
0
Species in Lepidostoma: Lepidostoma bryanti, Lepidostoma cascadense, Lepidostoma cinereum, Lepidostoma costalis, Lepidostoma griseum, Lepidostoma pluviale, Lepidostoma podagrum, Lepidostoma quercina, Lepidostoma rayneri, Lepidostoma roafi, Lepidostoma stigma, Lepidostoma togatum, Lepidostoma unicolor, Lepidostoma vernalis
48 species (Lepidostoma acarol, Lepidostoma americana, Lepidostoma aporna, Lepidostoma astanea, Lepidostoma bakeri, Lepidostoma baxea, Lepidostoma cantha, Lepidostoma carolina, Lepidostoma carrolli, Lepidostoma compressa, Lepidostoma deceptiva, Lepidostoma delongi, Lepidostoma ermanea, Lepidostoma errigena, Lepidostoma etnieri, Lepidostoma excavatum, Lepidostoma flinti, Lepidostoma frosti, Lepidostoma glenni, Lepidostoma hoodi, Lepidostoma jewetti, Lepidostoma knulli, Lepidostoma latipennis, Lepidostoma lescheni, Lepidostoma liba, Lepidostoma licola, Lepidostoma lobatum, Lepidostoma lotor, Lepidostoma lydia, Lepidostoma mexicana, Lepidostoma mitchelli, Lepidostoma modesta, Lepidostoma morsei, Lepidostoma ontario, Lepidostoma ormae, Lepidostoma ozarkense, Lepidostoma pictilis, Lepidostoma prominens, Lepidostoma recina, Lepidostoma reosa, Lepidostoma sackeni, Lepidostoma serratum, Lepidostoma sommermanae, Lepidostoma spicata, Lepidostoma stylifer, Lepidostoma tibialis, Lepidostoma veroda, and Lepidostoma weaveri) aren't included.