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Mayfly Species Baetis flavistriga (BWO)

Pictures Below
This is one of the most widespread and abundant Baetis species, and it may produce fishable hatches under a variety of conditions.

This species is known in angling books by several old synonyms (Synonym: A former name of a taxon, usually a species. Entomologists frequently discover that two insects originally described as different species are one in the same, and they drop one of the names. The dropped name is said to be a synonym of the remaining name. These changes take a while to trickle into the common knowledge of anglers; for example, Baetis vagans is now a synonym of Baetis tricaudatus.), including Baetis quebecensus, Baetis levitans, Baetis cingulatus, and Baetis phoebus, in addition to the correct name.

Where & When

Regions: East, Midwest, West

Time Of Year (?): May through August

The first flies of this species make their appearance a few weeks after Baetis tricaudatus. Because the species is a combination of widely varying types in different places, it's hard to piece the information together into reliable hatch dates for the different broods in any given location. The best hatches for which this species is credited occur in June.

Nymph Biology

Current Speed: Any; best in fast

Substrate: Gravel

Pictures of 3 Mayfly Specimens in the Species Baetis flavistriga:

Male Baetis flavistriga (BWO) Mayfly NymphMale Baetis flavistriga (BWO) Mayfly Nymph View 8 PicturesThis nymph keys to Baetis assuming the villipore is present (hard to see in my photos or scope), and within that genus it tentatively keys to the flavistriga species complex, of which Baetis flavistriga itself is by far the most common in Washington state, so that's the most likely ID.
Collected July 6, 2020 from Mystery Creek #249 in Washington
Added to by Troutnut on July 12, 2020
Baetis flavistriga (BWO) Mayfly NymphBaetis flavistriga (BWO) Mayfly Nymph View 1 Pictures
Collected June 19, 2011 from the Kwethluk River in Alaska
Added to by Bnewell on June 26, 2011
Baetis flavistriga (BWO) Mayfly NymphBaetis flavistriga (BWO) Mayfly Nymph View 5 PicturesThis specimen keys to the Baetis flavistriga complex, which could be either flavistriga or Baetis phoebus.
Collected August 3, 2020 from the East Fork Big Lost River in Idaho
Added to by Troutnut on August 19, 2020

Recent Discussions of Baetis flavistriga

Baetis flavistriga computatii 7 Replies »
Posted by CaseyP on Jan 22, 2007
Last reply on Jan 19, 2009 by Taxon

pleased to report the emergence of a new baetis flavistriga which i have christened computatii

forum visitors using the Firefox browser who put on their bookmarks toolbar have undoubtedly noticed a tiny dark mayfly icon in a blue box next the bookmark.

well, it's breeding. came back this evening from a week out of town to discover that the little troutnut computatii had a pal over next the bookmark where formerly there was only a generic white icon. am waiting for it to show up next the other two sites that have only generic icons.

now our resident boffins will help me with the Latin ending on the new name, (i tried to use the genitive plural) and then we'll ask Jason how he got these virtual flies to multiply.

Replyflavistriga broods
Posted by Konchu on Jan 18, 2009
Anyone have observations that they are willing to share of different flavistriga broods?

Jason says that B. flavistriga is a "combination of widely varying types in different places, it's hard to piece the information together into reliable hatch dates for the different broods in any given location." This is stated very well.

As part of my bug work, I'm trying to tease apart some of these "varying types" to see what, if anything, they might represent. Tapping into the experience base here might help.

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