#triepeolus

[northerlyy]

Longhorn-cuckoo Bee (Genus Triepeolus), taken September 29, 2025, in Georgia, US

A beautiful (but, sadly, dead) cuckoo bee clamped onto a grass seed by its mouth! I presume this individual's cause of death is fungus due to its position, but it could have just died in the night while "sleeping" on this grass stalk. Cuckoo bees are super cool! Behaving similarly to the cuckoo bird, well-known for its nest parasitism, these bees lay their eggs in the nests of other bees, capitalizing on the shelter and food stores created by other bees to raise their young for less effort! Many prefer to parasitize the nests of burrowing bees, so it's very common to see small bees buzzing around the ground in the late spring, searching for burrows to stake out. Most of the cuckoo bees I see are red, however, so it was a nice change to see a black and white one, even if it was dead!

[usgsbiml]

Trans Genus Red-eyed Bee. Meet Triepeolus distinctus. While most Triepeolus invade the nests of Melissodes, this one invades the nests of Dieunomia, a bee not even in the same family as Melissodes.  Found in sandpit across the river from my house. Nearest records: OH, GA

[toddjdreyer]

Had some trouble IDing this one, thankfully someone on IG helped. Possible example of Triepeolus lunatus / Lunate Longhorn-Cuckoo, found in my backyard pollinator patch.

[bee-safari-blog]

Triepeolus bee - the “smily-faced bee.” A name given in reference to the smiling face on the front of its thorax. On every one of these I see the “face” seems a little different. This one has a bit of a glum smile. Anyhow, aren’t those green eyes wonderful? A parasitic bee, and the rare generalist that isn’t as picky as its cousins about what species it parasitizes. #insects #bees #triepeolus #greeneyes #bugs #photooftheday #buzz #pollinator #parasiticbee #canonmacro #cuckoobee #show_us_macro #macroworld_tr #insects_of_our_world #beesofinstagram

[usgsbiml]

New species for the state of Maryland, this is Triepeolus concavus. As are all Triepeolus this one is a nest parasites. In this case, it's host is Svastra obliqua, an uncommon bee that loves large composites and is a good indication of high-quality habitat. In this case, the high-quality habitat was at Blackwater national wildlife refuge in the marshlands of Dorchester County, Maryland. Photography by Wayne Boo

[usgsbiml]

Newish species. (Triepeolus melanarius) or is it? If you want to name a new species you have to get that name published in a recognized journal (as an aside, there are some tricky, and slightly shady, self published journals that focus on the publication of species names that give main-stream taxonomists fits, but what part of human society does not have a component that tries to game the official paradigm? (If you want to have some fun go to the "code" and read through the complexities of taxonomy that arise after a couple of hundred years of combining and recombining and unrecombining and misspellings and double naming plus the joys of Latin endings by people who do not know Latin at:https://www.iczn.org/the-code/the-international-code-of-zoological-nomenclature/the-code-online/)). In the handsome specimen at hand, Molly Rightmyer published its name (in the proper way). However, she notes that the identification of this species as a species that did not have a name and was worthy of publication with a name have been around for decades and decades. The name she used was given by Timberlake (long deceased) in a manuscript that was never published (no relation that I know of to Justin). Fortunately, the specimens were kept in various archaic storage faults called "museums" around the country and she was able to re-create the descriptions and publish it as a now legitimatized species.  Demonstrating once the quite way our race is supported and ultimately saved by taxonomists.

[usgsbiml]

The Mysterious Triepeolus subnitens.  I am not sure why I use the term "mysterious" here as almost all bee species (yes even honey bees) are mysterious.  But parasitic bees are considered particularly mysterious.  First we should point out that they make up about 20% of the entire bee fauna.  Second, as nest parasites, they are de facto less common than their hosts and therefore generally rare.  Third, people have a super hard time finding the nests of most bee species and consequently, we have fewer specimens to look at for groups like Triepeolus and a devil of a time really determining who they parasitize with 100% confidence.  For example, our friend, T. subnitens is said to parasitize Svastra obliqua, but only based on someone seeing a T.s. go into a S.o. nest hole (side note:  Most Triepeolus parasitize Melissodes).  That's it, sample size 1 + circumstantial evidence (maybe it was just checking the nest out, for example).  This lack of understanding of something so fundamental irritates me, particularly when so many people play Tennis.  Just think of how much more we would know if everyone now play Tennis instead looked for bee nests and their parasites.  Head spinning.  Photo by beelab tech Erick Hernandez. "This bee was collected in the California Central Valley in Yolo County for research on small-scale restoration in agricultural areas. Claire Kremen's 10-year study of hedgerows shows the benefits of planting native shrubs and forbs in agricultural areas for native bees. To learn more about the Kremen Lab and hedgerows"

[usgsbiml]

Triepeolus concavus:  Svastra Home Invader.  Triepeolus are a primarily New World group and lay their eggs mostly, but not entirely, in the nests of long-horned bees (Eucerini), mostly Melissodes.  Interestingly (to me), I can't find any records of them parasitizing Eucera (in the strictly old fashioned sense) but if you google around you will see mentions on websites that they do.   I feel like these websites are incorrect, so someone please correct me if I am wrong.   Eucera are a spring long-horn and maybe Triepeolus just don't do spring (I certainly know of no spring records).  In any case the species at hand invades the hulking long-horn group of Svastra, not Melissodes.  Consequently, they are a bit larger than most Triepeolus (as if anyone cared).  This bee was collected in the California Central Valley in Yolo County for research on small-scale restoration in agricultural areas. Claire Kremen's 10-year study of hedgerows shows the benefits of planting native shrubs and forbs in agricultural areas for native bees. Photo by Erick Hernandez.