Advice to find spring, specialist, or rare bees

Pollen specialist bees are less common. Colletes, Andrena, and Osmia fly in early spring. Andrena have among the most species and specialists of Asteraceae (aster or daisy family). Eumellisodes are associated with Cirsium (thistle). Specialists also visit common flowers at times, e.g. Solidago. Some species also have habitat specialization (e.g. Melittidae and bogs; Lasioglossum vierecki or Crabronid wasps and sand).

Brood parasites are uncommon on flowers, but may be lower to ground by nests of host bees or wasps (e.g. Sphecodes, Nomada, Coelioxys, Psithyrus, Chrysididae). If collecting insects, using bowl traps or sweeping through plants at ground level with sturdier nets are ways to find them. Traps are also useful for small species in general.

Highly diverse groups include some uncommon species (e.g. Braconidae, Diapriidae, Ichneumonidae, Pompilidae, Dialictus).

Advice: Start in early spring. Visit many flowers or habitats, like urban gardens and parks, and more natural meadows, forest edges, and wetlands, and specific habitats/plants with specialist associations. Garden with native or specialist plants. Or add nest material, like sand, soil, twigs, plant stems, water, or artificial bee or wasp nests (bee hotels/homes).

Bee sources: Pollen Specialist Bees of the Eastern United States Host Plants for Pollen Specialist Bees of the Eastern United States

Does anyone have advice or experience? Or experience planting specialist flowers or using artificial nests?

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I’ve also been wanting to find specialist bees for a while. Yesterday evening I came across a blooming redbud tree with lots of specialist bees like Osmia and (I think) Colletes, so I think looking for blooming redbuds might help. Of course, most of the bees were rather high up, so I couldn’t get many good pics, and most of them were rather blurry as well.

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That’s a good point.

So far the only bee in general I’ve seen is Colletes inaequalis. Nesting in the ground in an area where there isn’t even flowers yet.

with a bee hotel you’re most likely to get a lot of non-natives (to US) like Osmia. taurus and O. cornifrons. The papers out on bee hotels (Packard ones) point to bee hotels not being very good for conservation/bees

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That’s interesting, I’ll check out those articles. There’s definitely potential for non-natives, or wasps (unless wanted). My take is their overall value is debated, and there can be some value if used in a careful/intentional way. Megachile also include some natives.

Different nest tube diameters can affect spp. I’ve read papers about trap-nesting bees/wasps in the NYS Montezuma wetland complex, Toronto green roofs, and Hawaii native coastal or mountain habitats (native Hylaeus).

If using hotels, brands with good reviews for protecting from water, pests, etc. are recommended (bees don’t survive well in some common brands). I’m trying out 2 “Crown Bees” nests for the 1st time, for Megachile and Osmia.

Ceratina are naturally common, but can also nest in pith plant stems if added to habitats, or if living plant stems are trimmed.

Where is O cornifrons from? I’ve heard that it’s non-native to US, but it’s not listed as introduced, and the Midwest seems to be their stamping grounds, except for a few on the west coast?

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That’s a great advice, even with total lockdown and no ability to go outside when I wanted last year I got 19 species of bees around my house and in some rare “travels” also pretty close to where I live by checking Tussilago farfara as the main source of insects, though last year spring was exceptional and now we’re not even close to the stage of spring that was last year in March. Depending on species they can be scared of you but can be totally not caring about you looking at them and even moving the flower. Plus it seems sandy environments are the focus of many Hymenoptera nesting activity, so seeking for them sounds a logical thing to do.


That’s great. I agree it’s good to be able to find them close to home. I also haven’t been able to observe or travel much overall.

I think Asia? They made it to St Louis not too too long ago (i’m pretty sure). As far as we know we caught the first specimens of it in rural parts of the St Louis Metro (MO side) in 2018. Or at least specimens that Mike Arduser has identified/confirmed.


It continues to amaze me how many common, even weedy, plants there are for which I find no information on pollinators.


Yeah. Weed-like flowers can harm other plants, but also support pollinators during times when less other flowers are blooming. Sources like Xerxes and some farmers defend growing spotted knapweed for its optimal pollinator-qualities (including for butterflies). Others consider it a weed. In northeastern US, goldenrod (especially), knapweed, erigeron, queen anne’s lace, purple loosestrife, etc. in developed/urban areas attract many bees.

Yes, Osmia cornifrons comes from East Asia.
In central Europe we don’t have much problem with exotic bee species (Megachile sculpturalis is extending its range) but the problem with bee hotels is that they often are set up in places not suitable to solitary bees and wasps (both are absolutely legitimate bee hotel users), eg where are very few flowering plants, and there is no accompanying effort to make the vicinity of hotel more “green”. Just putting the hotel and sometimes even Osmia cocoons to colonize it.
“Weeds” - at least wild native species - are very important to bees. Especially in farmland, when there are large fields of one crop (even bee-pollinated), margins with wildflowes are crucial for bees.


To give a backyard advice, if your yard is like mine in the Midwest, than you have a lot Maples, I guess planners love those because they grow fast. It’s really difficult to get things to grow under maples do their roots, but I have had luck getting Virginia Bluebells, Columbines, and Virginia Waterleaf to take hold. Unfortunately, I haven’t been able to get them to really spread, but they come back every year, and I periodically add to them, gives a nice early spring spread. If anybody has had other success with native plants under Maples, I would love some pointers.


Yesterday, I found a population of Perdita in southern Florida ( I just stumbled across them in the beach dunes and they seemed to only be visiting Helianthus debilis flowers. I am wondering if their habitat and flower preferences could identify them to species?

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Another hotel use is studying bees/wasps otherwise hard to observe. Cocoons can be reared in experimental conditions, and developing stages or parasites can be studied (bee health), and they help study state/county spp. diversity.

Somewhat like hotels, urban habitats in general have some habitat limitations to try to avoid (although some remain), to maximize conservation benefits. There’s also research on new ways or technologies to improve habitat quality (green roofs are a good example of experimental habitats with pros and cons).

Exotic spp. are a global issue, and seem impossible to reduce once present (like Megachile, Anthidium, Pseudoanthidium, in US), aside from emphasizing native plants. Hopefully Vespa mandarinia (“murder hornets”) can be stopped in US. In that case, colonies are actually being tracked and removed. The iNat. community’s work is now one of the best ways invasive species are monitored (also see iMapInvasives for plants).

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That’s great. I don’t know FL fauna well yet. I’d check which species are in Cockerellia (click taxon, then Taxonomy. And check Perdita on to see a fuller spp. list). Then search for a FL bee checklist species source (Google Scholar), or use iNat/GBIF maps to see which occur in south FL. There may be multiple lookalike species. You’re right, sometimes habitat and flower give more indication though.

Thanks for the advice! I tried checking iNat but, unfortunately, there are no other South Florida observations of Perdita on FL (except one genus level, blury one). I’ll check GBIF today.

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Yes of course, I personally used “trapnests” (which technically are the same as bee hotels) in my research eg :) I haven’t mentioned it as scientists probably will use them regardless of their usefulness in protection of bees, when they need to for experimental purposes, and I trust that they know what they’re doing and how not to do harm.

By the way, another benefit from bee hotels can be in some circumstaces their educational purpose. As solitary bees are not aggressive by their nests, such nesting aggregation can be great place to teach children about them. In fact, not only children. At least it’s my experience, my interest in wild bees began with one such lesson by red mason bee experimental breeding aggregation :)