Perdita obscurata, Delaware, and an oft overlooked bee tree: the Persimmon

[Sam Droege]

All

Last week Jay Davis from the State of Delaware came over to the lab.  For the past few years he has covered his state looking for uncommon bees with great results.  On this trip to the lab he showed me a particularly interesting find.  Two specimens of the very rarely collected Perdita obscurata.  

Collecting Technique Tip: He collected these 2 females by climbing onto the cab of his truck and extending his pole as far as it would go to reach the blooms of a native American persimmon tree (Diospyrus virginiana).  

What Does This Mean: This represents a big jump in distributional records (that we know of) as the nearest previous collections came from the sandhills of North Carolina.  

When looking at the 176 records present in GBIF, it turns out that over half were recorded by Ted Mitchell in the 1950s...on persimmon!  The remaining records largely did not have plant data, but a theme was that collection localities were all largely located in areas of deep sand.  This is also the case with Jay's specimens.  Jarrod Fowler's work (Pollen Specialist Bees of the Eastern United States) has this species likely having a specialization on persimmon, but, really, who looks at persimmons when so much is in bloom at the same time?

So, do others have similar experiences with either P. obscurata or with persimmon collecting?  A quick google check shows people suggesting that the dioicous persimmons are good for honey bees, but no mention of other bees and I could not find any mention of anyone looking at persimmon pollination systems (but would suspect that someone must have... if only for the similar asian species.  Of interest is a record from Robertson (found via the lovely GLOBI system search) of P. novaeangliae on persimmon (same Perdita subgenus).  This is possibly a misdet by Robertson or other error as this species appears strongly associated with Lyonia but worth checking into. 

In similar fashion, another spring Perdita in the same subgenus is P. bradleyi for which there are several regional records but its pollen preferences are unclear and may also be a tree of some kind. (Side Note: Jay has found several instances where this species was found flying over the entrance/workings of fox dens in sand.  In areas that do not have the unnatural disturbance of farming, sand mining, etc...fox and coyote dens may indeed be important for exposing open deep sand for sand specialists....particularly in a more wooded environment)

So, back to persimmons, it would be worth the time for folks in the range of persimmons (Mid-Atlantic south to Texas) AND who have deep sand to stand on the tops of their vehicles and do some persimmon netting this year.  I would suspect that we would find this species occurring from the Pine Barrens of NJ south through DE, MD, VA etc. along the sandhill line that defines some of our interior former coastlines.  Similar locations in the central sandridge of Florida (several collections of P. obscurata here already) and the coastal sands of the interior Gulf Coast down into Texas as well as any interior Texas sand areas. The Mississippi River Delta sands also would have possibilities. In central and western Texas another persimmon species (D. texana) adds some alluring possibilities.  Moving into Mexico and points south, many many more possibilities as persimmon and Perdita diversity expand.

Outside Thermalito

Persimmons ripen with the first frost.
The bitterness inflicted on them
takes their bitterness away.

Would that there were some other way.

- D. A. Powell

[Tanner Bland]

Hi Sam,

I’ve been working on collating all of Timberlake’s floral associations for Perdita over the last few years. He reported several Alloperdita, including the species you mentioned, being Ilex and Diospyros specialists. Two very different families of plants, but maybe there’s some overlap in the pollen morphology/phytochemistry? 

I suspect that Alloperdita have a much broader range than we give them credit. They are some of the largest Perdita next to Xerophasma (which, according to Bossert et al. 2022 is the sister subgenus to Alloperdita), so I would suspect they have some decent flight capability for their size. If I’m not mistaken, P. (X.) bequaertiana is the largest known Perdita and has one of the largest ranges for the genus. Seems like an odd coincidence. 

If Xerophasma have this wide of a range relative to Onagraceae, maybe Alloperdita would reflect the same distributional patterns relative to Diospyros and/or Ilex. It would be really interesting to find an Alloperdita visiting D. texana. I haven’t come across a record of any Perdita collecting pollen from that species, but it would make a lot of sense. If anyone has validated records I could add to my list, I would greatly appreciate it.

I’ve attached a screenshot from my excel file of the floral hosts reported from Timberlake that I deemed plausible (having a high proportion of validated female observations on a flower and not counting single/doubletons). It’s a short list, but that’s the way things go I suppose. Not sure about the misdet for Lyonia, but possible. There are also records for the subgenus on Gaylussacia, so maybe Alloperdita have a strong preference for Ericales?

Thanks for sharing! This is really fascinating. Looking forward to hearing more from folks about this. 

Best,

-Tanner

Tanner Bland
MS Entomology and Insect Science
University of Arizona

Tucson Bee Collaborative Program Coordinator

Arizona-Sonora Desert Museum
309-840-4739 | tbl...@desertmuseum.org

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[Neil S Cobb]

quick back of the envelope on average range size for the two subgenera mentioned and the rest of Perdita for North America

	Range size km2
Xerophasma	225,131
Alloperdita	330,997
All other Perdita	243,069

Neil S. Cobb,

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[Jack Neff]

Sam:  Diospyros texana is a very common dioecious shrub in central Texas where it produces a lot of flowers which are ignored by most bees except Osmia ribifloris, Apis and the occasional carpenter bee.  If one is interested in  large Perdita one should also check Callomacrotera, very large (for Perdita) Asteraceae associated species with a very limited range in coastal Mexico.  In contrast, Perdita minima, one of the smallest of bees, has a very large range (eastern California to western Texas).  I doubt body size has much to do with species range in bees but it might be an interesting study.

Jack

John L. Neff Central Texas Melittological Institute 7307 Running Rope Austin,TX 78731 USA 512-345-7219

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[Neil S Cobb]

just plotting raw numbers for 42 Perdita with ITD suggests there are other factors besides size. Smaller species seem to be limited and the two largest species have large ranges, but a lot of variation in between. P. minima is the smallest species shown.

Neil S. Cobb,

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[Tanner Bland]

Thanks for the plots Neil, those are really interesting. I appreciate the added nuance, it’s certainly not as straightforward as I suggested. It was just speculation on my end. I also wonder though how many populations may be undersampled in Perdita, particularly for rare species like Xerophasma and Alloperdita. If no one is looking for them, how would we know where they occur?

Great point about P. minima. In any case would make for an interesting study in range size vs. body size. Seems like an interesting group for that kind of hypothesis. Is there anyone doing ITD measurements on Perdita more broadly? Would love to connect about that.

I would assume host plant range would be a major driving factor in Perdita range sizes, especially with the specialists. That would explain P. minima/cladothricis/marcialis ranges with Chamaesyce being so widely distributed out west. With how widespread Diospyros is out east, that might suggest a wider distribution than the data would suggest for some Alloperdita if they really are Diospyros specialists. But again, just speculation. I’m sure landscape factors like soil type are playing a huge role here too.

-Tanner

Tanner Bland
MS Entomology and Insect Science
University of Arizona

Tucson Bee Collaborative Program Coordinator

Arizona-Sonora Desert Museum
309-840-4739 | tbl...@desertmuseum.org

[Neil S Cobb]

Tanner, 

Happy to share our distributions of Perdita with you if you want to look at them. I do not know of anyone doing a focused study on size in Perdita. The numbers that I have are just you know something I had in our large spreadsheet. I'm sure there's more data out there on on different Perdita species. I hate to suggest this but if you spent just one afternoon at the u of a collection you could easily double the number of species that we had ITD data for. I assume all of Bob's bees are in the u of a collection . Also the sample size for subgenera besides Perdita is pretty small. 

Cheers, Neil

Neil S. Cobb,

Biodiversity Outreach Network  Office: 11 W Silver Spruce Ave, Flagstaff, AZ 86001-3541       ID  84-2609936

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[James Cane]

Hi Folks- I stumbled on Perdita bradleyi nesting in the Alabama interior right at the "The Fall Line" (where Piedmont gives way to coastal sands). Described its nests but did not establish its floral host. For sure there were no persimmons anywhere in the vicinity, though. I would have eaten some come autumn!

yours, jim 

On Tue, Feb 24, 2026 at 11:56 AM Sam Droege <droe...@gmail.com> wrote:

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[jbpascarella]

Dan Bennett of Stephen F Austin State University and I collected many specimens of Perdita obscurata in the Sandhills Loop Trail of the Big Thicket National Forest in Hardin County Texas. This is a very sandy ridge surrounded by wetlands. No pollen data as from pan traps  but would be interesting to do focal surveys on Persimmons. 

John Pascarella

Sam Houston State University

Huntsville Texas

[Droege, Sam]

Interesting to note that both persimmons, willows, and hollies in the East all have Perdita specialists and are dioecious.  The only other spring plant specialist Perdita (that we know of) is P. novaeangliae on Lyonia.  The many remaining Perdita specialists in the East all appear to be summer to fall species.

 

Bloom — is Result — to meet a Flower

And casually glance

Would cause one scarcely to suspect

The minor Circumstance

Assisting in the Bright Affair

So intricately done

Then offered as a Butterfly

To the Meridian —

To pack the Bud — oppose the Worm —

Obtain its right of Dew —

Adjust the Heat — elude the Wind —

Escape the prowling Bee

Great Nature not to disappoint

Awaiting Her that Day —

To be a Flower, is profound

Responsibility —

 

        - Emily Dickinson

 

 

From: beemon...@googlegroups.com <beemon...@googlegroups.com> On Behalf Of Tanner Bland
Sent: Tuesday, February 24, 2026 6:06 PM
To: Neil S Cobb <neil...@gmail.com>
Cc: jlna...@yahoo.com; droe...@gmail.com; beemon...@googlegroups.com
Subject: [EXTERNAL] Re: [Beemonitoring] Perdita obscurata, Delaware, and an oft overlooked bee tree: the Persimmon

 

 

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Thanks for the plots Neil, those are really interesting. I appreciate the added nuance, it’s certainly not as straightforward as I suggested. It was just speculation on my end. I also wonder though how many populations may be undersampled in Perdita, particularly for rare species like Xerophasma and Alloperdita. If no one is looking for them, how would we know where they occur?

 

Great point about P. minima. In any case would make for an interesting study in range size vs. body size. Seems like an interesting group for that kind of hypothesis. Is there anyone doing ITD measurements on Perdita more broadly? Would love to connect about that.

 

I would assume host plant range would be a major driving factor in Perdita range sizes, especially with the specialists. That would explain P. minima/cladothricis/marcialis ranges with Chamaesyce being so widely distributed out west. With how widespread Diospyros is out east, that might suggest a wider distribution than the data would suggest for some Alloperdita if they really are Diospyros specialists. But again, just speculation. I’m sure landscape factors like soil type are playing a huge role here too.

 

-Tanner

Tanner Bland
MS Entomology and Insect Science
University of Arizona

Tucson Bee Collaborative Program Coordinator

Arizona-Sonora Desert Museum
309-840-4739 | tbl...@desertmuseum.org

On Tue, Feb 24, 2026 at 3:17 PM Neil S Cobb <neil...@gmail.com> wrote:

just plotting raw numbers for 42 Perdita with ITD suggests there are other factors besides size. Smaller species seem to be limited and the two largest species have large ranges, but a lot of variation in between. P. minima is the smallest species shown.

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[drdon...@aol.com]

Tanner,

Clint Gibson has recently documented the following hosts for Perdita (Alloperdita) floridensis in central Florida: Vaccinium arboreum, Lyonia glabra and Ilex fruticosa (records in iNat). Tim McMahon and I also found it using V. arboreum at Ordway-Swisher Biological Station in Putnam Co. 

Don Harvey

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