Some photographs of Chelostoma philadelphi, the most common guest at my mason bee hotel in past years. Approximately 7 mm in length and all black unless covered in pollen. Seems to prefer nest holes that are 1/8″ in diameter. In looking at photographs online they seem to show up on a variety of flowers (perhaps with preference for asters), but females are reported (Sedivy et al. 2008) to collect only Philadelphus pollen for use in nest provisions for her brood.
I gave a Zoom lecture last night on why people should care about native bees, and promised the audience (friends of Belmont Hills Library, in Bala Cynwyd, PA) that I’d share some links, photographs, and answers to some of the questions at the end. If you have any lingering questions or thoughts, please don’t hesitate to contact me. Good luck attracting bees, and thanks again for the invitation.
My blog posts I referenced
- Guide to building and managing a mason bee hotel
- Where to buy mason bee houses
- The horrors of mass-produced bee houses
- Effects of mosquito sprays on humans, pets, and wildlife
- Identifying mantid egg cases in Pennsylvania
- My Instagram account
Links of interest
- Native Beeology (Timothy J. Stanley)
- Bee City USA
- Native Bee Awareness Initiative (Facebook)
- Native Bee Allies (Facebook)
- Little Free Libraries: Interrogating the impact of the branded book exchange (PDF)
- Pollen specialist bees
- The Humane Gardener
- The Bee-Friendly Garden
- Our Native Bees
- 100 Plants to Feed the Bees
- Victory Gardens for Bees
- The Bees in Your Backyard
- Bees: An Identification and Native Plant Forage Guide
- The A Bee C Book
Answers to questions
- Good native ground cover to replace English ivy? A: golden groundsel (Packera aurea).
- Honey from any native bees? A: yes, from stingless bees. I have a few photographs from Costa Rica and Mexico. It’s more liquidy than European honey bee honey.
- Are yellow jackets wasps or bees? A: wasps
- How deep do ground-nesting bees dig? A: I looked up the record and in some species the tunnels can extend down 10 feet or more. But 12 to 18″ is more typical.
- Do figs actually eat wasps? A: Figs in the wild are pollinated by wasps, but as I mentioned, the varieties we grow in the United States don’t require pollination, so the crunch is not due to wasps within. Fig and biology fans should read Gods, Wasps, and Stranglers: the Secret History and Redemptive Future of Fig Trees.
- Is it worth keeping hostas in pots for leafcutter bees A: It is never worth keeping hostas alive for any reason. But leafcutter bees will use them, I’ve read.
Photographs I showed or meant to show
For more photographs of bees (and wasps), my full collection is on SmugMug.
Last week I found hundreds of pure green Augochlora (Augochlora pura) foraging for pollen on Zea mays at Stroud Preserve in West Chester, Pennsylvania. Here’s my favorite capture, which shows a bee cutting open an anther with her mandibles.
I was a tad surprised to see a wind-pollinated plant so mobbed with bees, but a later search of the internet suggested I shouldn’t have been. Even honey bees forage on corn, though the pollen is apparently not as desirable as other sources (e.g., Höcherl et al. 2011). This is also the reason why spraying a cornfield with insecticides can easily cause problems for any bees (and pollen wasps) that collect pollen.
This next photographs shows a better view of the scopa (modified hairs that hold the electrostatically-charged pollen) on the legs and abdomen. It also shows off how incredibly large corn pollen is (perhaps 85 microns, per some estimates, which is huge). Wind-pollinated plants with large pollen are odd.
The final photograph shows some pollen grains set in motion by the foraging bee. The odd look (line segments with bright dot in middle) are presumably caused by the flash freezing the fast-moving grains only in the middle of the exposure (1/200 of a second). I’m not exactly sure why the grains are bright. It could be because they are strongly backlit by sun, but it could be something related to how pollen grain exines bend light (they can cause a pollen corona on allergy-alert days). Someday it might be fun to get a rear-curtain flash configured to better capture such motion.