Tag Archives: pollen

Welcoming native bees

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

Links of interest

Articles

Bee books

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.

#BeeBest

Augochlora pura foraging for pollen on maize

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.

Augochlora pura foraging for pollen on corn (Zea mays)

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.

Augochlora pura scopa with corn pollen

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.

Pure Green Augochlora (Augochlora pura) collecting pollen from corn

Theobroma cacao flower

Here are some close-ups of Theobroma cacao flowers at Longwood Gardens in Kennett Square. The plant is economically important (because chocolate) so people fuss over pollination a lot, but its bizarre floral anatomy is noteworthy regardless of the species’ value. First, here’s a photograph of a stem bearing a developing fruit and a flower:

Longwood Gardens’ meadow, Kennett Square, PA.

The catchiest structures are the pointy red staminodes, stamens that became neutered over evolutionary time, which probably have roles in visual attraction of pollinators (ceratopogonid midges) and in preventing self pollination. The real stamens are enclosed in translucent petal pouches.

According to one scenario I read, the flies first land on the exterior of the pouch, then crawl inside to lap up nectar from minute glands on the adaxial surface near the anthers. During their foraging they get coated with pollen, and some of the pollen gets deposited on the style (small white structure encircled by the staminodes) when they exit the pouch. Here’s a close-up that shows the translucent pouches:

Theobroma cacao anther sacs

Presumably some of transferred pollen is from previous visits at different trees (because most types are self-incompatible). These flies do such a terrible job pollinating that farmers often just do it themselves with paintbrushes and forceps. There’s even speculation that the domestication of T. cacao some 1500 years ago slowly changed the plant enough that the original pollinator(s) (bees?) were lost, with the midges being the only insects still interested in the meager nectar rewards.

The photograph below the “parallel staminodes” variant of the flower.

Theobroma cacao (chocolate tree) flower with parallel staminodes. Longwood Gardens, Kennett Square, PA.