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.
Just a pic of the latest mason bee hotel I made, this one for my sister. It’s heavy, but designed to slide into a medium USPS flat rate box. Sides are cedar, top is exterior-grade plywood sprayed with a preservative. Blocks are made from old dimensional lumber (circa 1906), with 5/16″ holes that are 6″ deep. Block unit is removable so that pupae can be protected from parasites, birds, and weather once all the holes are sealed. Next spring, new blocks will be popped in while the current blocks are set outside (inside a box that has a small escape hole) to release their occupants.
For details and links on building mason bee houses, please see my earlier post. If you already have one and own a nice camera, please post photographs of residents on iNaturalist, then add to my Bee and Wasp Hotels project. There are multiple species of mason bees, plus you’ll get leafcutter bees, and nest-provisioning wasps. All of these residents will, of course, attract parasites such as cuckoo wasps.
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.