Wednesday, June 13, 2012

Bees in the wind

WIND: The wind was so tumultuous yesterday. It tapered by mid-day, but at dawn it was at it's strongest. I was struck by the different ways the leaves of different trees moved with the wind. The compound leaves all had this wispy graceful way of flowing with the wind, while the stout leaves of the buckthorns seemed obstinate and reluctant to bend under the wind's influence. Last year I had girdled a Norway maple, this year the tree had both leafed out and flowered, which was impressive. During the windstorm I put my ear to the exposed wood to listen to the wind strain and contort the tree's long fibers. It sounded like the achings in the belly of a large boat. When I put my ear against the part of the bole that still had bark on it, the sounds were muffled, but still echoed that deep resonant strain on the tree.
BEES: The day quickly warmed and I spent some time watching our three beehives. It was funny watching the guard bees act as bouncers to returning foragers. Each colony has its own scent and the guards would presumably tip off the others if a bee from another hive tried to enter. Most of the time there were two bees guarding the entrance to the hive. The pair was constantly vigilant and would approach each bee entering (if only for a brief moment). I'm not sure how one bee will replace another as guard (how long could a sentry keep its guard up before it started to lose focus?), but I watched a pair on active duty for about 10 minutes without being replaced. Others guards would go into the hive or I'd lose track of who was who every couple of minutes.

In the video, all the bees returning with huge yellow balls attached to their rear legs are foragers carrying pollen back to the hive. Bees collect pollen for raising brood, and it is the colonies only source of protein, fat, vitamins, starches, and essential minerals. Pollen has a slight negative charge, bees have a slight positive charge, so a bee will literally pull the pollen right off a flower's anther. Bees are covered with hairs, which increases their surface area and their for the attractive force to pollen. While out foraging they will clean themselves and pack the pollen into "pollen basket," or corbicula, on their hind legs.

Not all pollen is created equal and protein concentration can range from 2% to over 60% protein!! Plants can be pollinated by animals or the wind, and so not surprisingly, the 2%-ers are wind pollinated (anemophilous), and the 60%-ers are pollinated by insects (entomophilous) and/or vertebrates (zoophilous). I've been out in Centennial Woods checking which species the bees are feeding on and I've spotted them on most of the clovers in flower - birdsfoot trefoil, crown vetch, cow vetch, and red clover. I haven't seen them on the flowers of white clover, but I've noticed an abundance of ants on these. Turns out white clover also has one of the lowest protein concentrations of the clover family (Fabaceae). Members of the pea famliy (Fabaceae), like clover, tend to have pollen with the higher concentrations of protein. Their flowers are also highly specialized for attracting insects. I'll post soon a video of insects manipulating birdsfoot trefoil flowers to show this. Asters also tend to have pretty high concentrations of protein in their pollen.

For a great description of other activities different castes within the bee hierarchy are responsible for, check out:

For more on pollen concentrations:

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