Thursday, February 16, 2012

Pollinator of the Week: Megachile

Megachile the 'big lip' of bees
I hope that I am impressing someone with my ability to identify a bee seen only as a bum protruding from a flower. This should be especially impressive too, since the bee I'm claiming this is, a species of Megachile, belongs to a family defined by its  'big lip'. In old Greek 'mega' means something impressively large and 'chillo' means 'lip'. I could be wrong here, because 'chilli' also means a thousand (must be where we get our 'kilogram', kilometre'). But after working my way through the chapter in Charles Michener's massive Bees of the World (2nd Edition, Johns Hopkins University Press, 2007), I know these bees have 'a rectangular labrum that is longer than broad' - aka a big lip.
Snapdragon & Megachile with scopa
The reason that I can be fairly certain of the genus is because unlike many of the bees we are familiar with, species of Megachile do not use their legs to carry pollen, but the undersides of their metasoma (=+/- abdomen). Notice the dense brush of long yellowish hairs above (and also the large mandibles). This field of pollen-collecting hairs is called a 'scopa' (not to be confused with the card game popular in Italy, nor with 'scope' which is what the spellchecker insists on).
Megachile with full scopa over Eurybia conspicua
The abdominal scopa is, perhaps, better seen in my point-and-shoot moment of blurry glory above. The camera obviously preferred the flowers to the bee, but the picture is still illustrative. The common name of these bees, however, is not 'Yellow-bellied Bees', but Leaf-cutter Bees. Consider the large mandibles visible in the snapdragon pollinating bee above - very useful for cutting our circular bits of leaf or petal. These bees nest in burrows in wood and line their nests with plant material. I'm sure some people take offence at this behaviour and pay outrageous sums to have their gardens sprayed to save their roses from a trivial bee tax. In my garden Leaf-cutter Bees seem to prefer my peas, but I still have more than I can eat every year, so I do not begrudge them a safe haven for their young.
Megachile, I think, possibly a male
In fact, I have several of Splendor Awaits experimental bee homes. The only bees that made use of them last summer were Megachile species. A few wasps also seem to be interested, but I guess many of the bees in my backyard nest in the ground and patches of bare soil would do more to encourage them.
Adrian's bee hotels stuffed with leaf circles & baby bees


  1. The leaf cutters I have noticed in our garden seem to enjoy scalloping rose leaves the most.

    Glad to know at least one bee condo is working! I am going to cut some more bamboo with narrower diameters to replace some of the larger pieces in your other condo.

    And thanks for the link!

  2. Cool pictures. I am trying to pay more attention to native pollinators and attract them to my garden, too.