While trying to stake The Most Infuriating Plant in My Garden™ this morning (more about that in another post), I came across this:
This is my Thermopsis lanceolata (syn. T. lupinoides) , and I’m not upset in the least that it’s been chewed up that way. I just wish I could find the little guys that did it, so I could watch them either at work or in their nesting site! Bees in general have been making themselves pretty scarce around here this summer, but I have never seen evidence of leafcutter bees in my garden until now.
Leafcutter bees (Megachile spp.) are a type of solitary bee. There are about 140 species of leafcutters in North America. Apparently they have a hankering for legume blossoms, which would explain why they were attracted to my Thermopsis, except that it failed to flower again this year (I seriously can’t figure this plant out – it’s definitely taking its own sweet time to “establish”). Leafcutters munch out half circles of leaves to use in their nests, which may be found in the cavities of trees or fallen logs, or in hollow plant stems.
I read an interesting article at Pollination Canada that described how the alfalfa leafcutter bee (Megachile rotundata) was introduced in Canada in the 1960s in order to resurrect the alfalfa industry. Apparently all the land that was cleared for agriculture in the country in the early twentieth century had destroyed the habitat of solitary bees, and as honeybees can’t properly pollinate alfalfa (because they’re thieves and have no attention spans), growers were desperate for a solution to their pollination problems. Alfalfa leafcutter bees were brought in from Europe, and were highly successful.
Do you have solitary bees in your garden? Do you help them out by offering places to nest?
For more reading, check out this post about the Domestication of the Alfalfa Leafcutter Bee at Pollination Canada.