Those Cute Little Houses - Leafcutter Bees

Letter of the Week:

I've thought this over for a bit and I just wonder what a woolly mammoth would have tasted like. They dug one up last year in Siberia - it must have weighed a few tons so... that might be the best place to get a roast or two as I hear that things are tight in Russia and a few extra dollars might help them.

I think those roasts would be pretty tough chewing my friend. Although I have heard that A-1 Steak Sauce will tenderize the toughest of meats. I've had a few more submissions for the Meat Treats list. Keep them coming...

Last week I mentioned a letter I got requesting information about leafcutter bees:

I think you should do an article on leafcutter bees. I'm sure there are thousands of people wondering what those cute houses are for.

Ever wonder what those wooden "buildings" are that you see located all over the alfalfa fields? They come in all sorts of shapes and sizes with various colours and patterns on them. They're the summer homes of the leafcutter bee.

Alfalfa flowers are composed of a central column lodged between two petals. When an insect lands on the flower, this central column springs forward and blasts the visitor with pollen. Honeybees don't put up with this treatment and learn to steal nectar from the base of the flower, thereby avoiding the pollen completely. Obviously, this isn't any good for the reproduction of the alfalfa plant. Enter the leafcutter bee.

About four decades ago it was discovered that the leafcutter bee was more tolerant than the honeybee to these "attacks" by the alfalfa flowers. Until this time, alfalfa growers had been plagued by poor yields. The leafcutter, which had been accidentally introduced to North America from the Mediterranean area, was already widely distributed here. And because of it's strong need for pollen it was willing to put up with a little abuse to get it. On many farms, leafcutters have become an absolute necessity, increasing harvests between 500 and 1,000 %.

Those "cute little houses" that you see situated throughout the alfalfa crop are lined with thick Styrofoam blocks in which thousands of holes have been drilled. After being stored at 4°C over the winter, the nesting blocks full of leafcutter cocoons are warmed up to 29°C to finish the bees' development and then released into the fields. They immediately begin building nests by filling the Styrofoam holes in the houses with leaf clippings from the alfalfa plants. After they stock up on nectar and pollen, they lay an egg in the nest and cap the cell with more leaf clippings. After working all summer and laying between 12 and 15 eggs each, the leafcutters die and the beekeepers remove the Styrofoam blocks (the nesting blocks) from the houses and store them for the winter.

Leafcutters have become big business across Canada - some 4 billion bees are reared each year. In fact, Saskatchewan has become to leafcutters what Switzerland is to cheese. And you know how much I love cheese. Last year a gallon of 10,000 leafcutter cocoons sold for $120, making prairie leafcutters a multi-million-dollar business. For more information, check the Microsoft Encarta Online Encyclopedia.

As always, send me your suggestions for future columns on crang.com. See you next week when we'll be discussing the metric clock.

© September 30, 2000