Looking for the Perfect Pollinator
Say, you want to begin beekeeping to not only help support one of nature’s greatest pollinators, but to also help support your own garden. You begin your research to find some honey bees; but none of them fit the bill quite right. Something or other just doesn’t make them the perfect pollinator for your yard
So, you get yourself some Blue Orchard Mason bees instead. That’s great! We need all the pollinators we can get. It’s not just the honey bees that are suffering, and the mason bees are a great choice for localized pollination (their range is much smaller than a honeybee’s). They are little pollinator powerhouses.
But they do have a downside. You see, whereas honeybees pollinate plants from early spring and into the fall, Mason bees only pollinate the fruits, nuts, and early flowers of the spring. By the time summer rolls around, they’ve built their nesting cells, laid an egg in each, filled each with pollen, and capped the cells over. Having assured the continuation of their species, the adult Mason bees die. Their young will hatch the following spring, to continue the cycle.
So, how do you assure pollinators for your summer vegetable garden, and all the summer and early fall flowers if all your mason bees are now gone?
A Different Kind of Pollinator
Enter Megachile rotundata, the Alfalfa Leafcutter Bee. This bee was naturalized across the country in 1940, and was credited with saving the American alfalfa industry. Alfalfa is used as a high protein feed for a variety of livestock. These bees saved the industry, because it turns out that they are 15 times more efficient at pollination than the honeybee.
Megachile rotundata are known as leafcutter bees because the female bees cut ¾ in circles out of leaves to use as nesting material in their nesting houses. They prefer the leaves of rose, josta, lilac, and pea plants, but have been known to use other leaves. Though the circular holes on the leaves aren’t pretty to look at, the circles of leaf material taken do not harm the plant, and are invaluable to these bees.
Just like the Blue Orchard Mason bees, Leafcutter bees are solitary bees. They do not live in large hives, and there is no queen. Instead, they build nests in hollow stems, and small holes in trees. People can provide suitable nests for leafcutter bees, if they would like to raise them in their yards. As with the Mason bees, a house that can be disassembled, or one that holds paper tubes, is preferable. This allows you to gently harvest the cocoons for safe keeping over the winter. Do not get the leafcutter cocoons wet – they are not waterproof.
Also as with the Mason bees, pollen is carried on the underbelly, and not in pollen sacks, making this bee a very effective pollinator. A really interesting thing about these bees is that they are bivoltine. This means that they are capable of producing two generations of offspring in a single season. After the female lays her eggs in the prepared nesting house, the eggs can either rapidly hatch and develop into adult bees, or the eggs can be overwintered, with mature adults emerging in the late spring to early summer of the next year. If the eggs laid developed rapidly and emerged as adults shortly after being laid, these second generation bees not only add to the number of overwintering cocoons, they also add a special boost to your garden, providing extra pollination in the late summer and early fall.
Unlike Mason bees, Leafcutter bees can and will sting if they are aggressively handled, but the sting is very mild, and virtually pain free. If you would like to make the addition of leafcutter bees to your garden pollinator series, they can be purchased from some garden stores, as well as online
For more information, check out the following links.
Lifecycle of a leafcutter bee – this schematic only shows one generation, but if conditions are suitable in your area, you may also see second generation bees.