Bee Mindful of These Hard-Working Natives

by 
Howard Goldstein, for the Shuttle
Howard Goldstein photo
A sweat bee visits a coneflower.

 The May garden can be glorious with the flowering of ornamental trees and shrubs like dogwood, viburnum, amelanchier and chokeberry, but also fruits — apples, cherries, pears, peaches, blueberries, cranberries and cane berries. 

Our native bees are the ones responsible for pollinating more than 70 percent of these agricultural crops. In April and May, bees are very busy collecting pollen and drinking nectar, which they combine along with their own body fluids to feed their hatching larvae. 

The small (quarter- to half-inch) native bees such as the mining bees (Andrenids), leaf cutters (Megachile), sweat bees (Agapostemon and Halictus) and mason bees (Osmia) are all actually better pollinators than imported European honeybees. For example, 300 mason bees can pollinate an orchard that takes 90,000 honey bees to pollinate.

You may be familiar with mason bees, which nest in straw-like mud tubes they construct to separate one egg from another. Artificial mason bee houses can be purchased or even made using a variety of small hollow stems. 

Leaf-cutter bees line their nests with pieces of leaves that they cut with their oversized jaws. (The genus name, Megachile, means large-lipped.)

All but the sweat bees are solitary, with each bee digging her own nest in which she lays her eggs and tends to the larvae. Sweat bees are often a shiny metallic green and derive their common name from their habit of landing on humans to drink our perspiration.

Mining bees outrank all other bees in the number of species known, with over 4,500 species worldwide. Andrenids get their common name from their habit of digging nest tunnels in the ground where they lay their eggs. These bees range from the size of a mosquito to 1 inch. North of Mexico, there are over 1,200 species in 13 different genera. 

We can thank mining bees for apples, blueberries and cranberries that they pollinate. Mason bees are important pollinators for apples, cherries, almonds, plums and cane berries (raspberries and blackberries). Sweat bees pollinate the flowers of onions, cane berries and alfalfa, although alfalfa farmers rely more on a type of leaf cutter bee, Megachile rotundata, to pollinate their alfalfa fields. This bee also pollinates melons.

So later this year, when munching on apples, cherries, plums, melons and blackberries, thank the mason, leaf cutter, sweat and mining bees that did so much of the work! 

Weavers Way Howard Goldstein chairs the Penn State Master Gardener Pollinator Garden at the Horticulture Center in West Fairmount Park. Reach him at howpau2@yahoo.com or philadelphiamg@psu.edu.