The tiny bee peering from behind a lupine flower is a Halictus bee. Halictus bees (family Halictidae) are also known as sweat bees because they are attracted to perspiration which often drips from one’s head after hauling compost all morning. Some sweat bee species are colorful metallic green but most are black with yellow or white markings. The female bees build nests underground although some species use wood. Eggs are laid in individual small cells on a supply of pollen and nectar for the larva, and then sealed over. The bees are solitary and, except for a few species under certain conditions of climate, do not form colonies. Some solitary species arrange the brood cells in groups resembling a honeycomb.
Bees in the genus Halictus and other Halictidae are pollinators of a wide variety of plants both wild and cultivated. Male Halictus marginalis pollinate the orchid Orchis galilaeae because its scent attracts them like a pheromone. Females of the species are not attracted to the orchid and nectar and feed on many other species of plants.
Honey bees, often regarded as major pollinators, are not universally present especially in cool temperate regions where large orchards and field crops are not grown. For small gardeners and orchardists wild bees like Halictus but also Colletes (plasterer bees), Bombus (bumblebees), and Osmia (mason bees) are important and necessary for crop production. Planting hedgerows of flowering shrubs at the edges of the yard or strips of flowering plants, even just some buckwheat or dill, along gardens will attract these and other pollinators and provide needed food for them. Plantings of flowering shrubs and flowering herbaceous plants containing a number of species that will bloom in succession over the growing season will ensure food supplies for pollinators.
The rough edges of the hedgerows with clumps of grasses, small piles of logs and rocks, and patches of bare soil mixed into them create valuable nesting and hibernation sites for these bees. If you have a small woodlot leave a few stumps and logs which mason bees can use for nesting sites.
By providing food, shelter, and habitat for bees not only will you be ensuring better pollination of your garden plants but you will also have made habitat for song birds and many other small forms of wildlife. And with a good section of flowering shrubs you will have a season-long display of flowers and later colorful fruit and autumn leaves.