What’s the buzz?

How you can help Maine’s bees

Watching bumble bees gently connect with flower petals in the early spring is one of the finest pleasures nature has to offer. While they might be called “bumble” bees, and they look rather rotund, they partake in one of the most delicate, not to mention important, operations – moving pollen from one plant to another in a quest for nectar.

Bumble bees are active even when it is surprisingly cool outside, as they have the extraordinary ability to warm themselves by shivering (despite what you may have learned in school about insects being cold-blooded and unable to regulate their own body temperature).

Leaf cutter bee

The habits of our native bees are fascinating, diverse and range widely. For example, Leafcutter bees cut leaves or use flower petals and roll them up to create cells. In each cell, they lay an egg and leave a little pollen, which will serve as food for the larva. Wrapping their young this way protects the larva from predators and pathogens and prevents the pollen from drying out. Some species place these egg bundles in pre-existing cavities like hollow plant stems, abandoned beetle tunnels, gaps in bark, or artificial nesting blocks, while others burrow in the ground.

A leaf cutter bee nest, constructed of rolled up leaves inside a cavity

The plight of honey bees is well known, and while they are facing a number of serious threats currently, they are not in danger of extinction. However, North America’s native bees are in trouble. According to the International Union for Conservation of Nature, 28% of our 48 species of bumble bees are at risk of extinction. Numbers for the other varieties of bees are unknown because they are not well studied.

Unlike honey bees, more than 90 percent of our nearly 4,000 native bee species, which include bumble, carpenter, cuckoo, leafcutter, mason, sweat, miner and sand bees – just to name a few – live not with other bees in hives, but alone in nests carved into soil, wood or hollow plant stems. For this reason, one of the most important things every homeowner can do is to leave the stems and leaves of dead plants in the fall so bees can overwinter in them. Likewise, in the spring, it is recommended that you do not clean up your garden beds until it has been 50 degrees Fahrenheit or warmer for at least seven consecutive days to give bees time to emerge from their overwintering sites.

In addition to planting native plants, which evolved with our native pollinators and provide the best food and habitat, gardeners should also avoid smothering ground nesting bees and other insects that have overwintered in the earth with thick mulch. It is best to wait until late spring before adding mulch to gardens.

Photo credits: Bumble bee by S. Robideau, leaf cutter bee by Bernhard Plank, leaf cutter bee nest by Subbu Subramanya