Apple blossoms and the golden northern bumble bee

The apple trees are thick with bloom across the Millcreek foothills, their branches heavy with clusters of white and pink flowers that catch the morning light. Each blossom opens for just a few days, releasing its brief abundance of nectar and pollen into the late spring air. If you are walking among these trees now, you might hear the low, steady hum that means the golden northern bumble bee has found them too.

This threatened native bee emerges from winter dormancy just as the apple blossoms open. The timing is not coincidental. The golden northern bumble bee is among the earliest of the bumble bees to fly, and apple trees provide one of the richest nectar sources available in late spring. A single foraging worker can visit dozens of blossoms in a morning, her fuzzy body picking up pollen as she pushes deep into each flower for the nectar at its base. The pollen sticks to the branched hairs that cover her thorax and legs, creating the dusty yellow coating that marks a successful foraging trip. When she visits the next blossom, some of that pollen brushes onto the flower's stigma, completing the exchange that will produce the apple's fruit.

The relationship runs deeper than a simple trade. Apple blossoms bloom for only two weeks, but they bloom reliably, year after year, in the same locations. This predictability matters to a bee species that builds its colony slowly, with queens that must survive the winter alone and workers that don't reach peak numbers until midsummer. The golden northern bumble bee depends on this early season abundance to fuel the colony's growth. Without sufficient protein from apple pollen and energy from apple nectar, the colony cannot produce the new queens that will survive to start colonies the following year. The apple trees, in turn, produce larger, more symmetrical fruit when pollinated by native bees rather than the introduced honeybees that also visit the blossoms. The golden northern bumble bee's size and behavior make it particularly effective at transferring pollen between flowers, even in cool weather when honeybees stay in their hives.

But this native bee faces pressures that the apple trees do not. Habitat loss, pesticide exposure, and competition from introduced species have reduced golden northern bumble bee populations across the West. The bee that once foraged widely through mountain meadows and valley orchards now persists in scattered populations, making each remaining foraging site more critical. The apple orchards and backyard trees of the Millcreek area provide essential habitat during the narrow window when queens are establishing new colonies and workers are building the population that will carry the species through another year. Listen for that low hum among the apple blossoms. It carries the sound of an ancient partnership, still unfolding in the warm air of late spring.