Bumble Bee (Bombus sp.) - on Vancouver Island. Important pollinators
Bumble bees are a temperate climate bee able to control body temperature. Solar heating and internal heating by shivering, have enabled habitation of northern climates. Adaptations such as being able to vibrate rather than contract thorax muscles enable bumble bees to beat their wings more efficiently saving flight energy and help warm themselves. The longer hairs (bristles) insulate too. Bumblebees cannot fly until the thorax flight muscles are at least 30c. So adaptations such as shivering, rubber band like flight muscles, longer bristles and warming in the sun contribute to their niche success. Given these adaptations, Bombus can forage under cloudy skies too.
The queen having over wintered in stasis, emerges in early spring. She lays eggs, producing from her constructed wax cells, female worker bees. This is the start of the underground hive. The queen lays eggs and looks after the young. Worker bees forage and feed on the nectars of the many flowers available to them. Gathered nectars and pollens are usually brought back to their underground hives. These colonies can range from as few as 20 to more than 400 As the colony increases its numbers, drones (males) and new queens are produced. The queen initially emits pheromones and acts of aggression to suppress worker bee egg laying. At this time, eggs laid by workers are eaten. Initial drone offspring are from the queen. Later in the season, when the queen's ability to suppress worker egg laying is diminished, workers do lay male eggs. This reproductive competition provides an adaptive strategy for the future colony health. Young queens leave the nest in fall mating with forced out males. Drones and workers then perish with oncoming cold weather. The mated queens carrying fertilized eggs, for workers and new queens enter a hibernation state in the fall. Usually only one queen occupies a nest.
Flower pollination happens while the bees collect nectar and pollen. As the bees move from flower to flower, a dusting from the anthers is collected into the worker's hind leg pollen baskets. Nectar is gathered with their long proboscis tongues and deposited in their crops. These nectars and pollens are brought back to nourish the larvae or stored in have wax cells. Flower patches can be up to 2 km from their colony and Bombus can continue gathering available pollens and nectars from the same patch every day. Only a few days stored food is contained in the nest. The drones only feed themselves and not contribute gathered nectar.
We need to support our bees. Bombus bees are particularly important for maintaining the health of our native wildflower species. The are delightful to watch and contribute to our appreciation of the world around us. Not only for their wonderful adaptations but pure and simple existence. Xeroscapped or groomed yards with a plentitude of flowers will welcome them especially, a provision of open dirt areas thy can burrow into.
