Bumblebees are familiar fuzzy insects, recognized for their pollination efforts. Many people often wonder about their living arrangements, particularly if they make their homes underground. The truth about where bumblebees reside is varied, encompassing a range of nesting strategies.
Bumblebee Nesting Habits
While some bumblebee species establish colonies beneath the earth, it is not a universal practice. Bumblebees are opportunistic nesters, adapting existing cavities they discover rather than excavating their own burrows. There is considerable diversity in nesting preferences across the more than 250 known bumblebee species.
Each queen, after emerging from hibernation, embarks on a search for a suitable, pre-existing site to begin her colony. She seeks dry, enclosed spaces that offer some form of insulating material. This adaptability allows various species to thrive in different environments, selecting sites that best meet their specific needs for colony development.
Where Bumblebees Build Their Homes
Bumblebees exhibit a wide range of choices for their nesting sites, both below and above ground. Underground, common locations include abandoned burrows of rodents such as mice or voles, which often come with insulating material like grass and fur.
Above ground, bumblebees can be found nesting in dense grass tussocks, particularly those with natural indentations. Other suitable above-ground sites include compost heaps, leaf litter, and log piles. They also utilize hollow spaces in trees, wall cavities, and even man-made structures like sheds or abandoned bird boxes. These varied locations provide protected environments.
The Purpose of Nest Locations
The specific locations chosen by bumblebees for their nests offer several biological advantages important for colony survival and growth. Protection from predators is a significant factor, as underground or hidden nests are less visible and accessible to animals like badgers, shrews, and certain birds. The enclosed nature of these sites also makes it easier for the bees to defend their colony.
Insulation against temperature extremes is another factor influencing nest site selection. Bumblebees maintain a relatively stable brood temperature, ideally between 28 and 32 degrees Celsius, for optimal development. Underground nests and those with ample insulating material help buffer against both excessive heat and cold, reducing the energy expenditure required for thermoregulation. Nest sites must also provide stability for the growing colony and its stored food resources, such as honey and pollen, while remaining relatively dry to prevent waterlogging.