Understanding honeybee hives

Andrew Barron from Macquarie University, along with David Khoury and Mary Myerscough from the University of Sydney, have developed a model that explores how food availability and bee death rates combine to determine the fate of a bee colony.

Honeybees (Apis mellifera) are increasingly in demand as pollinators for various agricultural food crops, but globally their populations are in decline, with honeybee colony failure rates on the increase. 

The model predicts the complex interactions between food availability and forager bee death rates using simple differential equations. The equations represent the transitions of eggs laid by the queen to brood, then hive bees and finally forager bees, and the process of social inhibition that regulates the rate at which hive bees begin to forage.

“We assume that food availability can influence both the number of broods successfully reared to adulthood and the rate at which bees transition from hive duties to foraging,” said Barron. “It is imperative that we understand exactly how colonies respond to forager deaths.”

Low death rates and high food availability results in stable bee populations, with population size strongly determined by forager bee death rate. When death rates are higher, food stores in a colony reflect a balance of food collection and food use. When death rates of forager bees exceed a critical threshold (which may be caused by diseases, pesticides or adverse environmental conditions), the colony fails.

With the current debate over the impact of pesticides on bee populations around the world, the researches say their model has particular significance.

“Our model will add to an increased understanding of the how changes in the environment - both natural and by human intervention - are really effecting bee colonies,” said Barron.

This work was recently published in the PLoS ONE journal.