During the last decade, North American scientists have become greatly disturbed by the undisputable collapse of honeybee colonies. They understand the crucial role of bees but they are baffled by the honeybees’ decline. It has now been postulated through a mathematical model that hives with too few bees are weak and vulnerable. In fact, the “model indicates that any or all suspected environmental factors, alone or in combination, could lead to hive collapse by destabilizing a hive’s adult bee population.” This mathematical model, created by University of Idaho [UI] professor Brian Dennis in collaboration with William Kemp, UI alumnus and U.S. Department of Agriculture scientist, reveals the potential problem of hives with too few bees.
Bees thrive in a highly structured social existence which has always given them exceptional adaptation over countless years. However, now they seem to lack hardiness or resistance to environmental problems. Both Dennis and Kemp state, using their model, that these various factors weaken a hive’s adult bees. In a typical hive collapse, the bees fail to thrive and end up deserting their hive or die off en masse or one by one. Researchers have been attempting to identify the actual cause of such collapses, whether from viruses, poor nutrition, parasites, fungi, pesticides. Even global warming has been explored.
Bees exist in their socially-structured hive by strict cooperation. Each adult worker bee has a particular job and all join together, making the hive function almost “as a single organism.” Worker bees provide food for all bees in the hive and serve the egg-laying queen, eggs, larvae and pupae. Other tasks of the workers include maintaining and regulating the hive’s temperature, searching and finding food sources, teaching other bees where food can be found or is available, gathering and transporting food back to the hive. Bees vehemently guard the hive against natural enemies and predators, fighting to the death.
When a hive does not have an adequate number of worker bees, it cannot thrive. A queen produces only so many eggs. When there are not enough adult worker bees to keep up with the functions of a successful hive, then the hive’s survival is threatened. If adult bee numbers drop below critical hive size, collapse may follow. Science Daily notes that, normally, critical hive size would pose no problem for bees during good environmental circumstances.
However, Dennis and Kemp’s model found an unexpected surprise: Critical hive size turned out to be extraordinarily sensitive to any degrading of cooperative hive functions.
According to Dennis and Kemp and their concentration on adult worker numbers, when more adult workers were in a hive, there were fewer deaths in their ranks. Furthermore, larger numbers of worker bees resulted in far better “rearing effectiveness, or how well eggs, larvae and pupae are nurtured and raised to adulthood.” It is reasonable, therefore, to find that factors in the environment disturbing rearing effectiveness or leading to increased deaths of adult bees, could put a hive below critical hive size. Ultimately this would result in failure of the hive.
Dennis and Kemp conclude:
Much might be gained from coordinated regional management of pesticides for beekeepers and crop producers and from conservation programs that contribute to improving foraging resources for all pollinator species.
Let’s not forget that bees pollinate crops, vegetables and orchards. If bees continue their decline, we face devastating disruption in our food production.