It surprises many people to learn that honey bees are not native to the New World. The earliest records indicate that honey bees, Apis mellifera, were brought to North America from Europe in 1621. However today, honey bee populations, as well as the populations of other pollinators, are now declining. This decline is documented in a 2007 report by the National Academies of Science, The Status of Pollinators in North America. Due to this report and the mapping of the honey bee genome, as well as the phenomenon known as colony collapse disorder (CCD) and the media’s response to it, there has been a lot of attention paid to this tiny creature.
Worldwide, honey bees are a critical player in the pollination of many native plants as well as in the production of important food, fiber and seed crops. The loss of honey bee colonies could result in lower quality, higher priced foods or the total absence of some foods from the marketplace. There may be a number of reasons why honey bees are declining including loss of habitat, poor nutrition, exposure to pesticides, diseases, and the introduced parasitic mite, Varroa destructor, that is considered to be the most devastating pest of A. mellifera worldwide. The race is on to understand what is happening to our bees and what can be done to save them.
There are approximately seven known honey bee species. All are native to Asia, except the one species brought to the Americas, Apis mellifera, which is native to Africa and Europe, but may have originated in Africa. Its presence for thousands of years on a continent where ecosystems range from desert to savannah to tropical rain forest has resulted in a highly diverse population of unique subspecies, each well adapted to its specific habitat. The subspecies have unique mechanisms that equip them to thrive, even in places that appear unsuitable for honey bees. One such mechanism is defensive behavior: these bees are, after all, the parent population of the Africanized (aka “killer”) bee, now ubiquitous throughout most of South America and all of Central America and Mexico as well as the southern United States. In addition, African bees reproduce (swarm) and abscond (leave the nest) more often than do their European counterparts and they are able to migrate long distances to find the nectar and pollen resources they need. African bees also appear to be better equipped to deal with the diseases and pests that plague nearly all keepers of A. mellifera in other parts of the world.
A 2009 United States Department of Agriculture, International Science Education grant awarded to Penn State’s Center for Chemical Ecology in collaboration with the International Center for Insect Physiology and Ecology (ICIPE), enabled Jim and Maryann Frazier, Jim Tumlinson, beekeeper Tom McCormack, and graduate students, Dan Schmehl and Tracy Conklin, to visit Kenya. The goal was to study the biology and behavior of African bees and learn how they are kept by beekeepers in East Africa. What was discovered on this trip was a surprise not only to us, but also to ICIPE colleagues, Elliud Muli and Baldwyn Torto. Varroa mites, thought not to be present in East Africa, were discovered in all the ICIPE colonies, yet the bees did not appear to be suffering from the infestation. This initial discovery led us, and later our ICIPE colleagues, to survey additional colonies. It is now clear that the mite is widespread throughout much of Kenya and is also present on the coast of Tanzania as well as in Ghana.
In 2010, an expanded Penn State/ICIPE team that included Christina Grozinger and Harland from Penn State, and Dan Masiga from ICIPE, returned to Kenya with funding provided by a Gates-NSF-BREAD grant (Basic Research to Enable Agricultural Development). Also joining the team was visiting scientist Diana Sammataro (USDA/ARS). The 2010 goal was to identify the geographic distribution of the four known A. mellifera subspecies in Kenya, to characterize their Varroa mite and disease loads and to look for certain behavioral characteristics. We also hoped to learn what impact Varroa mites are having on the honey bee populations and whether or not different subspecies are responding differently to the Varroa infestations. We spent the month of June visiting beekeepers, collecting samples and measuring honey bee colony health parameters at fifteen different locations in central Kenya and along the eastern coast. We also conducted extensive interviews with twenty-seven beekeepers.
Honey bee populations declining
Based on the colonies that we inspected, the beekeeper interviews we conducted, and the experience of the ICIPE beekeeping staff, the health of honey bee populations in Kenya appears to be declining. In general, there are fewer hives being colonized by swarms or migrating colonies of bees than in the past. Hives containing bees are small and are not producing much honey. Colonies in areas where beekeeping has traditionally thrived due to abundant nectar and pollen resources seem to be less affected, than are those in areas with poor or limited resources. Potential factors contributing to the decline in health may include loss of foraging areas (deforestation and increased clearing of land for farming), drought and climate change, pesticide use, and, of course, the presence of the parasitic mite, Varroa destructor, and the viruses it can transmit. Over the next year, we and our ICIPE counterparts will analyze the samples we have collected, monitor the health of the colonies we visited and conduct additional experiments to increase our understanding of these bee subspecies and their abilities to withstand many of the same pressures that are causing bees to decline in other areas of the world.
We learned from the beekeepers we interviewed that there is an unlimited market for honey. Individuals have the potential to generate income from keeping bees and producing honey, but access to good-quality beekeeping equipment and adequate training is limiting their success. It is important to understand why Kenyan honey bees are not thriving and to find out what needs to be done to ensure healthy, productive populations. We are hopeful that what we learn in Africa will provide clues to help ailing honey bee populations around the world.