The Apis Information Resource Newsletter for November 25, 2015 has been published . It features the latest on Africanized Honey Bees, excerpted here:
Africanized honey bees are back in the news for a number of reasons. They are spreading northward in California and have been found for the first time in the San Francisco Bay area . News outlets can’t resist the opportunity to speculate about these “killer bees” and what they might mean to the area’s human population.
“There are a few reasons why the range of Africanized bees in California and other states is important.. For one, these bees are highly aggressive…People in California, Arizona and Texas (as well as several other states) have been seriously injured or killed after enduring thousands of stings from Africanized bees, which are quick to defend their hives.
“…scientists don’t just want to track the migration of Africanized bees because of their killer instincts. They are also curious about the spread of the Africanized bees’ more desirable qualities, such as their resistance to some of the diseases and mites that are killing off honey bees in other parts of the country…”
The concensus by most observers is that the bees could be moving northward due to warmer temperatures, but they don’t really pose an extreme threat to the human population in the region.
Meanwhile Africanized bees have made a splash in Puerto Rico for another reason. They are becoming more manageable and less “aggressive.” When they first arrived on the island there were considerable human deaths due to attacks, but these have fallen off drastically according to scientists at the University of Puerto Rico.
One hypothesis is that the ratio of guard honey bees to foragers has fallen due to lack of food, principally in the rainy season. Another is that somehow the bees have become more “european” in behavior through genetic shifts: “In conclusion, we demonstrate that on the oceanic island of Puerto Rico, defense and other tropical adaptations observed in other Africanized bee populations are uncoupled. This could be due to a genetic drift, founder effect, or strong selection for foraging and for ectoparasite resistance… The recently completed genome project and a genome-wide analysis of variation in this population and mainland populations could help resolve the contribution of different processes to the mosaic of traits observed in Puerto Rican honey bees.
“Studies on Africanized bees on this (and other) oceanic island(s) provide a new model for the study of behavioral evolution on islands. Understanding these gentle bees that can maintain low populations of mites thereby escaping both chemical treatments and possibly viral infections is of topical interest. This is especially important because of recent concerns that many factors including Varroa mites, viral diseases (transmitted by mites), and chemicals used to control mites negatively affect bee health.”
The good news about all this is the recognition that these diverse gene pools might provide some hope in the continual fight against the Varroa bee mite. It is well known that for some reason Africanized stock is able to tolerate the mites much better than European honey bees. On the flip side a population of European bees off the coast of Brazil on an island has beaten all the odds observed in other parts of the world and continues to thrive without treatment was reported as far back as 1996. A wrinkle in this is that the mites maybe different on the island than on the mainland. It is known that certain populations of Varroa destructor, specifically the Japanese haplotype, are not as problematic as the Korean, which is found in many areas with lots of losses due to mites, including the U.S. Investigators continue looking at the honey bees on Brazil’s Fernando de Noronha Island for further clues about this evolving mystery.
A final story concerning Africanized honey bees is playing out some four hours south of here. It focuses again with the expected hyperbole about “aggressive honey bees,” Thought to have arrived via ships directly from tropical America, a different population appears to have emerged from that known elsewhere in the U.S. (Texas, Arizona, California). How this will play out in the future is unknown. What is indisputable is that the final history of the insect has yet to be told and in fact may devolve into something as diverse as the honey bee genome itself.