Thursday, September 27, 2012

Killer Bees

Killer Bee statue in Hidalgo, Texas
     The term "Killer Bees" refers to Africanized bees which were originally produced by cross-breeding European bees (Apis mellifera) with African bees (Apis mellifera scutellata) which are a sub-species of the European or Western honey bee and are native to central and southern Africa.  In 1956, to produce the "perfect" honey bee for tropical Brazil, 26 African Tanganyikan queen bees were imported to Brazil and bred with European drones.  Queen excluders were put on the entrances of the hives to prevent introduction of these African queen bees into the Brazilian environment. In 1957 a replacement beekeeper unknowingly removed the queen excluders releasing the African queens and starting the migration of the Africanized bees through the western hemisphere.  Here is some additional information on Africanized bees provided by the University of California (Africanized Bees).  The map below show the yearly migration of the Africanized bees.




     I draw an analogy between the phenomena of the "Killer Bee" and the movie "Jaws".  The movie inspired an unfounded paranoia of entering any water even that not inhabited by sharks.  Myself, having worked and lived in bear country and swum with sharks for years pride myself in possessing a sense of calm and objectivity when dealing with potentially dangerous situations.  Nevertheless I recall hearing the unforgettable music from the movie "Jaws" every time I encountered a shark in the water after that.  The reality is that while sharks and "killer bees" do pose a threat it is important to put it into perspective and not create an exaggerated paranoia.  The city of Hidalgo, Texas where the first Africanized bees in the U.S. were identified built a larger than life statue of the "Killer bee" on wheels which is still brought out for festivals and parades.  In reality driving a car and riding a bike are far more dangerous.  It is important to note that beekeepers in Central and South America are presently using Africanized bees.  While they do produce a higher yield of honey they replace the native bees (Stingless Bees of the Maya) and do not pollinate all of the native plants.
     The distinguishing features of the Africanized bee are: Swarms more frequently (smaller swarms up to 10 times a year potentially inhabiting smaller cavities); more likely to migrate as a response to seasonal dearth (In many parts of Africa their ancestors migrated annually due to extreme seasonal drought - Queen of the Savannah is a great movie about the ordeals of the African bee); more likely to abscond (entire colony leaves) in response to stress; more aggressive defensiveness when in a resting swarm; more likely to inhabit ground nests than European bees; greater area and more aggressive defense of hive; proportionally more guard bees; more bees act in defense of a hive and do so for a greater distance (i.e. several hundred bees to a disturbance 40 meters away and may follow for a quarter of a mile); The Africanized bee has also shown a greater propensity to be aggressive to darker colours such as darker coloured dogs suggesting a link to it's greatest enemy in Africa, the dark coloured honey badger; has difficulty surviving longs periods without forage (i.e. long, dry summer periods or cold winters). Here is a research article on the DNA of Africanized bees (DNA of Africanized Bees).

1985 Africanized Bee Alert


     The Africanized bee's sting is no more venomous than the European bee and like the European bee it can only sting once.  They respond to disturbances faster, in greater numbers and for farther distances.  The prescribed defense is to retreat quickly (covering your head) to the shelter of a building or automobile.  The undesireable, aggressive traits appear to be passed by the Africanized drones so many American beekeepers are counter attacking the migration of the Africanized bees by drone-flooding or raising an inordinate number of European drones to ensure a majority European mating.  Other defence measures include frequent requeening to remove any Africanized queens and extermination of wild bee nests.  However, most scientists believe that the northward migration is unpreventable and that with time the Africanized bees will adapt to periods of dearth or cold.  They have adapted to and inhabit colder areas at the foot hills of the Andes Mountains in South America.  While there is no way to predict their arrival in Canada one deterrent is the antiquated and bizarre Canadian bee import restrictions (We can import bees from New Zealand, Australia and Chile - Canadian bee import regualtions) that make the movement of bees from the U.S. to Canada impractical.  This is why most of our imported bees in Vancouver come from New Zealand. 


     For additional information on Africanized Bees in America go to Saguaro National Park Africanized Bees  and The Africanized Honey Bees in America.  For instructional material go to Africanized Honey Bees (Power Point Presentation).

     It is autumn and for many of us beekeepers it is time to watch for wasps.  Wasps leave their nests this time of year and go out and forage.  While some will occasionally enjoy nectar they are primarily insectivores and will kill your bees and attempt to enter the hives.  For strong colonies this is not usually a problem but as a counter measure beekeepers often use entrance reducers and wasp traps.  All of our wasps will die this winter except for the new, mated queens.  This year I have identified 6 species of wasps in my garden: Vespula pensylvanica (western yellowjacket-Queen); Potter Wasp; Polistes dominula- European paper wasp; Male Vespula germanica (German Wasp - Yellowjacket); Dolichovespula maculata (bald-faced hornet) and the beautiful green eyed Bembicini (Bembix) or Sand wasp.  While I have observed a smaller yellow wasp and a similar sized Blackjacket wasp I have not made positive identification.  I have seen the western yellowjackets killing the odd bee in front of the hives but no sign of any attempted entry.  Last year I witnessed the girls mass attack of a large bald-faced hornet trying to enter the hive.  It was very violent  as the wasp attempted to fly away with a few of the girls attached.  
    We are still in our Indian summer with beautiful days, active, foraging bees and lots of flowers still available.  Soon it will be time to prepare the hives for winter, extract some honey and wax up my skis.

Bembicini (Bembix) or Sand wasp (Green eyes)


0 comments:

Post a Comment

Recent Posts