There are many reasons why and how African bees can move into a given
area and become the predominant type. Tom Rinderer found out years ago
that African bees surpass European bees in drone production. However,
at the edge of their range, African advantages may be outweighed by
disadvantages, such as the tendency to produce more bees and less
honey.
> The geographical types differed significantly in the number of drones leaving their colonies. Colonies of Africanized bees had an average of 66 drones leaving their hives per day while European colonies had an average of 13. Of the drones from Africanized colonies, an average of 1.2 or 2 % were parasitic European drones. Of the drones from European colonies, an average of 7.1 or 55 % were parasitic Africanized drones. Africanized colonies contained far more drones than did European colonies (A = 65, E = 6 ; Table 1 : Home drones : P = 0.002). Overall, Africanized colonies contained many more drones and the majority of drones in European colonies were Africanized. These two conditions resulted in 91 % of the drones in the study being Africanized.
DIFFERENTIAL DRONE PRODUCTION BY AFRICANIZED AND EUROPEAN HONEY BEE COLONIES
Thomas E. RINDERER
Anita M. COLLINS
Richard L. HELLMICH II,
Robert G. DANKA
Robert SPENCER
United States Department of Agriculture
Agricultural Research Service Honey-Bee Breeding, Genetics and
Physiology Laboratory
IN: Apidologie
* * *
> The expansion of Africanized honeybees (AHB) through the Americas has been one of the most spectacular and best-studied invasions by a biotype. African and European honeybees (EHB) hybridize, but with time, tropical and subtropical American environments have become dominated by AHB that exhibit only 20–35% genetic contribution from western European bees, and a predominance of African behavioral and physiological traits.
> EHB persist in temperate environments. Clines between AHB and EHB exist in ecotones of South and Central America, and are forming in North America. What individual-level genetic, behavioral and physiological traits determine the relative success of the AHB as an invader in the neotropics, and of the EHB in temperate areas? Preference for pollen versus nectar may be an important trait mediating these ecological trade-offs, as preference for pollen enhances nutrient intake and brood production for the AHB in the tropics, while a relative preference for nectar enhances honey stores and winter survival for EHB.
> AHB exhibit morphological (higher thorax-to-body mass ratios) and physiological (higher thorax-specific metabolic rates) traits that may improve flight capacity, dispersal, mating success and foraging intake. Enhanced winter longevity, linked with higher hemolymph vitellogenin levels, may be a key factor improving winter survival of EHB. Data from South America and distributions of AHB in the southwestern United States suggest that AHB–EHB hybrids will extend 200 km north of regions with a January maximal temperatures of 15–16 C.
> The formation of biotypic clines between AHB and EHB represents a unique opportunity to examine mechanisms responsible for the range limit of invaders. Study of the imminent formation of the hybrid zone between AHB and EHB in North America provides a temporary opportunity to examine the factors that determine range limits in these important species, and to generate models with economically important predictions.
"Environmental physiology of the invasion of the Americas by
Africanized honeybees"
Harrison, Jon - ARIZONA STATE UNIV.
Fewell, Jennifer - ARIZONA STATE UNIV.
Anderson, Kirk - ARIZONA STATE UNIV.
Loper, Gerald - RETIRED USDA-ARS
IN: Integrative & Comparative Biology
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