Africanization in the United States: replacement of feral European honeybees (Apis mellifera L.) by an African hybrid swarm.
The expansion of Africanized honeybees from South America to the southwestern United States in <50 years is considered one of the most spectacular biological invasions yet documented. In the American tropics, it has been shown that during their expansion Africanized honeybees have low levels of introgressed alleles from resident European populations. In the United States, it has been speculated, but not shown, that Africanized honeybees would hybridize extensively with European honeybees. Here we report a continuous 11-year study investigating temporal changes in the genetic structure of a feral population from the southern United States undergoing Africanization. Our microsatellite data showed that (1) the process of Africanization involved both maternal and paternal bidirectional gene flow between European and Africanized honeybees and (2) the panmitic European population was replaced by panmitic mixtures of A. m. scutellata and European genes within 5 years after Africanization. The post-Africanization gene pool (1998-2001) was composed of a diverse array of recombinant classes with a substantial European genetic contribution (mean 25-37%). Therefore, the resulting feral honeybee population of south Texas was best viewed as a hybrid swarm.
Pinto
M Alice
MA
Department of Entomology, Texas A&M University, College Station, Texas 77843-2475, USA. apinto@iph.pt
Rubink
William L
WL
Patton
John C
JC
Coulson
Robert N
RN
Johnston
J Spencer
JS
D000349:Africa; D000483:Alleles; D000818:Animals; D001516:Bees / Q000145:classification / Q000235:genetics*; D003198:Computer Simulation; D004272:DNA, Mitochondrial; D005788:Gene Pool; D008040:Genetic Linkage; D005819:Genetic Markers; D014644:Genetic Variation; D005828:Genetics, Population; D006824:Hybridization, Genetic; D018895:Microsatellite Repeats; D011157:Population Dynamics; D011995:Recombination, Genetic; D013781:Texas; D013997:Time Factors; D014481:United States
D004272:DNA, Mitochondrial; D005819:Genetic Markers