Africanization in the United States: Replacement of Feral European Honeybees (Apis Mellifera L.) by an African Hybrid Swarm

By Pinto, M. Alice; Rubink, William L. et al. | Genetics, August 2005 | Go to article overview

Africanization in the United States: Replacement of Feral European Honeybees (Apis Mellifera L.) by an African Hybrid Swarm


Pinto, M. Alice, Rubink, William L., Patton, John C., Coulson, Robert N., Johnston, J. Spencer, Genetics


ABSTRACT

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.

THE evolutionary significance of natural hybridization has been debated for decades (MAYR 1942; ANDERSON 1949; HARRISON 1993; ARNOLD 1997). At one extreme, it has been argued that natural hybridization is an evolutionary dead end due to formation of inviable and/or infertile hybrids (MAYR 1942; BARTON and HEWITT 1985, 1989). At the other extreme, it has been suggested that natural hybridization may lead to new evolutionary lineages due to formation of relatively fit hybrids that expand into novel habitats (ANDERSON 1948; ARNOLD 1997; ELLSTRAND and SCHIERENBECK 2000; BLEEKER 2003). A third potential evolutionary outcome is expansion of an intermixed form within the resident progenitor's habitat, in which case the degree of mixing between hybridizing forms may range from formation of a hybrid swarm to genetic assimilation of one form by the other (GUILDS et al. 1996; RHYMER and SIMBERLOFF 1996; PERRY et al. 2001). Natural hybridization and introgression have been reported in a growing number of biological invasions (RHYMER and SIMBERLOFF 1996). Such invasive events are of great interest to the discipline of evolutionary biology because they provide unique opportunities to study evolutionary processes at initial stages of secondary contact of divergent genomes.

Our study of hybridization, which deals with one of the most spectacular biological invasions yet documented, that of the Africanized honeybees (Apis mellifera L.), builds on the previous studies of Africanization. Africanized honeybees derive from a founder population of the tropical-evolved African subspecies Apis mellifera scutellata brought from South Africa into Brazil in 1956 to interbreed with previously imported temperateevolved European honeybees. The purpose of the introduction was to create a honeybee better adapted to tropical conditions, because the European honeybee colonies were poor honey producers and would survive only when intensively managed (NoGUEiRA-NETO 1964; KERR 1967). Soon after the introduction, queens of A. m. scutellata-were accidentally released into the natural environment (SPIVAK et al. 1991) and their descendants have since expanded throughout South and Central America and have established large feral populations where European colonies could not thrive (TAYLOR 1988; ROUBIK and BOREHAM 1990; WINSTON 1992). The leading edge of the expanding front reached the southern United States in 1990, only 33 years after initial release (SuGDEN and WILLIAMS 1990). Prior to arrival of Africanized honeybees, the United States sustained large feral and managed populations of honeybees predominantly derived from eastern (A. in. ligustica, A. in. carnica, and A. m. caucasia) and western (A. …

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Africanization in the United States: Replacement of Feral European Honeybees (Apis Mellifera L.) by an African Hybrid Swarm
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Full screen

matching results for page

Cited passage

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited passage

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.