Africanized honey bees' gene secrets uncovered

The genetic powerhouse of Africanized Honey Bees (AHB) that has enabled their rapid spread from Brazil in the 1950s to the USA in the 1990s is outlined in this month's US Agricultural Research magazine.

AHBs now occupy large parts of South West USA but their progress north has been much less than originally predicted. Rainfall, not temperature, seems to define theit current limits. AHBs are not spreading into areas where rainfall is more than 55 inches a year and spread throughout the year, but researchers are reluctant to claim that this is a causal relationship.

Not only do AHB colonies have faster growth rates but they also tend to replace European Honey Bee (EHB) colonies rather than hybridize with them. Several factors are thought to assist the genetic takeover — which takes about three years. EHB queens mate disproportionately with AFB drones, but even when there is an equal EHB/AHB semen mix, the AHB semen is used first. AHB queens are also more successful fighters which gives them a distinct advantage if they encounter EHB viirgins in their colony. Some AHB traits are also genetically dominant.

Curiously. AHB colonies also have a greater resistance to varroa, the parasite which is threatens Apis mellifera colonies across the western world. If AHB's resistance to varroa can be understood, it could have significant implications in the battle against varroa.

The success of AHB in the USA is also attracting the interest of a geneticist developing models of how Homo sapiens may have interacted with the European population of Neanderthals. Honeybee generations, unlike human's, are short enough to track invasion and gene flow with rapid results.