Drone surrounded by worker bees. © INRA, MORISON Nicolas

Scientists flying to the rescue of bees

Well-bred bees

  

Updated on 03/23/2017
Published on 05/01/2014

A queen is born

New queens are born in the spring, and their life starts like a Shakespearean drama: the first-born, or strongest, kills her rival sisters in order to reach the throne. A few days later, she leaves the hive for her nuptial flight. Males from her colony, and also from neighbouring hives, try to follow and mate with her. Ten or fifteen males will achieve this, and the queen can thus fill her spermatheca with 4 or 5 million spermatozoa that will serve to fertilise her eggs throughout her life. But what might be true in wild colonies is generally no longer so in modern beekeeping: at present, beekeepers increase the number of their hives by introducing queens they have bred or purchased from a colleague. A few days after their birth, these queens will be taken to sites where males from the surrounding area congregate, in order to mate.

Swarming: a queen is pushed out of the hive

In the spring, when future queens are still in their cells, the old queen leaves the hive followed by a court made up of thousands of worker bees who have previously filled themselves with honey. Their aim is to try and form a new colony elsewhere. Once the pathfinders have found an appropriate site, the workers start to build up cells, the queen starts laying and the cycle can recommence. Swarming is a phenomenon that is feared by beekeepers because it may signify the loss of a queen, more than half of worker bees and a large proportion of honey reserves. It is nevertheless the natural process for the dispersal of bees.

The rearing of males

For the first time in the world, INRA researchers in Avignon have managed to rear males under controlled conditions, from birth to sexual maturity. This represents an amazing feat because males are not always much loved within a hive: they represent useless mouths to feed, and at the least sign of stress the workers will start to mistreat them, and they may even be expelled or killed. To achieve this scientific feat, the researchers reproduced miniature hives in a cage to be populated by a few hundred bees. They introduced newborn males whose larval development had been completed in a traditional hive. By controlling different parameters - temperature, population, access to food, etc. - the research team was able to achieve excellent survival rates among these males: 60-70% of them survived and reached sexual maturity (20 days after birth), as opposed to 30% or 40% in a hive. This rearing technique is already being used to test the effects of pesticides and parasites on bee reproduction. It will also enable control over fertilisation of the queen. As in farmed livestock units, it will then be possible to choose the best lines to inseminate the queen.

Towards improvements to bee breeding

Nine species of domestic bees exist in the world, and the European honey bee (Apis mellifera) is by far the most widespread because of its high productivity and lack of aggressiveness. This species counts around 25 breeds or geographical subspecies. There are also certain local ecotypes of French origin, such as the Landes honey bee. But by importing bees from other European countries, or even Australia, a great many crosses and hybridisations are also made to improve traits of apicultural interest. A project led by INRA is aiming to characterise the genetic diversity of honey bees and establish criteria that would be of interest to beekeepers (honey and royal jelly productivity, pathogen resistance, non-aggressiveness, etc.). This work will then make it possible to propose a breeding plan for the best performing bee lines.

The genome of Apis mellifera laid bare

2006 marked an important milestone for bee specialists, as it was the year which saw publication of the complete genome of this insect, carried out by a major international consortium in which INRA research scientists participated. Some traits in this genome, which counts between 11 and 15 thousand genes, surprised the researchers; for example, the small number of genes linked to immunity and detoxification.