Breeding disease-resistant 'hygienic' honey bees

Background

Hygienic testing using the freeze dried techniqueHygienic testing using the freeze dried technique

Disease is a major problem for honey bee colonies. Hygienic worker bees remove dead or infected larvae and pupae from their cells. This reduces the spread of diseases within a colony. Previous research in the USA has shown that hygienic colonies produce as much honey but are resistant to brood diseases such as foulbrood and chalkbrood. Hygiene also disrupts the breeding cycle of Varroa mites thereby slowing down mite population growth so that beekeepers with hygienic hives will find it easier to control Varroa. Hygiene is a natural genetic trait meaning that it can be bred using normal breeding methods. Hygiene is rare in British hives. Previous LASI research by Professor Ratnieks has found that only about 10 per cent of British hives are hygienic. He has developed a more effective method of breeding for hygiene via 'intracolony selection'. To do this, a hygienic colony is kept in an observation hive to determine which workers are most hygienic (ie, remove dead brood killed by freezing). Daughter queens are reared that have the same father as the hygienic workers. DNA markers are used to identify them. In this way breeding for hygiene is more effective and rapid.

Freeze-killed broodThe removal of freeze-dried brood indicates a hygienic colony

Main aims

To breed and test a stock of hygienic, native British black honey bees, Apis mellifera mellifera, and to make this available to beekeepers to use in queen rearing and in hives.

Current status

This project commenced in autumn 2008. A survey of University of Sussex hives has identified hygienic colonies. These are providing much of the stock needed for the breeding programme. Additional Apis mellifera mellifera (black bee) stock for hygiene testing is being obtained from UK beekeepers, including BIBBA (Bee Improvement and Bee Breeders Association) and from black bee breeders in North West Europe. Colonies which are hygienic then undergo behavioural tests in where individually marked worker bees are observed to determine which ones actually carry out the hygienic behaviour. Queens of the same 'patriline' are then reared. This is known as 'intracolony selection'. The University of Copenhagen (Dr Annette Jensen) has agreed to carry out the genetic testing needed in intracolony selection. Honey bees live in colonies and this makes it less easy to breed them. Each colony is headed by a mother queen mated to 10-20 males. As a result there is great genetic variation within a colony. Intracolony selection enables breeding to focus on the part of the colony that has desirable traits, in this case hygiene.

Virgin queensNewly emerged virgin queens in cages

Personnel

Mr. Norman Carreck (researcher), Dr. Karin Alton (researcher), Mr. Gianluigi Bigio (doctoral student), Mr. Mike Kavanagh (volunteer helper).

Funding

The major funders of project are Mr. Michael Chowen, Rowse Honey Ltd., and BBKA (British Beekeepers Association).

Queen mating hivesQueen mating hives in the queen mating apiary