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Drone surrounded by worker bees. © INRA, MORISON Nicolas

Scientists flying to the rescue of bees

Honey: sweetness under the microscope

Honey production has declined in recent years: after a reasonable performance in 2012 (16,000 tonnes), it did not even reach 15,000 tonnes in 2013, according to the French Beekeepers' Union. These figures should be compared with those in the 1990s, when French production easily exceeded 30,000 tonnes. The result is that France has become a major honey importer: 26,000 tonnes last year. There are thus many reasons for concern, and it is necessary to look more closely at honey production in particular regions, a task that has been taken up by a group of INRA research scientists.

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

Lavender honey: a gourmet pleasure under threat?

Lavender honey, with its characteristic odour and golden yellow colour, is one of the most widely appreciated types of honey. It is also the most expensive. It is therefore easy to understand why beekeepers rush to exploit lavender fields each year: 50% of honey production in the Provence-Côte-d'Azur Region comes from these sheets of purple. But these beekeepers may experience problems during this end of season harvest. From one year to the next, production can fluctuate for reasons that are as yet unexplained.  In addition, droughts - such as those in 2003 and 2005 - lavender disease and bee colony fatigue are of increasing concern to beekeepers. To gain a clearer understanding of these issues, the Observatory on Lavender Honey was set up in 2008.

The Observatory at the bedside of hives in Provence

For the past six years, the Observatory on Lavender Honey has been monitoring 550 hives in Provençal lavender fields. Every two days, the hives are weighed in order to determine their honey reserves, and their populations of adult bees and larvae are calculated. The health status of colonies is also examined, and toxic products (herbicides, insecticides and fungicides) are analysed.

The researchers have therefore managed to generate some important findings for beekeepers. The first is that there is enormous variability between hives and apiaries with respect to honey production. The second is that this production is closely dependent on the population dynamic in the hive: a colony that contains a large brood at the start of a campaign will succeed better than one which is highly-populated but fatigued. This observation should enable beekeepers to better prepare their hives before placing them in lavender fields. Finally, good health status is crucial: one or two cases of Varroa per 100 bees can cause a 5 to 6 kg loss of honey in a hive.

The scientists have also measured the impact of climate: rainfall prior to flowering promises an abundant harvest. On the other hand, rain during honey flow means the bees are redundant, thus reducing production. 

Transhumance: travelling bees

In order to increase honey production and find areas that are more favourable to their bees, many beekeepers move their hives from region to region during a year. This is the transhumance of bees, and it has been practised for a very long time. Thus depending on its stop-overs, the same hive might produce garrigue honey, followed by acacia honey and lavender honey. However, these moves may tire and stress the bees, which can affect their productivity. In addition, depending on the environments visited, some transhumance voyages may have more impact on colonies than others. One of the objectives of ResAPI, a programme initiated in 2012 to identify levers for action to reduce the winter mortality of bees, is to characterise the physiological and health status of colonies before overwintering, while taking account of the trips they have experienced during transhumance.