Marla Spivak’s lecture was concerned with the effects of floral landscape on honeybee health. As she is US based, she was working from a background of large scale migratory beekeeping operations often in monocultural landscapes. Between pollinating contracts there might be as many as 8,000 colonies in holding yards. The pollinating job you will all have heard of is the Californian almonds which uses 1.6 million colonies at a density of 2 per acre. The beekeepers get paid up to $160 a hive provided they cover 5 frames. Almond pollen is high in protein, which is good for the bees.
Much of Marla’s work was done in North Dakota, which is a major honey producing area. However things are changing there as lots more soya and maize is being grown (probably GM!). There is, however some ‘set aside’ land.
She was relating landscape to colony to individual bees. Bees need diverse sources of pollen to maintain a healthy immune system. The problem was how to test if a colony is healthy based on landscape quality by performing a ‘blood test’ on the bees. She compared 3 sites with diverse flora with 3 with industrially grown soya and maize, using a grid overlaid on frames to make counting easier. She found no great differences at colony level. Hypopharyngeal glands were similar in both, but abdominal lipids (fat bodies) were better in bees from diverse landscapes, also vitagellens (sp?) used for nutrition and immunity.
What it boiled down to was that more colonies died in poorer landscapes, but they expect winter losses around 30%.