I have visited the INRA (Institute National de la Recherce Agronomique) station near Avignon. At that site, several scientists are working on projects that concern honey bee pollination and other topics. With the huge changes occurring in the Bures-sur-Yvette facility (see letter of July 15, 1997), it would appear that the one near Avignon will take a greater leadership role in French applied bee research.
Under the guidance of Bernard Vaissiere, the pollination laboratory (Laboratoire de Pollinisation Entomophile, 84914 Avignon Cedex 9, France, ph (33) 4 90 31 61 69, fax (33) 4 90 31 62 70), is studying:
1. Pollen flow in various plants (almonds, white clover, kiwifruit and melon). .These studies seek to determine the relative importance of insect-mediated pollen flow in the overall pollination of these crops, as well as the fruit and seed set in relation with pollination intensity (production and transfer of pollen onto stigmas and subsequent fruit andseed output).
2. Pollen viability and interactions with the stigma. This is done by carefully measuring different parameters in relation with the assessment of the effectiveness of pollinating agents (wind and insects).
3. Foraging ecology and effectiveness of honey bees , including aspects of foraging area fidelity, and alternative pollinators such as bumble bees.. As part of their research, Dr. Vaissiere and colleagues have shown that cantaloupe pollen viability on the body of honey bees can vary considerably depending on whether these bees that are gathering pollen or not (Naturwissenschaften, Vol. 83, pp.84-86, 1996). Foraging behavior, therefore, becomes a variable in effective pollination. They have have also found strong evidence for pollen transfer between worker bees inside the beehive and have demonstrated the effectiveness of honey bees in pollinating kiwifruit orchards (J. Econ. Entomol. vol. 89,pp.453-461, 1996).. The incidence of pollen morphology on its collection effectiveness by honey bees is also being investigated (Grana vol. 33, pp. 128-138, 1994). Dr. Vaissiere’s tendency to move work into the applied arena has been responsible for several papers in the popular press and continuing work with organizations like ADAPI that are practically oriented and. This is a refreshing approach, one more closely aligned with the philosophy of other French researchers. Finally, the pollination unit has collaborations with other French research organizations.
The Avignon station also has research efforts in other areas. Dr. Yves Le Conte is continuing his study on the effects of brood pheromone in a colony. It is thought to be responsible for worker bees’ ability to recognize brood sex and developmental stage. This primer brood pheromonone has also been shown to keep worker bees from developing their ovaries (CR Acad. Sci. Paris, Sciences de la vie/Life Sciences, 317, pp. 511-5, 1994), a condition that was thought to be almost totally under queen pheromonal control. Brood pheromone was identified by Dr. Le Conte and colleagues at the INRA station in Bures-sur-Yvette, just outside of Paris and reported in Naturwissenschaften, Vol. 77, pp. 334-336, 1990. Like many pheromones, that of the brood is probably a mixture of substances and there may also be some mechanical signals that are used in conjunction with chemical cues. The original and subsequent studies report a specific triglyceride that causes bees to cluster on artificial queen cells and several materials that not only keep worker ovarial development, but also been found to control worker feeding behavior and hypopharyngeal gland development.
Brood pheromone is also attractive to the Varroa bee mite. One study shows that queen brood produces only about half the amount of these attractive materials which might explain why queen brood is not as parasitized as that of workers and drones (Apidologie, 25, pp. 314-321, 1994). Another reveals that certain related materials also attract Varroa to drone brood (Science, Vol. 245, pp. 639-40, 1989). This has led to further research at Avignon station on Varroa control using these materials. Dr. Le Conte’s students reported on their work in this area at the FNOSAD meeting in La Ciotat, France in March 1997.
Another area of study at the avignon station is effects of pesticides on honey bees. Luc Belzunce, a toxicologist, and Marc-Edouard Colin, a pathologist, have looked at the synergy that might occur when several pesticides are used together. They have shown this using both a pesticide and fungicide. Whereas these materials alone do not affect bees, when applied together, there is greater mortality (Pesticide Science, Vol. 36, pp. 115-119, 1992). Dr. Colin has also been looking at the resistance of Varroa to fluvalinate and has published a paper on use of essential oils in mite control from the plant family labiatae (tyme and sage). Results showed a moderate amount of control. However, Dr. Colin confirms that essential oils are not effective on mites sealed in brood and suggests that such a technology should be best used after a large summer honey flow (J. Appl. Ent., Vol. 110, pp. 19-25, 1990).