Study Of Honeybee’s Visiting Behavior On Rice And Rice Pollens Diffusion Via Honeybee

Transgenic Bt rice is able to control lepidopteran pests effectively and reduce the consumption of pesticides. However, rice features prominently in our Chinese diet and the safety of transgenic rice is always the focus question, before the commercial promotion it is necessary to make a detailed risk assessment of transgenic rice. We discover that honeybee visits rice flower during florescence. To assess the risk of gene drift of transgenic rice, we investigated the flower visiting behavior of honeybee and the distance of rice pollen dispersed by honeybee. The results are described as below:1. Pollen volatiles of transgenic KMD strains.We analyzed the volatiles of rice pollen of KMD1, KMD2and KCK using GC-MS method. The result shows that all these three varieties of rice pollen contain a-pinene, benzaldehyde and limonen, which can evoke honeybee’s CPE reaction, but linalool is absent. The retention time of these components is the same as the standard samples, but the response values are lower, which indicate that the content of these components in rice pollen is low.2. Visiting behavior of European honeybee to KMD strainsThe average visiting times of honeybee to KCK, KMD1and KMD2is7.52±0.27sec (n=285),7.21±0.28sec (n=275) and7.07±0.28sec (n=280); average interval times is4.36±0.27sec (n=285),4.36±0.28sec (n=275) and4.22±0.28sec (n=280); visiting frequency is32.79±17.24tassels/5min;33.71±17.49tassles/5min和31.16±17.49tassels/5min. There is no significant difference among these three transgenic rice strains.3. Rice pollen flow mediated by honeybeeA two-year investigation reveals that honeybee can carry rice pollens to at least500m away from rice pollen source. The amount of rice pollens carried by honeybee gradually decreased as the flying distance increased. The viability test of pollens at distance500m indicated that81.1±2.0%(n=6) of pollens are still alive. The examination of pollen density in air shows that the average value in plots treated with honeybee is103±12(n=44) while that in the control plots without honeybee is71±7 (n=45), which indicates that visiting behavior of honeybee can significantly increase the pollen density in air.