Studies over three years in natural population shown that as nectar robbers of Glechoma longituba

male carpenter bee of Xylocopa sinensis is smaller than the female one.Moreover

detailed studies indicated that male and female bees have different behavior and effects when visiting flowers.For example

the visit frequency in a certain population for male bees was 4 times than that of female ones;average duration of single visit was shorter for male bees than female bees（2.18 s vs.7.48 s）

and the visited flower number during a bout for male individuals is significantly more than that of female individual（42.48 vs.（8.81）.） Consequently

the female bee resulted in higher extent of destruction on the corolla

ovule and nectary in comparison with male bee;fruit set from visited flowers due to male bees is significantly higher than female ones under opening condition（34.72% vs.73.59%）.We therefore postulated that the length

rigidity of corolla and nectar production of flower in G.longituba must be an adaptive consequence of its nectar robbing visitors;The behavior differentiation of Xylocopa sinensis during foraging may result from the difference pattern of distribution of the food resource for the male and female individuals.