Occurrence pattern of an undescribed gall midge in the fig of Ficus benjamina

In Xishuangbanna tropical region,an undescribed species of gall midge on Ficus benjamina lays its eggs in the ovary of female flowers,producing a large gall in which the larva feeds on the gall's tissue to complete its life cycle.We investigated the occurrence of gall midge on F.benjamina through systematic sampling at a fixed time and location in 2010.Eighteen crops were sampled and gall midges found to occur in 17 of them.The percentage of figs attacked by gall midges was over 60% in 13 of the crops,reaching as high as 100%.Gall midges parasitized only up to 6% of female flowers and on average produced fewer than forty individuals in a single fig.The occurrence of gall midges reduced the number of seeds produced and had a deadly effect on the reproduction of pollinators.We observed the behaviour of eclosion,mating and flight of the gall midge.We found that all gall midges colonizing a single fig took 5—7 days to complete eclosion,and that the eclosion peak appeared in the 2nd—3rd day.In one day,eclosion peaks occured at 8:00—10:00 in the morning and 8:00—12:00 at night.The peak of activity after eclosion was at 8:00—11:00 in the morning.Male gall midges emerged first and assisted female gall midges to emerge.Once a female had emerged,a male would mate with her.Female gall midges left the natal fig trees after mating to search for appropriate trees for egg-laying.However,after mating,male gall midges died under the natal trees.Our results provide a basis for future study of the technology of gall midge control.