笔管榕榕小蜂的群落结构与物种多样性

Abstract

Ficus superba Miq. var. japonica Miq.(Ficus,Moraceae),a kind of deciduous and monoecious tree,is a common tree species in Fujian Province. There are various species of fig wasps in its syconia,constituting a fig-fig wasp symbiotic system with Ficus superba Miq. var. japonica Miq. From July 2011 to July 2012,thirty plants of Ficus superba Miq. var. japonica Miq. from different sites in Fuzhou were observed and collected at regular intervals. A total of 50817 fig wasps were collected from 830 syconia in 15 batches. Seven fig wasp species,belonging to 6 families,7 genera were found.Platyscapa ishiiana was the unique pollinator,whereas the others were non-pollinating fig wasps,belonging to families Pteromalidae,Eurytomidae,Eulophidae and subfamily Epichrysomallinae,respectively. Among the non-pollinating fig wasps,Philotrypesis sp.,Acophila mikii,Otitesella ako,Sycophila sp.,Sycobiomorpha sp. were common species,which could be collected almost all year round; whereas Aprostocetus sp. was rare,only two individuals were collected in the whole the year. The fig wasp species in Ficus superba Miq. var. japonica Miq. did not show obvious changes in different months and different seasons,but the numbers of different fig wasp species changed obviously. Among the 12 months of the year,there are 9 months dominated by pollinators,but January,September and November were dominated by non-pollinators. Some species of non-pollinators(Aophila mikii,Sycophila sp.,Philotrypesis sp. and Otitesella ako) often occurred explosively. In general,there were 1—2 species dominating in the non-pollinator population in each batch,but the dominant species usually altered across batches. Therefore,there was not a single species consistently dominating among the non-pollinators.The community of wasps in Ficus superba Miq. var. japonica in Fuzhou exhibited a diversity index of 0.72,evenness index of0.37,richness index of 0. 55 and dominant concentration index of 0. 68. The sex ratios in the 6 fig wasp species were analyzed. The sex ratio in the pollinator species was extremely biased to female,while those in the non-pollinator species were less biased. It could be inferred that the sex ratio of fig wasps is related to the wing type of male wasps and the place of mating. The number of non-pollinators showed extremely significant negative correlations with the total number of pollinators,the number of female pollinators,and the number of male pollinators,but an extremely significant positive correlation with the sex ratio of pollinators. These results suggest that non-pollinators have negative impacts on both female and male pollinators,but the effect on female pollinators is greater than that on male pollinators,resulting in its sex ratio increased. Among the non-pollinator species,Acophila mikii Ishii.,Sycobiomorpha sp.,and Otitesella ako Ishii belong to gall-makers,while Philotrypesis sp. and Sycophila sp. belong to inquilines or hyperparasitics,which displayed greater negative impacts on pollinating wasps. The results of this study provide a scientific basis for fig-fig wasps coevolution research,urban greening and biodiversity conservation.