Genetic Diversity And Morphological Characteristics Of Apis Cerana Cerana In Urban Greenspaces Of Shanghai

Pollinating insects have extremely high economic values and contribute greatly to ecological functioning.In addition to pollinating crops,they also play an important role in maintaining the health of urban ecosystems.However,urbanization often accompanies habitat loss and fragmentation,which is a crucial factor driving the decrease in biodiversity of pollinating insects worldwide and the shortage of germplasm resources.Recent studies have found that the diversity of Hymenoptera（including bees）in urban green spaces is higher than that in suburban areas,which may be their potential refuge.To understand whether urban green spaces can harbor Hymenoptera species,this study focuses on the Chinese native pollinating insect Apis cerana cerana,we aim to understand whether A.cerana cerana can effectively spread among spatially isolated urban green spaces.We collected A.cerana cerana samples from 20 green spaces nearby the Daning park in Shanghai,and used 12 pairs of microsatellite markers to genotype the collected samples.We revealed the genetic diversity of A.cerana cerana populations,and its relationships with main green space characteristics.Moreover,we explored the dispersal pattern among studied populations through genetic differentiation analysis.We also measured the morphological characters related to the abilities of flight,collection capability and fecundity of collected samples and compared these characters between urban and suburban populations,to further improve our understanding of the maintenance of Apis cerana cerana population in urban green spaces.The main results are as follows.1)The A.cerana cerana population in urban green spaces has a high level of genetic diversity（H_E=0.766）.There was no significant relationship between genetic diversity and green space area,but we detected significant negative correlations between heterozygosity（H_O）and greenbelt isolation（reflected by the reciprocal of vegetation coverage within a range of 250 meters around green spaces）（P=0.0492）and positive correlations between inbreeding coefficient(F_IS)and isolation（P=0.0426）.There was significant negative correlations between allelic richness（A_R）and indices of green space quality,including flowering plant richness（P=0.0472）,establishment time（P=0.0361）,and spraying frequency（P=0.0375）.2)The degree of genetic differentiation of the Apis cerana cerana population in the green space is low(F_ST=0.022),and genetic variations mainly existed within the population（96%）.The two genetic clustering analyses using STRECTURE and DAPC mutually confirmed the absence of apparent genetic structure among our studied populations,and we failed to find significant isolation by distance and isolation by resistance patterns,reflecting strong gene flow among the populations.These results indicate that the spatial isolation in the studied area has no significant impacts on the spread of A.cerana cerana and all studied populations form a large metapopulation via strong gene flow.3)The comparisons based on 8 morphological characters showed that the wax secretion ability（wax mirror spacing W_D,wax mirror area S_W）,collection ability（basal tarsal node width M_T,mouthpiece length L_M）in urban greenspaces were significantly higher than those in suburban greenspaces（P<0.001）,and body color correlation（S_b/S₄）of Apis cerana cerana was significantly lighter than suburban green spaces（P<0.001）,suggesting that A.cerana cerana in urban greenspaces may have enhanced ability to exploit scattered nectar sources and build nests,benefiting their utilization of urban greenspaces and surrounding habitats.In summary,A.cerana cerana in urban green space maintains high genetic diversity and low genetic differentiation,which is related to its strong dispersal ability to connect different green spaces and form a large metapopulation within our study area.These findings suggest that urban green spaces can indeed be used as a refuge for A.cerana cerana.Moreover,we found that the quality of green spaces substaintially affected the genetic diversity,such as spraying pesticide,indicating that the current green space management measures are not conducive to the maintenance of A.cerana cerana populations.Therefore,considering specific conservation plans based on the characters of pollinating insect species in urban green space construction may optimize the protection of pollinating insects in cities.