Comparative analysis of the microbiome of sympatric wintering Bean Geese,Domestic Ducks,humans,and soil at Shengjin Lake of China reveals potential public risk to human health

The gut microbiota of migratory waterbirds is affected by various complex factors,including cross-species transmission,which increases the risk of pathogen spreading among sympatric animals and poses a potential public health risk to humans.In this study,we investigated the microbial communities of wintering Bean Geese(Anser fabalis),Domestic Ducks(A.platyrhynchos domesticus),humans,and soil using high-throughput sequencing of the 16S rRNA gene region in Shengjin Lake,China.In total,6,046,677 clean reads were obtained,representing 41,119 operational taxonomic units(OTUs)across the four groups.The dominant microbial phyla were the Proteobacteria,Firmicutes,Bacteroidota,and Actinobacteriota.The Sorensen similarity index and alpha and beta diversity results showed that the gut microbial communities of Bean Geese and Domestic Ducks were more similar to those of the other pairs.Network analysis revealed that Faecalibacterium prausnitzii,Pseudomonas fragi,and Bradyrhizobium elkanii were hubs of the three major modules.Fourteen common microbiomes were iden-tified in Bean Geese,Domestic Ducks,humans,and soil in Shengjin Lake.A total of 96 potential pathogens were identified among the four groups,with 20 specific potentially pathogenic microbiomes found in the gut of Bean Geese.Some of these pathogens are responsible for significant financial losses in the poultry industry and pose risks to human health.Klebsiella pneumoniae,Morganella morganii,Escherichia coli,and Ralstonia insidiosa are potential core pathogens found in the four groups at Shengjin Lake that can cause diseases in humans and an-imals and facilitate cross-species transmission through various media.Therefore,humans are at risk of con-tracting these pathogens from migratory birds because of their frequent contact with domestic poultry.However,further studies are required to explore the potential pathogenic species and transmission pathways among sympatric wintering Bean Geese,Domestic Ducks,humans,and soil.

Effects of elevated CO2 on the interspecific competition between two sympatric species of Aphis gossypii and Bemisia tabaci fed on transgenic Bt cotton

Effects of elevated CO2 （twice ambient vs. ambient） and Bt CrylAc transgene （Bt cotton cv. 33B vs. its nontransgenic parental line cv. DP5415） on the interspecific competition between two ecologically similar species of cotton aphid Aphis gossypii and whitefly biotype-Q Bemisia tabaci were studied in open-top chambers. The results indicated that elevated CO2 and Bt cotton both affected the population abundances of A. gossypii and biotype-Q B. tabaci when introduced solely （i.e., without interspecific competition） or two species coexisted （i.e., with interspecific competition）. Compared with ambient CO2, elevated COe increased the population abundances ofA. gossypii and biotype-Q B. tabaci as fed on Bt and nontransgenic cotton on 45 （i.e., seedling stage） and 60 （i.e., flowering stage） days after planting （DAP）, but only significantly enhanced aphid abundance without interspecific competition on the 45-DAP nontransgenic cotton and 60-DAP Bt cotton, and significantly increased whitefly abundance with interspecific competition on the 45-DAP Bt cotton and 60-DAP nontransgenic cotton. In addition, compared with nontransgenic cotton at elevated CO2, Bt cotton significantly reduced biotype-Q B. tabaci abundances without and with interspecific competition during seedling and flowering stage, while only significantly decreasing A. gossypii abundances without interspecific competition during the seedling stage. When the two insect species coexisted, the proportions ofbiotype-Q B. tabaci were significantly higher than those ofA. gossypii on Bt and nontransgenic cotton at the same CO2 levels, and elevated CO2 only significantly increased the percentages of biotype-Q B. tabaci and significantly reduced the proportions of A. gossypii on seedling and flowering nontransgenic cotton. Therefore, the effects of elevated CO2 were favorable for biotype-Q B. tabaci to out-compete A. gossypii under the predicted global climate change.

Three-dimensional niche partitioning between two colonially nesting ardeid species in central China

Background:Interspecific competition is known to be strongest between those species that are both closely related and sympatric.Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet.According to the niche partitioning hypothesis,it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition.We tested niche partitioning between the colonially nesting Little Egret(Egretta garzetta)and Cattle Egret(Bubulcus ibis)in temporal,spatial and trophic dimensions.Methods:Field study was conducted in three mixed egret colonies in Yangxian County,southwest Shaanxi Prov-ince,central China.For each nest colony we recorded its spatial location,the height of nesting trees and of nests,the height of roosting trees and of roosting individuals within the trees.We determined the first egg-laying and first hatching dates of the two species.Craw dissection of storm-killed egret nestlings was used to measure the diet.Six transects were surveyed to study foraging habitat selection.Results:We found that hatching time of Little Egrets peaked earlier(by about 1 month)than that of Cattle Egrets.Cattle Egrets nested and roosted higher than Little Egrets.The foraging habitats used by Little Egrets were dominated by river banks(73.49%),followed by paddy fields(13.25%)and reservoirs(10.84%),whereas Cattle Egret foraging sites were characterized by grasslands(44.44%),paddy fields(33.33%)and river banks(22.22%).Little Egrets consumed more fishes(65.66%)and Odonata larvae(13.69%)than Cattle Egrets,while Cattle Egrets were found feeding mainly on Coleoptera(29.69%)and Orthoptera(23.29%).Little Egrets preyed on larger mean biomasses of food items than Cattle Egrets.Conclusions:Our results confirm the niche partitioning hypothesis as a mechanism for coexistence among ecologi-cally similar species.In two coexisting egret species,niche partitioning is multidimensional,such that the two coexist-ent species occupy differing ecological space based on all three temporal,spatial and trophic niche dimensions.

Maintenance of species boundaries in three sympatric Ligularia(Senecioneae,Asteraceae)species

The key process in speciation concerns the formation and maintenance of reproductive isolating barriers between diverging lineages. Although species boundaries are frequently investigated between two species across many taxa, reproductive isolating barriers among multiple species （：〉2） that would represent the most common phenomenon in nature, remain to be clarified. Here, we use double digest restriction-site associated DNA （ddRAD） sequencing to examine patterns of hybridization at a sympatric site where three Ligularia species grow together and verify whether those patterns contribute to the maintenance of boundaries among species. The results based on the RAD SNP datasets indicated hybridization Ligularia cyathiceps x L. duciformis and L. duciformis x L. yunnanensis were both restricted toFls plus a few first-generation backcrosses and no gene introgression were identified, giving rise to strong reproductive isolation among hybridizing species. More- over, hybrid swarm simulation, using HYBRIDLAB, indicated the RAD SNP datasets had sufficient discriminatory power for accurate hybrid detection. We conclude that parental species show strong reproductive isolation and they still maintain species boundaries, which may be the key mechanism to maintain species diversity of Ligualria in the eastern Qinghai-Tibetan Plateau and adjacent areas. Moreover, this study highlights the effectiveness of RAD sequencing in hybridization studies.