近30年京津冀地区湖泊面积的变化

利用遥感、气候和社会经济统计数据,探究1987-2017年间京津冀地区湖泊面积的变化及其与自然和社会因素的关系。结果表明,该地区湖泊面积过去30年间整体上呈减少趋势,每年减少约2%,这是自然和人为因素双重影响的结果。可分为3个阶段:前10年(1987-1996年),湖泊面积增加约4.8×10~2 km^2 (约占76%),由自然因素主导(R^2=0.849,p=0.001);1997-2009年的13年间,湖泊面积呈减少趋势(减少约4.7×102km^2,占43%),主要由人为因素主导(R^2=0.536,p=0.013);最近8年(2010-2017年)中,湖泊面积呈增加趋势(增加约2.3×10~2 km^2,占36%),也主要由人为因素导致。虽然最近8年来该地区湖泊面积减少的趋势得到扭转,但地表水资源供需矛盾仍然严峻。

珠江下游颗粒沟链藻Aulacoseira granulata (Ehrenberg) Simonsen及形态相近种赫组基沟链藻Aulacoseira herzogii (Lemmerman) Simonsen的形态学研究

采用扫描电镜(SEM)技术,对采自珠江下游的沟链藻属2个物种颗粒沟链藻Aulacoseira granulata(Ehrenberg)Simonsen和赫组基沟链藻A.herzogii(Lemmerman)Simonsen的形态特征进行了观察和描述,并与其他相近种的形态异同点进行了比较分析。

Untargeted metabolomics to evaluate antifungal mechanism:a study of Cophinforma mamane and Candida albicans interaction

Microbial interactions between filamentous fungi and yeast are still not fully understood.To evaluate a potential anti-fungal activity of a filamentous fungus while highlighting metabolomic changes,co-cultures between an endophytic strain of Cophinforma mamane(CM)and Candida albicans(CA)were performed.The liquid cultures were incubated under static conditions and metabolite alterations during the course were investigated by ultra-performance liquid chromatography-tandem mass spectrophotometry(UPLC-MS/MS).Results were analyzed using MS-DIAL,MS-FINDER,METLIN,Xcalibur,SciFinder,and MetaboAnalyst metabolomics platforms.The metabolites associated with catabolic processes,including the metabolism of branched-chain amino acids,carnitine,and phospholipids were upregulated both in the mono and co-cultures,indicating fungal adaptability to environmental stress.Several metab-olites,including C20 sphinganine 1-phosphate,myo-inositol,farnesol,gamma-undecalactone,folinic acid,palmitoleic acid,and MG(12:/0:0/0:0)were not produced by CA during co-culture with CM,demonstrating the antifungal mecha-nism of CM.Our results highlight the crucial roles of metabolomics studies to provide essential information regarding the antifungal mechanism of C.mamane against C.albicans,especially when the lost/undetected metabolites are involved in fungal survival and pathogenicity.

Preliminary Study on Geographical Variation of Cytochrome b gene and ITS2-rDNA among Populations of Rhynchophorus ferrugineus

The Red Palm Weevil （RPW）, Rhynchophorus ferrugineus （Olivier）, （Coleoptera, Curculionidae, Rhynchophorinae）, is an invasive species that is originated from Southeast Asia. It has invaded Middle East, several countries of the Mediterranean Basin, Caribbean （Island of Curacao, Netherland Antilles）, Lebanon and United States of America （Laguna Beach, Orange County, California） during the last three decades where it attacks palm trees. This study investigated the geographical variation among geographic populations of RPW collected from twelve invaded countries using cytochrome b （Cytb） and ITS2 partial sequences. The comparison among the Cytb sequences resulted in three different haplotypes designated as HB 1 to HB3. The three haplotypes were subdivided into two phylogenetic groups according to their geographic positions： （1） the ＂Multi-Continent＂ group containing HB 1 haplotype detected in eight populations belonging to three different Continents such as Africa-Egypt, Asia-Kingdom of Saudi Arabia and Turkey and Europe-Spain, Italy, Greece, Cyprus and France, and （2） the ＂Asian＂ group includes four populations from Iran （harboring HB2 haplotype）, Pakistan, UAE, and Oman （harboring HB3 haplotype）. This mitochondrial pattern of genetic diversity suggests that the tested RPW populations subdivided genetically into different sub-populations under the influence of genetic drift. According to these results we concluded that the twelve studied RPW populations are originating from different source populations in the RPW area of origin.

Animal personality and the ecological impacts of freshwater non-native species

While the ecological impacts of invasive species have been demonstrated for many taxonomic groups, the potential effects of behavioural variation among nonnative individuals （i.e. personality） on these impacts have been largely overlooked. This is despite the fact that recent studies have demonstrated that, by nature, the three first stages of biological invasions （i.e. transport, establishment and spread） can lead to personalitybiased populations. Freshwater ecosystems provide a unique oppor tunity to investigate this issue, notably because the ecological impacts of nonnative species have been extensively documented and because animal personality has been widely studied using freshwater model species. Here, we aim at developing some per spectives on the potential effects of animal personality on the ecological impacts of freshwater nonnative species across levels of biological organizations. At the individual level, personality types have been demonstrated to affect the physiolo gy, metabolism, life history traits and fitness of individuals. We used these effects to discuss how they could subsequently impact invaded popula tions and, in turn, recipient communities. We also discussed how these might translate into changes in the structure of food webs and the functioning of invaded ecosystems. Finally we discussed how these perspectives could interact with the management of invasive species .

Insect immune resistance to parasitoids

Insect host-parasitoid interactions involve complex physiological, biochemical and genetic interactions. Against endoparasitoids, immune-competent hosts initiate a blood cell-mediated response that quickly destroys the intruders and envelops them in a multilayered melanotic capsule. During the past decade, considerable progress has been made in identifying some of the critical components of the host response, mainly because of the use of efficient molecular tools. This review examines some of the components of the innate immune response of Drosophila, an insect that has served as an exceptionally good experimental model for studying non-self recognition processes and immune cell signaling mechanisms. Topics considered in this review include hematopoiesis, proliferation and adhesion of hemocytes, melanogenesis and associated cytotoxic molecules, and the genetic aspects of the host-parasitoid interaction.

Suitability of three Ostrinia species as hosts for Macrocentrus cingulum： A comparison of their encapsulation abilities

Two cornborer species, Ostrinia furnacalis （Lepidoptera： Crambidae） and O. nubilalis, are major corn pests in Asia and Europe, respectively. In both continents, the larval endoparasitoid Macrocentrus cingulum （Hymenoptera： Braconidae） develops on another, closely related stemborer, O. scapulalis, which feeds on mugwort and other dicotyledons. M. cingulum also emerges from O. furnacalis in Asia and （9. nubilalis in North America, but not from O. nubilalis in Europe. We assessed the ability of three populations of each of the three Ostrinia species to encapsulate foreign bodies of a size similar to that of a M. cingulum egg. We conclude that variations in encapsulation ability alone cannot account for the differences observed in the field between parasite emergence rates in these different host species and geographic areas.

Effects of a sex ratio gradient on female mate-copying and choosiness in Drosophila melanogaster

In many sexually reproducing species, individuals can gather information about potential mates by observing their mating success. This behavioral pattern, that we call mate-copying, was reported in the fruit fly Drosophila rnelanogaster where females choosing between 2 males of contrasting phenotypes can build a preference for males of the phenotype they previously saw being chosen by a demonstrator female. As sex ratio is known to affect mate choice, our goal was to test whether mate-copying is also affected by encountered sex ratios. Thus, we created a gradient of sex ratio during demonstrations of mate-copying experiments by changing the number of females observ- ing from a central arena 6 simultaneous demonstrations unfolding in 6 peripheral compartments of a hexagonal device. We also tested whether the sex ratio experienced by females during demon- strations affected their choosiness （male courtship duration and double courtship rate） in subse- quent mate-choice tests. Experimental male：female sex ratio during demonstrations did not affect mate-copying indices, but positively affected the proportion of both males courting the female during mate-choice tests, as well as male courtship duration, the latter potentially explaining the for- mer relationship. As expected, the sex ratio affected female choosiness positively, and Drosophila females seem to have evolved a mate-copying ability independently of sex ratio, and a capacity to adapt their choosiness to male availability. This suggests that, as in many animal species, individuals, especially females, can adapt their mate choice depending on the current sex ratio.

Parentage analysis in Gabonese colonies of soil-feeding termites belonging to the Cubitermes sp. affinis subarquatus complex of species （Termitidae＂ Termitinae）

Cubitermes spp. are widely distributed soil-feeding termite species in sub- Saharan Africa which play a fundamental role in soil structure and fertility. A complex of at least four cryptic species （i.e., Cubitermes sp. affunis subarquatus complex of species） has been recently described using molecular markers. In order to investigate the breeding system of these species, five microsatellite markers were used to carry out parentage and re- latedness analyses in 15 Gabonese colonies. Monogamy was confirmed as the predominant reproductive organization in Cubitermes spp. （76% of the colonies）. Within 30% of these monogamous colonies, a high relatedness between reproductives was shown, suggesting that mating between related individuals occurs. However, Cubitermes colonies can deviate from monogamy. Indeed, parental contributions by at least two related reproductives of the same sex were revealed in four colonies and polyandry was demonstrated in two of them. Infiltration of reproductives in the colony is the most plausible explanation for such cases of polygamy in Cubitermes spp.

Functional responses to deforestation in fish communities inhabiting neotropical streams and rivers

Background Deforestation is a widespread disturbance for neotropical freshwater ecosystems.While biodiversity declines have been associated with deforestation,its functional consequences for stream and river fish faunas remain poorly understood.In this study,we explored how deforestation affects the different facets of the functional structure of fish communities inventoried using environmental DNA metabarcoding in 64 river and 35 stream sites of French Guiana.Specifically,we investigated how functional richness,divergence,evenness and identity of fish faunas are affected by deforestation.Results We showed that anthropogenic disturbances in French Guiana are modifying the functional diversity of freshwater fish communities.These disturbances not only affected the amount of functional traits held by the communities but also the identity of the traits and the internal structure of the functional space.Consequently,different facets of the functional diversity supported by fish assemblages were altered.In streams,deforestation did not affect the overall diversity of traits but reduced functional redundancy,underlined by a shift in functional identity towards assemblages dominated by pelagic detritivores.In contrast,river fish faunas experienced a decline in functional richness,paired with shifts in functional identity and a loss of fish species with extreme functions.Conclusions The response to deforestation differed between streams and rivers,but it supports the hypothesis that deforestation is linked to functional changes in fish assemblages.By diminishing the range of the functions in rivers or by jeopardizing the redundancy of functions in streams,deforestation could severely hamper the functioning and stability of neotropical freshwater ecosystems.

Is non-host pollen suitable for generalist bumblebees？

Current evidence suggests that pollen is both chemically and structurally protected. Despite increasing interest in studying bee-flower networks, the constraints for bee development related to pollen nutritional content, toxicity and digestibility as well as their role in the shaping of bee-flower interactions have been poorly studied. In this study we combined bioassays of the generalist bee Bombus terrestris on pollen of Cirsium, Trifolium, Salix, and Cistus genera with an assessment of nutritional content, toxicity, and digestibility of pollen. Microcolonies showed significant differences in their development, non-host pollen of Cirsium being the most unfavorable. This pollen was characterized by the presence of quite rare 37-sterols and a low digestibility. Cirsium consumption seemed increase syrup collection, which is probably related to a detoxification mixing behavior. These results strongly suggest that pollen traits may act as drivers of plant selection by bees and partly explain why Asteraceae pollen is rare in bee generalist diet.

Estimating Aboveground Carbon Dynamic of China Using Optical and Microwave Remote-Sensing Datasets from 2013 to 2019

Over the past 2 to 3 decades,Chinese forests are estimated to act as a large carbon sink,yet the magnitude and spatial patterns of this sink differ considerably among studies.Using 3 microwave(L-and X-band vegetation optical depth[VOD])and 3 optical(normalized difference vegetation index,leaf area index,and tree cover)remote-sensing vegetation products,this study compared the estimated live woody aboveground biomass carbon(AGC)dynamics over China between 2013 and 2019.Our results showed that tree cover has the highest spatial consistency with 3 published AGC maps(mean correlation value R=0.84),followed by L-VOD(R=0.83),which outperform the other VODs.An AGC estimation model was proposed to combine all indices to estimate the annual AGC dynamics in China during 2013 to 2019.The performance of the AGC estimation model was good(root mean square error=0.05 Pg C and R^(2)=0.90 with a mean relative uncertainty of 9.8% at pixel scale[0.25°]).Results of the AGC estimation model showed that carbon uptake by the forests in China was about+0.17 Pg C year^(-1) from 2013 to 2019.At the regional level,provinces in southwest China including Guizhou(+22.35 Tg C year^(-1)),Sichuan(+14.49 Tg C year^(-1)),and Hunan(+11.42 Tg C year^(-1))provinces had the highest carbon sink rates during 2013 to 2019.Most of the carbon-sink regions have been afforested recently,implying that afforestation and ecological engineering projects have been effective means for carbon sequestration in these regions.

On the presence of the giant freshwater prawn,Macrobrachium rosenbergii,in French Guiana confirmed by citizen science and genetic analyses

We report for the first time the presence of self-sustaining populations of Macrobrachium rosenbergii in French Guiana.Genetic analyses of the cytochrome c oxidase subunit I marker(COI)confirmed the identity of the species as well as historical records about the introduction of the species from commercial stocks.Despite the limited presence of Macrobrachium rosenbergii in French Guiana,the species is recorded in several river basins,including two where the species has never been farmed.This suggests that the species is able to disperse locally and highlights its potential invasive nature in the territory.