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1.
Management of semi-natural grasslands should be based on the requirements of plants as well as their pollinators since conditions beneficial for plants are not necessarily beneficial for their pollinators and vice versa. The factors affecting the reproductive success (fruit set) of Platanthera bifolia and Platanthera chlorantha and their pollinators in agricultural landscape and woodlands were studied. In the years 2014–2016, we observed and caught moths during the flowering period of Platanthera species (late June–mid July) in four pure P. bifolia, five pure P. chlorantha and nine mixed populations under management or no management in Estonia. We determined pollinator species richness, pollinator abundance, fruit set and visibility of Platanthera plants in each population. We found that pollinator assemblages of P. bifolia and P. chlorantha did not differ between managed and unmanaged sites. Pollinator abundance had an effect on the fruit set of P. bifolia but not on that of P. chlorantha. Presence or absence of management, visibility of plants and rarefied pollinator species richness did not affect the fruit set of either plant species. Pollinator abundance was significantly higher in unmanaged populations of both plant species but rarefied pollinator species richness was higher only in unmanaged populations of P. chlorantha. Based on our findings the recommendations for management of semi-natural grasslands are to promote larger landscape diversity for the benefit of moth abundance by leaving unmanaged patches in different parts of a grassland in different years and rotational and post-fruiting management for higher reproductive success of orchids.  相似文献   

2.

Aims

Rytidosperma species are native Australian grasses which have different growth rates and phosphorus (P) requirements. This study examined the role of root morphology traits in response to P supply.

Methods

Nine Rytidosperma species ranging from slow- to fast-growth were examined along with Lolium perenne and Bromus hordeaceus. Plants were grown in a glasshouse for 47 days in soil supplied with six levels of P between 0 and 60 mg P per pot. Root mass, length and diameter, root hair length and density, and extent of mycorrhizal colonisation were measured.

Results

Across all species there was a positive correlation (P < 0.001) between P uptake and root mass, length and root hair cylinder volume (RHCV; estimated using root diameter, root hair length and root length) at all levels of P supply. An exception was the RHCV of B. hordeaceus, where expected P uptake was not achieved due to a markedly reduced root length at low-P supply. For the Rytidosperma species, morphological plasticity for specific root length, root mass fraction and root hair length ranged from 1.5-fold to 2.7-fold between high- and low-P supply. However, across all species and P levels no single root morphological trait was identified for universally increasing the size of the root system and P uptake.

Conclusions

Fast-growing species took up more P as a result of an overall larger root mass, greater root length and larger RHCV.
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3.
We use public records from 1980 to 2014 to analyse survival of the EU Annex IV species Aeshna viridis in Sweden, a dragonfly strongly associated with the plant Stratiotes aloides. We clustered localities with S. aloides based on assumed dispersal abilities of A. viridis, using a dispersing radius of 2–100 km, calculating the proportion of sites with S. aloides that A. viridis is able to reach. If mean dispersal capability is high (40 km or above) 92.6 % or more of the localities are connected. For a good disperser, the probability of long-time survival is good. We further analysed the species richness of other Odonata and aquatic plants at 98 localities from the dataset. A. viridis co-occurred with more Odonata in the presence of S. aloides and running water but not in lakes. S. aloides sites had a higher number of other aquatic plants. Area had no impact on the occurrence of the species. For the present situation we surveyed 32 localities with known occurrence of the species. Only half of the sites for S. aloides contained any specimens while A. viridis occurred in the same number of sites. The species co-occurred in only 8 of 32 sites. In four sites A. viridis larvae appeared among Menyanthes trifoliata, Phragmites australis, Potamogeton natans and Sphagnum spp., indicating that at high latitudes A. viridis breeds among other species. Indirect monitoring based only on S. aloides would underestimate the number of populations of the dragonfly.  相似文献   

4.

Key message

Fine mapping of Yr47 and Lr52 in chromosome arm 5BS of wheat identified close linkage of the marker sun180 to both genes and its robustness for marker-assisted selection was demonstrated.

Abstract

The widely effective and genetically linked rust resistance genes Yr47 and Lr52 have previously been mapped in the short arm of chromosome 5B in two F3 populations (Aus28183/Aus27229 and Aus28187/Aus27229). The Aus28183/Aus27229 F3 population was advanced to generate an F6 recombinant inbred line (RIL) population to identify markers closely linked with Yr47 and Lr52. Diverse genomic resources including flow-sorted chromosome survey sequence contigs representing the orthologous region in Brachypodium distachyon, the physical map of chromosome arm 5BS, expressed sequence tags (ESTs) located in the 5BS6-0.81-1.00 deletion bin and resistance gene analog contigs of chromosome arm 5BS were used to develop markers to saturate the target region. Selective genotyping was also performed using the iSelect 90 K Infinium wheat SNP assay. A set of SSR, STS, gene-based and SNP markers were developed and genotyped on the Aus28183/Aus27229 RIL population. Yr47 and Lr52 are genetically distinct genes that mapped 0.4 cM apart in the RIL population. The SSR marker sun180 co-segregated with Lr52 and mapped 0.4 cM distal to Yr47. In a high resolution mapping population of 600 F2 genotypes Yr47 and Lr52 mapped 0.2 cM apart and marker sun180 was placed 0.4 cM distal to Lr52. The amplification of a different sun180 amplicon (195 bp) than that linked with Yr47 and Lr52 (200 bp) in 204 diverse wheat genotypes demonstrated its robustness for marker-assisted selection of these genes.
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5.
Artibeus jamaicensis is a medium-sized frugivorous microchiropteran bat that complements its diet with nectar and pollen during the dry season. We investigated which species of pollen are carried by A. jamaicensis in order to determine its potential role as a plant pollinator in the northern Yucatan Peninsula. We collected pollen from the fur of 192 individuals throughout the year from April 2004 to March 2005. We recorded pollen from nine plant species of eight families and found five unidentified pollen types, with the highest pollen species richness recorded in June. A. jamaicensis moved pollen of Erythrina standleyana and Mimosa bahamensis, which have not hitherto been reported as visited by this species. The most abundant pollen in the samples was found to be that of three tree species: Ceiba pentandra, C. aesculifolia and Lysiloma latisiliquum. Very few samples contained pollen in the rainy season, when the bats fed mainly on fruits. A. jamaicensis can fly several kilometres among foraging locations and dispersed large amounts of pollen from tree species growing near cenotes as well as those not present at cenotes but occurring in other forest fragments, highlighting its importance as a pollen vector among forest fragments in the largely deforested landscape of the Yucatan Peninsula, helping to reduce the negative effects of forest fragmentation. Ceiba appears to benefit from the role of A. jamaicensis as a pollen vector, and the species play an important ecological role in the Yucatán landscape, supplying shade, nectar and fruit for wildlife.  相似文献   

6.
Genetic variability of trees influences the chemical composition of tissues. This determines herbivore impact and, consequently, herbivore performance. We evaluated the independent effects of plant genotype and provenance on the tannin content of holm oak (Quercus ilex) and their consequences for herbivory and performance of gypsy moth (Lymantria dispar) larvae. Oak seedlings of 48 open-pollinated families from six populations were grown in a common garden in central Spain. Half the plants were subjected to defoliation by gypsy moth larvae and the other half were destructively sampled for chemical analysis. Tannin content of leaves did not differ significantly among populations but differed significantly among families. Estimates of heritability (h 2) and quantitative genetic differentiation among populations for tannin content (Q ST) were 0.83 and 0.12, respectively. Defoliation was not related to the tannin content of plants nor to spine and trichome densities of leaves, although positive family–mean associations were observed between defoliation and both seed weight and plant height (P < 0.003). Among the oak populations, differential increase in larval weight gain with defoliation was observed. Leaf tannin content in Q. ilex is genetically controlled but does not influence defoliation or predict performance of the larvae. Different efficiencies of food utilisation depending on the oak genotypes indicate that other plant traits are influencing the feeding patterns and fitness of L. dispar and consequent population dynamics.  相似文献   

7.

Key message

Expression of synthesized cecropin B genes in the citrus phloem, where Candidatus Liberibacter asiaticus resides, significantly decreased host susceptibility to Huanglongbing.

Abstract

Huanglongbing (HLB), associated with Candidatus Liberibacter asiaticus bacteria, is the most destructive disease of citrus worldwide. All of the commercial sweet orange cultivars lack resistance to this disease. The cationic lytic peptide cecropin B, isolated from the Chinese tasar moth (Antheraea pernyi), has been shown to effectively eliminate bacteria. In this study, we demonstrated that transgenic citrus (Citrus sinensis Osbeck) expressing the cecropin B gene specifically in the phloem had a decreased susceptibility to HLB. Three plant codon-optimized synthetic cecropin B genes, which were designed to secrete the cecropin B peptide into three specific sites, the extracellular space, the cytoplasm, and the endoplasmic reticulum, were constructed. Under the control of the selected phloem-specific promoter GRP1.8, these constructs were transferred into the citrus genome. All of the cecropin B genes were efficiently expressed in the phloem of transgenic plants. Over more than a year of evaluation, the transgenic lines exhibited reduced disease severity. Bacterial populations in transgenic lines were significantly lower than in the controls. Two lines, in which bacterial populations were significantly lower than in others, showed no visible symptoms. Thus, we demonstrated the potential application of the phloem-specific expression of an antimicrobial peptide gene to protect citrus plants from HLB.
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8.
In this study, blood samples of 259 Acrocephalus sp. warblers were molecularly analysed for Anaplasmataceae and Rhodospirillaceae based on PCR amplification of 16S rRNA gene fragments. One bird blood sample (from Reed Warbler, Acrocephalus scirpaceus) yielded a sequence with 99.8% identity to Haematospirillum jordaniae. This is the first molecular evidence for the occurrence of this species in the blood of any vertebrate other than human. Another bird blood sample (from Marsh Warbler: Acrocephalus palustris) yielded a Wolbachia sequence, closely related to a moth endosymbiont with 99.8% identity. A nematode origin of Wolbachia DNA detected here in avian blood can be excluded, because results of phylogenetic analysis showed its closest alignment with insect wolbachiae. This is the first finding of insect Wolbachia DNA in the circulatory system of birds, which can be explained either by the inoculation of wolbachiae by blood-sucking vectors, or passing of Wolbachia DNA from the gut into the blood of this insectivorous bird species.  相似文献   

9.
Asterias amurensis is a starfish native to the northern Pacific that was introduced into southern Australia in the 1980s. It is widely viewed as one of Australia’s most serious invasive marine pests, but there are few methods available to control new or established populations. The role of Coscinasterias muricata in controlling the distribution of Asterias in Port Phillip Bay, and its potential to eliminate new infestations of Asterias were investigated. Laboratory feeding trials, where alternative mussel prey were available, showed Coscinasterias consumed Asterias at the rate of ~45/year. Field surveys in Port Phillip Bay showed that most Coscinasterias occurred at depths shallower than 15 m, while most Asterias occurred at depths greater than 15 m, and the ratio of Asterias/Coscinasterias only exceeded 45 at depths greater than 15 m. Consequently, if laboratory and field feeding rates are similar, Coscinasterias would be expected to exert significant control over Asterias populations at depths shallower than 15 m, and augmenting Coscinasterias populations at sites of new Asterias infestations may help eliminate newly-established populations.  相似文献   

10.
Cultivating insect pest-resistant varieties is one of the most effective ways to prevent or mitigate pest infestation in Chinese cabbage (Brassica campestris ssp. chinensis). Via the agrobacterium tumefaciens-mediated transformation method, this study introduced the protease inhibitor encoding gene sporamin into two widely cultured cultivars ‘Youdonger’ and ‘Shanghaiqing’, of the common variety of Chinese cabbages (B. campestriss ssp. chinensis var. communis), getting transgenic plants with high sporamin expression. In vitro insect bioassays indicated that, compared with the wild type plants, the transgenic plants exhibited improved resistance to diamondback moth (Plutella xylostella L.) The analysis of inheritance pattern of exogenous sporamin in the progenies of single copy insertion transgenic lines demonstrated that sporamin could be inherited and expressed stably in transgenic progenies. Field survey of the insect resistance under the normal culture condition confirmed the enhanced resistance in transgenic progenies to diamondback moth. Our results strongly suggest that sporamin is an efficient candidate gene for insect-resistant genetic engineering in Chinese cabbage.  相似文献   

11.
Understanding how biotic interactions and abiotic conditions affect plant performance is important for predicting changes in ecosystem function and services in variable environments. We tested how performances of Astragalus rigidulus and Potentilla fruticosa change along gradients of biotic interactions (represented by plant species richness, abundance of the dominant plant species Kobresia pygmaea, and herbivory intensity) and abiotic conditions (represented by elevation, aspect, and slope steepness) across a semi-arid landscape in central Tibet. Redundancy analyses showed that the biotic variables explained 30 and 39 % of the variation in overall performance of A. rigidulus (P = 0.03) and P. fruticosa (P = 0.01), respectively. Abiotic variables did not contribute significantly to variation among A. rigidulus populations. Plant size decreased with species richness in both species and was larger on south- rather than north-facing slopes. Reproductive effort for both species was significantly negatively related to the abundance of K. pygmaea and both species had larger reproductive effort on south- rather than north- and west-facing slopes. The proportion of biomass allocated to sexual reproduction in P. fruticosa was negatively correlated with K. pygmaea abundance and herbivory intensity. The population density of P. fruticosa was positively related to elevation, species richness, and K. pygmaea abundance. We conclude that plant performance at a local scale was more strongly related to biotic than abiotic conditions, but different components of plant performance responded differently to predictor variables and the responses were species-specific. These findings have important implications for rangeland management under changing environmental conditions.  相似文献   

12.
Epizootic disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is a major driver of amphibian declines, yet many amphibians declined before the pathogen was described. The Relict Leopard Frog, Rana onca (=Lithobates onca), was nearly extinct, with the exception of populations within a few geothermal springs. Growth of Bd, however, is limited by high water temperature, and geothermal springs may have provided refuge during outbreaks of chytridiomycosis. We conducted field surveys and laboratory experiments to assess the susceptibility of R. onca to Bd. In the field, we found Bd at one of the two areas where remnant populations of R. onca still occur, but not in the other. In the laboratory, we infected juvenile frogs from these two areas with two hypervirulent Bd isolates associated with declines in other ranid species. In our experiments, these Bd isolates did not affect survivorship of R. onca and most infections (64%) were cleared by the end of the experiments. We propose that R. onca either has inherent resistance to Bd or has recently evolved such resistance. These results may be important for conservation efforts aimed at establishing new populations of R. onca across a landscape where Bd exists. Resistance, however, varies among life stages, and we also did not assess Bd from the local environment. We caution that the resistance we observed for young frogs under laboratory conditions may not translate to the situation for R. onca in the wild.  相似文献   

13.
The genetic structure of Sakhalin spruce (Picea glehnii) was studied across the natural range of the species, including two small isolated populations in south Sakhalin and Hayachine, by using six microsatellite loci and maternally inherited mitochondrial gene sequences. We also analyzed P. jezoensis, a sympatric spruce in the range. Genetic diversity of P. glehnii was higher in central Hokkaido and the lowest in the Hayachine. Bayesian clustering and principal coordinate analysis by using the microsatellites indicated that the Hayachine was clearly distinct from other populations, implying that it had undergone strong genetic drift since the last glacial period. P. glehnii harbored four mitochondrial haplotypes, two of which were shared with P. jezoensis. One of the two was observed without geographical concentration, suggesting its derivation from ancestral polymorphism. Another was observed in south Sakhalin and in P. jezoensis across Sakhalin. The Bayesian clustering—by using four microsatellite loci, including P. jezoensis populations—indicated unambiguous species delimitation, but with possible admixture of P. jezoensis genes into P. glehnii in south Sakhalin, where P. glehnii is abundantly overwhelmed by P. jezoensis; this might explain the occurrence of introgression of the haplotype of P. jezoensis into P. glehnii.  相似文献   

14.
The main threats to primates worldwide are the degradation, fragmentation, and loss of their habitats; hunting (especially for bushmeat); and illegal trade. For many species, the most important threat is forest fragmentation, resulting in small populations that are restricted to isolated forest patches. In this situation, primates are particularly vulnerable to disease. The Endangered blonde capuchin (Sapajus flavius) is now restricted to a few forest patches in Northeast Brazil. We investigated the occurrence of parasites and bacterial diseases in one of three free-ranging groups of S. flavius in a small forest patch in Paraíba state, Northeast Brazil. We tested for antibodies against Leishmania spp., Trypanosoma cruzi, Toxoplasma gondii, Leptospira spp. (24 strains), and Brucella spp.. We used molecular analysis to detect Plasmodium spp., and evaluated blood smears for the presence of hemoparasites. All individuals tested negative for Leptospira spp. and B. abortus, but 8 of 48 (16%) presented antibodies for both Leishmania spp. and T. cruzi. We identified antibodies to T. gondii in 12% of the individuals tested. Plasmodium brasilianum infection was present in 4% of the individuals tested, and blood smears showed microfilariae parasites in 46% of the individuals tested. The occurrence of these infectious diseases in S. flavius may pose a significant threat in terms of reduced recruitment and poor survival rates, and an understanding of the influence of pathogens is crucial for the management of small populations of primates.  相似文献   

15.
Three species of the gelechiid moth genus Photodotis new to science are described from central Laos: P. daedalea sp. n., P. lurida sp. n., and P. reclinata sp. n.  相似文献   

16.
Harmonia axyridis Pallas (1773) (Coleoptera: Coccinellidae) is the well-studied system of invasive insect species. Native and invasive parts of the area of H. axyridis are isolated geographically. We studied the species composition and the distribution of bacterial symbionts Spiroplasma and Rickettsia in seven localities of the native area and six localities of the invasive area of H. axyridis. Rickettsia was detected in H. axyridis populations for the first time. We found that the proportion of beetles infected with Rickettsia in native and invasive populations of H. axyridis is about 0.03. Spiroplasma was found only in native populations of H. axyridis. The proportion of infected individuals with Spiroplasma in native populations of H. axyridis is about 0.08. All studied native populations of H. axyridis are infected with Spiroplasma, while all invasive populations are not. We discuss the possible influence of Spiroplasma and Rickettsia in the formation of invasive populations of H. axyridis.  相似文献   

17.
In the Azores Islands, two Euphrasia L. (Orobanchaceae) endemic species are recognized: Euphrasia azorica H.C.Watson, an annual herb, in Flores and Corvo, and Euphrasia grandiflora Hochst. ex Seub., a semi-shrub, in Pico, São Jorge and Terceira. Both species are highly endangered and protected by the Bern Convention and Habitats Directive. A population genetics study was conducted with new microsatellite primer pairs in 159 individuals of E. azorica and E. grandifolia, sampled from populations in Flores, Corvo, Pico and São Jorge. Allele sizing suggested that E. azorica is a diploid while E. grandiflora is a tetraploid. Euphrasia grandiflora revealed higher genetic diversity then E. azorica. The E. grandiflora population of Morro Pelado in São Jorge, displayed higher genetic diversity when compared with all others, while the E. azorica population of Madeira Seca in Corvo, showed the lowest. Private and less common bands were also overall higher in E. grandiflora populations. Population genetic structure analysis confirmed a distinctiveness between the two Azorean endemic Euphrasia, in addition to island-specific genetic patterns in E. azorica. The genetic structure obtained for E. grandiflora was complex with the populations of Cabeço do Mistério in Pico Island and of Pico da Esperança in São Jorge sharing the same genetic group, while a putative spatial barrier to gene flow was still retrieved between both islands. Although some populations of both species might benefit from propagation actions, studies are needed on plant host species and translocations between islands or between some populations of a same island should be avoided, due to the occurrence of putative ESUs. Eradication of invasive species and control of grazing will be fundamental to promote in situ restauration.  相似文献   

18.
Estimating occupancy patterns and identifying vegetation characteristics that influence the presence of butterfly species are essential approaches needed for determining how habitat changes may affect butterfly populations in the future. The montane butterfly species, Parnassius clodius, was investigated to identify patterns of occupancy relating to habitat variables in Grand Teton National Park and Bridger-Teton National Forest, Wyoming, United States. A series of presence–absence surveys were conducted in 2013 in 41 mesic to xeric montane meadows that were considered suitable habitat for P. clodius during their flight season (June–July) to estimate occupancy (ψ) and detection probability (p). According to the null constant parameter model, P. clodius had high occupancy of ψ?=?0.78?±?0.07 SE and detection probability of p?=?0.75?±?0.04 SE. In models testing covariates, the most important habitat indicator for the occupancy of P. clodius was a strong negative association with big sagebrush (Artemisia tridentata; β = ??21.39?±?21.10 SE) and lupine (Lupinus spp.; β?=???20.03?±?21.24 SE). While P. clodius was found at a high proportion of meadows surveyed, the presence of A. tridentata may limit their distribution within montane meadows at a landscape scale because A. tridentata dominates a large percentage of the montane meadows in our study area. Future climate scenarios predicted for high elevations globally could cause habitat shifts and put populations of P. clodius and similar non-migratory butterfly populations at risk.  相似文献   

19.
Despite the great variety of habitats in Madagascar, Eulemur has successfully populated most forested habitats on the island. Although the high dietary flexibility of Eulemur is often credited as one of the drivers of its evolutionary success, other behavioral evidence suggests a limited capacity for dietary switching. To shed light on the feeding strategies of Eulemur, we compared the dietary flexibility between populations of this genus with that of another widespread lemur taxon, Propithecus. We hypothesized that Eulemur would show greater dietary flexibility than Propithecus, which has a digestive system specialized for folivory, and that Eulemur living in dry forests would switch its diet from fruit to other food seasonally. To examine these hypotheses, we performed a phylogenetic least-squares analysis on 10 populations of Eulemur and 7 of Propithecus to assess the contribution of environmental variables and body mass on their dietary flexibility while controlling for phylogenetic relatedness. Eulemur relied heavily on fruit and did not show large variations in primary food over the year. Propithecus consumed leaves and fruits equally and exhibited considerable flexibility across seasons. Therefore, in contrast to our predictions, the anatomical specialization for fiber digestion heightens dietary flexibility in Propithecus. At the intrageneric level, we found similar ecogeographic variation; populations of both genera with heavier body mass consumed more fruit. As we predicted, Eulemur in drier habitats switched the diet from fruit to alternative food more frequently. To compensate for low dietary flexibility, Eulemur mostly adopts a power-feeding strategy by which it increases energy expenditure to acquire patchily distributed fruit resources.  相似文献   

20.
The article presents the genetic parameters of the populations of lizards of the Darevskia raddei complex (D. raddei nairensis and D. raddei raddei) and the populations of D. valentini calculated on the basis of the analysis of variability of 50 allelic variants of the three nuclear genome microsatellite-containing loci of 83 individuals. It was demonstrated that the Fst genetic distances between the populations of D. raddei nairensis and D. raddei raddei were not statistically significantly different from the Fst genetic distances between the populations of different species, D. raddei and D. valentini. At the same time, these distances were statistically significantly higher than the Fst distances between the populations belonging to one species within the genus Darevskia. These data suggest deep divergence between the populations of D. raddei raddei and D. raddei nairensis of the D. raddei complex and there arises the question on considering them as separate species.  相似文献   

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