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1.
Philos Trans R Soc Lond B Biol Sci ; 377(1853): 20210159, 2022 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-35491588

RESUMEN

Pollination plays a central role in both crop production and maintaining biodiversity. However, habitat loss, pesticides, invasive species and larger environmental fluctuations are contributing to a dramatic decline of pollinators worldwide. Different management solutions require knowledge of how ecological communities will respond following interventions. Yet, anticipating the response of these systems to interventions remains extremely challenging due to the unpredictable nature of ecological communities, whose nonlinear behaviour depends on the specific details of species interactions and the various unknown or unmeasured confounding factors. Here, we propose that this knowledge can be derived by following a probabilistic systems analysis rooted on non-parametric causal inference. The main outcome of this analysis is to estimate the extent to which a hypothesized cause can increase or decrease the probability that a given effect happens without making assumptions about the form of the cause-effect relationship. We discuss a road map for how this analysis can be accomplished with the aim of increasing our system-level causative knowledge of natural communities. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.


Asunto(s)
Biodiversidad , Polinización , Biota , Producción de Cultivos , Ecosistema
2.
Philos Trans A Math Phys Eng Sci ; 380(2227): 20210245, 2022 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-35599557

RESUMEN

Understanding the conditions of feasibility and stability in ecological systems is a major challenge in theoretical ecology. The seminal work of May in 1972 and recent developments based on the theory of random matrices have shown the existence of emergent universal patterns of both stability and feasibility in ecological dynamics. However, only a few studies have investigated the role of delay coupled with population dynamics in the emergence of feasible and stable states. In this work, we study the effects of delay on generalized Loka-Volterra population dynamics of several interacting species in closed ecological environments. First, we investigate the relation between feasibility and stability of the modelled ecological community in the absence of delay and find a simple analytical relation when intra-species interactions are dominant. We then show how, by increasing the time delay, there is a transition in the stability phases of the population dynamics: from an equilibrium state to a stable non-point attractor phase. We calculate analytically the critical delay of that transition and show that it is in excellent agreement with numerical simulations. Finally, following a similar approach to characterizing stability in empirical studies, we investigate the coefficient of variation, which quantifies the magnitude of population fluctuations. We show that in the oscillatory regime induced by the delay, the variability at community level decreases for increasing diversity. This article is part of the theme issue 'Emergent phenomena in complex physical and socio-technical systems: from cells to societies'.


Asunto(s)
Biota , Ecosistema , Modelos Biológicos , Dinámica Poblacional
3.
PLoS One ; 17(4): e0267444, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35446908

RESUMEN

Natural ecosystems are comprised of diverse species and their interspecific interactions, in contrast to an ecological theory that predicts the instability of large ecological communities. This apparent gap has led ecologists to explore the mechanisms that allow complex communities to stabilize, even via environmental changes. A standard approach to tackling this complexity-stability problem is starting with a description of the ecological network of species and their interaction links, exemplified by a food web. This traditional description is based on the view that each species is in an active state; that is, each species constantly forages and reproduces. However, in nature, species' activities can virtually stop when hiding, resting, and diapausing or hibernating, resulting in overlooking another situation where they are inactive. Here I theoretically demonstrate that adaptive phenotypic change in active and inactive modes may be the key to understanding food web dynamics. Accurately switching activity modes can greatly stabilize otherwise unstable communities in which coexistence is impossible, further maintaining strong stabilization, even in a large complex community. I hypothesize that adaptive plastic change in activity modes may play a key role in maintaining ecological communities.


Asunto(s)
Ecosistema , Cadena Alimentaria , Adaptación Fisiológica , Biota , Modelos Biológicos
4.
Nat Commun ; 13(1): 1921, 2022 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-35396388

RESUMEN

Quaternary climatic oscillations had a large impact on European biogeography. Alternation of cold and warm stages caused recurrent glaciations, massive vegetation shifts, and large-scale range alterations in many species. The Eurasian steppe biome and its grasslands are a noteworthy example; they underwent climate-driven, large-scale contractions during warm stages and expansions during cold stages. Here, we evaluate the impact of these range alterations on the late Quaternary demography of several phylogenetically distant plant and insect species, typical of the Eurasian steppes. We compare three explicit demographic hypotheses by applying an approach combining convolutional neural networks with approximate Bayesian computation. We identified congruent demographic responses of cold stage expansion and warm stage contraction across all species, but also species-specific effects. The demographic history of the Eurasian steppe biota reflects major paleoecological turning points in the late Quaternary and emphasizes the role of climate as a driving force underlying patterns of genetic variance on the biome level.


Asunto(s)
Evolución Biológica , Cambio Climático , Teorema de Bayes , Biota , Ecosistema , Filogenia
5.
Appl Radiat Isot ; 184: 110202, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35390624

RESUMEN

The analysis procedure of five biota samples's organically bound tritium (OBT) based on oxidation combustion and liquid scintillation counter (LSC) measurement was established. The combustion experiment under one atmospheric pressure in the presence of Pt-Al2O3 catalyst were carried out. The experiment results shown that the combustion recovery of five samples ranged from 86.4 % to 91.1 %, the combustion recovery of glucose monohydrate is about 93.7 %, which indicate that combustion recovery of biota samples differed from one species to another. Meanwhile, The counting efficiency of quenching agents CH3NO2 and CCl4 decreases from 20.3 % to 0 and from 19.3 % to 0 respectively as the quench agent mass increases from 10 µL to 500 µL. The counting efficiency of quenching agent HNO3 decreases from 22.4 % to 14.6 % as the quench agent mass increases from 10 µL to 500 µL. The SQP (E) value of CH3NO2 and CCl4 decreases as the mass of quenching agents increases, while the SQP (E) value of HNO3 increases as the quench agent mass increases. The SQP(E) of three tested quench agents ranges from 401.8 to 738.4, which covers the SQP(E) range of all the monitored biota samples in recent years. Therefore, the mapped curves and fixed equations are applicable. In addition, comparison experiment of four biota samples between two laboratories shown a relative deviation from 1.2 % to 12.8 %.


Asunto(s)
Biota , Dióxido de Nitrógeno , Conteo por Cintilación , Tritio/análisis
6.
Nat Commun ; 13(1): 1569, 2022 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-35322027

RESUMEN

The Chengjiang Biota is the earliest Phanerozoic soft-bodied fossil assemblage offering the most complete snapshot of Earth's initial diversification, the Cambrian Explosion. Although palaeobiologic aspects of this biota are well understood, the precise sedimentary environment inhabited by this biota remains debated. Herein, we examine a non-weathered core from the Yu'anshan Formation including the interval preserving the Chengjiang Biota. Our data indicate that the succession was deposited as part of a delta influenced by storm floods (i.e., produced by upstream river floods resulting from ocean storms). Most Chengjiang animals lived in an oxygen and nutrient-rich delta front environment in which unstable salinity and high sedimentation rates were the main stressors. This unexpected finding allows for sophisticated ecological comparisons with other Burgess Shale-type deposits and emphasizes that the long-held view of Burgess Shale-type faunas as snapshots of stable distal shelf and slope communities needs to be revised based on recent sedimentologic advances.


Asunto(s)
Biota , Fósiles , Animales , Evolución Biológica , Inundaciones , Minerales , Ríos
7.
Sci Total Environ ; 828: 154303, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35257761

RESUMEN

We evaluated the distribution of eleven groups of pharmaceutically active compounds (PhACs) in surface waters and biota of different trophic levels, in five sites of two lowland urban rivers in Argentine. Twenty-nine out of 39 PhACs and two metabolites were detected in at least one water sample (2-9622 ng/L), eleven detected in biofilms (1-179 ng/g d.w.) and eight in the macrophyte Lemna gibba (4-112 ng/g d.w). The two more polluted sites had a similar distribution of the main groups of compounds. In surface waters, the largest concentrations were for the analgesic acetaminophen (9622 ng/L), the antibiotic sulfamethoxazole (326 ng/L), the antihypertensive valsartan (963 ng/L), the ß-blocking agent atenolol (427 ng/L), the diuretic hydrochlorothiazide (445 ng/L) and the psychiatric drug carbamazepine (99 ng/L). The antibiotic ciprofloxacin exhibited the highest concentration in the biofilm (179 ng/g d.w.) and in the macrophyte L. gibba (112 ng/g d.w.) Several compounds were detected in the water but not in the biota (e.g., codeine and bezafibrate), and others (e.g., azithromycin and citalopram) were found in the biota but not in the surface water. Significant bioaccumulation factors (>1000 L/kg d.w.) were obtained for venlafaxine and ciprofloxacin in biofilm. Our results show that PhACs may accumulate in several biological compartments. Within an environmental compartment, similar PhACs profile and concentrations were found in different sites receiving urban pollution. Among different compartments, biofilms may be the most suitable biota matrix to monitor the immediate reception of PhACs in the biota. Our results indicate that the presence of PhACs in urban rivers and their accumulation in the biota could be incorporated as symptoms of the urban stream syndrome.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , Antibacterianos , Biota , Ciprofloxacina , Monitoreo del Ambiente/métodos , Preparaciones Farmacéuticas , Agua , Contaminantes Químicos del Agua/análisis
8.
New Phytol ; 234(6): 2073-2087, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35307841

RESUMEN

The replacement of native birch with Norway spruce has been initiated in Norway to increase long-term carbon storage in forests. However, there is limited knowledge on the impacts that aboveground changes will have on the belowground microbiota. We examined which effects a tree species shift from birch to spruce stands has on belowground microbial communities, soil fungal biomass and relationships with vegetation biomass and soil organic carbon (SOC). Replacement of birch with spruce negatively influenced soil bacterial and fungal richness and strongly altered microbial community composition in the forest floor layer, most strikingly for fungi. Tree species-mediated variation in soil properties was a major factor explaining variation in bacterial communities. For fungi, both soil chemistry and understorey vegetation were important community structuring factors, particularly for ectomycorrhizal fungi. The relative abundance of ectomycorrhizal fungi and the ectomycorrhizal : saprotrophic fungal ratio were higher in spruce compared to birch stands, particularly in the deeper mineral soil layers, and vice versa for saprotrophs. The positive relationship between ergosterol (fungal biomass) and SOC stock in the forest floor layer suggests higher carbon sequestration potential in spruce forest soil, alternatively, that the larger carbon stock leads to an increase in soil fungal biomass.


Asunto(s)
Micorrizas , Picea , Betula/microbiología , Biota , Carbono , Bosques , Picea/microbiología , Suelo/química , Microbiología del Suelo , Taiga , Árboles
9.
Sci Rep ; 12(1): 4171, 2022 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-35264620

RESUMEN

There is interest in utilizing wood ash as an amendment in forestry operations as a mechanism to return nutrients to soils that are removed during harvesting, with the added benefit of diverting this bioenergy waste material from landfill sites. Existing studies have not arrived at a consensus on what the effects of wood ash amendments are on soil biota. We collected forest soil samples from studies in managed forests across Canada that were amended with wood ash to evaluate the effects on arthropod, bacterial and fungal communities using metabarcoding of F230, 16S, 18S and ITS2 sequences as well as enzyme analyses to assess its effects on soil biotic function. Ash amendment did not result in consistent effects across sites, and those effects that were detected were small. Overall, this study suggests that ash amendment applied to managed forest systems in amounts (up to 20 Mg ha-1) applied across the 8 study sties had little to no detectable effects on soil biotic community structure or function. When effects were detected, they were small, and site-specific. These non-results support the application of wood ash to harvested forest sites to replace macronutrients (e.g., calcium) removed by logging operations, thereby diverting it from landfill sites, and potentially increasing stand productivity.


Asunto(s)
Contaminantes del Suelo , Suelo , Biota , Agricultura Forestal , Bosques , Suelo/química , Contaminantes del Suelo/análisis
10.
J Radiol Prot ; 42(2)2022 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-35343442

RESUMEN

The International Atomic Energy Agency (IAEA) has organised programmes on the development, comparison and testing of environmental assessment models and approaches for estimating the radiation exposure of humans and wildlife since the 1980s. The latest of these programmes was called MODARIA (Modelling and Data for Radiological Impact Assessment) and was run in two phases from 2012 to 2015 (MODARIA I) and 2016 to 2019 (MODARIA II). Both phases of the MODARIA programme had the overall objective to improve capabilities in the field of environmental transfer of radionuclides and public and non-human biota exposures assessment, by means of acquisition of improved data for model testing and comparison, reaching consensus on modelling philosophies, approaches and parameter values and building an international forum for the exchange of information. This paper provides an overview of the work undertaken during both phases of the MODARIA programme and its outputs. The overall aims and objectives of a new programme to follow on from MODARIA are described.


Asunto(s)
Energía Nuclear , Monitoreo de Radiación , Biota , Radioisótopos/análisis
11.
Water Res ; 215: 118274, 2022 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-35298994

RESUMEN

Disentangling the drivers and mechanisms that shape microbial communities in a river-influenced coastal upwelling system requires considering a hydrologic dimension that can drive both deterministic and stochastic community assembly by generating hydrological heterogeneity and dispersal events. Additionally, ubiquitous and complex microbial interactions can play a significant role in community structuring. However, how the hydrology, biotic, and abiotic factors collectively shape microbial distribution in the hydrologically complicated river plume-upwelling coupling system remains unknown. Through underway sampling and daily observations, we employed 16S and 18S ribosomal RNA sequencing to disentangle drivers and mechanisms shaping the protist-bacteria microbiota in a river-influenced coastal upwelling system. Our findings indicate that the composition of microbial communities was water mass specific. Collectively, water mass, local water chemistry (mostly temperature) and biotic interaction (mostly cross-domain biotic interaction) shaped the protistan-bacterial communities. In comparison to protists, bacteria were more influenced by abiotic factors such as temperature than by cross-domain biotic factors, implying a stronger coupling of geochemical cycles. Both deterministic and stochastic processes had an effect on the distribution of microbial communities, but deterministic processes were more important for bacteria and were especially pronounced for upwelling communities. The co-occurrence network revealed strong associations between the protistan assemblages Orchrophyta and Ciliophora and the bacterial assemblages Alphaproteobacteria, Deltaproteobacteria, and Bacteroidetes, which may reflect predation and mutualism interactions. Overall, this study emphasizes the importance of taking water masses, temperature and domains of life into account when seeking to understand the drivers and assemblies of protist-bacteria microbiome dynamics in coastal upwelling systems, which is especially true given the complex and dynamic nature of the coastal ecosystem.


Asunto(s)
Microbiota , Agua , Bacterias/genética , Biota , Temperatura
12.
Zoolog Sci ; 39(1): 1-6, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35106989

RESUMEN

Marine stations have continued to contribute significantly to understanding the physiology, taxonomy, development, ecology, and evolution of animals. There are more than 50 marine stations of national universities in Japan, and historically their establishments were closely related to the initial stage of zoology in the country. More than 10 years ago, Japanese Association for Marine Biology (JAMBIO) was established to facilitate the collaboration among marine stations in the activities of research, education and administration. One of the successful activities of JAMBIO that contribute to zoology is the JAMBIO Coastal Organism Joint Surveys, in which scientists and students at multiple marine stations, as well as those from research institutes or museums, stay at a marine station for a few days, and collect and make a record of marine organisms. As of 2021, 22 surveys have been performed and new species have been reported from taxa such as Cnidaria, Nematoda, Platyhelminthes, Annelida, Mollusca, Arthropoda, and Echinodermata.


Asunto(s)
Organismos Acuáticos , Biota , Animales , Anélidos , Equinodermos , Japón , Nematodos
13.
Proc Biol Sci ; 289(1969): 20212690, 2022 02 23.
Artículo en Inglés | MEDLINE | ID: mdl-35193401

RESUMEN

How patterns in community diversity emerge is a long-standing question in ecology. Studies suggested that community diversity and interspecific interactions are interdependent. However, evidence from high-diversity ecological communities is lacking because of practical challenges in characterizing speciose communities and their interactions. Here, I analysed time-varying interaction networks that were reconstructed using 1197 species, DNA-based ecological time series taken from experimental rice plots and empirical dynamic modelling, and introduced 'interaction capacity', namely, the sum of interaction strength that a single species gives and receives, as a potential driver of community diversity. As community diversity increases, the number of interactions increases exponentially but the mean interaction capacity of a community becomes saturated, weakening interspecific interactions. These patterns are modelled with simple mathematical equations, based on which I propose the 'interaction capacity hypothesis': that interaction capacity and network connectance can be two fundamental properties that influence community diversity. Furthermore, I show that total DNA abundance and temperature influence interaction capacity and connectance nonlinearly, explaining a large proportion of diversity patterns observed in various systems. The interaction capacity hypothesis enables mechanistic explanations of community diversity. Therefore, analysing ecological community data from the viewpoint of interaction capacity would provide new insight into community diversity.


Asunto(s)
Biota , Ecosistema
14.
Mar Pollut Bull ; 175: 113398, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35114550

RESUMEN

The advent of Multicollector ICP-MS inaugurated the analysis of new metal isotope systems, the so-called "non-traditional" isotopes. They are now available tools to study geochemical and ecotoxicological aspects of marine metal contamination and hence, to push the frontiers of our knowledge. However, such applications are still in their infancy, and an accessible state-of-the-art describing main applications, obstacles, gaps, and directions for further development was missing from the literature. This paper fills this gap and aims to encourage the marine scientific community to explore the contributions of this newly available information for the fields of chemical risk assessment, biomonitoring, and trophic transfer of metal contaminants. In the current "Anthropocene" epoch, metal contamination will continue to threaten marine aquatic ecosystems, and "non-traditional" isotopes can be a valuable tool to detect human-induced changes across time-space involving metal contaminants, and their interaction with marine biota.


Asunto(s)
Ecosistema , Contaminantes Químicos del Agua , Biota , Monitoreo del Ambiente , Humanos , Isótopos/análisis , Metales/análisis , Contaminantes Químicos del Agua/análisis
15.
Philos Trans R Soc Lond B Biol Sci ; 377(1847): 20210032, 2022 03 28.
Artículo en Inglés | MEDLINE | ID: mdl-35125006

RESUMEN

The origin and early evolution of animal development remain among the many deep, unresolved problems in evolutionary biology. As a compelling case for the existence of pre-Cambrian animals, the Ediacaran embryo-like fossils (EELFs) from the Weng'an Biota (approx. 609 Myr old, Doushantuo Formation, South China) have great potential to cast light on the origin and early evolution of animal development. However, their biological implications can be fully realized only when their phylogenetic positions are correctly established, and unfortunately, this is the key problem under debate. As a significant feature of developmental biology, the cell division pattern (CDP) characterized by the dynamic spatial arrangement of cells and associated developmental mechanisms is critical to reassess these hypotheses and evaluate the diversity of the EELFs; however, their phylogenetic implications have not been fully realized. Additionally, the scarcity of fossil specimens representing late developmental stages with cell differentiation accounts for much of this debate too. Here, we reconstructed a large number of EELFs using submicron resolution X-ray tomographic microscopy and focused on the CDPs and associated developmental mechanisms as well as features of cell differentiation. Four types of CDPs and specimens with cell differentiation were identified. Contrary to the prevailing view, our results together with recent studies suggest that the diversity and complexity of developmental mechanisms documented by the EELFs are much higher than is often claimed. The diverse CDPs and associated development features including palintomic cleavage, maternal nutrition, asymmetric cell divisions, symmetry breaking, establishment of polarity or axis, spatial cell migration and differentiation constrain some, if not all, EELFs as total-group metazoans. This article is part of the theme issue 'The impact of Chinese palaeontology on evolutionary research'.


Asunto(s)
Fósiles , Paleontología , Animales , Biota , Embrión de Mamíferos , Filogenia
16.
Philos Trans R Soc Lond B Biol Sci ; 377(1847): 20210042, 2022 03 28.
Artículo en Inglés | MEDLINE | ID: mdl-35125007

RESUMEN

Here we report on a new Early Cretaceous eutherian represented by a partial skeleton from the Jiufotang Formation at Sihedang site, Lingyuan City, Liaoning Province that fills a crucial gap between the earliest eutherians from the Yixian Formation and later Cretaceous eutherians. The new specimen reveals, to our knowledge for the first time in eutherians, that the Meckelian cartilage was ossified but reduced in size, confirming a complete detachment of the middle ear from the lower jaw. Seven hyoid elements, including paired stylohyals, epihyals and thyrohyals and the single basihyal are preserved. For the inner ear the ossified primary lamina, base of the secondary lamina, ossified cochlear ganglion and secondary crus commune are present and the cochlear canal is coiled through 360°. In addition, plesiomorphic features of the dentition include weak conules, lack of pre- and post-cingula and less expanded protocones on the upper molars and height differential between the trigonid and talonid, a large protoconid and a small paraconid on the lower molars. The new taxon displays an alternating pattern of tooth replacement with P3 being the last upper premolar to erupt similar to the basal eutherian Juramaia. Parsimony analysis places the new taxon with Montanalestes, Sinodelphys and Ambolestes as a sister group to other eutherians. This article is part of the theme issue 'The impact of Chinese palaeontology on evolutionary research'.


Asunto(s)
Euterios , Fósiles , Animales , Biota , Mamíferos , Filogenia
17.
Sci Total Environ ; 824: 153764, 2022 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-35151735

RESUMEN

Equilibrium passive sampling has been applied in numerous abiotic environmental matrices. This approach was extended to biological material. In this work, a passive equilibrium sampling method for the measurement of HOCs in biota was developed as an innovative alternative because classical exhaustive extraction techniques are time-consuming and error-prone. The newly developed method is based on the well-proven SPME fiber method for sediment. Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were used as model lipophilic organic pollutants. Partition coefficients of PAHs and PCBs between the lugworm tissue and the PDMS sampling phase were determined. Polydimethylsiloxane (PDMS) coated glass fibers were directly inserted in homogenized lugworm tissue and glass fibers were analyzed using gas chromatography coupled to mass spectrometry. The method application on lugworms from tidal sand flats near Wilhelmshaven showed that the mean body residue values of PCBs (4 µg g-1) and PAHs (256 µg g-1) were about five times higher for PCBs and more than 22 times higher for PAHs compared to literature data for the North Sea area. This high level of contamination might be a consequence of the oil processing refinery located in direct proximity to the sampling site. This novel approach of applying the SPME method to biota will make biological monitoring more effective and holistic, because seasonally and area-wide changes in all environmental compartments can be recorded quickly.


Asunto(s)
Bifenilos Policlorados , Hidrocarburos Policíclicos Aromáticos , Contaminantes Químicos del Agua , Biota , Monitoreo del Ambiente/métodos , Cromatografía de Gases y Espectrometría de Masas , Compuestos Orgánicos/análisis , Bifenilos Policlorados/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes Químicos del Agua/análisis
18.
J Radiol Prot ; 42(2)2022 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-35114655

RESUMEN

This work aimed to estimate the radiation doses to humans and non-human biota arising from the operation of the atomic centre Centro Atómico Ezeiza (CAE), Buenos Aires, Argentina. To this end, atmospheric and liquid average discharges for the period 2014-2016, corresponding to all the facilities of the CAE in normal operation were considered. The PC-CREAM 08 and CROM8 codes were applied taking into account local characteristics and reference values. The radiation doses to both humans and non-human biota estimated were considerably lower than the values recommended to protect people and the environment. Thus, it is possible to conclude that both the environment and the human population near the CAE are extremely unlikely to experience any harmful radiological effects caused by the operation of this atomic centre.


Asunto(s)
Monitoreo de Radiación , Biota , Humanos , Radiografía
19.
Sci Rep ; 12(1): 2621, 2022 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-35173265

RESUMEN

Stingless bees are the largest group of eusocial pollinators with diverse natural histories, including obligate cleptobionts (genus Lestrimelitta) that completely abandoned flower visitation to rely on other stingless bees for food and nest materials. Species of Lestrimeliita are thought to specialize upon different host species, and deception through chemical similarity has been proposed as a mechanism to explain this phenomenon. In the Yucatan Peninsula of Mexico, Scaptotrigona pectoralis is a species chemically distinct from, and not preferred as a host by, locally widespread Lestrimeliita niitkib; witnessing attacks on S. pectoralis colonies offered the opportunity to test the sensory deception hypothesis to cletoparasitism. Analysis of cuticular profiles revealed that the Lestrimelitta attacking S. pectoralis differed significantly in odour bouquet to L. niitkib and, in contrast, it resembled that of S. pectoralis. Further analyses, including morphometrics, mtDNA barcoding, and the examination of taxonomic features, confirmed the existence of two sympatric Lestrimelitta species. The results give support to the hypothesis of chemical deception as a cleptobiotic strategy in Lestrimelitta sp. This is the first evidence that sympatric cleptobionts of the same genus select hosts in accordance with species-specific cuticular profiles, with possible consequences for ecological adaptation and the evolution of these remarkable organisms and the community of stingless bee hosts.


Asunto(s)
Abejas/genética , Abejas/fisiología , Especificidad de la Especie , Simpatría , Adaptación Biológica , Animales , Abejas/clasificación , Evolución Biológica , Biota , Código de Barras del ADN Taxonómico , ADN Mitocondrial/genética , Ecología
20.
Sci Total Environ ; 825: 154069, 2022 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-35217047

RESUMEN

Mercury (Hg) is a global, persistent and inevitable pollutant, the toxicity of which is mostly reflected in its species including inorganic Hg (InHg) and methyl mercury (MeHg). Using diffusive gradients in thin films (DGT) is deemed as a reliable technique to determine the bioavailability of pollutants. This study is the first attempt to assess the integrated toxicity of mercury species mixtures in sediments to the aquatic biota based on the DGT technique. In the course, the Daya Bay under serious anthropogenic influences was selected as the study case. The results showed that the DGT concentrations of InHg and MeHg were detected as 0.30-1.93 µg/L and 0.28-1.94 µg/L respectively in the surface sediments collected from the Daya Bay. In terms of the toxicity of single mercury species, the risk quotient (RQ) values of InHg and MeHg significantly exceeded 1, indicating that the adverse effects of InHg and MeHg should not be ignored. In terms of the integrated toxicity of mercury species mixtures, the probabilistic biological risk assessment results demonstrate that Daya Bay features low (3.32%) probability of toxic effects in its surface sediments to the aquatic biota.


Asunto(s)
Contaminantes Ambientales , Mercurio , Contaminantes Químicos del Agua , Biota , Ecotoxicología , Monitoreo del Ambiente/métodos , Sedimentos Geológicos , Mercurio/análisis , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad
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