Mass Abundance Research Articles

Soluble salts at the Phoenix Lander site, Mars: A reanalysis of the Wet Chemistry Laboratory data

The Wet Chemistry Laboratory (WCL) on the Phoenix Mars Scout Lander analyzed soils for soluble ions and found Ca2+, Mg2+, Na+, K+, Cl−, SO42−, and ClO4−. The salts that gave rise to these ions can be inferred using aqueous equilibrium models; however, model predictions are sensitive to the initial solution composition. This is problematic because the WCL data is noisy and many different ion compositions are possible within error bounds. To better characterize ion concentrations, we reanalyzed WCL data using improvements to original analyses, including Kalman optimal smoothing and ion-pair corrections. Our results for Rosy Red are generally consistent with previous analyses, except that Ca2+ and Cl− concentrations are lower. In contrast, ion concentrations in Sorceress 1 and Sorceress 2 are significantly different from previous analyses. Using the more robust Rosy Red WCL analysis, we applied equilibrium models to determine salt compositions within the error bounds of the reduced data. Modeling with FREZCHEM predicts that WCL solutions evolve Ca–Mg–ClO4-rich compositions at low temperatures. These unusual compositions are likely influenced by limitations in the experimental data used to parameterize FREZCHEM. As an alternative method to evaluate salt assemblages, we employed a chemical divide model based on the eutectic temperatures of salts. Our chemical divide model predicts that the most probable salts in order of mass abundance are MgSO4·11H2O (meridianiite), MgCO3·nH2O, Mg(ClO4)2·6H2O, NaClO4·2H2O, KClO4, NaCl·2H2O (hydrohalite), and CaCO3 (calcite). If ClO3− is included in the chemical divide model, then NaClO3 precipitates instead of NaClO4·2H2O and Mg(ClO3)2·6H2O precipitates in addition to Mg(ClO4)2·6H2O. These salt assemblages imply that at least 1.3wt.% H2O is bound in the soil, noting that we cannot account for water in hydrated insoluble salts or deliquescent brines. All WCL solutions within error bounds precipitate Mg(ClO4)2·6H2O and/or Mg(ClO3)2·6H2O salts. These salts have low eutectic temperatures and are highly hygroscopic, which suggests that brines will be stable in soils for much of the Martian summer.

Chemical abundances associated with gamma-ray bursts: nucleosynthesis in afterglows

Gamma-ray burst (GRB) ejecta carries huge amounts of energy expanding into the surrounding medium and heats up these materials, making it possible that nucleosynthesis can take place in such hot sites in afterglow stage. Here, we study possible changes in chemical abundances in the GRB afterglow processes of Wolf-Rayet (WR) star wind environments (Case A) and constant density surroundings (Case B). We find that the light element of lithium-beryllium-boron could occur in the afterglows via He+He process and spallation reactions. Some isotopes of F, Ne, Mg, Al, Si, P, S and Fe-group elements are also new species formed in the afterglows via proton-, neutron- and alpha-capture. The results show that the nucleosynthetic yields might be a diagnostic of the GRB's ambient environment. Our calculations indicate that Mg, Al, Si, P, Cr, Mn, Fe and Co have trended to appear in Case A, while Ne, Ti and Ni trend to occur in Case B. Furthermore, although some species have occurred both in Cases A and B, their mass fractions are quite different in these two cases. Here, we show that the mass fractions of Li-7, Be-7, Mg-24 and Si-30 are higher in Case A than that in Case B, but F-18 gives an opposite conclusion. Nucleosynthetic outputs might also be an indice to estimate the luminosity-temperature relation factor beta. In this study, when beta reduces, the mass abundances of B-11 and Ne-20 are higher in Case B than that in Case A; in contrast, as the beta becomes larger, this trend would be reversed; therefore, perhaps we could select the above elements as the indicators to estimate the properties of the surroundings around the GRBs. We also suggest that the spectroscopic observations of a GRB afterglow could only reveal the nucleosynthetic outputs from the interaction site between the GRB jet and its ambient matter, but could not represent the original composition of the pre-GRB surrounding medium.

Hydrogen-induced Ostwald ripening of cobalt nanoparticles on carbon nanotubes

Nanoparticles on carbon nanotubes can be used as a high surface area catalyst or as a means to produce well-defined particles. In this study, cobalt nanoparticles were formed on xxsingle-walled carbon nanotubes during hydrogen exposure at an elevated temperature. The average particle size increased as a function of reaction time ranging from 1.5 to 40 nm, indicating hydrogen-induced Ostwald ripening which is remarkable for a nonhydrogen-absorbing material. Mass abundances and cobalt shells were observed which possibly contained hydrogen. The combination of large surface area, high atomic mobility, and hydrogen-induced Ostwald ripening resulted in a novel method to prepare various cobalt nanoparticle shapes and sizes.

Seasonal Dynamics of the Plant Community and Soil Seed Bank along a Successional Gradient in a Subalpine Meadow on the Tibetan Plateau

BackgroundKnowledge about how change the importance of soil seed bank and relationship between seed mass and abundance during vegetation succession is crucial for understanding vegetation dynamics. Many studies have been conducted, but their ecological mechanisms of community assembly are not fully understood.MethodologyWe examined the seasonal dynamics of the vegetation and soil seed bank as well as seed size distribution along a successional gradient. We also explored the potential role of the soil seed bank in plant community regeneration, the relationship between seed mass and species abundance, and the relative importance of deterministic and stochastic processes along a successional gradient.Principal FindingsSpecies richness of seed bank increased (shallow layer and the total) and seed density decreased (each layer and the total) significantly with succession. Species richness and seed density differed significantly between different seasons and among soil depths. Seed mass showed a significant negative relationship with relative abundance in the earliest successional stage, but the relationships were not significant in later stages. Seed mass showed no relationship with relative abundance in the whole successional series in seed bank. Results were similar for both July 2005 and April 2006.ConclusionsThe seed mass and abundance relationship was determined by a complex interaction between small and larger seeded species and environmental factors. Both stochastic processes and deterministic processes were important determinants of the structure of the earliest stage. The importance of seed bank decreased with succession. The restoration of abandoned farmed and grazed meadows to the species-rich subalpine meadow in Tibetan Plateau can be successfully achieved from the soil seed bank. However, at least 20 years are required to fully restore an abandoned agricultural meadow to a natural mature subalpine meadow.

A high-sensitivity ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry (UHPLC-HR-TOFMS) method for screening synthetic cannabinoids and other drugs of abuse in urine

The continuing emergence of designer drugs imposes high demands on the scope and sensitivity of toxicological drug screening procedures. An ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry (UHPLC-HR-TOFMS) method was developed for screening and simultaneous confirmation of both designer drugs and other drugs of abuse in urine samples in a single run. The method covered selected synthetic cannabinoids and cathinones, amphetamines, natural cannabinoids, opioids, cocaine and other important drugs of abuse, together with their main urinary metabolites. The database consisted of 277 compounds with molecular formula and exact monoisotopic mass; retention time was included for 192 compounds, and primary and secondary qualifier ion exact mass for 191 and 95 compounds, respectively. Following a solid-phase extraction, separation was performed by UHPLC and mass analysis by HR-TOFMS. MS, and broad-band collision-induced dissociation data were acquired at m/z range 50-700. Compound identification was based on a reverse database search with acceptance criteria for retention time, precursor ion mass accuracy, isotopic pattern and abundance of qualifier ions. Mass resolving power in spiked urine samples was on average FWHM 23,500 and mass accuracy 0.3 mDa. The mean and median cut-off concentrations determined for 75 compounds were 4.2 and 1 ng/mL, respectively. The range of cut-off concentrations for synthetic cannabinoids was 0.2-60 ng/mL and for cathinones 0.7-15 ng/mL. The method proved to combine high sensitivity and a wide scope in a manner not previously reported in drugs of abuse screening. The method's feasibility was demonstrated with 50 authentic urine samples.

VGS31b: a highly inclined ring along a filament in a void. Implication for the cold accretion

VGS31b is a highly-inclined ring galaxy found along a filament in a void (Kreckel et al. 2012). Detailed photometry, by using u, g, r, i, z SDSS images, has shown that the overall morphology of VGS31b is very tricky, due to (i) the presence of a highly inclined (72 deg) ring-like structure, which reaches the galaxy center tracing a "spiral-like" pattern, (ii) a one sided tail towards North-East and (iii) a bar in the central regions (Beygu et al. 2013). Such structure is reasonably the result of a "second event" in the evolution history of this galaxy, which could be a gravitational interaction with a companion galaxy or with the environment. The main aim of the present work is to address the most reliable formation scenario for this object, by comparing the observed properties, i.e. structure, baryonic mass, kinematics and chemical abundances, with the theoretical predictions. In particular, we have used archival spectroscopic data, to derive the metallicity in the ring: we found a very low, sub-solar average value of Z = 0.3 Zsun, comparable with other polar ring/disk galaxies, but lower than those measured for ordinary spirals of similar luminosity. The study of the chemical abundances in polar ring/disk galaxies and related objects has received an increasing attention in recent years, since it has revealed to be a key-parameter to disentangle among the formation scenarios suggested for this class of objects: major merging, tidal accretion or cold accretion. In the present work we check the cold accretion of gas through a "cosmic filament" as a possible scenario for the formation of the ring-like structure in VGS31b.

Nonlinear hydrodynamic simulations of radial pulsations in massive stars

AbstractWe investigate the radial pulsation properties of massive main-sequence stars using both linear and non-linear calculations. Using 20, 40, 60 and 85 solar-mass models evolved by Meynet et al. (1994), we calculate nonlinear hydrodynamic envelope models including the effects of time-dependent convection. Many of these models are massive enough to lose a significant amount of mass as they evolve, which also reveals more helium-rich layers. This allows us to investigate the dependence of pulsation on mass, metallicity and surface helium abundance. We find that as a model loses mass, the periods become longer relative to the period predicted by the period-mean density relation (period × $\sqrt{\overline{\rho}}$ is proportional to a constant, Q) for the initial model. Increased surface helium abundance causes a dramatic decrease in the period relative to that expected from Q, while changing the metallicity had little impact on the expected periods.

Environmental humidity and leaf-litter depth affecting ecological parameters of a leaf-litter frog community in an Atlantic Rainforest area

We studied a leaf-litter frog community from an Atlantic Rainforest area in the state of Espírito Santo, south-eastern Brazil. Frogs were sampled using 4 × 4-m plots. We recorded 348 individuals from 13 species. The estimated overall density of leaf-litter frogs in the study area was 6.6 frogs/100 m2 with an estimated overall frog biomass of 0.04 g/ha. Brachycephalus didactylus was the species with the highest estimated density and highest abundance. Five of the litter frog species recorded are considered endemic to the Atlantic Forest and two species are endemic to the state of Espírito Santo, including Euparkerella robusta, which is considered threatened as the result of habitat loss. The overall abundance of leaf litter was positively related to relative humidity and depth of the leaf litter. The relationship between frog body mass and frog abundance was significant, suggesting that a general biological trend in this relationship occurs in our study area.

Sarcoplasmic Masses in the Skeletal Muscle of a Stranded Pigmy Sperm Whale (Kogia breviceps)

We measured the abundance of sarcoplasmic masses within skeletal muscle myocytes of an adult female stranded pigmy sperm whale (Kogia breviceps). The presence of these masses in other species has been reported in association with myopathies, including myotonic dystrophy, the most frequently related pathology. Other histopathologic muscle changes included a high number of internal nuclei, variations in fiber size and shape, and the predominance of type I fibers.

Body mass and mast abundance influence foraging ecology of the American black bear (Ursus americanus) in Maine

We studied nutritional ecology of American black bears (Ursus americanus Pallas, 1780) in Maine, including active and hibernating bears during 5 years, across three study areas, using nitrogen stable isotope analyses of blood samples (n = 152). Our central finding, in two study areas, is positive correlation between body mass and δ15N. This suggests use of large body size to acquire or guard food resources that have relatively high δ15N, consistent with importance of ungulates as food for the largest bears in Maine. In these two study areas, hibernating bears across the spectrum of body mass showed greater δ15N during 2 years of beechnut (Fagus grandifolia Ehrh.) scarcity compared with 2 years of beechnut abundance. Adiposity, measured by serum leptin, was greater in hibernating bears following a season of beechnut abundance compared with one of beechnut scarcity. Total litter mass correlated positively with maternal serum leptin and negatively with maternal δ15N, supporting the importance of mast, including beechnuts, to reproductive success of bears in Maine. In the third study area, bears across the spectrum of body mass had greater δ15N in all years, consistent with food resources relatively high in15N that were available to bears of all sizes.

A slippery slope: logging alters mass–abundance scaling in ecological communities

Summary Natural ecosystems face ever‐increasing anthropogenic threats from activities such as logging. It is therefore important to: (i) understand anthropogenic impacts on key community characteristics with implications for community structure and function and (ii) identify metrics with mechanistic underpinnings, providing a more functional understanding of anthropogenic impacts on biodiversity. Mass–abundance scaling is the most fundamental property of ecological communities, with implications on energy and resource partitioning and on how species and population traits translate to community structure and function. In habitat patches representing a continuum of logging intensity, I examined the impact of logging on mass–abundance scaling in understorey bird species using mist netting and bird ringing. I used regression quantiles to estimate the slope and intercept of upper bound of the polygonal local‐scale mass–abundance relationship. I show that this slope becomes more negative (and the intercept higher) as logging intensity increases. Logging might therefore significantly alter resource and energy partitioning among species in natural communities. The mechanism underlying this pattern is likely to be an interaction between resource depletion, body size and density compensation. Larger species face more severe resource shortages from depleted resource availability and are expected to decline in abundance following logging, leading to more negative mass–abundance scaling. Density compensation by smaller species following large species decline can ‘push up’ the intercept of the mass–abundance relationship. This might result in both steeper slopes and higher intercepts in logged habitats. Synthesis and applications. This study shows for the first time that anthropogenic habitat change can alter fundamental community properties such as mass–abundance scaling and that this property of ecological communities was better at detecting logging impacts than other standard community measures. Identifying key metrics that provide a functional understanding of anthropogenic impacts on biodiversity is a crucial need, for both the assessment of these impacts and the continued monitoring of habitat change. This study highlights the need to supplement commonly used community descriptions with more mechanistic measures of human impacts on biodiversity.

SUPERNOVA EXPLOSIONS OF SUPER-ASYMPTOTIC GIANT BRANCH STARS: MULTICOLOR LIGHT CURVES OF ELECTRON-CAPTURE SUPERNOVAE

An electron-capture supernova (ECSN) is a core-collapse supernova (CCSN) explosion of a super-asymptotic giant branch (SAGB) star with a main-sequence mass $M_{\rm ms}\sim7-9.5M_\odot$. The explosion takes place in accordance with core bounce and subsequent neutrino heating and is a unique example successfully produced by first-principle simulations. This allows us to derive a first self-consistent multicolor light curves of a CCSN. Adopting the explosion properties derived by the first-principle simulation, i.e., the low explosion energy of $1.5\times10^{50}$ erg and the small $^{56}$Ni mass of $2.5\times10^{-3}M_\odot$, we perform a multigroup radiation hydrodynamics calculation of ECSNe and present multicolor light curves of ECSNe of SAGB stars with various envelope mass and hydrogen abundance. We demonstrate that a shock breakout has peak luminosity of $L\sim2\times10^{44}$ erg/s and can evaporate circumstellar dust up to $R\sim10^{17}$ cm for a case of carbon dust, that plateau luminosity and plateau duration of ECSNe are $L\sim10^{42}$ erg/s and $t\sim60-100$ days, respectively, and that a plateau is followed by a tail with a luminosity drop by $\sim4$ mag. The ECSN shows a bright and short plateau that is as bright as typical Type II plateau supernovae, and a faint tail that might be influenced by spin-down luminosity of a newborn pulsar. Furthermore, the theoretical models are compared with ECSN candidates: SN 1054 and SN 2008S. We find that SN 1054 shares the characteristics of the ECSNe. For SN 2008S, we find that its faint plateau requires an ECSN model with a significantly low explosion energy of $E\sim10^{48}$ erg.

Developing a molecular imaging agent for Met using onartuzumab (MetMAb).

11083 Background: Developing an imaging agent to assess Met expression would aid in diagnosis and monitoring tumor response to Met-targeted therapies. Onartuzumab (MetMAb), a Met selective humanized one-armed monoclonal antibody, has been studied in Phase I-II clinical trials in which it was generally well tolerated and has shown the most benefit in patients with MET positive tumors. Methods: Studies to assess Met-binding were executed using the human gastric carcinoma cell line MKN-45 which exhibits a high level of Met expression. Murine PET studies and biodistribution assays were performed using MKN-45 xenografts. Results: Plasma shed Met concentration is directly related to total tumor burden (p < 0.001). The absence of a positive correlation between shed Met and %ID in blood indicates that binding of tracer to shed Met present in plasma is unlikely. There are positive correlations between tumor mass, Met abundance, and phosphoMet content and uptake of 89Zr-df-onartuzumab in MKN-45 mouse xenografts. Lastly, tumor mass, Met, pMet and 89Zr-df-onartuzumab uptake were all significantly decreased by drug treatment. Conclusions: MKN-45 tumor uptake of 89Zr-df-onartuzumab correlated significantly with tumor mass and Met abundance. Blood tracer uptake did not positively correlate with the presence of plasma shed Met. The amounts of Met, pMet, as well as 89Zr-df-onartuzumab image intensity correlated significantly with tumor size (all Spearman p values < 0.001).Tumor volumes and Met content were significantly decreased in TKI treated versus control mice, which correlated with imaging results.89Zr-df-onartuzumab has potential utility for imaging Met to identify patients for treatment with Met-targeted therapeutics and to identify the emergence of Met-driven acquired resistance to other molecularly targeted cancer therapies.

Sex-biased parasitism is not universal: evidence from rodent–flea associations from three biomes

The distribution of parasites among individual hosts is characterised by high variability that is believed to be a result of variations in host traits. To find general patterns of host traits affecting parasite abundance, we studied flea infestation of nine rodent species from three different biomes (temperate zone of central Europe, desert of Middle East and tropics of East Africa). We tested for independent and interactive effects of host sex and body mass on the number of fleas harboured by an individual host while accounting for spatial clustering of host and parasite sampling and temporal variation. We found no consistent patterns of the effect of host sex and body mass on flea abundance either among species within a biome or among biomes. We found evidence for sex-biased flea infestation in just five host species (Apodemus agrarius, Myodes glareolus, Microtus arvalis, Gerbillus andersoni, Mastomys natalensis). In six rodent species, we found an effect of body mass on flea abundance (all species mentioned above and Meriones crassus). This effect was positive in five species and negative in one species (Microtus arvalis). In M. glareolus, G. andersoni, M. natalensis, and M. arvalis, the relationship between body mass and flea abundance was mediated by host sex. This was manifested in steeper change in flea abundance with increasing body mass in male than female individuals (M. glareolus, G. andersoni, M. natalensis), whereas the opposite pattern was found in M. arvalis. Our findings suggest that sex and body mass are common determinants of parasite infestation in mammalian hosts, but neither of them follows universal rules. This implies that the effect of host individual characteristics on mechanisms responsible for flea acquisition may be manifested differently in different host species.

A SILAC-based Approach Identifies Substrates of Caspase-dependent Cleavage upon TRAIL-induced Apoptosis

The extracellular ligand-induced extrinsic pathway of apoptosis is executed via caspase protease cascades that activate downstream effectors by means of site-directed proteolysis. Here we identify proteome changes upon the induction of apoptosis by the cytokine tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) in a Jurkat T cell line. We detected caspase-dependent cleavage substrates by quantifying protein intensities before and after TRAIL induction in SDS gel slices. Apoptotic protein cleavage events are identified by a characteristic stable isotope labeling with amino acids in cell culture (SILAC) ratio pattern across gel slices that results from differential migration of the cleaved and uncleaved proteins. We applied a statistical test to define apoptotic substrates in the proteome. Our approach identified more than 650 of these cleaved proteins in response to TRAIL-induced apoptosis, including many previously unknown substrates and cleavage sites. Inhibitor treatment combined with triple SILAC demonstrated that the detected cleavage events were caspase dependent. Proteins located in the lumina of organelles such as mitochondria and endoplasmic reticulum were significantly underrepresented in the substrate population. Interestingly, caspase cleavage is generally observed in not only one but several members of stable complexes, but often with lower stoichiometry. For instance, all five proteins of the condensin I complex were cleaved upon TRAIL treatment. The apoptotic substrate proteome data can be accessed and visualized in the MaxQB database and might prove useful for basic and clinical research into TRAIL-induced apoptosis. The technology described here is extensible to a wide range of other proteolytic cleavage events.

Saturn layered structure and homogeneous evolution models with different EOSs

The core mass of Saturn is commonly assumed to be 10–25M⊕ as predicted by interior models with various equations of state (EOSs) and the Voyager gravity data, and hence larger than that of Jupiter (0–10M⊕). We here re-analyze Saturn’s internal structure and evolution by using more recent gravity data from the Cassini mission and different physical equations of state: the ab initio LM-REOS which is rather soft in Saturn’s outer regions but stiff at high pressures, the standard Sesame-EOS which shows the opposite behavior, and the commonly used SCvH-i EOS. For all three EOS we find similar core mass ranges, i.e. of 0–20M⊕ for SCvH-i and Sesame EOS and of 0–17M⊕ for LM-REOS. Assuming an atmospheric helium mass abundance of 18%, we find maximum atmospheric metallicities, Zatm of 7× solar for SCvH-i and Sesame-based models and a total mass of heavy elements, MZ of 25–30M⊕. Some models are Jupiter-like. With LM-REOS, we find MZ=16–20M⊕, less than for Jupiter, and Zatm≲3× solar. For Saturn, we compute moment of inertia values λ=0.2355(5). Furthermore, we confirm that homogeneous evolution leads to cooling times of only ∼2.5Gyr, independent on the applied EOS. Our results demonstrate the need for accurately measured atmospheric helium and oxygen abundances, and of the moment of inertia for a better understanding of Saturn’s structure and evolution.

Using mass scaling of movement cost and resource encounter rate to predict animal body size–Population density relationships

The negative relationship between body mass and population abundance was documented decades ago and forms one of the most fundamental scaling-laws in ecology. However, current theory fails to capture observed variations and the subject continues to raise controversy. Here we unify empirically observed size–abundance relationships with theory, by incorporating allometries in resource encounter rate and metabolic costs of movements. Fractal geometry is used to quantify the underlying resources distributions. Our model predicts that in environments packed with resources, body mass to population abundance relationships is less negative than the commonly assumed −3/4 power law. When resources are more patchily distributed, we predict a more negative exponent. These predictions are consistent with empirical observations. The current research provides an important step towards synthesizing metabolism, resource distribution and the global scaling of animal abundance, explaining why size–abundance relationships vary among feeding guilds and ecosystems.

Analysis of iridoid glucosides from Paederia scandens using HPLC–ESI-MS/MS

Iridoid glycosides are an important class of natural products and have many biological activities. Iridoid glucosides in an extract of the plant species Paederia scandens were investigated using reversed-phase high performance liquid chromatography and electrospray quadrupole time-of-flight-type tandem mass spectrometry. The elemental composition of most of the compounds was determined by accurate mass and relative isotopic abundance (RIA) measurements. In positive ion mode, the fragmentation of [M+NH4](+) precursor ions was carried out using low energy collision-induced electrospray ionization tandem spectrometry. The neutral losses of NH3, H2O, Glc, and the side chain of the iridoid moiety were the main fragmentation patterns observed. For simple iridoid glycosides, the main differences were related to the side chains. Fragmentation of the [M-H](-)precursor ions was achieved for the compounds possibly having phenolic acid group. The connection order of the iridoid, sugar, and phenolic acid moieties, and the linkage of the 6-OH group of the sugar to the phenolic acid were unambiguously confirmed using a combination of MS/MS spectra in both positive and negative ion modes, and our previous work. For some trace dimeric iridoid glucosides, the connection order between the asperuloside and paederoside moieties was determined by the characteristic product ions; this was supported by D-labeling experiments. A total of 24 iridoid glucosides, including 14 new species, were identified or tentatively characterized based on exact mass, RIA values, tandem mass spectra, and D-labeling experiments.

Exceptional preservation of microbial lipids in Paleozoic to Mesoproterozoic sediments

Exceptional preservation of microbial lipids in Paleozoic to Mesoproterozoic sediments

Ecological correlates of body size in gamasid mites parasitic on small mammals: abundance and niche breadth

We studied ecological correlates of body size (abundance and niche breadth) in gamasid mites parasitic on small mammals in 28 regions of the Palearctic. We predicted that smaller species would be characterized by higher abundance than larger species, all else (e.g. host species) being equal. We also predicted that host specificity of mites would decrease (that is, number of host species they use would increase) with an increase in their body size. We focused on mites collected from host bodies that include a) species that feed solely on host’s blood (obligate exclusive haematophages), b) species that feed on both host’s blood and small arthropods (obligate non‐exclusive haematophages), and c) facultative haematophages. We expected that the relationship between body size and abundance and/or host specificity would be more pronounced in obligate exclusively haematophagous mites than for obligate non‐exclusively and facultative haematophagous mites. Across all mite species across regions, mean abundance correlated negatively with body size. The same was true for obligate haematophagous species, but not for facultative haematophages. When mite communities on the same host in a location were considered, the negative body mass–abundance relationship was found in only 3 of 44 communities. Nevertheless, a meta‐analytic (across host species) estimate of the slope of this relationship appeared to be significantly negative. No significant relationship between mite body size and host specificity was found in the analyses across all mite species as well as in obligate exclusive or obligate non‐exclusive haematophages. However, the number of hosts used by facultative haematophagous mites decreased significantly with an increase in their body size. We explain the relationships between morphological (body size) and ecological (abundance and niche breadth) properties of ectoparasites by their interactions with hosts or physical environment.