Do dingoes suppress the activity of feral cats in northern Australia?

Large predators can have profound impacts on community composition. Not only do they directly affect prey abundance, they also indirectly affect prey abundance through their direct effects on smaller predators. In Australia, dingoes fill the role of a large predator and, in southern Australia, have clear impacts on introduced foxes. Their effect on introduced cats, however, is less clear. Here we present data from multiple sites across northern Australia (where foxes are absent), which reveal a negative correlation between cat and dingo activity. This relationship could arise because cats avoid areas where dingoes are active, or because cats are less abundant in areas with high dingo densities, or a combination of both. At a subset of our study sites, we experimentally reduced dingo (but not cat) abundance by poison baiting. This resulted in a 55% drop in dingo activity within 4 weeks of baiting, but without a compensatory increase in cat activity. This suggests the negative correlation between cat and dingo activity is not a simple consequence of cats reactively avoiding areas with higher dingo traffic, but rather, that there are fewer cats in areas where dingoes are more active. This study is a rare demonstration of the potential for dingoes to affect the behaviour and potentially the population size of feral cats, and therefore reduce the impact of feral cats on vulnerable native prey species.     

Antarctic DNA barcoding; a drop in the ocean?

Coordinated, circum-Antarctic sampling expeditions during International Polar Year 2008/09 have given access to comprehensive collections suitable for DNA barcoding. Collaborations between the Census of Antarctic Marine Life (CAML), the Marine Barcode of Life project and the Canadian Centre for DNA Barcoding have enabled the Antarctic scientific community to initiate large-scale DNA barcoding projects to record the genetic diversity of Antarctic marine fauna, coordinated by the CAML Barcoding Campaign. A total of 20,355 marine specimens from more than 2,000 morphospecies covering 18 phyla are in the processing pipeline, and to date, 11,530 sequences have been processed with the remainder due by the end of 2010. Here, we present results on the current geographic and taxonomic coverage of DNA barcode data in the Southern Ocean and identify the remaining gaps. We show how DNA barcoding in the Antarctic is answering important questions regarding marine genetic diversity and challenging current assumptions of species distribution at the poles.     

Dispersal and divergence across the greatest ocean region: Do larvae matter?

For marine, benthic animals, duration of planktonic larval stagesis expected to correlate with dispersal ability, and thus speciesranges, at least where planktonic dispersal is necessary toreach habitats. Yet past analyses of larval duration and speciesranges across the insular Pacific show at most a weak correlation.So, do larvae matter in determining species ranges in such anisland setting? We analyze an extensive dataset on cowries andfind, again, that estimated larval duration does not correlatewith species ranges. Several factors can obscure a real correlation,however, including estimation error, intraspecific variation,other factors affecting dispersal, poor taxonomy, and remoteendemics. We show that taking these into consideration greatlyimproves correlation. Further evidence for the importance oflarval duration comes from diversity and speciation patterns.Diversity of poor dispersers drops more rapidly eastward acrossthe Pacific and leads to taxonomic differences in communitycomposition across the basin. Geographic scale of differentiationis strongly influenced by larval duration and leads to the mostrapid diversification at intermediate dispersal capacities.A major lesson from the phylogenetically corrected cowrie datasetis that without accurate and appropriate taxonomy, clear andimportant distributional and diversity patterns can become obscured.Inappropriate taxonomic scale can also obscure macroecologicalpatterns: cowrie tribes/subfamilies show substantial variationin the steepness of their diversity cline across the Pacificand in their proportional local abundance, showing the importanceof ecological traits in controlling distributions. In contrastsuch variation was not evident in a study focused at the familylevel in corals and fishes.     

Are copepods important grazers of the spring phytoplankton bloom in the western Irish Sea?

The spring phytoplankton bloom and copepod grazing were studied at a coastal and offshore station in the western Irish Sea during 1997. Maximum chlorophyll standing stocks of 132.8 mg m^-2 inshore and 199.4 mg m^-2 offshore were measured in late April. At that time, mean water column temperatures were 10 and 8C at the coastal and offshore station, respectively. Spring bloom production at the coastal station was estimated as 31.2 g C m^-2 and was dominated by the diatom Guinardia delicatula. Offshore, production was 28.2 g C m^-2 and the bloom was composed of small (10 m) phytoflagellates and the silicoflagellate Dictyocha speculum. Maximum copepod abundance (189 and 544 x 10³ individuals m^-2, inshore and offshore, respectively) coincided with the spring bloom. Pseudocalanus and Temora ingestion rates were derived from measurements of gut pigment fluorescence, and were found to vary during the course of the spring bloom as a result of changes in gut content. Grazing by late copepodite and adult Pseudocalanus and Temora was variable inshore, but overall accounted for 17% of bloom production. Offshore, 22% of bloom production was grazed with maximum grazing (76% of daily production) occurring at the end of the bloom. Large copepod species were not major grazers of the spring bloom. Greater utilization of spring bloom production by copepods in the western Irish Sea compared to regions of the North Sea is attributed to differences in population size at the time of the bloom.      

Carbon or nitrogen limitation in marine copepods?

The elemental limitation of copepod production can be studiedusing stoichiometric models, which balance carbon (C) and nitrogen(N) in ingested food and predator biomass, and assume that theelement in shortest supply is used as efficiently as possible.A model of this type was developed which has two important features:(i) it is assumed that a maximum N net production efficiencyof 1.0 is possible, although assimilation of N may be <1.0;and (ii) assimilation of C in the gut is handled by dividingfood into biochemical compounds. Model results suggested thatmarine copepods should commonly be limited by C, owing to theirlow C net production efficiency, and the low food C:N ratiostypical of the upper ocean. Nevertheless, the work demonstratedthat copepods might still preferentially ingest protein-richprey to maximize production because the associated C is easilyassimilated. A comparison of model predictions with two experimentalstudies, however, revealed that in the studies copepods werenot utilizing N as efficiently as would be expected by stoichiometrictheory. This finding suggests that copepod nutrition is morecomplicated than simple elemental limitation by C or N: imbalancesof specific compounds, such as essential amino acids, may becontrolling production. In addition, the nutritional requirementsof copepods may vary on a seasonal basis in a complex manner.     

Do we need nasal vaccines against COVID 19 to suppress the transmission of infections?

Covid-19 vaccines have within the first year prevented about 14 million deaths but did not induce a strong mucosal immune response. Data from US, UK, Singapore and Israel showed a variable and mostly modest effects of vaccination on virus excretion during breakthrough infections. Contact studies showed decreased transmission of infection from vaccinated index cases, but the effect varied according to dominant virus type, with study type and the nature of the contact group and diminished with time after vaccination. Some researchers suspect that it is unlikely to stop the pandemic with injected vaccines alone. Promising animal experiments were conducted with mucosal vaccines. Mice nasally immunized with a chimpanzee adenovirus vector mounted a mucosal immune response, were protected against viral challenge after a single vaccine dose and suppressed nasal replication of the challenge virus. Phage T4 expressing SARS-CoV-2 spike and nucleocapsid induced a sterilizing lung immunity in nasally vaccinated mice. Also hamsters intranasally immunized with the prefusion-stabilized spike protein showed no infectious virus in nasal turbinates upon challenge. Other studies showed that intranasal vaccination with an adenovirus vaccine reduced but did not eliminated viral transmission from infected to naïve hamsters. Intranasal vaccination of rhesus macaques with adenovirus vaccines also substantially reduced or even suppressed viral replication in the upper and lower respiratory tract. Human data on mucosal SARS-CoV-2 vaccines are so far limited to safety and immunogenicity studies. Aerosolized adenovirus vaccines given either as a booster or as primary immunization were safe and induced similar or superior immune response than injected vaccines while an aerosolized influenza vectored vaccine induced only a weak humoral and cellular immune response. Overall 100 mucosal SARS-CoV-2 vaccines are in development and 20 are in clinical trials. First human trials demonstrate that this will not be an easy task.     

How are the vertical migrations of copepods controlled?

Using Calanus finmarchicus (Gunnerus) as a model organism, a hypothesis is suggested to explain the diel and seasonal vertical migrations of herbivorous copepods in boreal and polar waters. The hypothesis is based on the following assumptions. Hungry copepods are assumed to react to food smell by increased swimming. High lipid content is assumed to turn the copepods upside down. Light avoidance is assumed to operate solely while the copepods are satiated. The following three major peaks in downflux of phytoplankton remains are assumed to reach 1000 m depth or more: pre- and post-spring bloom peaks and the autumn increase. A minor “afternoon peak” in short-range downflux of phytoplankton is also assumed to exist. The assumptions are used to explain the following main traits in copepod migrations. The afternoon increase in downflux of phytoplankton material induces upward swimming of hungry copepods. If satiated, light avoidance brings them down again at dawn. The late stages of many species of copepods accumulate large amounts of lipids and if the above assumptions are valid, they will be turned upside down and swim down if activated. During midsummer, the downflux does not reach deep water and the copepods are assumed to spend some time in midwater until they moult. Copepods moulting from stage V into female adults use up to half of their lipids to produce eggs, which are more anteriorly located. This is assumed to turn their bodies back into an upright position and the copepods are assumed to swim up to the surface again when they smell sinking phytoplankton remains. Fat copepods are assumed to follow the downflux of phytoplankton material down to diapause depths, especially at the end of the spring bloom and in autumn. It is assumed that enough lipids are used up during the diapause to turn the copepods into head-up position again. The smell of fast-sinking fecal pellets containing prebloom phytoplankton is assumed to bring the copepods up from diapause again in late winter. The probable implications for the survival of cod larvae are discussed.     

Flowering and fruiting phenology in the coastal shrublands of Doñana,south Spain

Flowering and fruiting phenological patterns at the individual-, population-, and community level were studied in a southern Spanish scrub community composed of 30 shrub species. Few individuals of any species produced a high number of flowers. Intrapopulation deviation in the peak time of flowering showed a strong and positive skewness. Relative flowering duration, however, displayed a virtually normal distribution. Generally, species flowering in spring have a short flowering time, while species flowering earlier or later in the year show significantly longer flowering periods. Species were in bloom throughout the year, but there was a major peak during spring and two lesser ones in autumn and early summer. Shallow rooting taxa in typically mediterranean genera displayed a strategy of spring flowering and summer fruiting. Summer and autumn flowering occurred among heath-like shrubs of relatively wet places, and forest-associated, vertebrate-dispersed species which commonly have underground storage organs. Species with ripe fruits presented two peaks, the major one during the summer including the majority of taxa with seeds dispersed by non-vertebrate agents. There was a minor fruiting peak in autumn dominated by taxa that rely on vertebrates for dispersal. The complex seasonal patterns observed are interpreted in relation to environmental conditions and physiological constraints on species living in a highly seasonal climate.     

Have we been underestimating the effects of ocean acidification in zooplankton?

Understanding how copepods may respond to ocean acidification (OA) is critical for risk assessments of ocean ecology and biogeochemistry. The perception that copepods are insensitive to OA is largely based on experiments with adult females. Their apparent resilience to increased carbon dioxide (pCO₂) concentrations has supported the view that copepods are ‘winners’ under OA. Here, we show that this conclusion is not robust, that sensitivity across different life stages is significantly misrepresented by studies solely using adult females. Stage‐specific responses to pCO₂ (385–6000 μatm) were studied across different life stages of a calanoid copepod, monitoring for lethal and sublethal responses. Mortality rates varied significantly across the different life stages, with nauplii showing the highest lethal effects; nauplii mortality rates increased threefold when pCO₂ concentrations reached 1000 μatm (year 2100 scenario) with LC₅₀ at 1084 μatm pCO₂. In comparison, eggs, early copepodite stages, and adult males and females were not affected lethally until pCO₂ concentrations ≥3000 μatm. Adverse effects on reproduction were found, with >35% decline in nauplii recruitment at 1000 μatm pCO₂. This suppression of reproductive scope, coupled with the decreased survival of early stage progeny at this pCO₂ concentration, has clear potential to damage population growth dynamics in this species. The disparity in responses seen across the different developmental stages emphasizes the need for a holistic life‐cycle approach to make species‐level projections to climate change. Significant misrepresentation and error propagation can develop from studies which attempt to project outcomes to future OA conditions solely based on single life history stage exposures.     

Marine chitinolytic enzymes,a biotechnological treasure hidden in the ocean?

Applied Microbiology and Biotechnology - Chitinolytic enzymes are capable to catalyze the chitin hydrolysis. Due to their biomedical and biotechnological applications, nowadays chitinolytic enzymes...     

Where Do the Eyes Really Go in the Hollow-Face Illusion?

The hollow-face illusion refers to the finding that people typically perceive a concave (hollow) mask as being convex, despite the presence of binocular disparity cues that indicate the contrary. Unlike other illusions of depth, recent research has suggested that the eyes tend to converge at perceived, rather than actual, depths. However, technical and methodological limitations prevented one from knowing whether disparity cues may still have influenced vergence. In the current study, we presented participants with virtual normal or hollow masks and asked them to fixate the tip of the face's nose until they had indicated whether they perceived it as pointing towards or away from them. The results showed that the direction of vergence was indeed determined by perceived depth, although vergence responses were both somewhat delayed and of smaller amplitude (by a factor of about 0.5) for concave than convex masks. These findings demonstrate how perceived depth can override disparity cues when it comes to vergence, albeit not entirely.     

Deconstructing latitudinal species richness patterns in the ocean: does larval development hold the clue?

The consistent decrease in species richness with latitude shows several exceptions among marine organisms. We hypothesize that contrasting latitudinal diversity gradients can be explained by differences in critical life-history attributes, such as mode of larval development (MLD). We deconstructed latitudinal species richness patterns of marine benthic invertebrates according to MLD to elucidate differences in patterns of species richness and to reveal underlying processes. The patterns of species richness were remarkably similar across taxa within MLD but differed between MLD. Species richness decreased polewards in planktotrophic species and increased in direct developers. Temperature explained most of the variation in species richness. Low temperature at high latitudes may generally favour direct developing species, but, together with low chlorophyll- a concentration, limit the distribution of planktotrophic species. The contrasting influence of temperature on different MLDs might be explained by its effect on the length of planktonic life and on brooding costs.     

Do Hormones in Milk Affect the Function of the Neonatal Intestine?

The presence of a number of peptide hormones and other biologicallyactive peptides (BAP) in the milk of various species, togetherwith the low proteolytic activity in the gastrointestinal tractof newborns and "permeability" for macromolecules, suggeststheirpotential significance for the neonate I review the presence of hormones and other biologically activepeptides (BAP) in milks of various species. Furthermore, I summarizedata demonstrating the effects of orogastrically administeredBAP with special attention to epidermal growth factor.     

Do rural impoundments in coastal Bay of Fundy,Canada sustain adequate habitat for wildlife?

In Canada and elsewhere in North America, impoundments are created in compensation for historic wetland loss and for habitat loss due to development projects, but these new sites are infrequently evaluated to determine how effectively they function. The Cumberland Marsh Region (CMR), located at the head of the Bay of Fundy, Canada, is of importance to migratory birds and has been subject to 300+ years of anthropogenic alteration, including impoundment creation on diked and drained tidal marsh in the last five decades. Wetland managers have noticed a pervasive decline in impoundment productivity leading to reduced waterbird usage (senescence). To understand factors that promote senescence, we analyzed abiotic and biotic proxies in sediment archives from six freshwater impoundments in two coastal watersheds to assess spatial trends across the CMR within recent decades. Our results demonstrate that impoundment productivity is driven by autochthonous nutrient sources (C/N between 7.7 and 14.4), but biogeochemical conditions can be highly variable among impoundments despite their proximity. Biogeochemical variation among top-of-core sediment samples from each impoundment was generally minimal, and thus we believe that the aging of impoundments has resulted in low productivity and organic matter accumulation due to dike stabilization and declines in nutrient loading. We conclude that these freshwater impoundments (in the CMR and likely other similar settings) are not highly productive, and may not provide abundant forage and optimal wildlife habitat which is expected of these systems; adaptive management strategies and hydrologic rehabilitation merit consideration to enhance ecological functioning. Understanding landscape attributes, hydrologic dynamics, and conditions prior to and after major human alterations should be a priority in future compensation projects.     

Do neurons in the vertebrate CNS migrate on laminin?

In adult rat brain the extracellular matrix glycoprotein, laminin, is found only in basement membranes, but is transiently expressed by astrocytes after brain injury. Here, I show that laminin also appears in immature brain cells during CNS development, and that its presence coincides with phases of neuronal migration. In early embryos, laminin is seen throughout the whole thickness of the forming brain, and is apparently synthesized by the cells, as judged by its intracytoplasmic localization. As development proceeds, intracellular laminin becomes restricted to the periventricular regions while punctate deposits of laminin follow the course of vimentin-positive radial glial fibers. In most brain regions, the adult pattern of laminin expression is achieved by birth. In the post-natal rat cerebellum, however, laminin is detected in external granule cells, in Purkinje cells, and in punctate deposits along the radial Bergmann glial fibers. By day 24 after birth, when the migration of external granule cells is complete, all laminin immunoreactivity disappears from these structures. The transient expression of laminin in regions where neurons are migrating raises the possibility that laminin plays a role in neuronal migration during CNS development.     

Do Markets Worsen Economic Inequalities? Kuznets in the Bush

Integration into a market economy or economic development can erode the quality of life of indigenous people by, for example, increasing income inequalities. The Kuznets hypothesis predicts that the link between income inequality and income (a proxy for economic development) resembles an inverted U. We test the hypothesis using a survey of 511 households from 59 villages of Tsimane' Amerindians, a horticultural-foraging society in the tropical rain forest of Bolivia. We measure village inequalities of three economic outcomes: income, imputed annual value of rice production, and wealth. We used three indices of inequality: the coefficient of variation, the standard deviation of the logarithm, and the Gini coefficient. Explanatory variables include either income and income squared, wealth and wealth squared, or imputed annual rice production and production squared. We used village-to-town distance as a control. We find little evidence that integration to the market increases inequalities of economic outcomes, with two exceptions: Wealth bore the predicted inverted U-shaped relation with wealth inequalities, and imputed rice production bore a U-shaped relation to inequality, but only when (a) using adult equivalents to express household size and (b) the Gini coefficient and the coefficient of variation to measure inequality; in no case were results robust to different econometric specifications. We advance several explanations for why economic development might not accentuate economic inequalities among relatively autarkic rural economies.     

Do the beneficial fungi manage phytosanitary problems in the tea agro-ecosystem?

BioControl - In recent years, Fungal Biocontrol Agents (FBCAs) have played a significant role in the biological control of pests and plant pathogens of several economically important crops,...     

How Do Alien Plants Fit in the Space-Phylogeny Matrix?

Recent advances in the field of plant community phylogenetics and invasion phylogenetics are mostly based on plot-level data, which do not take into consideration the spatial arrangement of individual plants within the plot. Here we use within-plot plant coordinates to investigate the link between the physical distance separating plants, and their phylogenetic relatedness. We look at two vegetation types (forest and grassland, similar in species richness and in the proportion of alien invasive plants) in subtropical coastal KwaZulu-Natal, South Africa. The relationship between phylogenetic distance and physical distance is weak in grassland (characterised by higher plant densities and low phylogenetic diversity), and varies substantially in forest vegetation (variable plant density, higher phylogenetic diversity). There is no significant relationship between the proportion of alien plants in the plots and the strength of the physical-phylogenetic distance relationship, suggesting that alien plants are well integrated in the local spatial-phylogenetic landscape.