Hemispheric asymmetries in biodiversity: a serious matter for ecology

[FIRST PARAGRAPH] Penguins have been receiving a lot of bad press lately. They are considered somehow counter, spare, strange. Unlike most plant and animal groups, they do not show a peak of species richness towards the equator and a decline towards the poles. This more conventional spatial pattern is conveniently known as the latitudinal diversity gradient because of the strong covariance of richness and other measures of biodiversity that it describes. It is one of the most venerable, well-documented, and controversial large-scale patterns in macroecology (Willig et al. 2003). Equatorial peaks in species richness have characterised the planet since the Devonian (408–362 million years ago) (Crame 2001) and are typical of a wide range of both terrestrial and marine plants and animals (Gaston 1996; Willig et al. 2003). Despite the fact that this pattern has been documented since the late 1700s, sustained interest in both the regularity of the pattern and its likely underlying mechanisms is relatively modern. The realisation that human activity is posing substantial threats to biodiversity has quickened the pace of this interest (Willig et al. 2003). Where the peaks in richness lie (biodiversity hotspots), how these peaks relate to centres of endemism (areas that support large numbers of species that occur nowhere else), and how these patterns are likely to change through time, especially in the face of major environmental change, are major concerns. Without such knowledge, conservation is unlikely to succeed

Rapid cold-hardening in a Karoo beetle, Afrinus sp.

In the insect rapid cold-hardening response, survival at subzero temperatures is greatly improved by a brief pre-exposure at a milder temperature. It is predicted that insects with minimal cold tolerance capabilities living in variable environments should use rapid cold-hardening to survive sudden cold snaps. This is tested in Afrinus sp., a beetle that lives in an exposed habitat on rock outcrops in the Karoo Desert, South Africa, where microclimate temperatures drop infrequently to below freezing. Afrinus sp. shows a significant rapid cold-hardening response: survival of a 2-h exposure to -6.5°C is much improved after pre-exposure to -2°C, to 0°C with a 2-h return to the rearing temperature, and to 40°C, but not after pre-exposure to 0°C. Little is known about the mechanism of the rapid cold-hardening response, although the data suggest that rapid coldhardening may be mediated via several different mechanisms.Centre of Excellence for Invasion Biolog

Constraint and competition in assemblages: a cross continental and modeling approach for ants

The mechanisms leading to structure in local assemblages are controversial. On the one hand, assemblage structure is thought to be the outcome of local interactions determined by the properties of species and their responses to the local environment. Alternatively, this structure has been shown to be an emergent property of assemblages of identical individuals or of random sampling of a regional assemblage. In ants at baits, a combination of environmental stress and interspecific competition is widely held to lead to a unimodal relationship between the abundance of dominant ants and species richness. It is thought that in comparatively adverse environments, both abundance and richness are low. As habitats become more favorable, abundance increases until the abundance of dominant ants is so high that they exclude those that are subordinate and so depress richness. Here we demonstrate empirically that this relationship is remarkably similar across three continents. Using a null model approach, we then show that the ascending part of the relationship is largely constrained to take this form not simply as a consequence of stress but also as a result of the shape of abundance frequency distributions. While the form of the species-abundance frequency distribution can also produce the descending part of the relationship, interspecific competition might lead to it too. Scatter about the relationship, which is generally not discussed in the literature, may well be a consequence of resource availability and environmental patchiness. Our results draw attention to the significance of regional processes in structuring ant assemblages

Positive selection in glycolysis among Australasian stick insects

Background: The glycolytic pathway is central to cellular energy production. Selection on individual enzymes within glycolysis, particularly phosphoglucose isomerase (Pgi), has been associated with metabolic performance in numerous organisms. Nonetheless, how whole energy-producing pathways evolve to allow organisms to thrive in different environments and adopt new lifestyles remains little explored. The Lanceocercata radiation of Australasian stick insects includes transitions from tropical to temperate climates, lowland to alpine habitats, and winged to wingless forms. This permits a broad investigation to determine which steps within glycolysis and what sites within enzymes are the targets of positive selection. To address these questions we obtained transcript sequences from seven core glycolysis enzymes, including two Pgi paralogues, from 29 Lanceocercata species. Results: Using maximum likelihood methods a signature of positive selection was inferred in two core glycolysis enzymes. Pgi and Glyceraldehyde 3-phosphate dehydrogenase (Gaphd) genes both encode enzymes linking glycolysis to the pentose phosphate pathway. Positive selection among Pgi paralogues and orthologues predominately targets amino acids with residues exposed to the protein’s surface, where changes in physical properties may alter enzyme performance. Conclusion: Our results suggest that, for Lancerocercata stick insects, adaptation to new stressful lifestyles requires a balance between maintaining cellular energy production, efficiently exploiting different energy storage pools and compensating for stress-induced oxidative damag

New Genus and First Record of Hybotinae (Diptera: Empidoidea: Hybotidae) in Middle Miocene Dominican Amber.

A new fossil genus of the family Hybotidae is described, based on male and female specimens. The new genus is monotypic: Syneproctus caridadi gen. et sp. nov. It belongs to the subfamily Hybotinae and shares some characters with the extant genera Syneches Walker, 1852, Stenoproctus Loew, 1858 and Chillcottomyia Saigusa, 1986; however, the differences, principally in the wing venation (shortened cua cell, horizontal m-cu crossvein) and sclerotized mouthparts, support the description of a new genus. This is the first description of a new taxon of the subfamily Hybotinae from specimens preserved in Dominican amber

Further support for thermal ecosystem engineering by wandering albatross

On sub-Antarctic Marion Island, wandering albatross (Diomedea exulans) nests support high abundances of tineid moth, Pringleophaga marioni, caterpillars. Previous work proposed that the birds serve as thermal ecosystem engineers by elevating nest temperatures relative to ambient, thereby promoting growth and survival of the caterpillars. However, only 17 days of temperature data were presented previously, despite year-long nest occupation by birds. Previous sampling was also restricted to old and recently failed nests, though nests from which chicks have recently fledged are key to understanding how the engineering effect is realized. Here we build on previous work by providing nest temperature data for a full year and by sampling all three nest types. For the full duration of nest occupancy, temperatures within occupied nests are significantly higher, consistently by c. 7°C, than those in surrounding soils and abandoned nests, declining noticeably when chicks fledge. Caterpillar abundance is significantly higher in new nests compared to nests from which chicks have fledged, which in turn have higher caterpillar abundances than old nests. Combined with recent information on the life history of P. marioni, our data suggest that caterpillars are incidentally added to the nests during nest construction, and subsequently benefit from an engineering effect

Fingertip whole blood as an indicator of omega-3 long-chain polyunsaturated fatty acid changes during dose-response supplementation in women: comparison with plasma and erythrocyte fatty acids

The sensitivity of fingertip whole blood to reflect habitual dietary and dose-dependent supplemental omega-3 long-chain polyunsaturated fatty acid (n-3 LCPUFA) intake in premenopausal women was compared to that of venous erythrocytes and plasma fatty acids. Samples were obtained from women in a randomised, double-blind, placebo-controlled trial in which premenopausal women (n = 53) were supplemented with DHA-rich tuna oil capsules and/or placebo (Sunola oil) capsules (6 capsules per day) for 8 weeks to achieve doses of either 0, 0.35, 0.7 or 1.05 g/day n-3 LCPUFA. All blood biomarkers were very similar in their ability to reflect dietary n-3 LCPUFA intake (r = 0.38–0.46 for EPA and DHA intake), and in their dose-dependent increases in n-3 LCPUFA levels after supplementation (R2 = 0.41–0.51 for dose effect on biomarker EPA and DHA levels (mol %)). Fingertip whole blood is an effective alternative to erythrocytes and plasma as a biomarker n-3 LCPUFA intake in premenopausal women.Barbara J. Meyer, Cassandra Sparkes, Andrew J. Sinclair, Robert A. Gibson and Paul L. Els

Real-time measurement of metabolic rate during freezing and thawing of the wood frog, Rana sylvatica: Implications for overwinter energy use

Ectotherms overwintering in temperate ecosystems must survive low temperatures while conserving energy to fuel post-winter reproduction. Freeze-tolerant wood frogs, Rana sylvatica, have an active response to the initiation of ice formation that includes mobilising glucose from glycogen and circulating it around the body to act as a cryoprotectant. We used flow-through respirometry to measure CO2 production (VCO2) in real time during cooling, freezing and thawing. CO2 production increases sharply at three points during freeze-thaw: at +1°C during cooling prior to ice formation (total of 104±17 μl CO2 frog-1 event-1), at the initiation of freezing (565±85 μl CO 2 frog-1 freezing event-1) and after the frog has thawed (564±75 μl CO2 frog-1 freezing event-1). We interpret these increases in metabolic rate to represent the energetic costs of preparation for freezing, the response to freezing and the re-establishment of homeostasis and repair of damage after thawing, respectively. We assumed that frogs metabolise lipid when unfrozen and that carbohydrate fuels metabolism during cooling, freezing and thawing, and when frozen. We then used microclimate temperature data to predict overwinter energetics of wood frogs. Based on the freezing and melting points we measured, frogs in the field were predicted to experience as many as 23 freeze-thaw cycles in the winter of our microclimate recordings. Overwinter carbohydrate consumption appears to be driven by the frequency of freeze-thaw events, and changes in overwinter climate that affect the frequency of freeze-thaw will influence carbohydrate consumption, but changes that affect mean temperatures and the frequency of winter warm spells will modify lipid consumption

Scale issues in soil moisture modelling: problems and prospects

Soil moisture storage is an important component of the hydrological cycle and plays a key role in land-surface-atmosphere interaction. The soil-moisture storage equation in this study considers precipitation as an input and soil moisture as a residual term for runoff and evapotranspiration. A number of models have been developed to estimate soil moisture storage and the components of the soil-moisture storage equation. A detailed discussion of the impli cation of the scale of application of these models reports that it is not possible to extrapolate processes and their estimates from the small to the large scale. It is also noted that physically based models for small-scale applications are sufficiently detailed to reproduce land-surface- atmosphere interactions. On the other hand, models for large-scale applications oversimplify the processes. Recently developed physically based models for large-scale applications can only be applied to limited uses because of data restrictions and the problems associated with land surface characterization. It is reported that remote sensing can play an important role in over coming the problems related to the unavailability of data and the land surface characterization of large-scale applications of these physically based models when estimating soil moisture storage.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

History and Applications of Dust Devil Studies

Studies of dust devils, and their impact on society, are reviewed. Dust devils have been noted since antiquity, and have been documented in many countries, as well as on the planet Mars. As time-variable vortex entities, they have become a cultural motif. Three major stimuli of dust devil research are identified, nuclear testing, terrestrial climate studies, and perhaps most significantly, Mars research. Dust devils present an occasional safety hazard to light structures and have caused several deaths