Ecology and evolution of soil nematode chemotaxis.

Plants influence the behavior of and modify community composition of soil-dwelling organisms through the exudation of organic molecules. Given the chemical complexity of the soil matrix, soil-dwelling organisms have evolved the ability to detect and respond to these cues for successful foraging. A key question is how specific these responses are and how they may evolve. Here, we review and discuss the ecology and evolution of chemotaxis of soil nematodes. Soil nematodes are a group of diverse functional and taxonomic types, which may reveal a variety of responses. We predicted that nematodes of different feeding guilds use host-specific cues for chemotaxis. However, the examination of a comprehensive nematode phylogeny revealed that distantly related nematodes, and nematodes from different feeding guilds, can exploit the same signals for positive orientation. Carbon dioxide (CO(2)), which is ubiquitous in soil and indicates biological activity, is widely used as such a cue. The use of the same signals by a variety of species and species groups suggests that parts of the chemo-sensory machinery have remained highly conserved during the radiation of nematodes. However, besides CO(2), many other chemical compounds, belonging to different chemical classes, have been shown to induce chemotaxis in nematodes. Plants surrounded by a complex nematode community, including beneficial entomopathogenic nematodes, plant-parasitic nematodes, as well as microbial feeders, are thus under diffuse selection for producing specific molecules in the rhizosphere that maximize their fitness. However, it is largely unknown how selection may operate and how belowground signaling may evolve. Given the paucity of data for certain groups of nematodes, future work is needed to better understand the evolutionary mechanisms of communication between plant roots and soil biota.

Hybrid speciation in birds: allopatry more important than ecology?

Hybrid speciation was once thought to be rare in animals, but over the past decade, improved molecular analysis techniques and increased research attention have allowed scientists to uncover many examples. In this issue, two papers (Elgvin et al. 2011; Hermansen et al. 2011) present compelling evidence for the hybrid origin of the Italian sparrow based on nuclear and mitochondrial DNA sequences, microsatellites, and plumage coloration. These studies point to an important role for geographic isolation in the process of hybrid speciation, and provide a starting point for closer examination of the genetic and behavioural mechanisms involved.

Dialyse et écologie: est-il possible de faire mieux à l'avenir [Dialysis and ecology: can we do better in the future?].

Development of dialysis has saved the lives of many patients. However, haemodialysis and peritoneal dialysis are very demanding in resources such as water and electricity, and generate a large amount of waste. In this article, we will review the environmental aspects of dialysis. Different solutions will be discussed, such as recycling of water discharged during reverse osmosis, the integration of solar energy, recycling of waste plastics, and the use of other techniques such as sorbent dialysis. In a world where natural resources are precious and where global warming is a major problem, it is important that not only dialysis, but all branches of medicine become more attentive to ecology.

Linking life-history traits, ecology, and niche breadth evolution in north american eriogonoids (polygonaceae).

Abstract Macroevolutionary and microevolutionary studies provide complementary explanations of the processes shaping the evolution of niche breadth. Macroevolutionary approaches scrutinize factors such as the temporal and spatial environmental heterogeneities that drive differentiation among species. Microevolutionary studies, in contrast, focus on the processes that affect intraspecific variability. We combine these perspectives by using macroevolutionary models in a comparative study of intraspecific variability. We address potential differences in rates of evolution of niche breadth and position in annual and perennial plants of the Eriogonoideae subfamily of the Polygonaceae. We anticipated higher rates of evolution in annuals than in perennials owing to differences in generation time that are paralleled by rates of molecular evolution. Instead, we found that perennial eriogonoid species present greater environmental tolerance (wider climate niche) than annual species. Niche breadth of perennial species has evolved two to four times faster than in annuals, while niche optimum has diversified more rapidly among annual species than among perennials. Niche breadth and average elevation of species are correlated. Moreover, niche breadth increases more rapidly with mean species elevation in perennials than in annuals. Our results suggest that both environmental gradients and life-history strategy influence rates and patterns of niche breadth evolution.

Seasonal variation of overall and cardiovascular mortality: a study in 19 countries from different geographic locations.

BACKGROUND: Cardiovascular diseases (CVD) mortality has been shown to follow a seasonal pattern. Several studies suggested several possible determinants of this pattern, including misclassification of causes of deaths. We aimed at assessing seasonality in overall, CVD, cancer and non-CVD/non-cancer mortality using data from 19 countries from different latitudes. METHODS AND FINDINGS: Monthly mortality data were compiled from 19 countries, amounting to over 54 million deaths. We calculated ratios of the observed to the expected numbers of deaths in the absence of a seasonal pattern. Seasonal variation (peak to nadir difference) for overall and cause-specific (CVD, cancer or non-CVD/non-cancer) mortality was analyzed using the cosinor function model. Mortality from overall, CVD and non-CVD/non-cancer showed a consistent seasonal pattern. In both hemispheres, the number of deaths was higher than expected in winter. In countries close to the Equator the seasonal pattern was considerably lower for mortality from any cause. For CVD mortality, the peak to nadir differences ranged from 0.185 to 0.466 in the Northern Hemisphere, from 0.087 to 0.108 near the Equator, and from 0.219 to 0.409 in the Southern Hemisphere. For cancer mortality, the seasonal variation was nonexistent in most countries. CONCLUSIONS: In countries with seasonal variation, mortality from overall, CVD and non-CVD/non-cancer show a seasonal pattern with mortality being higher in winter than in summer. Conversely, cancer mortality shows no substantial seasonality.

Stable isotope ecology of Miocene large mammals from Sandelzhausen, southern Germany

The carbon, oxygen, and strontium isotope composition of enamel from teeth of large Miocene herbivorous mammals from Sandelzhausen (MN5, late Early/early Middle Miocene) in the North Alpine foreland basin, were analyzed to infer diet and habitat. The mean enamel delta(13)C value of -11.4 +/- 1.0% (n = 53) for the nine taxa analyzed (including proboscideans, cervids, suids, chalicotheres, equids, rhinocerotids) indicates a pure C(3) plant diet for all mammals. (87)Sr/(86)Sr ratios of similar to 0.710 higher than those from teeth of the western Molasse Basin (0.708-0.709) seem to indicate preferential feeding of the mammals in the northeastern Molasse Basin. The sympatric herbivores have different mean delta(13)C and delta(18)O values which support diet partitioning and/or use of different habitats within a C(3) plant ecosystem. Especially the three sympatric rhinoceroses Plesiaceratherium fahlbuschi, Lartetotherium sansaniense, and Prosantorhinus germanicus show clear partitioning of plants and/or habitats. The palaeomerycid Germanomeryx fahlbuschi was a canopy folivore in moderately closed environments whereas Metaschizotherium bavaricum (Chalicotheriidae) and P. germanicus (Rhinocerotidae) were browsers in more closed forest environments. The horse Anchitherium aurelianense was probably a more generalized feeder than assumed from its dental morphology. The forest hog Hyotherium soemmeringi has the highest delta(13)C and lowest delta(18)O value of all analyzed taxa, possibly related to a frugivorous diet. Most taxa were water-dependent browsers that record meteoric water delta(18)O values of about -5.6 +/- 0.7% Vienna Standard Mean Ocean Water (VSMOW). Using a modern-day mean annual air temperature (MAT)-delta(18)OH(2)O relation a MAT of 19.3 +/- 1.5 degrees C can be reconstructed for Sandelzhausen. A Gomphotherium subtapiroideum tusk serially sampled for delta(18)O values does not record a clear pattern of seasonality. Thus most taxa were C(3) browsers in a forested and humid floodplain environment in the Molasse Basin, which experienced a warm-temperate to subtropical climate and possibly low seasonality.

Eotaxin-1 (CCL11) up-regulation in tears during seasonal allergic conjunctivitis.

PURPOSE: To compare in-season eotaxin-1 levels in tears of patients suffering from seasonal allergic conjunctivitis (SAC) with (1) tears of normal subjects and (2) tears of SAC patients out of season. METHODS: Tears of 11 SAC patients and six control volunteers were collected during the pollen season. Tears of five SAC patients showing a strong sensitivity to grass pollen (skin-prick tests and specific serum IgE) were collected both in season and out of season. ELISA measured eotaxin-1 level. RESULTS: Eotaxin-1 concentration in tears of SAC patients [2,100+/-503 (SEM) pg/ml] and normal subjects (1,193+/-176 pg/ml) were significantly different (P=0.0049). Regarding allergic patients, the clinical score (sum of five allergic criteria) was significantly different in season and out of season (P=0.0043) as was also the case with eotaxin-1 concentration (P=0.024). CONCLUSIONS: The eotaxin-1 concentration in tears of patients showing hay fever could confirm a diagnosis of seasonal ocular allergy.

Ecology and evolution of multigenomic arbuscular mycorrhizal fungi.

Arbuscular mycorrhizal fungi (AMF) form extremely important mutualistic symbioses with most plants. Their role in nutrient acquisition, plant community structure, plant diversity, and ecosystem productivity and function has been demonstrated in recent years. New findings on the genetics and biology of AMF also give us a new picture of how these fungi exist in ecosystems. In this article, I bring together some recent findings that indicate that AMF have evolved to contain multiple genomes, that they connect plants together by a hyphal network, and that these different genomes may potentially move around in this network. These findings show the need for more intensive studies on AMF population biology and genetics in order to understand how they have evolved with plants, to better understand their ecological role, and for applying AMF in environmental management programs and in agriculture. A number of key features of AMF population biology have been identified for future studies and most of these concern the need to understand drift, selection, and genetic exchange in multigenomic organisms, a task that has not previously presented itself to evolutionary biologists.

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 August 2010-30 September 2010

This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis x Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross-tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.

Diversity of social wasps (Hymenoptera, Vespidae, Polistinae) in three fragments of semideciduous seasonal forest in the northwest of São Paulo State, Brazil

Human exploitation of the forest in the northwest of São Paulo State has generated enormous fragmentation of that forest. Such disturbance has reduced the populations of insects in general. This work was a survey of social wasps (Hymenoptera, Vespidae; Polistinae) in three areas in different stages of regeneration: Paulo de Faria - SP (435 ha), Pindorama - SP (128 ha) and Neves Paulista - SP (1 ha). These three areas were chosen for comparative purposes. To capture the wasps, it was used: active collecting with attractant liquid (solution of water, salt and sugar) with the aid of a dorsal spray bag. During the period from July to December 2006, 414 social wasps were collected in Paulo de Faria, constituting seven species belonging to four genera; 111 social wasps were collected in Pindorama, constituting six species belonging to four genera, and 129 social wasps were collected in Neves Paulista constituting 12 species belonging to seven genera. In order to compare these three areas ecological indexes were calculated. Neves Paulista had the greatest diversity, and Paulo de Faria presented greater abundance. These factors were probably caused by neighboring areas and ecological corridors, which were limited in Paulo de Faria and Pindorama.

Timing of seasonal sales

We present a model of timing of seasonal sales where stores chooseseveral designs at the beginning of the season without knowingwich one, if any, will be fashionable. Fashionable designs have achance to fetch high prices in fashion markets while non-fashionableones must be sold in a discount market. In the beginning of theseason, stores charge high prices in the hope of capturing theirfashion market. As the end of the season approaches with goods stillon the shelves, stores adjust downward their expectations that theyare carrying a fashionable design, and may have sales to capture thediscount market. Having a greater number of designs induces a storeto put one of them on sales earlier to test the market. Moreover,price competition in the discount market induces stores to startsales earlier because of a greater perceived first-mover advantage incapturing the discount market. More competition, perhaps due todecreases in the cost of product innovation, makes sales occur evenearlier. These results are consistent with the observation that thetrend toward earlier sales since mid-1970's coincides with increasingproduct varieties in fashion good markets and increasing storecompetition.

Nutritional ecology of blowflies (Diptera, Calliphoridae): estimates of critical larval weight for pupation on two different

Under natural environmental conditions, blowflies utilize discrete and ephemeral feeding resources such as decaying carcasses. Competition for food on such feeding substrates is usually very severe, and only the individuals that are capable of attaining the critical larval weight for pupation will be able to survive. This critical weight is hitherto unknown for several blowfly species; therefore, the current work is aimed at obtaining such a critical value for four blowfly species of the genera Chrysomya and Lucilia, deploying two types of feeding substrate, namely, artificial diet and macerated bovine meat. On the whole, the critical weights ranged from 30 to 35 mg. The lowest larval weight which permitted pupation was 30.0 mg for Chrysomya megacephala reared on macerated bovine meat. This species was also the best adapted to pupation at low larval weights in relation to the maximum larval weight for males. Regarding the pupation of females, the best-adapted individual was a C. albiceps specimen exhibiting a critical weight that was equal to 39.20 % of the maximum value obtained. Concerning all the species and diet types, the female individuals exhibited the lowest critical weights that produced viable pupae, probably representing an evolutionary strategy that favoured the survival of females, responsible for the egg formation, contributing to the establishment of future generations. Regarding the loss (in percentage) of adult biomass in relation to the third instar larvae, the females of C. megacephala lost less weight than males in both feeding substrates. On the other hand, such a loss of weight occurred in males of C. albiceps and L. cuprina.

Behavioral ecology of Heteragrion consors Hagen (Odonata, Megapodagrionidae): a shade-seek Atlantic forest damselfly

Behavioral ecology of Heteragrion consors Hagen (Odonata: Megapodagrionidae): a shade-seek Atlantic forest damselfly. The intensity of the inter and intra-sexual selection can affect male behavioral traits as territorial fidelity and aggressiveness allowing the existence of different strategies. However, its differential success could be affected by environmental - as the diel variation in temperature - and physiological constrains - as the variation in thermoregulatory abilities. In this context, we present a behavioral analysis of Heteragrion consors (Zygoptera, Megapodagrionidae) trying to characterize its mating system, diel activity pattern, temporal budget, territoriality and reproductive biology. These data were obtained based on field observations using the focal individual method and mark-recapture techniques in 120 m of a shaded Atlantic Forest stream in Brazil. The males of this species were territorial, varying in its local fidelity, while the females appear sporadically. Males were perched in the majority of the time, but were also observed in cleaning movements, longitudinal abdominal flexion, wing flexion and sperm transfer during perch. The males presented a perched thermoregulatory behavior related to an exothermic regulation. Foraging and agonistic interactions were rare, but dominate the other behavioral activities. Abdominal movements associated to long lasting copula pointed to the existence of sperm competition in this species. Males performed contact post-copulatory guarding of the females. These observations pointed to a non-resource mating system for this species.