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The evolutionary theory of life histories predicts that there is a trade‐off between survival and reproduction: since adult survival in long‐lived organisms is high, then breeding investment is more variable and more dependent on conditions (e.g. food availability and individual experience). Clutch features influence fitness prospects, but how a bet hedger builds its clutch in temporally varying environments is quite unknown. Using 27‐year data on 2847 clutches of known‐age breeders, we analyse how Audouin's gulls (Larus audouinii), a species showing a combination of conservative and adaptive bet‐hedging breeding strategies, can allocate energy by laying clutches and eggs of different sizes. Results show that both food availability and age influenced clutch size and total egg volume in a clutch. Interestingly, we found an interaction between food and age on egg parameters: total volume in two‐egg clutches, laid mostly by younger breeders, did not significantly change with food availability and the quadratic pattern in clutch size over the range of ages was less marked as long as food conditions became harsher. With increased food, females invested more by building larger first eggs, whereas they were more conservative on second and third eggs. Furthermore, asymmetries in egg volume within three‐egg clutches increased with food availability for old females. Egg size profiles of two‐egg clutches suggest that gulls should exhibit progressive reduction of the size of the third egg before shifting to a two‐egg clutch size. Food availability influenced all parameters studied, whereas age affected the amount of energy allocated for producing eggs (their size and number) but not the way of allocating those energies (i.e. asymmetries within the clutch). Despite the range of factors affecting the clutch, results suggest that females can allocate the amount of resources in a clutch optimally to increase their fitness under variable environments via bet‐hedging. [ABSTRACT FROM AUTHOR]

Network neuroscience represents the brain as a collection of regions and inter‐regional connections. Given its ability to formalize systems‐level models, network neuroscience has generated unique explanations of neural function and behavior. The mechanistic status of these explanations and how they can contribute to and fit within the field of neuroscience as a whole has received careful treatment from philosophers. However, these philosophical contributions have not yet reached many neuroscientists. Here we complement formal philosophical efforts by providing an applied perspective from and for neuroscientists. We discuss the mechanistic status of the explanations offered by network neuroscience and how they contribute to, enhance, and interdigitate with other types of explanations in neuroscience. In doing so, we rely on philosophical work concerning the role of causality, scale, and mechanisms in scientific explanations. In particular, we make the distinction between an explanation and the evidence supporting that explanation, and we argue for a scale‐free nature of mechanistic explanations. In the course of these discussions, we hope to provide a useful applied framework in which network neuroscience explanations can be exercised across scales and combined with other fields of neuroscience to gain deeper insights into the brain and behavior. On the nature of explanations offered by network science: A perspective from and for practicing neuroscientists This paper focuses on the level of neural networks. It argues that tools and models in network science can successfully bridge explanations of neural and cognitive phenomena at multiple scales. On the basis of various examples, Bertolero and Bassett explain how network neuroscience can uncover aspects the neural mechanisms of cognitive phenomena. [ABSTRACT FROM AUTHOR]

Since 2009 the apple snail Pomacea maculata has become a new invader of Oryza sativa (rice) fields and wetlands in Europe, only invading the Ebro Delta (north‐eastern Spain) thus far. It is considered a highly invasive and damaging species, resulting in large economic losses worldwide.Despite the severe impact of the invasive apple snail on both cultivated and natural wetlands, it has become an abundant potential resource for native avian predators.In this study, stable isotope analysis was used to assess the consumption of the apple snail by the glossy ibis Plegadis falcinellus in the Ebro Delta.The results indicate the importance of the apple snail in the diet of this native bird. In particular, isotopic results indicated that apple snails and freshwater coleopterans were the main prey in the diet of glossy ibis chicks, accounting for 26–40% of their diet. Thus, this native bird species could potentially help in the biological control of this invasive snail, but is not expected to eradicate it.Although the spread of this pest in rice fields and wetlands is not desirable, we predict that the apple snail will follow a path similar to other invasive species, such as the red swamp crayfish Procambarus clarkii, in establishing itself as part of the wetland food web. [ABSTRACT FROM AUTHOR]

Recent European policies on the ban of fishing discards and the closure of open-air landfills are expected to reduce predictable and abundant food resources for generalist seabirds. In order to forecast the consequences of this reduction on seabird breeding investment it is important to understand whether diverse anthropogenic foraging resources act synergistically or not and whether their influence is mediated by density-dependent mechanisms. To assess these effects at large spatio-temporal scale, we measured mean egg volume as a proxy of breeding investment in ca 5000 three-egg clutches of the yellow-legged gull Larus michahellis from 20 colonies of the Western Mediterranean, located both along European and African coasts. In European gull colonies, egg volume increased with the availability of fishing discards and landfills in the vicinity of the colony. However, the landfill effect was weaker than the effect of fishing discards, probably due to the lower quality of waste as food for gulls. In contrast, none of the anthropogenic food subsidies influenced egg volume in African colonies, likely due to socio-economic differences (i.e. a much lower availability and predictability of both discards and waste food. Finally, results showed that the positive association between fishing discards and open-air landfills on egg volume was mediated by negative density-dependent mechanisms probably related to an increase in competition for food. [ABSTRACT FROM AUTHOR]

Dispersal is a key process for the population dynamics of spatially structured populations (at local and metapopulation levels), so the understanding of the mechanisms underlying the movement of individuals in space and time is important for evolutionary and ecological studies. Here we analyzed, for the first time, a long-term (1992-2009) multi-site capture- recapture database collected at four local populations of a long-lived seabird, the Audouin's gull Larus audouinii, covering 90% of its total world population. Those local populations show different ecological and demographic features that allow us to assess the influence of several key factors involved in breeding dispersal patterns at large spatio-temporal scales. A recently developed analytical tool in mark-recapture modelling, the multi-event approach, allowed us to obtain separate departure and settlement probabilities and test different biological hypotheses for each step of the dispersal process. Our results revealed that site fidelity was the most common strategy among breeders, and dispersal was only high from the site with the lowest population size and habitat quality. However, departures from the two largest local populations increased over the study period in response to severe ecological perturbations. Dispersers chose different settlement patches depending on their site of origin, with settlement choices determined by the population size of the destination colony rather than by the local reproductive performance, foraging area (a proxy of food availability) or distance to the destination site. Our results indicate that a breeding site is not abandoned by breeders unless a series of cumulative perturbations occur; once dispersing, settlement is directed towards densely populated sites, with dispersers using population size to rapidly assess the quality of the breeding patch. [ABSTRACT FROM AUTHOR]

Assessing population trends is a basic prerequisite to carrying out adequate conservation strategies. Selecting an appropriate method to monitor animal populations can be challenging, particularly for low-detection species such as reptiles. This study compares 3 detection-corrected abundance methods (capture-recapture, distance sampling, and N-mixture) used to assess population size of the threatened Hermann's tortoise. We used a single dataset of 432 adult tortoise observations collected at 118 sampling sites in the Plaine des Maures, southeastern France. We also used a dataset of 520 tortoise observations based on radiotelemetry data collected from 10 adult females to estimate and model the availability ( g0) needed for distance sampling. We evaluated bias for N-mixture and capture-recapture, by using simulations based on different values of detection probabilities. Finally, we conducted a power analysis to estimate the ability of the 3 methods to detect changes in Hermann's tortoise abundances. The abundance estimations we obtained using distance sampling and N-mixture models were respectively 1.75 and 2.19 times less than those obtained using the capture-recapture method. Our results indicated that g0 was influenced by temperature variations and can differ for the same temperature on different days. Simulations showed that the N-mixture models provide unstable estimations for species with detection probabilities <0.5, whereas capture-recapture estimations were unbiased. Power analysis showed that none of the 3 methods were precise enough to detect slow population changes. We recommend that great care should be taken when implementing monitoring designs for species with large variation in activity rates and low detection probabilities. Although N-mixture models are easy to implement, we would not recommend using them in situations where the detection probability is very low at the risk of providing biased estimates. Among the 3 methods allowing estimation of tortoise abundances, capture-recapture should be preferred to assess population trends. © 2013 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Climatic shifts may increase the extinction risk of populations, especially when they are already suffering from other anthropogenic impacts. Our ability to predict the consequences of climate change on endangered species is limited by our scarce knowledge of the effects of climate variability on the population dynamics of most organisms and by the uncertainty of climate projections, which depend strongly on the region of the earth being considered. In this study, we analysed a long-term monitoring programme (1988-2009) of Hermann's tortoise ( T estudo hermanni) aimed at evaluating the consequences of the drastic changes in temperature and precipitation patterns predicted for the Mediterranean region on the demography of a long-lived species with low dispersal capability and already suffering a large number of threats. Capture-recapture modelling of a population in the Ebro Delta ( NE Spain) allowed us to assess the effect of climate variability on the survival of tortoises. Winter rainfall was found to be the major driver of juvenile and immature survival, whereas that of adults remained high and constant across the study. Furthermore, local climate series obtained ad hoc from regional climate simulations, for this and 10 additional Mediterranean locations where tortoises occurred, provided us with reliable future climate forecasts, which were used to simulate the fate of these populations under three precipitation scenarios (mean, wet and dry) using stochastic population modelling. We show that a shift to a more arid climate would have negative consequences for population persistence, enhancing juvenile mortality and increasing quasiextinction risk because of a decrease in recruitment. These processes varied depending on the population and the climate scenario we considered, but our results suggest that unless other human-induced causes of mortality are suppressed (e.g. poaching, fire, habitat fragmentation), climate variability will increase extinction risk within most of the species' current range. [ABSTRACT FROM AUTHOR]

The presence of the Mediterranean pond turtle Mauremys leprosa in the Ebre Delta (Catalonia, north-east Spain) is well documented after the late 1970s, when the first reptile distribution lists were published. Owing to the fact that the species was considered scarce, a reintroduction programme based on the release of individuals at sites with potential habitat suitability was launched. From 1999 to 2001, 234 turtles of different ages were released and subsequently monitored until 2007, in order to make a conservation diagnosis using five assessment criteria. These criteria were body condition, individual growth, reproduction, survival and population growth rate. Despite the relatively large number of turtles released, no viable population resulted from the programme. Assessment criteria suggested that: (1) released individuals showed good physical condition and satisfactory growth (the only positive results); (2) reproduction was almost absent; (3) local survival was reduced compared with that of Spanish wild populations of the species; (4) temporary emigration was high; (5) the growth rate of the population was negative. In conclusion, the results suggested that the habitat at the Ebre Delta marshes may not be favourable to the species, and that the scarce historical data record may indicate a relatively low-quality habitat; the few records may correspond to individuals dispersing from the river, a more suitable habitat. Thus, we conclude that historically scarce records may be the result of natural patchiness and heterogeneous distributions, and they are not necessarily a good indicator of relict, decimated populations. Good assessment criteria, as those proposed and used here, are necessary tools to assess results in reintroduction projects to recover endangered chelonian populations. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigates the ranging behaviour and foraging-area requirements of the bird, Marsh Harrier, throughout the complete annual cycle in an agricultural area in the Iberian Peninsula. In this study, radiotagged Marsh Harriers are tracked using receivers and a Yagi antenna. Results show that male home-range size exhibits large variation between Marsh Harriers. It concludes that remaining close to breeding areas is significant in the pre-laying period.

Although reintroduction programmes are often implemented for recovering animal populations, projects seldom monitor the long-term survival of released animals. In addition, although many releases may occur in the same area, little is known about how the survival of successive release batches is affected by the presence of conspecifics and density dependence. Here, we use multi-state capture–recapture modelling (combining information from recaptures and recoveries) to analyse the survival of two batches of Hermann's tortoise Testudo hermanni hermanni released in a 10-year interval and monitored for 18 years at the Ebro Delta (western Mediterranean). We also tested whether the released animals experienced lower survival (i.e. a release cost) before becoming familiar with the new environment. Although we used a hard-release method, neither group experienced a short-term release cost. Annual survival of both groups differed and was not negatively affected by density-dependent factors. Annual survivorship of the first group of released tortoises was constant and very high (0.945,se=0.011), and similar to that estimated from several natural populations. The presence of a terrestrial predator in 1 year (before the release of the second group) significantly decreased the survival of tortoises (0.819,se=0.073). Strikingly, survival of the second batch was significantly lower than that of the first group after the first years of release (0.775,se=0.049). Although survivorship for the first group suggested that habitat quality was high, the second group seemed not to acclimate well to the new environment, possibly due to the presence of resident tortoises. From a management perspective, reintroduction programmes of the Hermann's tortoise are a successful strategy for its recovery. Nevertheless, it seems advisable to avoid: (1) the release of tortoises at the core of well-established populations and (2) areas with a high density of predators, which can jeopardize the reintroduction success, especially when the number of released individuals is small. [ABSTRACT FROM AUTHOR]

Hermann's tortoise ( Testudo hermanni), the best-known western Palaearctic tortoise species, has a rare natural distribution pattern comprising the Mediterranean areas of the Iberian, Apennine, and Balkan Peninsulas, as well as Sicily, Corsica and Sardinia. The western part of this range is traditionally considered habitat for T. h. hermanni, while T. h. boettgeri occurs in the Balkans. Taxonomy of this tortoise has been challenged in recent years, with the two subspecies being considered full species and the central Dalmatian populations of T. h. boettgeri being considered a third species, T. hercegovinensis. Using an mtDNA fragment approximately 1150 bp long (cytochrome b gene and adjacent portion of tRNA-Thr gene), we investigated mtDNA diversity with regard to contrasting concepts of two subspecies or three species. Seven closely related haplotypes were identified from the western Mediterranean and 15 different, in part much-differentiated, haplotypes from the Balkans. Western Mediterranean haplotypes differ from Balkan haplotypes in 16-42 mutation steps. One to seven mutation steps occur within western Mediterranean populations. Balkan haplotypes, differing in 1-37 nucleotides, group in parsimony network analysis into three major assemblages that display, in part, a similar degree of differentiation to that of western Mediterranean haplotypes relative to Balkan haplotypes. Rates of sequence evolution are different in both regions, and low divergence, palaeogeography and the fossil record suggest a slower molecular clock in the western Mediterranean. While monophyly in western Mediterranean haplotypes is well-supported, conflicting evidence is obtained for Balkan haplotypes; maximum parsimony supports monophyly of Balkan haplotypes, but other phylogenetic analyses (Bayesian, ML, ME) indicate Balkan haplotypes could be paraphyletic with respect to the western Mediterranean clade. These results imply a process of differentiation not yet complete despite allopatry in the western Mediterranean and the Balkans, and suggest all populations of T. hermanni are conspecific. In the western Mediterranean no clear geographical pattern in haplotype distribution is found. Distribution of Balkan haplotypes is more structured. One group of similar haplotypes occurs in the eastern Balkans (Bulgaria, Republic of Macedonia, Romania and the Greek regions Evvia, Macedonia, Peloponnese, Thessaly and Thrace). Two distinct haplotypes, differing in eight to nine mutation steps from the most common haplotype of the first group, are confined to the western slope of the Taygetos Mts. in the Peloponnese. Yet another group, connected over between four and 23 mutation steps with haplotypes of the eastern Balkan group, occurs along the western slope of the Dinarid and Pindos Mts. (Istria, Dalmatia, western Greece). Taygetos haplotypes are nested within other haplotypes in all phylogenetic analyses and support for monophyly of the other Balkan groups is at best weak. We conclude that using the traditional two subspecies model should be continued for T. hermanni. Phylogeographies of T. hermanni and Emys orbicularis, another codistributed chelonian, are markedly different, but share a few similarities. Both were forced to retreat to southern refuges during Pleistocene glaciations. With the advent of Holocene warming, E. orbicularis underwent rapid range expansion and temperate regions of Europe and adjacent Asia were recolonized from refuges in the Balkans and the northern Black Sea Region. By contrast, T. hermanni remained more or less confined to refuges and nearby regions, resulting in a much smaller range, and allopatric and parapatric distribution of haplotype groups and clades MtDNA lineages are more diverse in E. orbicularis than they are in T. hermanni on southern European peninsulas, indicating several distinct glacial refuges in close proximity and extensive intergradation during Holocene range expansion for E. orbicularis . In T. hermanni it is likely that only on the Balkan Peninsula was more than one refuge located, corresponding to the parapatric ranges of haplotype groups currently there. On the old western Mediterranean islands Corsica and Sardinia no differentiated (E. orbicularis) or only weakly differentiated haplotypes (T. hermanni) occur, even though there is evidence for the presence of both species on Corsica since at least the Middle Pleistocene. High mountain chains constitute major barriers separating distinct mtDNA clades or groups in each species. [ABSTRACT FROM AUTHOR]

A mutant species of the 185-residue chain of human interleukin-6 lacking 22-residues at its N-terminus and with a Cys→Ser substitution at positions 45 and 51 was produced in Escherichia coli. The 163-residue protein des-(A1–S22)-[C45S, C51S]interleukin-6, containing a single disulfide bridge, formed inclusion bodies. Mutant interleukin-6 was solubilized in 6 M guanidine hydrochloride, subjected to oxidative re folding and purified to homogeneity by ammonium sulfate precipitation and hydrophobic chromatography. The purity of the mutant species was established by electrophoresis, isoelectrofocusing and reverse-phase HPLC and its structural identity was checked by N-terminal sequencing of both the intact protein and several of its proteolytic fragments. Electrospray mass spectrometry analysis of mutant interleukin-6 gave a molecular mass of 18695±2 Da in excellent agreement with the calculated value. Circular dichroic, fluorescence emission and second-derivative ultraviolet absorption spectra indicated that mutant interleukin-6 maintains the overall secondary and tertiary structure, as well as stability characteristics, of the recombinant wild-type human interleukin-6. The urea-induced unfolding of mutant interleukin-6, monitored by circular dichroic measurements in the far-ultraviolet region, occurs as a highly cooperative process with a midpoint of denaturation at 5.5 M urea. The data of the reversible unfolding of mutant interleukin-6 mediated by urea were used m calculate a value of 20.9±0.4 kJ · mol-1 for the thermodynamic stability of file protein at 25°C in the absence of denaturant. The biological activity of mutant interleukin-6 was evaluated in vitro by the hybridoma proliferation assay, and in vivo by measuring thrombopoiesis in monkeys. Dose/response effects of the mutant were comparable or even higher than those of the wild-type protein. Overall the results of this study show that mutant interteukin-6 is a biologically active cytokine, which could find practical use as a therapeutic agent. [ABSTRACT FROM AUTHOR]

The production of recombinant human basic fibroblast growth factor (rhbFGF) in Escherichia coli cells yielded active forms of this polypeptide which, however, displayed a high degree of instability towards oxidative processes. Biochemical studies in our laboratory and those of others indicated that the reactivity of the four cysteine residues was the main cause of the observed instability. Several attempts to obtain more stable derivatives of rhbFGF were carried out by modification of the sulfhydryl groups. Among these, treatment of rhbFGF with iodoacetic acid led to the isolation of a partially carboxymethylated form (Cm-FGF). Peptide mapping analysis of the modified protein showed that two cysteines (78 and 96) were blocked by a carboxymethyl group. The remaining cysteines (34 and 101) were not modified under the conditions used and were found to be in the reduced form. Cm-FGF and unmodified rhbFGF showed similar affinity both for heparin and for high-affinity receptors. Cm-FGF was more stable than the unmodified molecule as measured by HPLC and SDS/PAGE analysis. Interestingly, Cm-FGF was more active than unmodified rhbFGF in stimulating proliferation of endothelial cells and DNA synthesis in 3T3 fibroblasts. This new derivative could represent a desirable complementation to rhbFGF for the development of more stable pharmaceutical formulations in wound healing applications. [ABSTRACT FROM AUTHOR]