Transcriptional profiling of retinal astrocytes identifies a specific marker and points to functional specialization.

Astrocyte heterogeneity is an increasingly prominent research topic, and studies in the brain have demonstrated substantial variation in astrocyte form and function, both between and within regions. In contrast, retinal astrocytes are not well understood and remain incompletely characterized. Along with optic nerve astrocytes, they are responsible for supporting retinal ganglion cell axons and an improved understanding of their role is required. We have used a combination of microdissection and Ribotag immunoprecipitation to isolate ribosome-associated mRNA from retinal astrocytes and investigate their transcriptome, which we also compared to astrocyte populations in the optic nerve. Astrocytes from these regions are transcriptionally distinct, and we identified retina-specific astrocyte genes and pathways. Moreover, although they share much of the "classical" gene expression patterns of astrocytes, we uncovered unexpected variation, including in genes related to core astrocyte functions. We additionally identified the transcription factor Pax8 as a highly specific marker of retinal astrocytes and demonstrated that these astrocytes populate not only the retinal surface, but also the prelaminar region at the optic nerve head. These findings are likely to contribute to a revised understanding of the role of astrocytes in the retina.

Fitness benefits of alternated chick provisioning in cooperatively breeding carrion crows.

In most bird species, parents raise offspring cooperatively. In some cases, this cooperation extends to helpers-at-the-nest who assist the breeders with a range of tasks. While cooperative food provisioning might merely arise incidentally, as a result of the efforts of carers that act independently from each other, recent studies suggest that birds may coordinate by taking turns in visiting the nest. However, evidence that such coordination emerges because individuals actively respond to each other's behaviour is controversial, and the potential benefits of carers' alternation remain unknown. We addressed this knowledge gap by analysing a multiyear dataset for cooperatively breeding carrion crows Corvus corone, comprising 8693 nest visits across 50 groups. Our results reveal that turn-taking does occur in this species and that all group members, regardless of their sex and social role (breeder/helper), tend to alternate at the nest with other carers rather than to make repeat visits. Importantly, we found that the body mass of nestlings increased significantly with the degree of carers' alternation, possibly because well-coordinated groups provided food at more regular intervals. Using earlier monitoring data, the observed increase in body mass is predicted to substantially boost postfledging survival rates. Our analyses demonstrate that alternation in nestling provisioning has measurable fitness benefits in this study system. This raises the possibility that cooperatively breeding carrion crows, as well as other bird species with similarly coordinated brood provisioning, exhibit specialized behavioural strategies that enable effective alternation.

En la mayoría de las especies de aves, los padres cooperan entre sí en el cuidado de sus crías. En algunos casos, la cooperación se extiende a individuos ayudantes que asisten a los reproductores en diferentes tareas. El aprovisionamiento cooperativo de las crías puede darse simplemente como resultado del esfuerzo de cuidadores que actúan de forma independiente, pero estudios recientes sugieren que las aves pueden coordinarse, tomando turnos a la hora de visitar el nido. Sin embargo, las evidencias de que dicha coordinación ocurre porque los individuos realmente responden al comportamiento de los demás es controvertida, y los potenciales beneficios de la alternancia al nido son desconocidos. Nosotros abordamos estos aspectos analizando una base de datos plurianual en la corneja negra Corvus corone, que incluye 8693 visitas al nido en 50 grupos. Nuestros resultados revelan que se produce toma de turnos en esta especie y que todos los miembros del grupo, independientemente del sexo y del estatus social (reproductor / ayudante), tienden a alternarse al nido con otros cuidadores, en vez de repetir visitas. Más importante aún, encontramos que la masa corporal de los polluelos aumentaba de forma significativa al aumentar el grado de coordinación de los cuidadores, posiblemente porque los grupos mejor coordinados aprovisionaban las crías a intervalos más regulares. Basándonos en datos anteriores, pudimos calcular que el incremento observado en masa corporal predice un aumento sustancial de la tasa de supervivencia de los volanderos. Nuestros análisis demuestran, por lo tanto, que la alternancia al nido tiene beneficios medibles en eficacia biológica. Esto conlleva la posibilidad de que las cornejas negras cooperativas, al igual que otras especies de aves con aprovisionamiento coordinado de las crías, exhiban estrategias comportamentales especializadas que permitan una eficiente alternancia al nido.

Reciprocity and interaction effectiveness in generalised mutualisms among free-living species.

Mutualistic interactions among free-living species generally involve low-frequency interactions and highly asymmetric dependence among partners, yet our understanding of factors behind their emergence is still limited. Using individual-based interactions of a super-generalist fleshy-fruited plant with its frugivore assemblage, we estimated the Resource Provisioning Effectiveness (RPE) and Seed Dispersal Effectiveness (SDE) to assess the balance in the exchange of resources. Plants were highly dependent on a few frugivore species, while frugivores interacted with most individual plants, resulting in strong asymmetries of mutual dependence. Interaction effectiveness was mainly driven by interaction frequency. Despite highly asymmetric dependences, the strong reliance on quantity of fruit consumed determined high reciprocity in rewards between partners (i.e. higher energy provided by the plant, more seedlings recruited), which was not obscured by minor variations in the quality of animal or plant service. We anticipate reciprocity will emerge in low-intimacy mutualisms where the mutualistic outcome largely relies upon interaction frequency.

Meta-analysis reveals drivers of restoration success for oysters and reef community.

Restoration aims to reverse the global declines of foundation species, but it is unclear how project attributes, the physical setting, and antecedent conditions affect restoration success. In coastal seas worldwide, oyster reef restoration is increasing to counter historical habitat destruction and associated declines in fisheries production and biodiversity. Yet, restoration outcomes are highly variable and the factors that enhance oyster production and nekton abundance and diversity on restored reefs are unresolved. To quantify the drivers of oyster restoration success, we used meta-analysis to synthesize data from 158 restored reefs paired with unstructured habitats along the United States Gulf and Atlantic coasts. The average recovery of oyster production was 65% greater in subtidal (vs. intertidal) zones, 173% greater in polyhaline (vs. mesohaline) environments and increased with tidal range, demonstrating that physical conditions can strongly influence the restoration success of foundation species. Additionally, restoration increased the relative abundance and richness of nektonic fishes and invertebrates over time as reefs aged (at least 8 years post-construction). Thus, the restoration benefits for provisioning habitat and enhancing biodiversity accrue over time, highlighting that restoration projects need multiple years to maximize ecosystem functions. Furthermore, long-term monitoring of restored and control sites is needed to assess restoration outcomes and associated drivers. Last, our work reveals data constraints for several potential drivers of restoration outcomes, including reef construction material, reef dimensions, harvest pressure and disease prevalence. More experimental and observational studies are needed to target these factors and measure them with consistent methods across studies. Our findings indicate that the assisted recovery of foundation species yields several enhancements to ecosystem services, but such benefits are mediated by time and environmental conditions.

Meta-analysis of ecosystem services associated with oyster restoration.

Restoration of foundation species promises to reverse environmental degradation and return lost ecosystem services, but a lack of standardized evaluation across projects limits understanding of recovery, especially in marine systems. Oyster reefs are restored to reverse massive global declines and reclaim valuable ecosystem services, but the success of these projects has not been systematically and comprehensively quantified. We synthesized data on ecosystem services associated with oyster restoration from 245 pairs of restored and degraded reefs and 136 pairs of restored and reference reefs across 3500 km of U.S. Gulf of Mexico and Atlantic coastlines. On average, restoration was associated with a 21-fold increase in oyster production (mean log response ratio = 3.08 [95% confidence interval: 2.58-3.58]), 34-97% enhancement of habitat provisioning (mean community abundance = 0.51 [0.41-0.61], mean richness = 0.29 [0.19-0.39], and mean biomass = 0.69 [0.39-0.99]), 54% more nitrogen removal (mean = 0.43 [0.13-0.73]), and 89-95% greater sediment nutrients (mean = 0.67 [0.27-1.07]) and organic matter (mean = 0.64 [0.44-0.84]) relative to degraded habitats. Moreover, restored reefs matched reference reefs for these ecosystem services. Our results support the continued and expanded use of oyster restoration to enhance ecosystem services of degraded coastal systems and match many functions provided by reference reefs.

La restauración de especies fundadoras promete revertir la degradación ambiental y restituir servicios ambientales perdidos, pero la falta de evaluación estandarizada de proyectos limita la comprensión de la recuperación, especialmente en sistemas marinos. Los bancos de ostión son restaurados para revertir declinaciones globales masivas y recuperar servicios ecosistémicos valiosos, pero el éxito de estos proyectos no ha sido cuantificado sistemática ni integralmente. Sintetizamos datos sobre los servicios ecosistémicos asociados con la restauración de ostiones de 245 pares de bancos restaurados y degradados y 136 pares de bancos restaurados y de referencia a lo largo de 3500 km de costa del Golfo de México y Atlántico norteamericanos. En promedio, la restauración se asoció con un incremento de 21 veces en la producción de ostión (media de proporción de respuesta log = 3.08 [95% IC 2.58-3.58]), mejoras entre 34 y 97% en el aprovisionamiento de hábitat (abundancia media = 0.51 [0.41-0.61], riqueza media = 0.29 [0.19-0.39], y biomasa media = 0.69 [0.39-0.99]), 54% más remoción de nitrógeno (media = 0.43 [0.13-0.73]), y 89-95% más nutrientes en sedimento (media = 0.67 [0.27-1.07]) y materia orgánica (media = 0.64 [0.44-0.84]) en relación con hábitats degradados. Más aun, estos servicios ecosistémicos de los bancos restaurados fueron muy similares en los bancos de referencia. Nuestros resultados sustentan el uso continuo y expandido de la restauración de ostiones para mejorar los servicios ecosistémicos de sistemas costeros degradados y que sean parecidos a las numerosas funciones proporcionadas por los bancos de referencia.

Maternal chemical defenses predict offspring defenses in a dendrobatid poison frog.

Within and among populations, alkaloid defenses of the strawberry poison frog (Oophaga pumilio) vary spatially, temporally, and with life history stage. Natural variation in defense has been implicated as a critical factor in determining the level of protection afforded against predators and pathogens. Oophaga pumilio tadpoles sequester alkaloids from nutritive eggs and are, thus, entirely dependent on their mothers for their defense. However, it remains unclear how tadpole alkaloid composition relates to that of its mother and how variation in maternally provisioned defenses might result in varying levels of protection against predators. Here, we demonstrate that natural variation in the alkaloid composition of a mother frog is reflected as variation in her tadpole's alkaloid composition. Tadpoles, like mother frogs, varied in their alkaloid composition but always contained the identical alkaloids found in their mother. Alkaloid quantity in tadpoles was highly correlated with alkaloid quantity in their mothers. Additionally, alkaloid quantity was the best predictor of tadpole palatability, wherein tadpoles with higher alkaloid quantities were less palatable. Mother frogs with greater quantities of alkaloids are, thus, providing better protection for their offspring by provisioning chemical defenses during one of the most vulnerable periods of life.

Effects of provisioning on the activity budget and foraging strategies of black-and-white snub-nosed monkeys (Rhinopithecus bieti) in the Baima Snow Mountain Nature Reserve, Yunnan, China.

Provisioning can significantly affect the ranging patterns, foraging strategies, and time budget of wild primates. In this study, we document for the first time, the effects of provisioning on the activity budget and foraging effort in an Asian colobine. Over 3-years, we used an instantaneous scanning method at 10-min intervals to collect data on the activity budget of a semiprovisioned breeding band (SPB) of black-and-white snub-nosed monkeys (Rhinopithecus bieti) (42-70 individuals) at Xiangguqing (Tacheng), Yunnan, China. We then compared the effects of provisioning in our study band with published data on a sympatric wild nonprovisioned breeding band (NPB) of R. bieti (ca. 360 monkeys) at the same field site. The SPB spent 25.6% of their daytime feeding, 17.1% traveling, 46.9% resting, and 10.3% socializing. In comparison, the NPB devoted more time to feeding (34.9%) and socializing (14.1%), less time to resting (31.3%), and was characterized by a greater foraging effort (1.74 versus 0.96, foraging effort = (feeding + traveling)/resting; see Methods). There was no difference between bands in the proportion of their activity budget devoted to traveling (15.7% vs. 17.1%). In addition, the SPB exhibited a more consistent activity budget and foraging effort across all seasons of the year compared to the NPB. These findings suggest that the distribution, availability, and productivity of naturally occurring feeding sites is a major determinant of the behavioral strategies and activity budget of R. bieti. Finally, a comparison of our results with data on six nonprovisioned R. bieti bands indicates that caution must be raised in meta-analyses or intraspecific comparisons of primate behavioral ecology that contain data generated from both provisioned and nonprovisioned groups.

Elastic Provisioning of Network and Computing Resources at the Edge for IoT Services.

The fast growth of Internet-connected embedded devices demands new system capabilities at the network edge, such as provisioning local data services on both limited network and computational resources. The current contribution addresses the previous problem by enhancing the usage of scarce edge resources. It designs, deploys, and tests a new solution that incorporates the positive functional advantages offered by software-defined networking (SDN), network function virtualization (NFV), and fog computing (FC). Our proposal autonomously activates or deactivates embedded virtualized resources, in response to clients' requests for edge services. Complementing existing literature, the obtained results from extensive tests on our programmable proposal show the superior performance of the proposed elastic edge resource provisioning algorithm, which also assumes an SDN controller with proactive OpenFlow behavior. According to our results, the maximum flow rate for the proactive controller is 15% higher; the maximum delay is 83% smaller; and the loss is 20% smaller compared to when the non-proactive controller is in operation. This improvement in flow quality is complemented by a reduction in control channel workload. The controller also records the time duration of each edge service session, which can enable the accounting of used resources per session.

Diving into the diet of provisioned smooth stingrays using stable isotope analysis.

Recreational fishing waste, produced from processing catches at shore-based fish cleaning facilities and discarded into adjacent waters, is foraged by various aquatic species. However, the potential alterations to the diet of consumers of these resources are poorly studied. Smooth stingrays (Bathytoshia brevicaudata) are a large demersal mesopredatory ray species and common scavenger of recreational fishing discards around southern Australia. Due to their attraction to fish cleaning sites, they are also common targets of unregulated 'stingray feeding' tourism where they are fed commercially produced baits (e.g., pilchards). This study provides a preliminary assessment of the diet of smooth stingrays provisioned recreational fishing discards and baits at two sites in southern New South Wales, Australia (Discard Site: recreational fishing discards only; Provisioning Site: recreational fishing discards and commercial baits) using stable isotope analysis of carbon (δ13 C) and nitrogen (δ15 N), and Bayesian stable isotope mixing models. Our results indicate that at both sites invertebrates, considered a main part of the natural diet of smooth stingrays, made a limited contribution to the diets of provisioned stingrays, while a benthic teleost fish that is a common recreational catch was the dominant contributor. As the assessed teleost is potentially a natural prey item for smooth stingrays, it remains unclear whether the contribution came from recreational fishing discards or natural foraging. However, due to smooth stingrays' typically opportunistic foraging strategy, we expected a greater mixture of resources from low to high trophic level prey than was observed. These results suggest that smooth stingrays have either lower reliance on invertebrates as a result of utilizing provisioned resources or higher reliance on teleost fishes than previously thought. Commercial bait products fed to stingrays at the Provisioning Site were not a major contributor to the diets of smooth stingrays, suggesting this activity has a low impact on their nutrition.

Exploring the role of nature-based typologies and stewardship schemes in enhancing urban green spaces: Citizen perceptions of landscape design scenarios and ecosystem services.

This research investigates the UK citizens' perceptions of the ecosystem services (ES) created using a range of Nature-Based Solutions (NBS) in urban green spaces (UGS). The longevity of the ES derived from UGS is dependent on the effective on-going maintenance of urban landscapes, therefore this paper also gathers data on direct UGS participation specifically through the lens of civic stewardship to assess the impact of such schemes upon ES. NBS typologies were created and used, in the mixed methods study, to gauge perceptions of and preferences for alternative urban landscape design. The UGS survey collected data from 345 respondents on ES and the NBS typologies. Twelve semi-structured interviews provide qualitative data on NBS typology preferences, perceptions, and understanding of ES as well as motivations behind civic engagement in UGS in the UK. Stewardship programmes were found to increase community resilience by providing additional ES. The results showed a preference for integrating complex, multifunctional UGS into the fabric of urban centres to ensure accessibility and to maximise engagement. More complex NBS typologies were perceived to provide additional ES when compared with traditional monoculture mown grass and shrub amenity planting. Mixed native planting and Tiny Forest NBS typologies were perceived as providing more provisioning, cultural, regulating, and supporting ES. Considering both UK citizens' perceptions of the ES gained from alternative NBS and stewardship schemes in UGS represents a holistic approach that can improve the design and management of NBS in cities. This study is the first to explore both concepts in the UK and suggests a holistic UGS approach to address urban challenges, including those related to Climate Change.

How far the types and wetland hydrological conditions influence its provisioning services in the Indian mature Ganges delta.

Present work intended to explore how far the Provisioning Service Value (PSV) of the mature Ganges deltaic wetlands is determined by its typology and a few physical attributes like hydrology and aquatic vegetations. Firstly, a field investigation was carried out in the representative sample sites, and field-measured PSV was calibrated with wetland types, hydrological security, and aquatic plant biomass to perform spatial estimation and mapping of PSV. The estimation yielded average annual PSV of entire wetlands as 146.5 × 105 Indian Rupee (INR)/km2/year, with the highest over bheries (embankments for fish and shrimp aquaculture) 176 × 105 INR/km2/year and lowest over marshy wetlands 107 × 105 INR/km2/year. Sensitivity analysis of this estimation showed in cases of 55% field visited sites, the field-measured PSV was outside the range of low standard regression residuals (-0.5 to 0.5). While searching for the reason behind such error in the estimation, the variability of the field-measured PSV was measured. Various inequality measures showed high inequality in inter and intra-hydrological conditions of the wetland. Analysis of variance (ANOVA) proved statistical significance of within-class variability. To explain the variability of PSV, Kernel Density Estimation (KDE) plotting was performed, incorporating a few other regional conditioning factors like wetland size, fish and shrimp aquaculture, perenniality, expenditure, and external feeding from the experience of the field. From this excesize, external feeding and expenditure were essential factors that should be incorporated along with the wetland characteristics and physical attributes for accurate estimation. Since producing spatial data layers of these factors with a finer resolution is difficult, the study suggests case-specific estimation of PSV instead of general spatial mapping.

Grazing management impacts on ecosystem services under contrasting climatic conditions in Texas and North Dakota.

Grazing management is an important factor affecting the delivery of ecosystem services at the watershed scale. Moreover, characterizing the impacts of climate variation on water resources is essential in managing rangelands. In this study, the effects of alternative grazing management scenarios on provisioning, regulating, and supporting services were assessed in two watersheds with contrasting climates; the Lower Prairie Dog Town Fork Red River (LPDTFR) Watershed in North Texas and the Apple Watershed in South Dakota. The impacts of heavy stocking continuous grazing, light stocking continuous grazing, Adaptive Multi-Paddock (AMP) grazing, and an ungrazed exclosure were compared using the Soil and Water Assessment Tool (SWAT) model. Our results indicate that the quantity of snow and timing of snow melt substantially influenced grazing management effects on ecosystem services in the Apple Watershed. In contrast, precipitation was the main factor influencing these effects in the LPDTFR Watershed because it highly affected the variation in water cycling, streamflow, sediment, and nutrient controls. Simulated results indicated that AMP grazing was the optimal grazing management approach for enhancing water conservation and ecosystem services in both watersheds regardless of climatic conditions. The Apple Watershed, which is a snow-dominated watershed, exhibited greater ecosystem service improvements under AMP grazing (50.6%, 58.7%, 74.4%, 61.5% and 72.6% reduction in surface runoff, streamflow, and sediment, total nitrogen (TN) and total phosphorus (TP) losses, respectively as compared to HC grazing) than the LPDTFR Watershed (46.0%, 22.8%, 34.1%, 18.9% and 38.4% reduction in surface runoff, streamflow, and sediment, TN and TP losses, respectively). Our results suggest that improved grazing management practices enhance ecosystem services and water catchment functions in rangeland-dominated areas, especially in colder climates.

Inverse Lansing Effect: Maternal Age and Provisioning Affecting Daughters' Longevity and Male Offspring Production.

AbstractMaternal age effects on offspring life history are known in a variety of organisms, with offspring of older mothers typically having lower life expectancy (the Lansing effect). However, there is no consensus on the generality and mechanisms of this pattern. We tested predictions of the Lansing effect in several Daphnia magna clones and observed clone-specific magnitude and direction of the maternal age effect on offspring longevity. We also report ambidirectional, genotype-specific effects of maternal age on the propensity of daughters to produce male offspring. Focusing on two clones with contrasting life histories, we demonstrate that maternal age effects can be explained by lipid provisioning of embryos by mothers of different ages. Individuals from a single-generation maternal age reversal treatment showed intermediate life span and intermediate lipid content at birth. In the clone characterized by the "inverse Lansing effect," neonates produced by older mothers showed higher mitochondrial membrane potential in neural tissues than their counterparts born to younger mothers. We conclude that an inverse Lansing effect is possible and hypothesize that it may be caused by age-specific maternal lipid provisioning creating a calorically restricted environment during embryonic development, which in turn reduces fecundity and increases life span in offspring.

Habitat Specialization by Wildlife Reduces Pathogen Spread in Urbanizing Landscapes.

AbstractUrban areas are expanding globally with far-reaching ecological consequences, including for wildlife-pathogen interactions. Wildlife show tremendous variation in their responses to urbanization; even within a single population, some individuals can specialize on urban or natural habitat types. This specialization could alter pathogen impacts on host populations via changes to wildlife movement and aggregation. Here, we build a mechanistic model to explore how habitat specialization in urban landscapes affects interactions between a mobile host population and a density-dependent specialist pathogen that confers no immunity. We model movement on a network of resource-stable urban sites and resource-fluctuating natural sites, where hosts are urban specialists, natural specialists, or generalists that use both patch types. We find that for generalists, natural and partially urban landscapes produce the highest infection prevalence and mortality, driven by high movement rates at natural sites and high densities at urban sites. However, habitat specialization protects hosts from these negative effects of partially urban landscapes by limiting movement between patch types. These findings suggest that habitat specialization can benefit populations by reducing infectious disease transmission, but by reducing movement between habitat types it could also carry the cost of reducing other movement-related ecosystem functions, such as seed dispersal and pollination.

Microbe Profile: Wigglesworthia glossinidia: the tsetse fly's significant other.

Wigglesworthia glossinidia is an obligate, maternally transmitted endosymbiont of tsetse flies. The ancient association between these two organisms accounts for many of their unique physiological adaptations. Similar to other obligate mutualists, Wigglesworthia's genome is dramatically reduced in size, yet it has retained the capacity to produce many B-vitamins that are found at inadequate quantities in the fly's vertebrate blood-specific diet. These Wigglesworthia-derived B-vitamins play essential nutritional roles to maintain tsetse's physiological homeostasis as well as that of other members of the fly's microbiota. In addition to its nutritional role, Wigglesworthia contributes towards the development of tsetse's immune system during the larval period. Tsetse produce amidases that degrade symbiotic peptidoglycans and prevent activation of antimicrobial responses that can damage Wigglesworthia. These amidases in turn exhibit antiparasitic activity and decrease tsetse's ability to be colonized with parasitic trypanosomes, which reduce host fitness. Thus, the Wigglesworthia symbiosis represents a fine-tuned association in which both partners actively contribute towards achieving optimal fitness outcomes.

Effects of parental drought on offspring fitness vary among populations of a crop wild relative.

Transgenerational plasticity is a form of non-genetic inheritance that can reduce or enhance offspring fitness depending on parental stress. Yet, the adaptive value of such parental environmental effects and whether their expression varies among populations remain largely unknown. We used self-fertilized lines from climatically distinct populations of the crop wild relative Lupinus angustifolius. In the parental generation, full-siblings were grown in two contrasting watering environments. Then, to robustly separate the within-generation and transgenerational response to drought, we reciprocally assigned the offspring of parents to the same experimental treatments. We measured key functional traits and assessed lifetime reproductive fitness. Offspring of drought-stressed parents produced less reproductive biomass, but a similar number of lighter seeds, in dry soil compared to offspring of genetically identical, well-watered parents, an effect not mediated by differences in seed provisioning. Importantly, while the offspring of parents grown in the favourable environment responded to drought by slightly increasing individual seed mass, the pattern of plasticity of the offspring of drought-grown parents showed the opposite direction, and the negative effects of parental drought on seed mass were more pronounced in populations from cooler and moist habitats. Overall, our results show that parental effects may override immediate adaptive responses to drought and provide evidence of population-level variation in the expression of transgenerational plasticity.

Evaluating landscape knowledge and lithic resource selection at the French Middle Paleolithic site of the Bau de l'Aubesier.

We report on the application of a novel approach to exploring the degree of landscape knowledge, wayfinding abilities, and the nature of decision-making processes reflected in the utilization of stone resources in the French Middle Paleolithic. Specifically, we use data from the site of the Bau de l'Aubesier to explore the reasons why a majority of the 350 raw material sources cataloged in the surrounding region appear not to have been utilized, including several located near the site and yielding high-quality lithic materials. To this end, we focus on the spatial relationships between sources as an explanatory variable, operationalized in terms of minimum travel times. Using geographic information system software and a generalized linear model of resource selection derived from the Bau assemblages, we compute source utilization probabilities from the perspective of hominins located off-site. We do so under three optimization scenarios, factoring in the intrinsic characteristics (e.g., quality) and time required to reach each source on the way to the Bau. More generally, we find that in slightly more than 50% of cases, seemingly viable sources may have been ignored simply because the minimum cost path leading back to the Bau passes through or requires only minimal deviations to reach, higher quality options. More generally, we found that throughout the entire region, a cost/benefit analysis of competing sources favors those from source areas known to have been utilized. Virtually all the available information on lithic procurement at the Bau is consistent with a model of landscape utilization premised on detailed knowledge of a very large area, an ability to accurately estimate travel times between locations, and a pragmatic strategy of stone resource exploitation based on minimizing costs (travel and search times) and maximizing utility.

Energetics, but not development, is impacted in coral embryos exposed to ocean acidification.

In light of the chronic stress and mass mortality reef-building corals face under climate change, it is critical to understand the processes driving reef persistence and replenishment, including coral reproduction and development. Here, we quantified gene expression and sensitivity to ocean acidification across a set of developmental stages in the rice coral, Montipora capitata. Embryos and swimming larvae were exposed to pH treatments of 7.8 (ambient), 7.6 (low) and 7.3 (extreme low) from fertilization to 9 days post-fertilization. Embryo and larval volume, and stage-specific gene expression were compared between treatments to determine the effects of acidified seawater on early development. Although there was no measurable size differentiation between pH treatments at the fertilized egg and prawn chip (9 h post-fertilization) stages, early gastrulae and larvae raised in reduced pH treatments were significantly smaller than those raised in ambient seawater, suggesting an energetic cost to developing under low pH. However, no differentially expressed genes were found until the swimming larval stage. Notably, gene expression patterns of larvae developing at pH 7.8 and pH 7.3 were more similar than those of larvae developing at pH 7.6. Larvae from pH 7.6 showed upregulation of genes involved in cell division, regulation of transcription, lipid metabolism and response to oxidative stress in comparison to the other two treatments. Although low pH appears to increase energetic demands and trigger oxidative stress in larvae, the developmental process is robust to this at a molecular level, with the swimming larval stage reached in all pH treatments.

The predicted impact of resource provisioning on the epidemiological responses of different parasites.

Anthropogenic activities and natural events such as periodic tree masting can alter resource provisioning in the environment, directly affecting animals, and potentially impacting the spread of infectious diseases in wildlife. The impact of these additional resources on infectious diseases can manifest through different pathways, affecting host susceptibility, contact rate and host demography. To date however, empirical research has tended to examine these different pathways in isolation, for example by quantifying the effects of provisioning on host behaviour in the wild or changes in immune responses in controlled laboratory studies. Furthermore, while theory has investigated the interactions between these pathways, this work has focussed on a narrow subset of pathogen types, typically directly transmitted microparasites. Given the diverse ways that provisioning can affect host susceptibility, contact patterns or host demography, we may expect the epidemiological consequences of provisioning to vary among different parasite types, dependent on key aspects of parasite life history, such as the duration of infection and transmission mode. Focusing on an exemplar empirical system, the wood mouse Apodemus sylvaticus, and its diverse parasite community, we developed a suite of epidemiological models to compare how resource provisioning alters responses for a range of these parasites that vary in their biology (microparasite and macroparasite), transmission mode (direct, environmental and vector transmitted) and duration of infection (acute, latent and chronic) within the same host population. We show there are common epidemiological responses to host resource provisioning across all parasite types examined. In particular, the epidemiological impact of provisioning could be driven in opposite directions, depending on which host pathways (contact rate, susceptibility or host demography) are most altered by the addition of resources to the environment. Broadly, these responses were qualitatively consistent across all parasite types, emphasising the importance of identifying general trade-offs between provisioning-altered parameters. Despite the qualitative consistency in responses to provisioning across parasite types, we predicted notable quantitative differences between parasites, with directly transmitted parasites (those conforming to SIR and SIS frameworks) predicted to show the strongest responses to provisioning among those examined, whereas the vector-borne parasites showed negligible responses to provisioning. As such, these analyses suggest that different parasites may show different scales of response to the same provisioning scenario, even within the same host population. This highlights the importance of knowing key aspects of host-parasite biology, to understand and predict epidemiological responses to provisioning for any specific host-parasite system.

A double-edged sword: parental care increases risk of offspring infection by a maternally vectored parasite.

Parental care can protect offspring from predators but can also create opportunities for parents to vector parasites to their offspring. We hypothesized that the risk of infection by maternally vectored parasites would increase with the frequency of mother-offspring contact. Ammophila spp. wasps (Hymenoptera: Sphecidae) build nests in which they rear a single offspring. Ammophila species exhibit varied offspring provisioning behaviours: some species enter the nest once to provision a single, large caterpillar, whereas others enter the nest repeatedly to provision with many smaller caterpillars. We hypothesized that each nest visit increases the risk of offspring parasitism by Paraxenos lugubris (Strepsiptera: Xenidae), whose infectious stages ride on the mother wasp (phoresy) to reach the vulnerable Ammophila offspring. We quantified parasitism risk by external examination of museum-curated Ammophila specimens-the anterior portion of P. lugubris protrudes between the adult host's abdominal sclerites and reflects infection during the larval stage. As predicted, Ammophila species that receive larger numbers of provisions incur greater risks of parasitism, with nest provisioning behaviour explaining ca 90% of the interspecific variation in mean parasitism. These findings demonstrate that parental care can augment, rather than reduce, the risk of parasite transmission to offspring.