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Maternal age can influence reproductive success and offspring fitness, but the timing, magnitude and direction of those impacts are not well understood. Evolutionary theory predicts that selection on fertility senescence is stronger than maternal effect senescence, and therefore, the rate of maternal effect senescence will be faster than fertility senescence. We used a 36‐year study of northern elephant seals (Mirounga angustirostris) to investigate reproductive senescence. Our dataset included 103,746 sightings of 1203 known‐age female northern elephant seals. We hypothesized that fertility (maternal reproductive success), offspring survival and recruitment into the breeding population, and male offspring production would decline with advanced maternal age. Furthermore, we hypothesized that older females would shorten their moulting haul out to allow for more time spent foraging. We found evidence for both fertility and maternal effect senescence, but no evidence for senescence impacting offspring recruitment or sex ratio. Breeding probability declined from 96.4% (95% CI: 94.8%–97.5%) at 11 years old to 89.7% (81.9%–94.3%) at 19 years old, and the probability of offspring survival declined from 30.3% (23.6%–38.0%) at 11 years old to 9.1% (3.2%–22.9%) at 19 years old. The rates of decline for fertility and maternal effect senescence were not different from each other. However, maternal effect senescence had a substantially greater impact on the number of offspring surviving to age 1 compared to fertility senescence. Compared to a hypothetical non‐senescent population, maternal effect senescence resulted in 5.3% fewer surviving pups, whereas fertility senescence resulted in only 0.3% fewer pups produced per year. These results are consistent with evolutionary theory predicting weaker selection on maternal effect than fertility senescence. Maternal effect senescence may therefore be more influential on population dynamics than fertility senescence in some systems. [ABSTRACT FROM AUTHOR]

ABSTRACT Hormones mediate life‐history trade‐offs. In female mammals, such trade‐offs have been studied predominantly in the contexts of oestrogen, progesterone and prolactin. We evaluate the hypothesis that prenatal and postnatal testosterone levels structure and regulate trade‐offs in females involving components of reproduction and survival. This hypothesis is predicated on the observation that testosterone confers competition‐related and survival‐related benefits, but also reproduction‐related costs, to female mammals. The hypothesis is supported by field and laboratory data from diverse non‐human animals, and data from healthy women. Most broadly, relatively low testosterone level in females has been associated with earlier, faster and higher offspring production, greater attractiveness to males, and reduced dominance or competitiveness, whereas higher testosterone level is associated with delayed and reduced reproduction but increased dominance, status, aggression, and resource accrual. The magnitude of testosterone‐mediated trade‐offs is expected to depend upon the strength of female–female competition, which represents some function of species‐specific ecology, behaviour and mating system. Testosterone‐associated trade‐offs have, until now, been virtually ignored in studies of female life history, reproductive physiology, evolutionary endocrinology, and female‐limited disease, probably due to researcher biases towards conceptualizing androgens as hormones with effects mainly restricted to males. [ABSTRACT FROM AUTHOR]

The role of epigenetics in regulating caste polyphenism in social insects has been debated. Here, we tested the importance of histone de/acetylation processes for the maintenance of queen hallmarks like a high fecundity and a long lifespan. To this end, we performed RNA interference experiments against histone deacetylase 3 (HDAC3) in the termite Cryptotermes secundus. Fat body transcriptomes and chemical communication profiles revealed that silencing of HDAC3 leads to signals indicative of queen hallmarks. This includes fostering of queen signalling, defence against ageing and a reduction of life‐shortening IIS (insulin/insulin‐like growth factor signalling) and endocrine JH (juvenile hormone) signalling via Kr‐h1 (Krüppel‐homologue 1). These observed patterns were similar to those of a protein‐enriched diet, which might imply that histone acetylation conveys nutritional effects. Strikingly, in contrast to solitary insects, reduced endocrine JH signalling had no negative effect on fecundity‐related vitellogenesis in the fat bodies. This suggests an uncoupling of longevity pathways from fecundity in fat bodies, which can help explain queens' extraordinary lifespans combined with high fecundity. [ABSTRACT FROM AUTHOR]

Altricial songbirds transform themselves from naked poikilotherms to fully feathered endothermic homeotherms over a matter of days from hatching to fledging. The ontogeny of endothermy is a developmental milestone for birds that not only face warmer average temperatures, but also increasingly frequent cold snaps and extreme weather. The timing of development of endothermy has been studied in altricial birds for over half a century. However, the determinants and constraints of the onset of endothermy are not yet fully understood. We experimentally investigated whether brood size influences the ontogeny of endothermic heat production in 4–8 day‐old nestling blue tits Cyanistes caeruleus in southern Sweden. The thermogenic response to a cooling challenge (15°C) increased with age overall. We found that 8‐day‐old nestlings from reduced broods had a slightly increased capacity for endothermic heat production compared to enlarged broods. This difference cannot be explained by body mass because this trait did not differ between brood size categories. Although a metabolic response was present in most nestlings by day 6, it was brief, not lasting more than a few minutes, and not sufficient to maintain a stable body temperature in any age group. Our study shows that incipient endothermy is present at an early age in nestling blue tits and may advance faster in reduced broods, but that individual nestlings lack sufficient insulation and thermogenic performance to maintain homeothermy independently during the first week of life. [ABSTRACT FROM AUTHOR]

Understanding an organism's niche and ecological role in its ecosystem is critical for conservation, especially for species that use multiple habitats at different life stages. The hawksbill sea turtle (Eretmochelys imbricata) is one such migratory animal that plays an ecologically important role in imperiled coral reef habitats. Hawksbill resource use strategies (e.g., generalism vs. specialism) in these foraging grounds are poorly understood, yet stable isotope analysis of carbon (δ13C) and nitrogen (δ15N) can provide information on the trophic niche and foraging location of consumers. Additionally, when a single sample is taken from a tissue that accretes through time, such as keratin, analyses can reveal information on the long-term foraging patterns of individuals. Here, we evaluate resource use strategies for 98 females within a nesting aggregation of hawksbills on the island of Antigua (17.159, -61.756) in the Eastern Caribbean. Stable isotope analysis of scute tissue collected from 2017 to 2019 revealed population-level generalism and varying degrees of individual specialization. Additionally, reproductive age was significantly related to niche width, with younger turtles showing higher variability in their isotopic record. Older turtles displayed overall smaller ranges in isotope values, indicating a narrowing of resource use with increased reproductive age amongst breeding adult females. These findings provide evidence of high variability in hawksbill diet, illustrate differences in ecological niche use across different ages, and highlight the necessity of evaluating multiple life stages to inform the conservation of this critically endangered species. [ABSTRACT FROM AUTHOR]

Photo-identification is a staple tool used in cetacean conservation studies since the 1970s to monitor individuals on a regional and ocean basin-wide scale to infer critical information about habitat use, suitability, and shifts. This technique has been extensively used on sperm whales globally since it was developed in 1982, initially using the tail fluke from deep diving whales and the dorsal fin when appropriate. From the mid 2010s onwards, the emergence of domestically available unoccupied aerial systems (drones) has reshaped how whale research can be conducted. Herein, we describe the suitability of aerial images to determine the identity of individual sperm whales (Physeter macrocephalus) using all available identifiable markings along their dorsal side to complement the use of fluke notches and dorsal fin scars photographed from the surface of the sea from boatbased platforms for photo-identification and to maximize opportunities to identify and monitor sperm whales. Drone data were gathered while flying over sperm whales in Andenes, Norway; Shetland, Scotland; Dursey Island, Ireland; and Faial and São Miguel Islands, Azores, Portugal, between 2017 and 2024, which enabled the entire dorsal surface of sperm whales to be captured and assessed. Aerial photographs and videos were used to differentiate between 336 individual sperm whales using physical characteristics. We identified the main features of sperm whales through aerial drone images, as well as their prevalence in Atlantic high latitude foraging grounds and lower latitude nursery grounds. We discuss the advantages of using aerial drone photographs to identify sperm whales in addition to traditional boat-based photo-identification. [ABSTRACT FROM AUTHOR]

Animal nests provide a beneficial environment for offspring development and as such, contribute to fitness. Gathering and transporting materials to construct nests is energetically costly, but the life history trade-offs associated with the types of nests built are largely unknown. Who contributes to building the nest could also mediate these trade-offs, as building a nest as a couple is expected to be less costly per individual than building alone. Using a comparative analysis of 227 songbird species globally, we found a fecundity cost associated with the type of nest a species builds. Species that build domed nests produce fewer broods per year than species building cups or platforms. Dome nesting species also have larger clutch sizes than open nesting species, but only when the nest is built by a couple and not when females build nests alone. This suggests that building domed nests represents a trade-off with investment in young, especially when females are solely responsible for nest building. More broadly, our results could explain macroevolutionary patterns, such as the recent finding that females, building on their own, more often build open cups rather than domed nests. [ABSTRACT FROM AUTHOR]

Understanding populations' responses to environmental change is crucial for mitigating human‐induced disturbances.Here, we test hypotheses regarding how three essential components of demographic resilience (resistance, compensation and recovery) co‐vary along the distinct life histories of three lizard species exposed to variable, prescribed fire regimes.Using a Bayesian hierarchical framework, we estimate vital rates (survival, growth and reproduction) with 14 years of monthly individual‐level data and mark‐recapture models to parameterize stochastic integral projection models from five sites in Brazilian savannas, each historically subjected to different fire regimes. With these models, we investigate how weather, microclimate and ecophysiological traits of each species influence their vital rates, emergent life history traits and demographic resilience components in varying fire regimes.Overall, weather and microclimate are better predictors of the species' vital rates, rather than their ecophysiological traits. Our findings reveal that severe fire regimes increase populations' resistance but decrease compensation or recovery abilities. Instead, populations have higher compensatory and recovery abilities at intermediate degrees of fire severity. Additionally, we identify generation time and reproductive output as predictors of resilience trends across fire regimes and climate. Our analyses demonstrate that the probability and quantity of monthly reproduction are the proximal drivers of demographic resilience across the three species.Our findings suggest that populations surpass a tipping point in severe fire regimes and achieve an alternative stable state to persist. Thus, higher heterogeneity in fire regimes can increase the reproductive aspects and resilience of different populations and avoid high‐severity regimes that homogenize the environment. Despite being more resistant, species with long generation times and low reproductive output take longer to recover and cannot compensate as much as species with faster paces of life. We emphasize how reproductive constraints, such as viviparity and fixed clutch sizes, impact the ability of ectothermic populations to benefit and recover from disturbances, underscoring their relevance in conservation assessments. [ABSTRACT FROM AUTHOR]

Polyphenisms occur when phenotypic plasticity produces morphologically distinct phenotypes from the same genotype. Plasticity is maintained through fitness trade‐offs which are conferred to different phenotypes under specific environmental contexts. Predicting the impacts of contemporary climate change on phenotypic plasticity is critical for climate‐sensitive animals like amphibians, but elucidating the selective pressures maintaining polyphenisms requires a framework to control for all mechanistic drivers of plasticity.Using a 32‐year dataset documenting the larval and adult histories of 717 Arizona tiger salamanders (Ambystoma mavortium nebulosum), we determined how annual variation in climate and density dependence explained the maintenance of two distinct morphs (terrestrial metamorph vs. aquatic paedomorph) in a high‐elevation polyphenism. The effects of climate and conspecific density on morph development were evaluated with piecewise structural equation models (SEM) to tease apart the direct and indirect pathways by which these two mechanisms affect phenotypic plasticity.Climate had a direct effect on morph outcome whereby longer growing seasons favoured metamorphic outcomes. Also, climate had indirect effects on morph outcome as mediated through density‐dependent effects, such as long overwintering coldspells corresponding to high cannibal densities and light snowpacks corresponding to high larval densities, both of which promoted paedomorphic outcomes.Both climate and density dependence serve as important proxies for growth and resource limitation, which are important underlying drivers of the phenotypic plasticity in animal polyphenisms. Our findings motivate new studies to determine how contemporary climate change will alter the selective pressures maintaining phenotypic plasticity and polyphenisms. [ABSTRACT FROM AUTHOR]

Intraspecific variability in parasite virulence holds significant ecological and evolutionary implications as it can result in uneven costs incurred by individuals of a host species. Obligate brood parasites, birds that lay their eggs in the nest of another species and do not raise their own young, differ in interspecific virulence, as some species kill all host nestmates directly while other species do not. However, variation in the intraspecific virulence of a brood-parasitic species has rarely been investigated. One source of this variability could arise through sexual size dimorphism, because many brood-parasitic species are sexually dimorphic in size starting at the nestling stage, and nestling size often impacts competitive ability in the brood. Here, we investigated the sex-specific effects of nestling brood-parasitic brown-headed cowbirds, Molothrus ater , on one of their hosts, the prothonotary warbler, Protonotaria citrea. We predicted that larger male cowbird nestlings would cause host chicks to have lower survival and size and altered life history in the form of delayed fledging. Using experimentally parasitized broods, we found that although male brood-parasitic cowbird nestlings are heavier than females, there was no effect of cowbird sex on the survival, size or fledging phenology of the host nestlings. Furthermore, there were no differences in fledging phenology between the male and female cowbird chicks. Instead, we found that wing length, which was similar between the parasitic nestlings' sexes, was an important predictor for age and order of fledging. These findings show that the extent of development is critical for the timing of fledging of both parasitic and host species. Notably, the lack of effect of cowbird nestling sex on host chick survival and fledging suggests that the presence of a parasite is more influential for host nestlings than the size of parasites. • Nest-sharing obligate brood parasite chicks often outcompete smaller host nestmates. • Several brood-parasitic species display sexual size dimorphism at the chick stage. • Sex-specific virulence of larger male parasitic chicks could affect host demography. • Parasitic chick sex did not affect host chick survival or fledging. • Parasites decreased host chick survival and delayed fledging regardless of mass. [ABSTRACT FROM AUTHOR]

Patterns of cohort decline are key demographic traits that provide a unique temporal perspective vital to understanding population dynamics. The discovery of multidecadal lifespans in tropical surgeonfishes in the 1990s created a paradigm shift to the notion that they are highly vulnerable species with low population recovery rates; however, research into the mortality patterns of surgeonfishes (Acanthuridae) has been sparse until recently. Recent studies on this family have demonstrated an unusual (possibly unique), two‐phase pattern of adult catch‐at‐age, whereby there is a population‐level shift from higher‐than‐expected rates of decline early in life to lower‐than‐expected decline rates for the remainder of the lifespan. To examine the geographic and phylogenetic ubiquity of this pattern, we compiled age‐based information from demographic samples of 70 populations of 25 tropical species spanning the Indo‐Central Pacific and Central‐Western Atlantic. Overall, we found that 79% of populations exhibited strong biphasic patterns, including 88% of populations across the Indo‐Central Pacific. By accounting for empirical relationships instead of using linear catch curves or classical assumptions of natural population decay based on lifespan, we demonstrate that surgeonfishes have turnover times that are two to four times faster than previously believed. Faster turnover times may suggest a higher level of sustainability for surgeonfish fisheries throughout the global tropics than previously estimated. [ABSTRACT FROM AUTHOR]

The life history of the Taiwanese spider wasp Minotocyphus formosanus (Pompilidae: Pepsinae) is reported, including the developmental process of the immature stages. The larva was attached by the spider wasp to the abdomen of the funnel-web spider Macrothele hungae (Mygalomorphae: Macrothelidae). In terms of mode of life, M. formosanus was established as a koinobiont ectoparasitoid. These biological findings are the first reports for not only the species M. formosanus, but also the genus Minotocyphus. [ABSTRACT FROM AUTHOR]

Summary: Accurate divergence times are essential for interpreting and understanding the context in which lineages have evolved. Over the past several decades, debates have surrounded the discrepancies between the inferred molecular ages of crown angiosperms, often estimated from the Late Jurassic into the Permian, and the fossil record, placing angiosperms in the Early Cretaceous. That crown angiosperms could have emerged as early as the Permian or even the Triassic would have major implications for the paleoecological context of the origin of one of the most consequential clades in the tree of life. Here, we argue, and demonstrate through simulations, that the older ages inferred from molecular data and relaxed‐clock models are misled by lineage‐specific rate heterogeneity resulting from life history changes that occurred several times throughout the evolution of vascular plants. To overcome persistent discrepancies in age estimates, more biologically informed and realistic models should be developed, and our results should be considered in the context of their biological implications before we accept inferences that are a major departure from our strongest evidence. [ABSTRACT FROM AUTHOR]

Simple Summary: The current state of rainbow trout, Oncorhynchus mykiss, was investigated 50 years after the first introduction of the species to the water bodies of the Balkhash basin. The wild form of the species from Kamchatka and the cultured form from European fish farms have successfully adapted to the local environmental conditions. Unlike in most other regions of the world, rainbow trout have not spread beyond the water bodies of their original introduction and have not significantly impacted native fish diversity. Rainbow trout, or mykiss (Oncorhynchus mykiss), is one of the most popular species used in aquaculture and has been naturalized worldwide, including in the Central Asian Balkhash basin, which has unique aboriginal fish fauna. Both rainbow trout from European farms and wild mykiss from Kamchatka were introduced to some mountain lakes and rivers of the Balkhash basin about 50 years ago. This study investigates the current distribution and life history traits of the alien species and its possible impact on the local fish fauna. This study showed that the rainbow trout occupies various habitats in the Ili River basin: mountain lakes, fast-flowing mountain rivers, and lowland rivers with slow currents and warm water (up to +27 °C). Rainbow trout from European fish farms dominate the mountain Middle Kolsay Lake, while the wild trout from Kamchatka occupies the small Ulken Kokpak River. Both co-occur in the Chilik River. Contrary to that in other regions, the distribution of rainbow trout in the Balkhash basin remained almost the same after their introduction. Broad intrapopulation variability in terms of size, growth rate, and maturation age was revealed, apparently as a result of adaptation to the new environment and intrapopulation competition. In particular, the growth rate has decreased, but life span, surprisingly, has increased as compared to the originally introduced fish. Intrapopulation variation in growth and maturity patterns was also noted. Differences in skin coloration between highland (cold-water) and lowland (warm-water) populations were discovered. The feeding mode of naturalized trout is insectivorous (insect imago), indicating that it occupies its own niche in the local fish communities. The largest population of rainbow trout was recorded in the Lower Kolsay Lake, lowering the population of native fish species, while in other localities, no negative impact on local fish communities was recorded. [ABSTRACT FROM AUTHOR]

The phenology of temperate perennials, including the timing of vegetative growth and flowering, is well known to be controlled by seasonal dormancy cycles. Dormant structures are known as buds and have specialized covering structures, symplastic isolation from the plant, and often autonomous stores of carbon and nitrogen reserves. In contrast, in annual plants, our current understanding of the control of the timing of flowering focuses on the mechanisms affecting floral initiation, the transition from a vegetative apical meristem to a inflorescence meristem producing flower primordia in place of leaves. Recently we revealed that annual crops in Brassicaceae exhibit chilling-responsive growth control in a manner closely resembling bud dormancy breakage in perennial species. Here I discuss evidence that vernalization in autumn is widespread and further discuss its role in inducing flower bud set prior to winter. I also review evidence that flower bud dormancy has a more widespread role in annual plant flowering time control than previously appreciated. [ABSTRACT FROM AUTHOR]

Movement is a key means by which animals cope with variable environments. As they move, animals construct individual niches composed of the environmental conditions they experience. Niche axes may vary over time and covary with one another as animals make tradeoffs between competing needs. Seasonal migration is expected to produce substantial niche variation as animals move to keep pace with major life history phases and fluctuations in environmental conditions. Here, we apply a time-ordered principal component analysis to examine dynamic niche variance and covariance across the annual cycle for four species of migratory crane: common crane (Grus grus, n = 20), demoiselle crane (Anthropoides virgo, n = 66), black-necked crane (Grus nigricollis, n = 9), and white-naped crane (Grus vipio, n = 9). We consider four key niche components known to be important to aspects of crane natural history: enhanced vegetation index (resources availability), temperature (thermoregulation), crop proportion (preferred foraging habitat), and proximity to water (predator avoidance). All species showed a primary seasonal niche "rhythm" that dominated variance in niche components across the annual cycle. Secondary rhythms were linked to major species-specific life history phases (migration, breeding, and nonbreeding) as well as seasonal environmental patterns. Furthermore, we found that cranes' experiences of the environment emerge from time-dynamic tradeoffs among niche components. We suggest that our approach to estimating the environmental niche as a multidimensional and time-dynamical system of tradeoffs improves mechanistic understanding of organism-environment interactions. [ABSTRACT FROM AUTHOR]

Capturing data on the life of fossorial vertebrates is difficult since access to the subterranean environment is made unfeasible by its density and opacity. Collecting specimens is only possible through excavation work, causing damage or even death to the specimens. Due to the obstacles of in situ studies, the scarce information comes from reports obtained indirectly, mainly through specimens preserved in museums. Considering the adaptations to fossoriality, investments in studying these groups could be very enlightening since they would contribute enormously to the knowledge of the evolutionary strategies developed throughout the colonisation of the subterranean world. Amphisbaena alba is the species of Amphisbaenia with the broadest geographic distribution in the world. It occupies virtually all countries in South America except for Chile and southern Argentina. This study, carried out over the last 36 years, aims to provide data on the biology and behaviour of A. alba in captivity and in the field. Our main objective is to provide subsidies to expand the knowledge of the life history of this species and, by extension, of amphisbaenians in general. [ABSTRACT FROM AUTHOR]

Evolutionary biology is poised for a third major synthesis. The first presented Darwin's evidence from natural history. The second incorporated genetic mechanisms. The third will be based on energy and biophysical processes. It should include the equal fitness paradigm (EFP), which quantifies how organisms convert biomass into surviving offspring. Natural selection tends to maximise energetic fitness, E=PcohGFQ$$ E={P}_{\mathrm{coh}}\mathrm{GFQ} $$, wherePcoh$$ {P}_{\mathrm{coh}} $$ is mass‐specific rate of cohort biomass production, G$$ G $$ is generation time, F$$ F $$ is fraction of cohort production that is passed to surviving offspring, and Q$$ Q $$ is energy density of biomas. At steady state, parents replace themselves with offspring of equal mass‐specific energy content, E$$ E $$ ≈ 22.4 kJ/g, and biomass, M$$ M $$ ≈ 1 g/g. The EFP highlights: (i) the energetic basis of survival and reproduction; (ii) how natural selection acts directly on the parameters of M$$ M $$; (iii) why there is no inherent intrinsic fitness advantage for higher metabolic power, ontogenetic or population growth rate, fecundity, longevity, or resource use efficiency; and (iv) the role of energy in animals with a variety of life histories. Underlying the spectacular diversity of living things is pervasive similarity in how energy is acquired from the environment and used to leave descendants offspring in future generations. [ABSTRACT FROM AUTHOR]

Aquatic invasive species (AIS) are a global threat to freshwater biodiversity and ecosystem services. Documenting AIS prevalence at broad spatial scales is critical to effective management and early detection. However, conventional monitoring for AIS is costly and is rarely applied at the resolution and scale required for effective management. Monitoring of AIS using environmental DNA (eDNA) has the potential to enable broadscale surveillance at a fraction of the cost of conventional methods, but key questions must first be addressed related to how eDNA detection probability varies among environments, seasons, and multiple species with different life histories.To quantify spatiotemporal variation in the detection probability of AIS using eDNA sampling, we surveyed 20 lakes with known populations of four aquatic invasive species: common carp (Cyprinus carpio), rusty crayfish (Faxonius rusticus), spiny waterflea (Bythotrephes longimanus), and zebra mussels (Dreissena polymorpha). We collected water samples at 10 locations per lake, five times throughout the open water season resulting in a total of 1,000 water samples. Quantitative polymerase chain reaction was used with species‐specific assays to determine the presence of each species' eDNA in water samples. With Bayesian occupancy models, we quantified the effects of lake and site characteristics and Julian date on eDNA detection probability.The probability of eDNA detection varied seasonally, and the seasonal variation was species‐specific and related to species life histories. Zebra mussel eDNA was generally the most detectable among the species we targeted, and detection probability peaked in midsummer when only six water samples were required to achieve a 95% probability of detection (80% Bayesian credible interval: 3–12 samples). Spiny waterflea eDNA detections also peaked in mid to late summer, but were overall the most difficult species to detect, requiring 160 samples for a 95% probability of detection (80% Bayesian credible interval: 67–1,616 samples). Common carp eDNA was most detectable in the spring and rusty crayfish eDNA was most detectable in the early autumn, corresponding to key life history events.Sampling for eDNA during the optimal time of the year for each species decreased the number of samples required to reach a 95% probability of detection by an order of magnitude or more.Our results are relevant for decision makers interested in using eDNA as a multi‐species monitoring tool and highlight the importance of life history in the efficacy of eDNA monitoring. [ABSTRACT FROM AUTHOR]

Understanding factors that influence population‐level responses to emerging threats in declining species is crucial for informed conservation action. In amphibian species impacted by the chytrid fungus (Batrachochytrium dendrobatidis), a pathogen that has caused amphibian declines globally, a commonly reported pattern is that more severe population declines tend to occur at higher elevations. Previous research has suggested that this pattern could be driven by reduced environmental suitability for chytrid fungus at lower elevations. However, delayed amphibian maturation, which is common in cold, high elevation populations, could also increase vulnerability to population decline. Here, we tackle this key knowledge gap, focusing on the critically endangered corroboree frogs (Pseudophryne corroboree and P. pengilleyi), which have experienced a pattern of extirpation at higher elevations, with remnant populations persisting at lower elevations. First, we quantify the age structure of two extant low elevation P. pengilleyi populations and museum specimens (both species) collected before the emergence of chytrid fungus in Australia. Male age to maturation varied from 1 to 3 years, with the extant population with higher chytrid prevalence displaying severe age structure truncation. Second, we use population simulations to calculate elasticity values under a range of scenarios with varying ages to maturation and chytrid‐associated mortality. When the population growth rate was fixed at 1, adult survival became increasingly important as age to maturation increases, particularly under a scenario of high chytrid‐associated mortality. Our simulation results indicate that delayed maturation could be a previously underappreciated factor associated with an increased risk of amphibian population decline and that earlier maturation could contribute to population persistence. Our study highlights the importance of examining variation in life history traits to better understand population‐level responses to novel threats and guide the development of appropriate conservation actions. [ABSTRACT FROM AUTHOR]

Breeding phenology can have strong demographic consequences. Yet, the reasons why coexisting animal species differ in breeding phenology have received little attention.We tested selection pressures that underlie life history variation, such as age‐specific mortality, diet, and body size to explain breeding phenology of 16 coexisting songbird species in arid shrubland in South Africa.The average start and end dates for the earliest and latest species differed by 1.5 months, with a gradient among remaining species. Nest predation risk generally increased through the season, although species differed in seasonal patterns. Species with lower annual adult mortality, greater seasonal increases in nest predation, and greater nest predation rates had earlier start and stop dates, thereby reducing demographic risks. Species with higher adult mortality had larger brood sizes that require more food and they bred later when food was more abundant. Evolved timing of breeding thereby reflected risk management and food availability related to longevity and brood size.These factors may place unrecognized constraints on within‐species responses to climate change. Given the importance of phenology for fitness, phenology should be integrated as a core life history trait in future theory, and evolutionary constraints need to be considered in responses to climate change. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Objectives: Nitrogen isotopes (δ15N) are widely used to study human nursing and weaning ages. Conventional methods involve sampling 1‐mm thick sections of tooth dentine—producing an averaging effect that integrates months of formation. We introduce a novel protocol for measuring δ15N by multicollector secondary ion mass spectrometry (SIMS). Materials and Methods: We sampled dentine δ15N on a weekly to monthly basis along the developmental axis in two first molars of healthy children from Australia and New Zealand (n = 217 measurements). Nitrogen isotope ratios were determined from measurements of CN− secondary molecular ions in ~35 μm spots. By relating spot position to enamel formation, we identified prenatal dentine, as well as sampling ages over more than 3 years. We also created calcium‐normalized barium and strontium maps with laser ablation‐inductively coupled plasma‐mass spectrometry. Results: We found rapid postnatal δ15N increases of ~2‰–3‰, during which time the children were exclusively breastfed, followed by declines as the breastfeeding frequency decreased. After weaning, δ15N values remained stable for several months, coinciding with diets that did not include meat or cow's milk; values then varied by ~2‰ starting in the third year of life. Barium did not show an immediate postnatal increase, rising after a few months until ~1–1.5 years of age, and falling until or shortly after the cessation of suckling. Initial strontium trends varied but both individuals peaked months after weaning. Discussion: Developmentally informed SIMS measurements of δ15N minimize time averaging and can be precisely related to an individual's early dietary history. [ABSTRACT FROM AUTHOR]

Several ecological processes – from population dynamics to species co‐existence – are driven by density dependence (DD) in population growth rate. Thus, to predict and manage ecological outcomes, we need a deep understanding of which factors and demographic traits drive variation in DD. In the insect pest Tribolium castaneum, we found large variation in DD across habitats but not across source populations. We modeled DD in population growth as the product of DD in fecundity and survival, experimentally estimating each parameter. Across habitats, survival parameters varied more than fecundity, including in simulations with varying parameter values. Thus, DD in survival drives variation in density‐dependent population growth. Hence, under strong density‐dependent selection, we expect evolutionary change in density‐dependent survival, provided sufficient genetic variance. Our general framework combining detailed experiments and simulations with a simple model can be used for other species to better understand the causes and consequences of density dependent population growth. [ABSTRACT FROM AUTHOR]

Environmental variability can significantly impact individual survival and reproduction. Meanwhile, high population densities can lead to resource scarcity and increased exposure to parasites and pathogens. Studies with insects can offer valuable insights into eco-immunology, allowing us to explore the connections between these variables. Here we use the moth Anticarsia gemmatalis to examine how increases in population density and immunological challenge during the larval stage shape its investment in immune defence and reproduction. Larvae reared at a high population density exhibited greater lytic activity against bacteria compared to those reared at low density, whilst bacterial challenge (i.e. bacteria-immersed needles) also increased lytic activity. There was no interaction between the variables population density and bacterial challenge, indicating that these are independent. Surprisingly, neither increase in lytic activity carried through to activity in prepupal haemolymph. Rearing of larvae at a high density delayed pupation and decreased pupal weight. The immunological stimulus did not significantly influence pupal development. Lower population density as a larva resulted in greater adult weight, but did not significantly influence lytic activity in the eggs or the number of eggs laid. Negative correlations were found between lytic activity in the eggs and the number of eggs, as well as between adult weight and the number of eggs. Overall, this study demonstrates that high population density and immune challenge trigger increased lytic activity in caterpillars, but this effect is transient, not persisting into later stages. The trade-offs observed, such as delayed pupation and reduced prepupal weights under high density, suggest a balancing act between immune investment and developmental aspects. The findings hint at a short-term adaptive response rather than a sustained strategy. The implications of delayed pupation and smaller adult moths could influence the moth's life history strategy, impacting its role in the ecosystem. Further research tracking larval immune investment and subsequent reproductive success will unveil the evolutionary dynamics of this relationship in changing environments. [ABSTRACT FROM AUTHOR]

Squamate reptiles are central for studying phenotypic correlates of evolutionary transitions from oviparity to viviparity because these transitions are numerous, with many of them being recent. Several models of life‐history theory predict that viviparity is associated with increased female size, and thus more female‐biased sexual size dimorphism (SSD). Yet, the corresponding empirical evidence is overall weak and inconsistent. The lizard Zootoca vivipara, which occupies a major part of Northern Eurasia and includes four viviparous and two non‐sister oviparous lineages, represents an excellent model for testing these predictions. We analysed how sex‐specific body size and SSD is associated with parity mode, using body length data for nearly 14,000 adult individuals from 97 geographically distinct populations, which cover almost the entire species' range and represent all six lineages. Our analyses controlled for lineage identity, climatic seasonality (the strongest predictor of geographic body size variation in previous studies of this species) and several aspects of data heterogeneity. Parity mode, lineage and seasonality are significantly associated with female size and SSD; the first two predictors accounted for 14%–26% of the total variation each, while seasonality explained 5%–7%. Viviparous populations exhibited a larger female size than oviparous populations, with no concomitant differences in male size. The variation of male size was overall low and poorly explained by our predictors. Albeit fully expected from theory, the strong female bias of the body size differences between oviparous and viviparous populations found in Z. vivipara is not evident from available data on three other lizard systems of closely related lineages differing in parity mode. We confront this pattern with the data on female reproductive traits in the considered systems and the frequencies of evolutionary changes of parity mode in the corresponding lizard families and speculate why the life‐history correlates of live‐bearing in Z. vivipara are distinct. Comparing conspecific populations, our study provides the most direct evidence for the predicted effect of parity mode on adult body size but also demonstrates that the revealed pattern may not be general. This might explain why across squamates, viviparity is only weakly associated with larger size. [ABSTRACT FROM AUTHOR]

Studies on Chinese immigration in Spain are usually focused on self-employed workers coming from southern China and who are considered as the majority of cases. But the population of southern self-employed Chinese doesn't cover the absolute majority homogeneously in order to represent the entire community. Through the lens of anthropology, we have discovered in their life histories that women from northern China moved to Spain due to the economic fall of China's northern area after the reforms (and socio-cultural changes derived from them) implemented towards the end of the 20th century and the beginning of the 21st century. They arrived on their own, in an irregular situation, unable to speak Spanish, and therefore their life in Spain began as employees of their southern compatriots. Due to this, their integration into the host society meant joining the existing Chinese community and adapting themselves to the modus vivendi framed by it. [ABSTRACT FROM AUTHOR]

The genus Prorocentrum is diverse and comprises mostly marine dinoflagellates with a worldwide distribution. One large, common and easily recognizable planktonic species of Prorocentrum was known for a long time as P. compressum. This name, however, is incorrectly linked to a basionym of a diatom. The confusing taxonomy of the now also lectotypified diatom name was recently resolved, and the next younger available name, Prorocentrum bidens, was proposed for the dinoflagellate species. Based on multiple strains from various localities we here provide the first detailed morphological study of P. bidens thereby propagating the correct nomenclature of this species. The cells of one strain differed consistently from material assigned to P. bidens, and Prorocentrum bisaeptum sp. nov. is described here to represent this closely related species. Both species possessed two pyrenoids per chloroplast and shared the arrangement of ten periflagellar platelets, including subdivisions of platelets 6 and 8. Cells of both species were either fully motile or, in an encapsulated stage, enclosed with actively beating flagella in a hyaline flexible envelope bounded by a thin surface layer. Prorocentrum bisaeptum differs from P. bidens by a more elongated shape of the cells and by a smooth (not foveate) surface of the thecal plates. Most importantly, one to four cells of P. bisaeptum are consistently enclosed within two nesting envelopes, whereas there is only one such structure tightly surrounding one or two cells of P. bidens. This study increases and improves our knowledge of the diversity within this important group of planktonic organisms. [ABSTRACT FROM AUTHOR]

In the genus Sporochnus (Sporochnales, Phaeophyceae), Okamura reported S. radiciformis and S. scoparius in Japan in 1922; however, S. scoparius was later synonymized with S. radiciformis, as Okamura's S. radiciformis was considered to be a young stage of S. scoparius. Therefore, only one species, S. radiciformis, has been recognized in Japan, until the reported occurrence of a second species, S. dotyi, and suggestion that the species identified as S. radiciformis in Japan was genetically distinct from true S. radiciformis described from Australia. We now report findings that based on molecular phylogeny (atpB, rbcL, atp6, cox3) and morpho-anatomical analyses confirming that the common Japanese Sporochnus species is distinct from true S. radiciformis, and we therefore describe a new species, S. keyari sp. nov. This new species differs from S. radiciformis in having less-branched erect thalli, longer terminal assimilatory filaments (trichothallic hairs), and larger unilocular zooidangia, and from S. bolleanus in having more robust thallus axes. In gross morphology, S. keyari is distinguished from S. dotyi, which is also distributed in Japan, in having more slender thalli and lacking greenish structural colour of the assimilatory filaments. In culture, unizoids (zoospores) released from unilocular zooidangia developed into monoicous gametophytes forming antheridia and oogonia at the distal ends of the filaments. Actual sexual fusion was not observed, but presumably fertilization occurred within oogonia and new sporophytes developed in situ within oogonia. Sporophytes were at first uniseriate, but later formed terete thalli by trichothallic growth, with terminal assimilatory filaments. [ABSTRACT FROM AUTHOR]

The fundamental trade‐off between current and future reproduction has long been considered to result in a tendency for species that can grow large to begin reproduction at a larger size. Due to the prolonged time required to reach maturity, estimates of tree maturation size remain very rare and we lack a global view on the generality and the shape of this trade‐off. Using seed production from five continents, we estimate tree maturation sizes for 486 tree species spanning tropical to boreal climates. Results show that a species' maturation size increases with maximum size, but in a non‐proportional way: the largest species begin reproduction at smaller sizes than would be expected if maturation were simply proportional to maximum size. Furthermore, the decrease in relative maturation size is steepest in cold climates. These findings on maturation size drivers are key to accurately represent forests' responses to disturbance and climate change. [ABSTRACT FROM AUTHOR]

Mutualisms constitute a diverse class of ecologically important interactions, yet their ecological and evolutionary stability remain topics of debate in coevolutionary theory. Recent theoretical and empirical work has suggested that coevolutionary arms races may be involved in the maintenance of mutualistic interactions, sustaining mutually beneficial outcomes for interacting species while producing exaggerated traits. Here we present an individual-based model that evaluates how asynchronous life histories—that is, partners with different average lifespans—change the dynamics of trait coevolution, the expected fitness outcomes for species involved, and the dynamics of selection differentials across time for each species. Results indicate that a longer-lived mutualist will consistently "lose" an otherwise balanced coevolutionary arms race, being outpaced in both the mean trait value and fitness outcome compared with a shorter-lived partner. Furthermore, linear selection differentials on mutualistic traits become increasingly divergent as life histories become increasingly asynchronous, with the longer-lived species experiencing persistent directional selection and the shorter-lived species experiencing weaker, more inconsistent selection. These results suggest that asynchronous life histories can complicate the maintenance of mutualistic interactions via coevolutionary arms races and that detecting coevolution via selection differentials may be difficult when life histories are sufficiently divergent. [ABSTRACT FROM AUTHOR]

The island syndrome is a widespread biological phenomenon that describes a suite of morphological, behavioural, demographic and life‐history changes associated with island dwelling. These similar evolutionary responses among disparate groups of animals and plants represent a remarkable case of convergent evolution. Among animals, birds are a highly suitable group to study the island syndrome; they are a comparatively data‐rich taxon, are frequent island colonisers, and sometimes display extreme adaptations such as the loss of flight. However, the avian island syndrome literature is fragmented, and multiple components are rarely considered together even though many are inextricably linked. We reviewed multi‐species comparative studies, single‐species or population‐level studies and anecdotal accounts, to summarise and assess the support for individual components of the island syndrome for birds, and to identify suites of traits that should be considered together. The weight of evidence for island syndrome patterns in morphology is substantial, but is more partial or even anecdotal for various aspects of behaviour, life history and physiology. Full validation of the island syndrome in birds will require the less‐studied components to be treated in a comparative framework, and for covarying components to be examined in an integrated way. An improved description of the scope of the syndrome will pave the way to understanding its drivers. [ABSTRACT FROM AUTHOR]

Objectives: Age at death estimation is a key element to many research questions in biological anthropology, archeology, and forensic science. Dental cementum is a tissue of choice for the estimation of age at death in adult individuals as it continues deposition for the entirety of an individual's life. Previous works have devised regression formulas correlating cementum thickness to age at death. However, interpopulation variances are unknown, and it is therefore not clear whether regressions based on a single population are applicable to individuals with different ancestries. Materials and Methods: Here, we use a sample (n = 52) of teeth from individuals with known age at tooth extraction/death of European, African, and East Asian ancestry to assess whether there are interpopulations differences in cementum growth rate. We measured growth rate in four different areas (2nd and 5th decile of both the lingual and buccal aspect of the root) of each tooth and used nonparametric tests to evaluate population differences in growth rate between homologous regions of the teeth. Results: The results of the analyses show that, even after controlling for tooth size, individuals of European ancestry have significantly lower growth rates than those of both African and East Asian ancestry across all four tooth areas. Discussion: These results call into question the applicability of the regression formulas derived from European ancestry individuals to individuals of other ancestries. [ABSTRACT FROM AUTHOR]

Some hosts harbor more parasites than others. Overdispersion of parasitism suggests that coevolution with parasites may be more important to the biology and ecology of certain species. We examined patterns of parasitism and host traits in fished decapod crustaceans, which are economically and ecologically important worldwide. Using a synthesis approach, we determine that host life history, including habitat, longevity, sociality, invasion history, and fisheries involvement, correlate with the number and type of parasite species harbored. Indicator species analysis revealed close relationships between decapods and certain parasite groups, including crabs with rhizocephalans and dinoflagellates; crayfish with mesomycetozoans, oomycetes, branchiobdellids, and fungi; lobsters with copepods and amoebae; and shrimp with viruses. In contrast, Nematomorpha and Nemertea appear to be under-represented and under-studied as parasite groups in decapods. Decapods that are commercially fished, aquacultured, introduced outside their native range, and/or exhibit parental care tend to have higher parasite species richness (PSR). Parasite richness also increases with how well-studied a host group is, which we addressed with a machine learning algorithm that predicts false negative associations. Geographic range is commonly positively correlated with parasite richness, however reliable ranges are not available for most decapod species, highlighting a significant future research need. Identifying patterns such as these increases our broad understanding of decapod disease ecology but also enabled us to develop a series of recommendations on how to focus future research, management, and aquaculture development efforts. [ABSTRACT FROM AUTHOR]

The efficiency of pistachio nuts was investigated on the multiplication of Ectomyelois ceratoniae (Zeller) (Lep: Pyralidae) by rearing a cohort of 61 eggs individually at 26 ± 1 ℃, 60 ± 10% RH, and 16:8 h L:D. The age-stage two-sex life table theory and bootstrapping were used to analyze the data. The survival probability from a newly born egg to larva, pupa, and male and female adults was 0.77, 0.52, and 0.26 and 0.24, respectively. The total immature duration of males (45.33 d) was significantly shorter than that of females (49.47 d). The mean female fecundity was 98.08 eggs/fertile female (n = 12) and 78.46 eggs/all females (n = 15), respectively. The life expectancy of a newborn E. ceratoniae was 34.83 d, and the reproductive value was 79.63 at age 49 d of the female. Female moths had slightly longer longevity (7.82 d) compared with males (7.58 d). The population parameters R0, r, and λ were 19.29 offspring, 0.0548 d−1, and 1.0563 d−1, respectively. When eggs are harvested and the discard age is 62 d, the maximum harvest rate is 0.9481. Therefore, for a daily harvest of 10,000 eggs, the daily recruits of 547 eggs, 421 larvae, 287 pupae, 134 females, and 143 males are required in a stable stage structure rearing system. Each larva damaged and fed upon 2 gr. of raw pistachio to complete its development. Consequently, about 842 gr. pistachio nuts must be provided daily to meet the larval feeding demand, which imposes a cost of about $10 (local retail price) to the rearing system as nutritional provision. [ABSTRACT FROM AUTHOR]

A long-term study of a population of desert seed-eating ant colonies of the red harvester ant, Pogonomyrmex barbatus, in New Mexico, USA, shows that a colony can live for 20–30 years—the lifespan of its founding queen. A colony's collective behaviour shifts in the course of its life history. These changes, generated by social interactions within the colony, adjust the behaviour of the colony as it grows older and larger, in response to its environment and neighbouring colonies. A worker lives only a year and performs different tasks as it ages, in response to interactions with other workers and the local surroundings. A colony's behaviour changes—becoming more stable and consistent—as the colony grows older, with more ants to participate in social interactions. A neighbourhood of colonies, often of similar age, grows old together. Colonies differ in how they regulate foraging behaviour collectively to manage water loss. These differences influence how foragers of neighbouring colonies partition foraging area. In a harsh but stable environment, the gradual behavioural shifts over a colony's lifespan allow it to adjust to slow changes in the composition of its neighbourhood and in environmental conditions. This article is part of the discussion meeting issue 'Understanding age and society using natural populations' [ABSTRACT FROM AUTHOR]

Living in groups offers social animals the significant advantage of accessing collective wisdom and enhanced information processing, enabling more accurate decisions related to foraging, navigation and habitat selection. Preserving group membership is crucial for sustaining access to collective wisdom, incentivizing animals to prioritize group cohesion. However, when individuals encounter divergent information about the quality of various options, this can create a conflict between pursuing immediate rewards and the maintenance of group membership to improve access to future pay-offs. In this study, I show that rational agents who seek to maximize long-term rewards will be more inclined to follow the decisions of their peers than those with short-term horizons. In doing so, they necessarily make less-rewarding decisions in the short-term, which manifests in a lower individual accuracy when choosing the better of two options. Furthermore, I demonstrate that intuitions about collective wisdom can be misleading in groups of agents who prioritize long-term rewards, with disagreement being a better signal for the accuracy of collective choices than consensus. These results demonstrate that observed patterns of sociality should be interpreted in the context of the life history of an individual and its peers, rather than through the lens of an isolated decision. This article is part of the discussion meeting issue 'Understanding age and society using natural populations'. [ABSTRACT FROM AUTHOR]

Exposure to early life adversity is linked to detrimental fitness outcomes across taxa. Owing to the challenges of collecting longitudinal data, direct evidence for long-term fitness effects of early life adversity from long-lived species remains relatively scarce. Here, we test the effects of early life adversity on male and female longevity in a free-ranging population of rhesus macaques (Macaca mulatta) on Cayo Santiago, Puerto Rico. We leveraged six decades of data to quantify the relative importance of 10 forms of early life adversity for 6599 macaques. Individuals that experienced more early life adversity died earlier than those that experienced less adversity. Mortality risk was highest during early life, defined as birth to 4 years old, but heightened mortality risk was also present in macaques that survived to adulthood. Females and males were affected differently by some forms of adversity, and these differences might be driven by varying energetic demands and dispersal patterns. Our results show that the fitness consequences of early life adversity are not uniform across individuals but vary as a function of the type of adversity, timing and social context, and thus contribute to our limited but growing understanding of the evolution of early life sensitivities. This article is part of the discussion meeting issue 'Understanding age and society using natural populations' [ABSTRACT FROM AUTHOR]

Objectives: Reconstruction of life histories for fossil and living primates draws on rate of enamel layering, termed Retzius periodicity (RP in days) expressed as surface perikymata, during dental crown formation. Disclosure of RP through thin sectioning is destructive; consequently, sample sizes are inadequate to detect the range of RPs present in discrete taxa. We propose an additional method to detect RPs at the population level based on twice‐yearly average recurrence of linear enamel hypoplasia (rLEH) in apes shown by prior studies. Materials and Methods: Casts of teeth from orangutans (Pongo pygmaeus) (n = 40) and Lufengpithecus lufengensis (n = 57) from Late Miocene Shihuiba, China, (133 and 138 LEH, respectively) were recorded with scanning electron microscope (SEM) and confocal microscopy to yield perikymata counts between episodes of LEH. Frequency distributions of aggregated perikymata counts between LEH were compared to frequency distribution of tooth‐specific ratios of perikymata counts between successive LEH (this latter step removes effects of RP differences within a sample). Results: Drawing on prior research, two successive intervals between LEH span 1 year on average. Ratios of successive to previous intervals between LEH show that orangutans and Lufengpithecus exhibit two asymmetric intervals centered on 5.3 and 6.7 months, likely reflecting the effect of axial tilt insolation on phenology. Estimated RPs are not unimodal but show a range from 7 to 12 in Lufenpithecus and 8 to 11 in Pongo, comparable to published values. Discussion: Repetitive LEH is sufficiently regular to detect additional RPs which, in the case of Lufengpithecus, have yet to be demonstrated histologically. [ABSTRACT FROM AUTHOR]

Summary: Increasing genome size (GS) has been associated with slower rates of DNA replication and greater cellular nitrogen (N) and phosphorus demands. Despite most plant species having small genomes, the existence of larger GS species suggests that such costs may be negligible or represent benefits under certain conditions.Focussing on the widespread and diverse grass family (Poaceae), we used data on species' climatic niches and growth rates under different environmental conditions to test for growth costs or benefits associated with GS. The influence of photosynthetic pathway, life history and evolutionary history on grass GS was also explored.We found that evolutionary history, photosynthetic pathway and life history all influence the distribution of grass species' GS. Genomes were smaller in annual and C4 species, the latter allowing for small cells necessary for C4 leaf anatomy. We found larger GS were associated with high N availability and, for perennial species, low growth‐season temperature.Our findings reveal that GS is a globally important predictor of grass performance dependent on environmental conditions. The benefits for species with larger GS are likely due to associated larger cell sizes, allowing rapid biomass production where soil fertility meets N demands and/or when growth occurs via temperature‐independent cell expansion. [ABSTRACT FROM AUTHOR]

Plant strategies are phenotypes shaped by natural selection that enable populations to persist in a given environment. Plant strategy theory is essential for understanding the assembly of plant communities, predicting plant responses to climate change, and enhancing the restoration of our degrading biosphere. However, models of plant strategies vary widely and have tended to emphasize either functional traits or life‐history traits at the expense of integrating both into a general framework to improve our ecological and evolutionary understanding of plant form and function. Advancing our understanding of plant strategies will require investment in two complementary research agendas that together will unify functional ecology and population ecology. First, we must determine what is phenotypically possible by quantifying the dimensionality of plant traits. This step requires dense taxonomic sampling of traits on species representing the broad diversity of phylogenetic clades, environmental gradients, and geographical regions found across Earth. It is important that we continue to sample traits locally and share data globally to fill biased gaps in trait databases. Second, we must test the power of traits for explaining species distributions, demographic rates, and population growth rates across gradients of resource limitation, disturbance regimes, temperature, vegetation density, and frequencies of other strategies. This step requires thoughtful, theory‐driven empiricism. Reciprocal transplant experiments beyond the native range and synthetic demographic modelling are the most powerful methods to determine how trait‐by‐environment interactions influence fitness. Moving beyond easy‐to‐measure traits and evaluating the traits that are under the strongest ecological selection within different environmental contexts will improve our understanding of plant adaptations. Plant strategy theory is poised to (i) unpack the multiple dimensions of productivity and disturbance gradients and differentiate adaptations to climate and resource limitation from adaptations to disturbance, (ii) distinguish between the fundamental and realized niches of phenotypes, and (iii) articulate the distinctions and relationships between functional traits and life‐history traits. [ABSTRACT FROM AUTHOR]

Caloric intake can greatly affect many aspects of an organism's life. A deficiency of calories can lead to stress resulting in decreased fecundity, insufficient calories to maintain tissues and increased lifespan. Conversely, increasing caloric density increases fecundity and decreases lifespan. Despite decades of work exploring food quality and quantity on physiology in the model species Drosophila melanogaster Meigan 1830 (Diptera: Drosophilidae) and the melanogaster group in general, relatively little work explores the physiological responses to diet manipulation in other Drosophila species, like the obscura species group. Here, we looked at the effects of five different caloric densities (0.5×, 0.75×, 1.0×, 1.5× and 3.0×) on food intake, body weight, body fat, fecundity and longevity in D. pseudoobscura Frolova & Astaurov, 1929 (Diptera: Drosophilidae). Comparing longevity and fecundity across diets, we found that heavy caloric concentration (3.0×) decreases lifespan and that calorie restriction (0.5× and 0.75×) led to significant decreases in fecundity and body weight. However, calorie concentration did not significantly increase D. pseudoobscura body fat. By expanding our understanding of the physiological responses to diet stress to D. pseudoobscura, we establish the framework for comparative work across Drosophila species. With this information, we can then identify which physiological responses to diet manipulation might be most conserved and comparable across species. [ABSTRACT FROM AUTHOR]

Culicoides oxystoma Kieffer (Diptera: Ceratopogonidae) has been vectoring several arboviruses, protozoa and nematodes, leading to mortality and morbidity of livestock and wild ruminants in the tropics and subtropics. Insight into the bacterial communities associated with the vector species must be worked out. This work tries to inventorize the bacterial communities associated with this important vector species. Acquisition of gut microbiota may be the parental origin, while some are obtained through feeding during larval stages. Culicoides oxystoma possesses semi‐aquatic life cycle strategies for egg‐laying and larval survival. The bacteria associated with C. oxystoma were compared throughout (i) life stages: egg, larval instars, pupa, adult: male and female obtained from laboratory colony; (ii) field‐collected adult: male and age‐graded females; and (iii) natural breeding substrate and artificial rearing substrate. The culture‐dependent bacteria were identified by Sanger sequencing of 16S rRNA, and haemolytic bacteria were screened on blood agar. Results show that Firmicutes and Proteobacteria are the predominant Phyla, of which Bacillus spp. was the most abundant across the life stages. Across the life history, Bacillus cereus, Bacillus pumilus, Bacillus tropicus, Lysinibacillus sp. and Paenibacillus sp. were retrieved routinely. Bacillus cereus and Alcaligenes faecalis were detected in the lab‐reared specimens and shared between the natural breeding site and rearing medium. From the adults trapped across two locations, B. cereus, Bacillus flexus, A. faecalis, Enterococcus faecium and Pseudomonas sp. were isolated. The bacterial species associated with this vector may influence various physiological traits, such as vectorial capacity, digestion and larval development, which need further investigation. [ABSTRACT FROM AUTHOR]

Fleas (Siphonaptera) are holometabolous insects with larval and adult stages that exhibit vastly different ecologies from each other. Adult fleas are parasitic and feed exclusively on the blood of a vertebrate host, whereas flea larvae do not live on hosts and consume dried faecal blood from adult fleas. Because flea larvae rely on adult flea faeces for food, excrement and eggs must fall in the same location; thus, larval density is likely high in these restricted habitats. However, the influence of larval density on the subsequent adult stage has not been examined. In the present study, we utilized egg density to investigate density‐dependent effects on larval development and adult body size in the cat flea (Ctenocephalides felis Bouché) (Siphonaptera: Pulicidae). Specifically, eggs were collected to create three different larval densities (n = 50, 100 and 150 per 56.7 cm2), and hatched larvae from all groups were fed an excess amount of adult faecal pellets. Larval development was measured by recording the proportion of eggs that developed to the pupal stage and the proportion of eggs that reached adulthood (eclosion). The body size of eclosed adults was quantified for both sexes using head length and length of the total body. We found that the number of eggs had no effect on the proportion of larvae that pupated or the proportion of larvae that eclosed; however, higher egg densities resulted in larger body sizes for both sexes. Overall, these data yield significant insight into how the ecology of larval fleas impacts the biology of the resultant adults. [ABSTRACT FROM AUTHOR]

The incorporation of epigenetics (i.e., change in gene activity without change in DNA sequence) into studies of gene regulation and phenotypic expression has contributed to a significant improvement in our understanding of the evolution of life history traits. One important epigenetic mechanism is DNA methylation, which in vertebrates generally means the addition of a methyl group to a cytosine thus altering gene expression. Here, we discuss progress and gaps in our knowledge of the role of DNA methylation in facilitating diversity across four life history trait classes in fishes: developmental processes, size and growth rates, aging and sexual maturity, and sex regulation. We discuss insights into the regulatory aspect of gene expression in fish which can ultimately influence phenotypic diversity and speciation. We discuss how temperature influences methylation patterns affecting multiple traits. DNA methylation influence on gene expression varies depending on tissue types and the location within the genome of the methylated site (i.e., DNA methylation can increase or decrease gene expression). The role of DNA methyltransferases is also a common denominator across all tissue types in influencing the global methylome status regardless of species or environmental stressor. Organismal development stage is equally important, a decrease in global methylation throughout early development generally corresponds to elevated gene expression associated with growth and development. Finally, we discuss general limitations of DNA methylation studies with a focus on fish. We then provide recommendations for future research. [ABSTRACT FROM AUTHOR]

Among human actions threatening biodiversity, the release of anthropogenic chemical pollutants which have become ubiquitous in the environment, is a major concern. Chemical pollution can induce damage to macromolecules by causing the overproduction of reactive oxygen species, affecting the redox balance of animals. In species undergoing metamorphosis (i.e. the vast majority of the extant animal species), antioxidant responses to chemical pollution may differ between pre- and post-metamorphic stages. Here, we meta-analysed (N = 104 studies, k = 2283 estimates) the impact of chemical pollution on redox balance across the three major amphibian life stages (embryo, tadpole, adult). Before metamorphosis, embryos did not experience any redox change while tadpoles activate their antioxidant pathways and do not show increased oxidative damage from pollutants. Tadpoles may have evolved stronger defences against pollutants to reach post-metamorphic life stages. In contrast, post-metamorphic individuals show only weak antioxidant responses and marked oxidative damage in lipids. The type of pollutant (i.e. organic versus inorganic) has contrasting effects across amphibian life stages. Our findings show a divergent evolution of the redox balance in response to pollutants across life transitions of metamorphosing amphibians, most probably a consequence of differences in the ecological and developmental processes of each life stage. [ABSTRACT FROM AUTHOR]

Among human actions threatening biodiversity, the release of anthropogenic chemical pollutants which have become ubiquitous in the environment, is a major concern. Chemical pollution can induce damage to macromolecules by causing the overproduction of reactive oxygen species, affecting the redox balance of animals. In species undergoing metamorphosis (i.e. the vast majority of the extant animal species), antioxidant responses to chemical pollution may differ between pre- and post-metamorphic stages. Here, we meta-analysed (N = 104 studies, k = 2283 estimates) the impact of chemical pollution on redox balance across the three major amphibian life stages (embryo, tadpole, adult). Before metamorphosis, embryos did not experience any redox change while tadpoles activate their antioxidant pathways and do not show increased oxidative damage from pollutants. Tadpoles may have evolved stronger defences against pollutants to reach post-metamorphic life stages. In contrast, post-metamorphic individuals show only weak antioxidant responses and marked oxidative damage in lipids. The type of pollutant (i.e. organic versus inorganic) has contrasting effects across amphibian life stages. Our findings show a divergent evolution of the redox balance in response to pollutants across life transitions of metamorphosing amphibians, most probably a consequence of differences in the ecological and developmental processes of each life stage. [ABSTRACT FROM AUTHOR]

In humans, gut microbiome (GM) differences are often correlated with, and sometimes causally implicated in, ageing. However, it is unclear how these findings translate in wild animal populations. Studies that investigate how GM dynamics change within individuals, and with declines in physiological condition, are needed to fully understand links between chronological age, senescence and the GM, but have rarely been done. Here, we use longitudinal data collected from a closed population of Seychelles warblers (Acrocephalus sechellensis) to investigate how bacterial GM alpha diversity, composition and stability are associated with host senescence. We hypothesised that GM diversity and composition will differ, and become more variable, in older adults, particularly in the terminal year prior to death, as the GM becomes increasingly dysregulated due to senescence. However, GM alpha diversity and composition remained largely invariable with respect to adult age and did not differ in an individual's terminal year. Furthermore, there was no evidence that the GM became more heterogenous in senescent age groups (individuals older than 6 years), or in the terminal year. Instead, environmental variables such as season, territory quality and time of day, were the strongest predictors of GM variation in adult Seychelles warblers. These results contrast with studies on humans, captive animal populations and some (but not all) studies on non‐human primates, suggesting that GM deterioration may not be a universal hallmark of senescence in wild animal species. Further work is needed to disentangle the factors driving variation in GM‐senescence relationships across different host taxa. [ABSTRACT FROM AUTHOR]

Body size is a trait that shapes many aspects of a species' development and evolution. Larger body size is often beneficial in animals, but it can also be associated with life history costs in natural systems. Similarly, miniaturization, the evolution of extremely small adult body size, is found in every major animal group, yet carries its own life history trade-offs. Given that these effects can depend on an animal's environment and life stage and have mainly been studied in species that are already specialized for their size, the life history changes associated with evolutionary shifts in body size warrant additional investigation. Here, we used Drosophila melanogaster populations that had undergone over 400 generations of artificial selection on body size to investigate the changes in life history traits associated with the evolution of extremely large and extremely small body sizes. Populations selected for small body size experienced strong trade-offs in multiple life history traits, including reduced female fecundity and lower juvenile viability. Although we found positively correlated changes in egg size associated with selection for both large and small body size, after adjusting for female body size, females from populations selected for large size had the lowest relative investment per egg and females from populations selected for small size had the highest relative investment per egg. Taken together, our results suggest that egg size may be a key constraint on the evolution of body size in D. melanogaster, providing insight into the broader phenomenon of body size evolution in insects. Graphical Abstract [ABSTRACT FROM AUTHOR]

Parental care is essential to offspring survival in many species. Understanding why males of some species provide care, whereas others do not, has received substantial attention. Previous research has found that sexual selection can favor paternal care, yet we still do not fully understand why sexual selection favors male care in some species but not others. It is also unclear when paternal care versus other preferred male trait(s) will be favored by sexual selection. We hypothesize that sexual selection can interact with basic life history to influence the conditions under which paternal care and/or another preferred male trait will be favored by sexual selection. We used a mathematical approach in which males alone provide parental care and exhibit a non‐care trait that is preferred in mate choice. Using this approach, we demonstrate that life‐history characteristics (stage‐specific mortality, fertilization success, gamete numbers) can interact with sexual selection to influence the evolution of paternal care and/or a preferred non‐care trait. In particular, whether (1) adult mortality, egg mortality, and fertilization success are high versus low and (2) a tradeoff exists between paternal care and a non‐care preferred trait will influence whether selection most strongly favors additional paternal care or a non‐care preferred trait. In general, we would expect strong selection for more male care when it is preferred in mate choice. In some cases, mate preferences for paternal care can inhibit selection for a preferred non‐care trait. Mate preferences for paternal care can also broaden the life‐history conditions under which we would expect the elaboration of male care to occur. [ABSTRACT FROM AUTHOR]

Investigating fundamental processes in biology requires the ability to ground broad questions in species‐specific natural history. This is particularly true in the study of behavior because an organism's experience of the environment will influence the expression of behavior and the opportunity for selection. Here, we provide a review of the natural history and behavior of burying beetles of the genus Nicrophorus to provide the groundwork for comparative work that showcases their remarkable behavioral and ecological diversity. Burying beetles have long fascinated scientists because of their well‐developed parenting behavior, exhibiting extended post‐hatching care of offspring that varies extensively within and across taxa. Despite the burgeoning success of burying beetles as a model system for the study of behavioral evolution, there has not been a review of their behavior, ecology, and evolution in over 25 years. To address this gap, we leverage a developing community of researchers who have contributed to a detailed knowledge of burying beetles to highlight the utility of Nicrophorus for investigating the causes and consequences of social and behavioral evolution. [ABSTRACT FROM AUTHOR]