Frontiers in Ecology and Evolution

Bird nests are fascinating microcosms harboring a wide range of arthropods parasitizing the nesting birds or feeding on prey remains, feces, and the nest material. Studies of these communities have been entirely based on emergence traps which collect live organisms out of the nests. The analysis of nest contents and environmental DNA (eDNA) via metabarcoding could expand our knowledge and identify prey, exuviae, and other animal remains in bird nests. Here, we investigated the potential of arthropod remains, nest dust, and feathers to better describe taxonomic diversity accumulated in 20 bird nests collected in Guelph (Canada). We used subsampling strategies and tested two extraction approaches to investigate the distribution of DNA in nests, account for low-quality DNA, and the presence of inhibitory substances. In total, 103 taxa were detected via metabarcoding. Arthropod remains delivered the highest number of taxa (n=67), followed by nest dust (n=29). Extractions with the PowerSoil kit outperformed DNeasy extractions coupled with PowerClean Pro inhibitor removal. The subsamples of the same nest showed 5.5% and 47.1% taxonomic overlap for arthropod remains and PowerSoil extracted nest dust, respectively, indicating a heterogeneous eDNA distribution in nests. Most detected species were either feeding in the nest, i.e., herbivorous / predatory, or bird food. We also detected molecular traces of 25 bird species, whose feathers were likely used as nest material. Consequently, the metabarcoding of bird nest materials provides a more complete picture of nest communities, which can enable future studies on functional diversity and better comparisons between nesting species.

Honey bees are social insects that have divided their work. Bees have two sexes, male and female. Female honey bees are queens and worker bees, while males are called drones. Worker bees have different tasks in the hive including gathering of food, its processing, caring for brood, protecting the hive, produce wax, nourish workers, drones and queen. Drones are male bees whose only role is to mate with a virgin queen. Many studies have dealt with physiology, behavior, morphology of workers and drones. This is the first study that compared differences in element accumulation and composition between workers and drones honey bees. It was observed that worker honey bees have higher concentration, from 116 % to 517 %, of most elements analyzed. Drones had higher concentration of essential elements to bees, Na, Mg, P, S, K, Zn, Cu and especially Se which was 2.2-fold higher. These differences can be attributed to environmental exposure; reproductive role of drones, high Se in sperm; but mostly to the food workers and drones eat. Worker bees feed on unprocessed food, mostly pollen, which is rich in minerals. Drones are fed by worker bees pre-processed food. Here we show that worker honey bees have a filtering mechanism that enables them to accumulate non-essential elements and not pass them on through the processed food to drones or larva.

Avian nests are complex structures that protect eggs and nestlings. Nest-building behaviour varies between species and habitats, and recent work has highlighted that in areas with high human activity and low availability of natural nest material, birds may use anthropogenic material to construct nests. However, we still know relatively little about how nest composition is affected by human presence, including along urban gradients. Here we present the results of a study where we examined how nest composition differed between an urban and a forest population of blue tits, and the impact that variation in nest composition had on reproductive success. We found a significant decrease in the amount of natural materials and an increase in anthropogenic materials in urban compared to forest nests. Earlier urban nests showed a higher amount of anthropogenic materials compared to late urban nests. The amount of moss incorporated in a nest was the strongest predictor of fledgling success, suggesting that the use of anthropogenic material by urban birds might be a maladaptation, and/or that urban birds are constrained in the amount of moss they can use to build their nests. Future studies should aim at quantifying the availability of natural materials to distinguish between these two hypotheses.

The unstable nature of freshwater ponds in arid landscapes represent a sizable challenge for strictly aquatic organisms, such as fishes. Yet the Arabian Desert, bordering the coastline of the Red Sea, plays host to a species very well adapted to such extreme environments: the Arabian pupfish, Aphanius dispar. In this study, we estimated patterns of hydrological connectivity; population structure and stable isotope for samples of A. dispar living in small, isolated ponds of nearly-freshwater in the Arabian desert and highly saline coastal lagoons along the Red Sea. The genomic and hydrological analyses indicate that populations are largely separated by drainage origin, as fish from desert ponds appear to be transported to coastal lagoons of the Red Sea along ephemeral river systems arising from flash flood events. Further, our study indicates there is an ecological change when being washed from pond environments to coastal waters, due to a significant shift in muscle stable isotopes ratios between both groups. Considering that the genetic breaks are mostly observed between drainage origin, this study suggests that A. dispar can survive large changes in salinity and ecological regimes over small time-scales.

Contaminant exposure can harm wildlife. However, measuring contaminant exposure in wildlife can be challenging due to accessibility of species and/or sampling tissue matrices needed to answer research questions regarding exposure. For example, in bats and other taxa that roost, it may be best to collect pooled feces from colonies for minimal disturbance to species of conservation concern, but fecal contaminant concentrations do not provide contaminant bioaccumulation estimates. Thus, there is a need for quantifying relationships between sample matrices for measuring contaminant exposure to answer research questions pertaining to wildlife health and addressing conservation needs. Our goal was to determine relationships between fecal and fur total mercury (THg). To do so, we collected paired feces and fur from Mexican free-tailed bats (Tadarida brasiliensis) in summer 2023 in western Oklahoma at a maternity roost with no known Hg point source. We analyzed THg in each sample matrix for each individual (n = 48). We found no relationship between individual fecal and fur THg. However, when averaged, fur THg was 6.11 times greater than fecal THg. This factor can be used as a screening-level risk assessment of under-roost feces, which could then be followed by direct assessments of fur THg concentrations and health impacts. We encourage the use of this conversion factor across other insectivorous bat species and sites for estimating initial risks of contaminant exposure with minimal disturbance to species of conservation concern, when timely research for conservation actions are needed, and when a contaminant point source is not yet known. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=103 SRC="FIGDIR/small/587502v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@4bac41org.highwire.dtl.DTLVardef@1a13deorg.highwire.dtl.DTLVardef@e8e58org.highwire.dtl.DTLVardef@1a33a9d_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical abstract created in BioRender under a free subscription. Cave icon created by artist Freepik at https://www.flaticon.com/free-icons/cave. HighlightsO_LIUnder-roost sampling for contaminant exposure minimizes species disturbance C_LIO_LIContaminant exposure relationships in tissues can aide in measuring wildlife health C_LIO_LIWe sampled Tadarida brasilliensis for paired fecal and fur total Hg (THg) C_LIO_LITHg in fur averaged 6.11 times greater than feces C_LIO_LIThis factor can be used as an initial risk assessment for under-roost fecal sampling C_LIO_LIMore invasive follow-up sampling (bat fur) can be justified following risk assessment C_LI

Despite overall stability, plasticity in endothermic body temperature (Tb) occurs, which may facilitate maintenance of crucial activities in the face of climate change-related environmental variations. However, this plasticity may be limited by physiological or energetic constraints, which are potentially exacerbated by other environmental stressors. For instance, chemical contamination may elevate energetic costs and have endocrine disrupting effects that undermine thermoregulation. We leveraged advanced biologging techniques to elucidate how Tb varies with different behavioral states and environmental conditions in a keystone Arctic seabird, the little auk (Alle alle). We additionally evaluated whether mercury (Hg) contamination independently affected Tb, or limited or increased state-dependent changes in Tb. Tb was highest and relatively invariable when birds were at the colony, and rebounded when birds were resting on sea ice, following declines while foraging (diving) in polar waters. These results suggest that the colony and sea ice function as thermal refuges for little auks. In addition, Tb increased with ambient temperature and relative humidity across behavioral states, and increased with wind speed when birds were flying. Little auks with higher Hg levels had higher, less variable, Tb across behaviors and environmental contexts, perhaps reflecting increased metabolic rates linked to detoxification costs. Results provide evidence for environment- and contaminant-related effects on Tb, but not interactive effects between the two, and suggest that loss of sea ice and increased environmental contamination under global change may have serious implications for Tb regulation and energy balance.

Invasive species pose a major threat to forest biodiversity, particularly on islands, such as the Galapagos. Here, invasive plants are threatening the remnants of the unique cloud forest and its iconic Darwins finches. We posit that food web disturbances caused by invasive Rubus niveus (blackberry), but also the management measures used to control it, could contribute to the rapid decline of the insectivourous warbler finch (Certhidae olivacea). We compared changes in long-term management, short-term management and unmanaged areas. We measured C:N ratios, {delta}15N-nitrogen and {delta}13C-carbon signatures in bird blood and arthropods, as indicators of resource use change, in addition to mass abundance and diversity of arthropods. We reconstructed the birds diets using isotope mixing models. The results revealed that finches in (Rubus-invaded) unmanaged areas foraged on abundant yet low quality arthropods and had shorter tarsi. Is this the first evidence of hidden hunger in degraded terrestrial ecosystems in Galapagos?

Cetaceans have varied their anatomical structure, physiology and metabolism to adapt to the challenges of aquatic life. Key to this change is the deposition of blubber. This adipose tissue plays a significant regulatory and signaling role in mammalian metabolism. As foraging disruption by human activities is emerging as a key conservation threat for cetaceans, we need to understand how selection for aquatic life might have altered key nutrient sensing pathways associated with adipose signaling. We compared selection pressure on those energy metabolism biological pathways by contrasting the rate of substitution observed in genes associated with them in cetacean and artiodactyl genomes. We then estimated the likely consequence of these selection pressures for pathway functions. Here we show that genes involved in the insulin, mTOR, SIRT and NF-{kappa}B pathways were under significant positive selection in cetaceans compared to their terrestrial sister taxon. Our results suggest these genes may have been positively selected to adapt to a glucose-poor diet and it is unlikely that fat depots signaling function in the same manner as in terrestrial mammals. Secondary adaptation to life in water significantly affected functions in nutrient sensing pathways in cetaceans. Insulin is not likely to play the same role in energy balance as it does in terrestrial mammals and adiposity is not likely to have the deleterious health consequences it has in terrestrial mammals. The physiological ecology of cetacean fat deposition, and therefore its value as a condition index, needs to be interpreted in this evolutionary context.

1. Energy intake is a fundamental currency in ecology that is critical to reproductive success, survival and lifetime fitness. Measuring foraging success in wild animals via biologgers has been a long-standing challenge. 2. Flying animals gain mass during foraging, and they must counteract the associated increased gravitational force by creating additional lift. Pennycuick (1996) proposed that wingbeat frequency (w) should vary with the square root of body mass [Formula], when other variables influencing wingbeat frequency are held constant. 3. We present a state-space model that estimates instantaneous changes in body mass by modelling this relationship with wingbeat frequency using animal-borne accelerometer and depth data. To demonstrate the usefulness of our proposed method, we applied it to biologging data from 55 thick-billed murres (Uria lomvia) during the incubation period. 4. Our mass estimates allowed us to identify areas associated with higher gains, and to demonstrate that foraging success was generally higher farther from the colony. However, 79% of foraging trips were associated with mass deficits. We performed simulation studies to assess the sensitivity of our method to parameter misspecification and the increase in accuracy gained from including the known mass at recapture. As estimates of energy intake allow for testing of long-standing hypotheses in foraging ecology, our method provides a new tool to help answer these questions with any animal that engages in flapping flight.

In this review, we journey with Diacamma indicum a Ponerine ant over the last decade as they relocate to new nests and discover the challenges they face along the way and how they solve them. Colony relocation is a goal oriented dynamic task that involves all the colony members and impacts the colonies fitness. After explaining how I initiated this journey, we examine colony composition of this species by analysing data from 1200 colonies collected over the last 13 years. On average colonies are constituted with 89.35 adult females, 0.29 males and 56.6 brood items of different development stages and these were significantly impacted by seasonality with Pre monsoon having the highest numbers. After explaining how colonies are collected and maintained in the lab, we explore the architectural components of the subterrain nests built by this species in the natural habitat. Colonies live in relatively simple single chambered nest that does not change significantly across seasons and consists of an entrance tunnel and a secondary runoff tunnel. All members of the colony are recruited to the new nest through tandem running and this species shows the highest documented tandem running speeds at 4.35 body lengths per second and a path efficiency of 83.95% with only 2.4% of tandem runs being unsuccessful in the natural habitat. Even in lab conditions, when colonies are given defined paths of different lengths, colonies showed significant preference to travel through short paths, highlighting their ability to optimizes their path even in the absence of chemical trails. A combination of experiments in the natural habitat and controlled experiments in the lab which are anchored in the umwelt of the organism has enabled us to understand how D. indicum functions and reveals the selection forces that are operating on the organization and performances of relocation. Our journey has brought to light several answers but has opened several more avenues for exploration branching out in different directions. With time and dedicated minds, we hope to continue on this route to marvel at the achievements of these superorganisms.

Understanding the spatial-temporal marine habits is crucial to conserving air-breathing marine animals that breed on islands and forage at sea. This study, focusing on little penguins from Phillip Island, Australia, employed tracking data to identify vital foraging areas during breeding season. Long-term data from sub-colonies and breeding stages were analysed using 50%, 75%, and 90% kernel utilisation distributions (KUDs). Breeding success, classified as low, average, or high, guided the exploration of site, year, and breeding stage-specific habitats. Using Marxan, a widely used conservation planning tool, the study proposes both static and dynamic spatial-temporal scenarios for protection based on KUDs. The dynamic approach, requiring less space than the static strategy, was more efficient and likely more acceptable to stakeholders. The study underscores the need for comprehensive data in conservation plans, as relying on one nesting sites data might miss essential foraging areas for penguins in other locations. This study demonstrates the efficacy of animal tracking data in spatial conservation prioritisation and marine spatial planning. The dynamic areas frequented emerged as a strategy to safeguard core regions at sea, offering insights to improve the conservation of iconic species like little penguins and promoting the health of islands and the entire marine ecosystem.

There are substantial gaps in our empirical knowledge of the effects of chemical exposure on aquatic life that are unlikely to be filled by traditional laboratory toxicity testing alone. One possible alternative of generating new toxicity data is cross-species extrapolation (CSE), a statistical approach in which existing data are used to predict the effect of a chemical on untested species. Some CSE models use relatedness as a predictor of chemical sensitivity, but relatively little is known about how strongly shared evolutionary history influences sensitivity across all chemicals. To address this question, we conducted a survey of phylogenetic signal in the toxicity data from aquatic animal species for a large set of chemicals using a phylogeny inferred from taxonomy. Strong phylogenetic signal was present in just six of thirty-two toxicity datasets, and there were no clear shared properties among those datasets with strong signal. Strong signal was rare even among chemicals specifically developed to target insects, meaning that these chemicals may be equally lethal to non-target taxa, including chordates. When signal was strong, distinct patterns of sensitivity were evident in the data, which may be informative when assembling toxicity datasets for regulatory use. Although strong signal does not appear to manifest in aquatic toxicity data for most chemicals, we encourage additional phylogenetic evaluations of toxicity data in order to guide the selection of CSE tools and as a means to explore the patterns of chemical sensitivity across the broad diversity of life.

O_LIThe hydrogen stable isotope ratios ({delta}2H) in tissues of terrestrial insects are widely applied to estimate natal origins in field populations. The hydrogen isotopes of insect tissues incorporate those of environmental waters through the insects metabolic processes. Water sources and abiotic environmental factors reflect changes in plant physiology, as indicated by the {delta}2H values of plants. However, the influence of plant physiology on the assimilation of hydrogen in insect tissues derived from water through feeding diets is still unknown. C_LIO_LIWe experimentally examined the influence of water on the {delta}2H values of maize leaf and of forewings of Mythimna separata (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Noctuidae). We prepared five specific water samples for cultivating maize, aiming to replicate the gradient of {delta}2H values observed in environmental waters across the Japanese archipelago. C_LIO_LIThe mean-percentage contribution of water to hydrogen in maize leaves was 17.6% (July-August) and 25.1% (September-October). Linear analyses indicated that 17.4% and 32.7% of hydrogen in M. separata and S. frugiperda forewings were derived from water through the consumption of maize leaves. The slope values of linear regression between the insect forewings and the maize leaves supplied in the final instar were closest to 1.0. These results indicated that the {delta}2H values of maize leaves and insect forewings reflected those of water resources. C_LIO_LIThis study presented the seasonal changes in climate conditions that affected the {delta}2H values of host plants and insect tissues. Changes in plant physiology with seasonal variations may influence the interpretation of the linear relationship between water and insect tissues on the estimation of natal origins. C_LI

Environmental DNA (eDNA) allows for efficient and convenient data collection using DNA segments to confirm species presence. There is little literature using eDNA to specifically examine tiger salamander presence in North Dakota. I sampled 8 different cattle ponds in Western North Dakota twice each using a set eDNA collection method from the United States Department of Agriculture. After collecting water samples, the filters were sent to Jonah Ventures for DNA extraction and metabarcoding. Samples were incubated, extracted, ran through a first round of Polymerase Chain Reaction (PCR) inspected on agarose gel. Then the amplicons-product of an amplified or replicated piece of DNA, were cleaned, a second round of PCR followed, then the amplicons were cleaned again. Finally sequencing and bioinformatics took place. Salamanders (genus Ambystoma) were detected at 5 of the 8 sites. Average single season Bayesian occupancy point estimate was 0.655 {+/-} (.165), with a detection probability of 0.735{+/-} (.156) over the two site visits. Of the covariates including elevation, surface area, and air temperature, air temperature on visit 2 had the best model but still was not significant. There was no significant correlation between any of the covariates and the naive detections. This method was effective in detecting the genus Ambystoma, however more work and greater sample site variation could elucidate impacts of species level presence absence data.

Forest pest insects cause major socio-economic impacts, global losses of millions of dollars, and ecosystem changes. A key challenge for their management is tracing regional dispersal events critical to outbreak dynamics. We developed an integrated tracing framework for pest insects by combining isotope geolocation, ecological data, and atmospheric modeling, and applied this framework to the eastern spruce budworm moth (Choristoneura fumiferana), the most severe defoliator of the North American boreal forest, to trace outbreak dispersal events. We first generated a North American model of bioavailable sulfur isotope ({delta}34S) variation in space (isoscape), which predominantly varied in response to oceanic sulfate deposition, and then calibrated it to spruce budworm tissues of known origin. We used an automated trap network with high temporal resolution to collect samples and identify potential immigration events of eastern spruce budworm to Nova Scotia, Canada. We traced the natal origin of these immigrants by integrating high-probability regions derived from{delta} 34S probabilistic assignments and HYSPLIT atmospheric dispersal models. Since high larval density is a strong predictor of budworm defoliation and emigration, HYSPLIT atmospheric dispersal models, which integrated spruce budworm behavioral constraints (e.g., flight velocity, altitude, and temperature thresholds), were started from defoliated areas to narrow-down the area of natal origin and estimate the migration route. We find that this integrated framework allows to narrow down the region of pest origins, restricting it to a few possible locations and demonstrating long-distance dispersal of spruce budworm across [~]400Km over the Gulf of St. Lawrence. Our framework demonstrates the utility of{delta} 34S geolocation in insect tracing, and that combining isotopic data with ecological indicators and atmospheric modeling offers an unprecedented resolution in understanding insect dispersal ecology. The approach is transferable to trace other migratory insect species to address conservation, agriculture, and bio-surveillance needs in the context of global environmental change.

Predynastic Egypt arose around 5700 BC when nomadic people settled in the Nile Valley. Without voluntary practice related to anthropic mummification, as will be seen with the Egyptian Dynastic empires, human remains from this period were naturally mummified because of the natural environmental conditions, possibly enveloped in plant mats and animal skins. This study focuses on four mummies from the Natural History Museum of Musee des Confluences in Lyon (France). The geographic origin of the mummies and climatic conditions at that time were deduced from o18O measurements on teeth and bones. These measurements confirm that the primary source of drinking water was the Nile, and that one mummy of unknown origin also originated from Upper Egypt like the other three. The diet and life habits of these individuals were inferred from carbon (o13C), nitrogen (o15N) and sulfur (o34S) isotope compositions of their skins and bone collagens. Our study is of particular interest as we were able to analyse the animal skins and plant material enveloping the mummies using the same isotopic systems. The mean o15N values obtained in human skins (17.9{+/-}2.4{per thousand}, AIR) were found to be high, and consistent with the values measured in animal skins (16.0{+/-}2.9{per thousand}, AIR). The analysed plants have even higher values, with an average of 22.1{+/-}2.2{per thousand}, AIR. The most probable explanation for the markedly elevated {delta}15N values observed in all the materials investigated is localised soil amendment practices. This is corroborated by the consistent nitrogen isotopic signatures across all the examined tissues, with a notable prevalence in plant tissues.

O_LIWildlife feces are a valuable noninvasive resource in ecological and conservation research. However, traditional preservation methods are unable to maintain morphological integrity while simultaneously preserving the biological and chemical composition of fecal samples. C_LIO_LIThis study presents a novel method for the preparation of fecal specimens through a multistep immersion process using sodium carboxymethyl cellulose, sodium benzoate, clotrimazole, ethanol, pyrethroid emulsion and polyvinylpyrrolidone solution. C_LIO_LIThe specimens produced by this method exhibited high mechanical strength, ensuring durability and resistance to handling damage. During a storage period of six months, this method successfully preserved the morphological characteristics of fecal samples while maintaining DNA integrity, with no signs of mold or insect damage. DNA extraction achieved a 100% success rate and species identification remained consistent with fresh samples, with BLAST match rates exceeding 99% in 15 specimens. In addition, heavy metals such as chromium, arsenic, and lead were detected in fecal samples from different species. C_LIO_LIBy allowing long-term preservation of fecal samples, this method transforms urine from a short-term diagnostic tool into a durable resource for monitoring biodiversity. It can extend the applications of fecal samples across spatial and temporal scales, reinforcing their role in ecological research and global conservation of biodiversity. C_LI

Assortative mating can play a major role in the divergence of a population with gene flow. In a fire salamander population near Bonn, Germany, the larvae differ genetically according to the habitat type they are found in, i.e. ponds or streams. Neither sound nor vision are a source for assortative mating in fire salamanders, but it is known that females can discriminate between sexes and habitat types of the males based on chemical cues. The adults share the same terrestrial habitat which leads to the question whether there is a habitat type-specific chemical fingerprint already existing in the larvae that may be used in the adult stage as the base for assortative mating. We took water samples and captured larvae at two ponds and two streams and used polydimethylsiloxane and TD-GC-MS to collect and analyze samples of the environmental background as well as from the surface of the larvae. We found a significantly different composition of chemical features in the environmental back-ground samples. Additionally, we found the larvae to carry habitat type-specific chemical features. These finding allow to speculate that the features on the larval surface may be used

Organisms must navigate complex interactions with host plants, microbial communities, and environmental cues to ensure their survival and reproductive success when adapting to novel environments. Host plant specialists can be used to study how these interactions affect fitness due to their ecological constraints. In specialist species, such as cactophilic Drosophila, it remains unclear how feeding preferences, nutritional value of the substrate, and microbial interactions collectively shape fitness outcomes. We used diverse laboratory media formulations to examine the fitness implications in Drosophila mettleri, a species that exclusively uses Saguaro cactus (Carnegiea gigantea) as its natural host plant. We found that D. mettleri did not preferentially feed on one medium compared to others, nor on C. gigantea supplemented media compared to controls. Microbial communities, especially on banana media with C. gigantea additives, appear to improve developmental success and can influence D. mettleri post-pupation success. Taken together, our results highlight the behavioral and environmental interplay between host plant substrate and microbial communities.

Stable isotopes of carbon and nitrogen characterize trophic relationships in predator-prey relationships, with clear differences between consumer and diet (discrimination factor, {Delta}13C, {Delta}15N). However, parasite-host isotopic relationships remain unclear, with {Delta}13C and {Delta}15N remaining incompletely characterized, especially for helminths. In this study, we used stable isotopes to determine discrimination factors for 13 parasite-host pairings of helminths in coral reef fish. {Delta}15N differences grouped according to phylogeny and attachment site on the hosts: {Delta}15N was positive for trematodes and nematodes from the digestive tract and varied for cestodes and nematodes from the general cavity. {Delta}13C showed more complex patterns with no effect of phylogeny or attachment site. A negative relationship was observed between {Delta}15N and host {delta}15N value among different host-parasite pairings as well as within 7 out of the 13 parings, indicating that host metabolic processing affects host-parasite discrimination values. In contrast, no relationships were observed for {Delta}13C. Our results indicate that host phylogeny, attachment site and host stable isotope value drive {Delta}15N of helminths in coral reef fish while {Delta}13C is more idiosyncratic. These results call for use of taxon- or species-specific and scaled framework for bulk stable isotopes in the trophic ecology of parasites.