Reduced Body Condition Research Articles

High post‐sex survival of the world's largest semelparous mammal

AbstractMales of the endangered northern quoll (Dasyurus hallucatus) are facultatively semelparous, often dying following their first breeding season. This is often driven by high breeding costs: males travel and mate extensively in breeding season, resulting in reduced body condition. Annual post‐breeding survival rates for male northern quolls have been recorded between 0% and 12.5% across their range in northern Australia. We highlight an observed 50% survival rate of male northern quolls (3 of 6) living into their second year in a Pilbara mining landscape. High male survival here may be attributed to above average rainfall in the landscape and reduced breeding opportunities, due to low female abundance—likely driven by large amounts of unfavourable mining land. This likely led to lower hormonal stress associated with breeding for males, as well as increased resource availability. Given northern quoll population persistence is highly dependent on breeding success, high survival of male northern quolls may inadvertently stabilize populations if they can breed again in a second year, though this is yet to be observed in the Pilbara region. Nevertheless, semelparity of male northern quolls likely varies with environmental and demographic factors, demonstrating that northern quoll populations may be resilient to disturbance in an unpredictable semi‐arid environment.

The microbiome at the interface between environmental stress and animal health: an example from the most threatened vertebrate group.

Nitrate pollution and global warming are ubiquitous stressors likely to interact and affect the health and survival of wildlife, particularly aquatic ectotherms. Animal health is largely influenced by its microbiome (commensal/symbiotic microorganisms), which responds to such stressors. We used a crossed experimental design including three nitrate levels and five temperature regimes to investigate their interactive and individual effects on an aquatic ectotherm, the European common frog. We associated health biomarkers in larvae with changes in gut bacteria diversity and composition. Larvae experienced higher stress levels and lower body condition under high temperatures and nitrate exposure. Developmental rate increased with temperature but decreased with nitrate pollution. Alterations in bacteria composition but not diversity are likely to correlate with the observed outcomes in larvae health. Leucine degradation decreased at higher temperatures corroborating accelerated development, nitrate degradation increased with nitrate level corroborating reduced body condition and an increase in lysine biosynthesis may have helped larvae deal with the combined effects of both stressors. These results reinforce the importance of associating traditional health biomarkers with underlying microbiome changes. Therefore, we urge studies to investigate the effects of environmental stressors on microbiome composition and consequences for host health in a world threatened by biodiversity loss.

A pilot study of a joint outdoor exercise program for dog owners and dogs

Increasing levels of physical inactivity is a global burden for mankind and is also an emerging problem in companion dogs. In both humans and dogs, insufficient physical activity is associated with increased risk for noncommunicable diseases and impaired quality of life (QoL). The aim of the current pilot study was to evaluate effects of a joint outdoor exercise program for dog owners (n = 22) and dogs (n = 22) with focus on QoL and body measurements. Results indicate that an eight-week exercise intervention alone, with a target distance of at least 2 km twice a week, may be sufficient to significantly increase self-reported QoL and acceptance of bodily appearance in dog owners despite no reductions in body measurements. In dogs, a significantly reduced body condition score (BCS) was registered, despite no considerable changes in feeding. The increased owner motivation for continued joint exercise suggests potential for lifestyle changes, which could be investigated in future studies including control groups and long-term follow-ups. The importance of the human-animal bond as a success factor for increased mutual physical activity and health benefits in both dog owners and dogs is recommended to be studied in a more in-depth manner.

Anatomical hooking location and bleeding occurrence in northern pike (Esox lucius) caught in recreational catch-and-release angling in a lake with reduced prey fish availability

Catch-and-release (C&R) is a common practice in recreational angling for northern pike (Esox lucius), whereby the angler releases the fish back into the water after capture with the expectation that it will survive with negligible stress and physical injuries. This may not always be the case, as hooking in critical anatomical locations, such as gills, esophagus, and stomach, increases the frequency of bleeding at the hook wound and has been recognized as a key determinant of post-release mortality in pike. Several factors (e.g. bait type and size, hook characteristics, and fish length) can influence the risk of hooking in critical locations, and the fish’s willingness to strike the fishing lure/bait may largely depend on previous feeding history and associated motivation to feed. In this respect, food deprivation and greater feeding motivation can be expected to result in an intensified response and more forceful attacks on fishing lures/baits, which could increase the risk of hooking injuries in sensitive tissues, as the fish may ingest the hook more deeply. Here, we assess the hooking location and bleeding occurrence in pike caught on soft plastic shads and baitfish in a shallow eutrophic lake. The prey fish density of this lake, primarily common roach (Rutilus rutilus), has been substantially reduced by seining as part of a lake restoration project. Experimental angling sessions took place at the end of 2020 and 2022, approximately 1–2 months and 25–26 months after the initial reduction in prey fish density, respectively. Removal of roach from the lake was also done regularly by seining after the angling sessions in 2020. Pike angled in 2022 had significantly lower body condition than individuals caught in 2020, indicating that mass removal of roach from the lake resulted in food shortage. The risk of hooking in critical locations (herein defined as hooking in gills and back of mouth) was not associated to angling year, body condition, or length of the pike. However, across the two angling years, the incidence of hooking in critical locations was higher for soft plastic shads compared to baitfish (24.2% versus 7.4%). Pike caught on soft plastic shads also bled more frequently than individuals caught on baitfish (19.7% versus 6.2%), most likely due to the fact that hooking in the gills almost exclusively occurred with soft plastic shads. Bleeding propensity was also not related to angling year, body condition, or fish length. Hence, the present study found no evidence that long-term reductions in food availability and resulting declines in body condition influence how pike strike and ingest fishing lures/baits, at least not in a manner that increases the risk of hooking injuries in sensitive locations. Instead, bait type seems to play the largest role for the observed bleeding patterns. We recommend that future studies investigate the potential effects of C&R angling on the post-release survival of pike with reduced body condition due to limited food availability.

Between-year and spatial variation in body condition across the breeding cycle in a pelagic seabird, the Red-billed Tropicbird.

Body condition in pelagic seabirds impacts key fitness-related traits such as reproductive performance and breeding frequency. Regulation of body condition can be especially important for species with long incubation periods and long individual incubation shifts between foraging trips. Here, we show that body condition of adult Red-billed Tropicbirds (Phaethon aethereus) at St Helena Island, South Atlantic Ocean, exhibited considerable variation between years (2013-2017) and between different stages of the breeding cycle. Females took the first incubation shift following egg laying, after which males and females alternated incubation shifts of varying length, ranging from <1 to 12 days. Body condition declined in both sexes during an incubation shift by an average of 22 g (2.83% of starting mass) per day and over the incubation period; mass loss was significantly greater during longer incubation shifts, later within a shift and later in the total incubation period. There was also significant differences in incubation behaviour and body condition between years; in 2015, coinciding with a moderate coastal warming event along the Angolan-Namibian coastlines, adults on average undertook longer incubation shifts than in other years and had lower body condition. This suggests that substantial between-year prey fluctuations in the Angola Benguela upwelling system may influence prey availability, in turn affecting incubation behaviour and regulation of body condition. Adults rearing chicks showed a significant reduction in body condition when chicks showed the fastest rate of growth. Chick growth rates during 2017 from two localities in the Atlantic Ocean: an oceanic (St Helena) versus neritic (Cabo Verde) population were similar, but chicks from St Helena were overall heavier and larger at fledging. Results from this multi-year study highlight that flexibility and adaptability in body condition regulation will be important for populations of threatened species to optimise resources as global climate change increasingly influences prey availability.

PSIII-7 Evaluation of Agolin-Pig on Sow and Piglet Performance During Lactation

Abstract Essential oils are being introduced in swine diets as an alternative to antibiotic usage. The objectives of this preliminary study were to determine the effects of Agolin-Pig, a combination of micro-encapsulated essential oils, on sow feed intake, sow health and body condition, piglet growth performance, and future evaluation of microbiota structure. The experimental design consisted of 26 sows randomly allotted to either control (n = 13) or treatment groups (n = 13). Both groups consumed diets that met NRC standards (NRC, 2012), with the treatment group receiving 200 ppm of Agolin-Pig in a premix made in-house for 2 weeks pre-farrowing, and throughout farrowing and lactation. Sow average daily feed intake (ADFI) and piglet average daily gain (ADG) were recorded and calculated to monitor effects of Agolin-Pig. Sow body weights, body condition scores (BCS), and Knauer Sow Caliper measurements were collected at the start of the trial, 1-week post-farrowing, and at weaning to determine the change in sow body condition during lactation. All data were analyzed using PROC Mixed procedure in SAS 9.4 (Cary, North Carolina) with treatment, week, and parity (P1 vs P≥2) as main effects, repeated measures of sows and piglets, and number nursed used as a covariate where appropriate. All sows significantly increased ADFI (P = 0.0001) between weeks 1, 2, and 3 as expected during lactation, regardless of treatment. There was no significant impact of Agolin-Pig treatment on sow ADFI and piglet ADG. Piglets significantly increased ADG each week for 3 weeks (P ± 0.0001). During lactation, Agolin-Pig significantly reduced the loss of body condition as measured by the caliper (P = 0.028). Calipers are proven to detect changes in body condition more accurately than visual, subjective BCS, indicating that the caliper identifies a reduction in body condition that may have been missed by BCS or weight change altered by lactation. The gilts in the control group tended to show a reduction in BCS compared with sows in the control group (P = 0.074). In comparison, there was no significant difference in BCS between gilts and sows in the Agolin-Pig treated group suggesting that Agolin-Pig is effective at reducing the loss of BCS in gilts during lactation. Current analysis of fecal microbiota and milk composition may give greater insight on the effects of Agolin-Pig on sows. Overall, Agolin-Pig was effective at reducing the loss of body condition during lactation, as measured by the caliper. Additionally, Agolin-Pig tended to reduce the difference in loss of body condition of gilts compared with the control group. The findings of this pilot study warrant future studies with greater sample size to determine the efficacy of Agolin-Pig on reducing body condition loss and impacting other performance measures during lactation in sows.

Effects of pejus and pessimum zone salinity stress on gill proteome networks and energy homeostasis in Oreochromis mossambicus.

Salinity tolerance in fish involves a suite of physiological changes, but a cohesive theory leading to a mechanistic understanding at the organismal level is lacking. To examine the potential of adapting energy homeostasis theory in the context of salinity stress in teleost fish, Oreochromis mossambicus were acclimated to hypersalinity at multiple rates and durations to determine salinity ranges of tolerance and resistance. Over 3000 proteins were quantified simultaneously to analyze molecular phenotypes associated with hypersalinity. A species- and tissue-specific data-independent acquisition (DIA) assay library of MSMS spectra was created. Protein networks representing complex molecular phenotypes associated with salinity acclimation were generated. O. mossambicus has a wide "zone of resistance" from 75g/kg salinity to 120g/kg. Crossing into the zone of resistance resulted in marked phenotypic changes including blood osmolality over 400mOsm/kg, reduced body condition, and cessation of feeding. Protein networks impacted by hypersalinity consist of electron transport chain (ETC) proteins and specific osmoregulatory proteins. Cytoskeletal, cell adhesion, and extracellular matrix proteins are enriched in networks that are sensitive to the critical salinity threshold. These network analyses identify specific proteome changes that are associated with distinct zones described by energy homeostasis theory and distinguish them from general hypersalinity-induced proteome changes.

Local weather affects body condition of three North American songbird species on the Texas Coast.

Body condition is a frequently used physiological indicator of avian health and can be affected by an array of environmental variables. Although a number of studies have investigated the specific effects of individual weather variables on body condition in birds, few have analyzed the effects of both temperature and precipitation within the context of an extreme weather event such as hurricanes. In this study, we examined the relationship between breeding-season body condition and daily maximum temperature, daily minimum temperature, and monthly total precipitation for three passerine bird species at the Welder Wildlife Refuge near Rockport, Texas. We also evaluated yearly changes in body condition over a 12-year period for northern cardinals (Cardinalis cardinalis), painted buntings (Passerina ciris), and white-eyed vireos (Vireo griseus), focusing on the extreme precipitation event of Hurricane Harvey, which caused heavy localized flooding. We found that body condition declined with average daily minimum and maximum temperatures, while precipitation had varied, species-specific effects in the three species analyzed. Our results also suggest that northern cardinals experienced a notable reduction in average body condition in the 2 years following Hurricane Harvey. Taken together, we conclude that short-term precipitation and temperature drivers can be important correlates of body condition in songbirds and that severe weather events may reduce body condition in some bird species.

Impacts of mining pollution on coastal ecosystems: is fish body condition a reliable indicator?

Identifying reliable biological indicators is fundamental to efficiently assess human impacts on biodiversity and to monitor the outcomes of management actions. This study investigates whether body condition is an appropriate indicator of putative effects from iron ore mining tailings on marine fishes, focusing on the world's largest mining disaster – known as the Mariana disaster, in Brazil. Eight species were used to test the hypothesis that individuals inhabiting an area severely impacted by tailings have reduced body condition in comparison to those in control areas near (<60 km) and distant (>120 km) from the impact site. Contrary to our prediction, no significant difference in condition was detected between the impacted area and both near and distant controls in seven of the eight species. The results indicate that body condition, as measured by the scaled mass index, has limited applicability as indicator of impact from mining pollution on the fishes analysed. Hypotheses that could explain our findings are proposed, including nutrient provisioning from continental drainage that could indirectly influence fish condition and compensate for the deleterious effects of mining pollution.

Anticoagulant rodenticides are associated with increased stress and reduced body condition of avian scavengers in the Pacific Northwest

Anticoagulant rodenticides (AR) have been used globally to manage commensal rodents for decades. However their application has also resulted in primary, secondary, and tertiary poisoning in wildlife. Widespread exposure to ARs (primarily second generation ARs; SGARs) in raptors and avian scavengers has triggered considerable conservation concern over their potential effects on populations. To identify risk to extant raptor and avian scavenger populations in Oregon and potential future risk to the California condor (Gymnogyps californianus) flock recently established in northern California, we assessed AR exposure and physiological responses in two avian scavenger species (common ravens [Corvus corax] and turkey vultures [Cathartes aura]) throughout Oregon between 2013 and 2019. AR exposure was widespread with 51% (35/68) of common ravens and 86% (63/73) of turkey vultures containing AR residues. The more acutely toxic SGAR brodifacoum was present in 83% and 90% of AR exposed common ravens and turkey vultures. The odds of AR exposure in common ravens were 4.7-fold higher along the coastal region compared to interior Oregon. For common ravens and turkey vultures that were exposed to ARs, respectively, 54% and 56% had concentrations that exceeded the 5% probability of toxicosis (>20 ng/g ww; Thomas et al., 2011), and 20% and 5% exceeded the 20% probability of toxicosis (>80 ng/g ww; Thomas et al., 2011). Common ravens exhibited a physiological response to AR exposure with fecal corticosterone metabolites increasing with sum ARs (ΣAR) concentrations. Both female common raven and turkey vultures’ body condition was negatively correlated with increasing ΣAR concentrations. Our results suggest avian scavengers in Oregon are experiencing extensive AR exposure and the newly established population of California condors in northern California may experience similar AR exposure if they feed in southern Oregon. Understanding the sources of ARs across the landscape is an important first step in reducing or eliminating AR exposure in avian scavengers.

Decadal decline in maternal body condition of a Southern Ocean capital breeder

The changing physical properties of the Southern Ocean are known to impact the recruitment and survival of Antarctic krill (Euphausia superba). For oceanic krill predators, the resulting reduced energy intake may lead to population-level effects likely preceded by an alteration in the animals’ body condition. This is especially true for capital breeders that rely on stored energy for successful reproduction. One such Southern Ocean capital breeder, the southern right whale (Eubalaena australis), has been monitored over the past 43 years in their South African wintering ground. Changes in the population have been documented in the past decade, including a decreased reproductive rate and a shift in foraging strategy. To evaluate if a reduced foraging success is an underlying factor, we assessed the temporal variation in morphological body condition through aerial photogrammetry. Results showed a 23% reduction in maternal body condition, potentially contributing to the decreased reproductive rate of the population. To the best of our knowledge, this is the first study to quantify a decadal reduction in the body condition of a capital breeder dependent on Southern Ocean productivity. Understanding the bioenergetic consequences of environmental change is vital to predicting species’ resilience to climate change.

Uncertain bioenergetics of North Atlantic right whales

Without substantive reduction in anthropogenic trauma, Critically Endangered North Atlantic right whales Eubalaena glacialis (NARWs) risk extinction. Decreasing population size is attributable to 2 main issues besides vessel collision: entanglement in fishing gear and changes in food availability due to ecosystem changes in the face of climate disruption. Both can affect NARW energetics, leading to reduced body condition, decreased reproductive success of individuals, and deterioration of overall population health. To measure the impact of these stressors and their interaction, energetic costs associated with entanglement and starvation were incorporated in a bioenergetics model, established for a generic female right whale. We compared models for a NARW living now, one from 2 decades ago, when the species’ abundance was increasing at approximately 2% yr-1, and a southern right whale (SRW) from a population increasing at approximately 6% yr-1. Parameter uncertainty associated with daily estimates of energy income, basal metabolic rate, and possible influences of baleen rack disruption from entanglement was so great that differences between the 3 generic right whale females were indistinguishable. Therefore, we included a stunted whale in the model. It was also indistinguishable from our first 3 model whales. Further, it made robust predictions of NARW energy budgets, let alone the impact of specific stressors of varying intensity, impossible. The capacity of bioenergetic modeling to inform conservation management of NARWs will be substantially enhanced by resolving these parameter uncertainties.

Age matters: Comparing life-stage responses to diluted bitumen exposure in coho salmon (Oncorhynchus kisutch)

Millions of liters of diluted bitumen (dilbit), a crude oil product from Canada's oil sands region, is transported through critical Pacific salmon habitat each day. While the toxicity of the water-soluble fraction of dilbit (WSFd) to early life-stages of salmon is known, quantitative data on life-stage differences in sensitivity to WSFd is missing. To fill this knowledge gap, we exposed two juvenile life-stages of coho salmon (O. kisutch) in parallel to very low (parts per billion), environmentally-relevant concentrations of WSFd for acute (48 h) and sub-chronic (4 wk) durations. The relative sensitivities of the two life-stages (fry and parr) were assessed by comparing the timing and magnitude of biological responses using common organismal and molecular endpoints of crude oil exposure. A significant reduction in body condition occurred in both fry and parr after 4 wk exposure to WSFd. Both life-stages also experienced a concentration-dependent decrease in time-to-loss-of-equilibrium during a hypoxia challenge test at both 48 h and 4 wk of exposure. Although organismal responses were similar, molecular responses were distinct between life-stages. In general, unexposed fry had higher baseline values of hepatic phase I biotransformation indicators than unexposed parr, but induction of EROD activity and cyp1a mRNA expression in response to WSFd exposure was greater in parr than in fry. Neither gst nor hsp70 mRNA expression, markers of phase II biotransformation and cell stress, respectively, were reliably altered by WSFd exposure in either life-stage. Taken together, results of this study do not support differential sensitivities of coho fry and parr to WSFd. All the same, the potential for ontogenic differences in the expression and induction of phase I biotransformation need to be considered because age does matter for these endpoints if they are used as bioindicators of exposure in post-spill impact assessments.

Stable isotopes indicate reduced body condition of caribou in disturbed areas

Abstract Understanding the impacts of disturbance on individual fitness is important for wildlife management, and critical for the conservation of species at risk. We compared the fitness and seasonal range use of 39 woodland caribou in Ontario study areas contrasted by their level of human disturbance. We previously showed that wolf density in the disturbed site was higher, likely due to human-modified landscapes favoring moose, the primary prey of wolves. In this paper we address three objectives. First, because the assimilation of dietary nitrogen is heavily influenced by metabolic processes related to stress, we hypothesized that ratios of nitrogen isotopes (N) may indicate changes in body condition in ungulates and be useful proxies for changes in fitness. Second, we predicted that increased predation risk from wolves in disturbed areas would result in measurable declines in caribou body condition. Third, we hypothesized that one mechanism for fitness declines among caribou in the disturbed area was increased wolf activity restricting caribou seasonal movements. We showed change in N in the tissues of caribou was correlated with body condition scoring using fat assessment. We used GPS collars to quantify seasonal range use and found that fitness was higher, and seasonal range overlap was lower, in caribou using the nondisturbed area. Winter fitness declines were significantly larger in the more disturbed area. Our study identifies another mechanism by which the cumulative effects of human-disturbed landscapes on caribou fitness could contribute to global declines in caribou populations.

Agriculturally intensified landscapes are associated with reduced body condition of lady beetles

ContextAgricultural intensification is contributing to a global species decline. Underlying mechanisms include toxic effects of pesticides on non-target organisms and reductions in habitat and food availability. However, the effects of agricultural intensification on body condition, particularly of ecosystem service-providing arthropods, are poorly understood.ObjectivesHere, we investigated whether variations in the body condition of common lady beetle species (Coleoptera: Coccinellidae) can be explained by the composition and configuration of the surrounding landscape. Assuming strong seasonal variation in food availability in intensively farmed regions, we included the entire period of lady beetle activity in our study.MethodsLady beetles were collected from April to September 2011 in 30 landscapes in southern Wisconsin, USA. We examined how body size, body density, and lipid content of the beetles responded to the percentage of intensive cropland, habitat diversity, and edge density in the surrounding landscape.ResultsThe strongest predictor of body condition was the percentage of intensive cropland. For every 10% increase in cropland, body density decreased by about 3.9% and lipid content by 6.4%. Landscape diversity and edge density correlated with body condition of individual species.ConclusionsIn agriculturally intensified landscapes, lady beetles with reduced body condition may produce fewer offspring, have lower survival rates, and exert less effective pest control. Thus, our results suggest a mechanistic link between landscape patterns and observed declines in lady beetle populations. Our results also show that the expansion of monocultures affects even common cropland-associated species such as Harmonia axyridis, suggesting a long-term decline in biocontrol services in simplified agricultural landscapes.

Dam parity structure and body condition during lactation influence piglet growth and gilt sexual maturation through pre-finishing.

Energy demands during lactation greatly influence sow body condition and piglet performance. We hypothesized that primiparous sows or sows with reduced body condition would produce piglets with reduced growth and delayed sexual maturation. Eight weekly farrowing seasons were used to evaluate sow body condition (post-farrowing, PF and weaning, WN) and piglet growth from 157 dams. Body condition was measured at PF and WN using sow calipers (last rib and hip) and 10th rib ultrasound. Sows were categorized as thin, moderate, or fat by caliper (PF or WN). Individual pig weights were recorded on approximately 1, 10, WN, 45, 100, and 145 d of age. At 100 and 145 d of age, 10th-rib backfat and loin eye area were measured on 567 pigs and first estrus was monitored in 176 gilts reserved for breeding selection beginning at approximately 170 d of age. Sows had similar (P > 0.10) PF last rib caliper measurements but at WN, first parity sows had the smallest caliper measurements compared to other parities (P < 0.05). Parities 1, 2, and 3 sows had similar (P > 0.10) loin eye area at PF; however, at WN first parity sows had the smallest loin eye area (P < 0.05; 38.2±0.63cm2). Parity 1 sows had the greatest (P < 0.05) reduction of backfat and loin eye area over the lactation period (-2.9±0.31mm and -2.6±0.49cm2, respectively). At 1 d of age and WN, piglets from first parity sows weighed the least (P < 0.05) but were the heaviest (P < 0.05) at 100 and 145 d of age. Pigs from first parity litters had larger (P < 0.05) loin eye area at 100 and 145 d of age and greater backfat (P < 0.05) at 145 d of age. Fat sows at WN (last rib or hip) had the lightest (P < 0.05) piglets at 10 d of age and WN. However, at 45 d of age, piglets from fat sows (last rib or hip) were heavier (P < 0.05) than piglets from moderate and thin sows. Tenth rib backfat at 100 and 145 d of age tended (P < 0.10) to be less in pigs reared by thin sows (PF and WN hip). Tenth rib loin eye area was similar among pigs reared by fat, moderate, or thin sows. Gilts developed in litters from fourth parity sows had (P < 0.05) delayed age at puberty in contrast to gilts from first or third parity sows (200.9±4.96 d vs. 189.0±2.29 d and 187.5±2.84 d, respectively). Although progeny body weights were typically less from first parity dams through 45 d of age, these progeny were similar or heavier at 100 and 145 d of age in contrast to progeny from other parities. Furthermore, gilt progeny from first parity dams did not have delayed pubertal attainment.

Sympatry leads to reduced body condition in chickadees that occasionally hybridize.

Both abiotic and biotic drivers influence species distributions. Abiotic drivers such as climate have received considerable attention, even though biotic drivers such as hybridization often interact with abiotic drivers. We sought to explore the (1) costs of co‐occurrence for ecologically similar species that hybridize and (2) associations between ecological factors and condition to understand how abiotic and biotic factors influence species distributions. For two closely related and ecologically similar songbirds, black‐capped and mountain chickadees, we characterized body condition, as a proxy for fitness, using a 1358‐individual range‐wide dataset. We compared body condition in sympatry and allopatry with several abiotic and biotic factors using species‐specific generalized linear mixed models. We generated genomic data for a subset of 217 individuals to determine the extent of hybridization‐driven admixture in our dataset. Within this data subset, we found that ~11% of the chickadees had hybrid ancestry, and all hybrid individuals had typical black‐capped chickadee plumage. In the full dataset, we found that birds of both species, independent of demographic and abiotic factors, had significantly lower body condition when occurring in sympatry than birds in allopatry. This could be driven by either the inclusion of cryptic, likely poor condition, hybrids in our full dataset, competitive interactions in sympatry, or range edge effects. We are currently unable to discriminate between these mechanisms. Our findings have implications for mountain chickadees in particular, which will encounter more black‐capped chickadees as black‐capped chickadee ranges shift upslope and could lead to local declines in mountain chickadee populations.

Body condition of females during tadpole attendance and its potential costs in a Neotropical foam-nesting frog (Leptodactylus podicipinus)

Parental care increases offspring survival, but may be costly for parents, reducing future survival and reproduction. Offspring attendance may increase predation risk, or reduce food intake, mating opportunities, and reproductive rate of parents. Anurans exhibit a great diversity of parental care behaviours and offer an opportunity to investigate the costs and benefits of parenting. Here, we measured the body condition of females of the Neotropical frog Leptodactylus podicipinus during tadpole attendance. By comparing attending and non-attending females, we tested the hypothesis that females providing care will have reduced body condition and food ingestion. Although fat body mass did not differ, attending females had significantly lower body mass, ovary mass, and stomach volume after 6 days of care. Overall, attending females may lose up to 40% of body mass due to parental care, while non-attending females gain mass. Although 27% of attending females had empty stomachs, prey diversity was higher. Additionally, the higher proportion of aquatic hemipterans and spiders preyed on by attending females may be explained by different microhabitat use and active protection of offspring. Our results indicate that parental care has the potential to affect future reproduction of females via reduction in body condition and food intake. Studies have shown the benefits related to offspring survival in anurans, but few addressed the costs to parents. By evaluating the potential costs of parenting in a frog species with aquatic tadpoles for the first time, our study contributes to fill this gap. Studies investigating the costs and benefits of parental care in different lineages of frogs will improve our knowledge on the evolution of parenting in this highly diverse group.

The influence of global climate change on accumulation and toxicity of persistent organic pollutants and chemicals of emerging concern in Arctic food webs.

This review summarizes current understanding of how climate change-driven physical and ecological processes influence the levels of persistent organic pollutants (POPs) and contaminants of emerging Arctic concern (CEACs) in Arctic biota and food webs. The review also highlights how climate change may interact with other stressors to impact contaminant toxicity, and the utility of modeling and newer research tools in closing knowledge gaps on climate change-contaminant interactions. Permafrost thaw is influencing the concentrations of POPs in freshwater ecosystems. Physical climate parameters, including climate oscillation indices, precipitation, water salinity, sea ice age, and sea ice quality show statistical associations with POPs concentrations in multiple Arctic biota. Northward range-shifting species can act as biovectors for POPs and CEACs into Arctic marine food webs. Shifts in trophic position can alter POPs concentrations in populations of Arctic species. Reductions in body condition are associated with increases in levels of POPs in some biota. Although collectively understudied, multiple stressors, including contaminants and climate change, may act to cumulatively impact some populations of Arctic biota. Models are useful for predicting the net result of various contrasting climate-driven processes on POP and CEAC exposures; however, for some parameters, especially food web changes, insufficient data exists with which to populate such models. In addition to the impact of global regulations on POP levels in Arctic biota, this review demonstrates that there are various direct and indirect mechanisms by which climate change can influence contaminant exposure, accumulation, and effects; therefore, it is important to attribute POP variations to the actual contributing factors to inform future regulations and policies. To do so, a broad range of habitats, species, and processes must be considered for a thorough understanding and interpretation of the consequences to the distribution, accumulation, and effects of environmental contaminants. Given the complex interactions between climate change, contaminants, and ecosystems, it is important to plan for long-term, integrated pan-Arctic monitoring of key biota and ecosystems, and to collect ancillary data, including information on climate-related parameters, local meteorology, ecology, and physiology, and when possible, behavior, when carrying out research on POPs and CEACs in biota and food webs of the Arctic.

Effects of rumen-protected methionine and lysine on milk yield and milk composition inHolstein dairy cows consuming a corn grain and canola meal-based diet

Methionine (Met) and lysine (Lys) are thought to be the two most important amino acids for lactation performance. Met and Lys dietary supplementation can thus be an effective approach to improve amino acid balance for lactation performance, particularly in early lactation. The purpose of this study was to determine how rumen-protected (RP) Met + Lys affect milk production, milk composition, and feed efficiency in primiparous Holstein dairy cows fed a corn grain and canola meal-based diet for 60 days (8.5 weeks) following calving. Two hundred primiparous Holstein dairy cows were randomly assigned to one of two dietary treatments based on their expected calving date: 1) a basal diet; or 2) a basal diet supplemented with RP Met + Lys. Milk production and feed consumption were tracked on a daily basis, and milk components were tested once a week. During the trial, drinking water was always available in front of the dairy cows. The RP Met + Lys considerably increased (p < 0.05) milk yield (+ 2.20 kg/d), fat corrected milk yield (+ 2.18 kg/d) and feed efficiency but had no effect on dry matter intake (p > 0.05). There was no effect of treatment on either starting or final body weight (p > 0.05). Cows receiving RP Met + Lys, on the other hand, showed a tendency (p = 0.09) of reduced body condition score (BCS) losses between weeks 1 and 8. The RP Met + Lys increased (p < 0.05) the proportion of milk fat, but had no effect on the other milk composition markers (p > 0.05). Except for milk crude protein, the yields of fat, true protein, lactose, and energy in milk were higher (p < 0.05) in cows fed RP Met + Lys vs. control cows. The results indicate that supplementing with RP Met + Lys after the first calving has a considerable impact on subsequent milk and milk fat production, as well as the yield of the majority of milk nutrients.