Survival of released pheasants, Phasianus colchicus, in Ireland

The survival of 250 hand-reared pheasants was assessed by resightings of tagged individuals following their release into an open-roofed pen on an estate in Ireland. The death rates per 10 days after release were approximated as 5.5% during the first 30 days, 11.6% between 31–70 days, 6.0% between 70–240 days and 2.3% between 241–365 days. The birds suffered their highest rate of loss (48.2%) during their first 10 days after leaving the release pen. This emergence-related mortality was the major factor influencing changes in the observed death rate following release. Predators, mainly foxes, were initially attracted to the area by the presence of inaccessible prey. Males suffered a higher rate of loss following their emergence from the release pen than did the females, possibly associated with the greater proportion of time thereafter spent outside the pen and hence at risk. The factors affecting the survival of hand-reared pheasants are discussed. It is suggested that reducing densities of birds within pens may increase subsequent survival without resorting to predator control.     

Great tits do not compensate over time for a radio‐tag‐induced reduction in escape‐flight performance

The use of biologging and tracking devices is widespread in avian behavioral and ecological studies. Carrying these devices rarely has major behavioral or fitness effects in the wild, yet it may still impact animals in more subtle ways, such as during high power demanding escape maneuvers. Here, we tested whether or not great tits (Parus major) carrying a backpack radio‐tag changed their body mass or flight behavior over time to compensate for the detrimental effect of carrying a tag. We tested 18 great tits, randomly assigned to a control (untagged) or one of two different types of a radio‐tag as used in previous studies in the wild (0.9 g or 1.2 g; ~5% or ~6–7% of body mass, respectively), and determined their upward escape‐flight performance 1, 7, 14, and 28 days after tagging. In between experiments, birds were housed in large free‐flight aviaries. For each escape‐flight, we used high‐speed 3D videography to determine flight paths, escape‐flight speed, wingbeat frequency, and actuator disk loading (ratio between the bird weight and aerodynamic thrust production capacity). Tagged birds flew upward with lower escape‐flight speeds, caused by an increased actuator disk loading. During the 28‐day period, all groups slightly increased their body mass and their in‐flight wingbeat frequency. In addition, during this period, all groups of birds increased their escape‐flight speed, but tagged birds did so at a lower rate than untagged birds. This suggests that birds may increase their escape‐flight performance through skill learning; however, tagged birds still remained slower than controls. Our findings suggest that tagging a songbird can have a prolonged effect on the performance of rapid flight maneuvers. Given the absence of tag effects on reproduction and survival in most songbird radio‐tagging studies, tagged birds in the wild might adjust their risk‐taking behavior to avoid performing rapid flight maneuvers.     

DNA metabarcoding quantifies the relative biomass of arthropod taxa in songbird diets: Validation with camera‐recorded diets

Ecological research is often hampered by the inability to quantify animal diets. Diet composition can be tracked through DNA metabarcoding of fecal samples, but whether (complex) diets can be quantitatively determined with metabarcoding is still debated and needs validation using free‐living animals. This study validates that DNA metabarcoding of feces can retrieve actual ingested taxa, and most importantly, that read numbers retrieved from sequencing can also be used to quantify the relative biomass of dietary taxa. Validation was done with the hole‐nesting insectivorous Pied Flycatcher whose diet was quantified using camera footage. Size‐adjusted counts of food items delivered to nestlings were used as a proxy for provided biomass of prey orders and families, and subsequently, nestling feces were assessed through DNA metabarcoding. To explore potential effects of digestion, gizzard and lower intestine samples of freshly collected birds were subjected to DNA metabarcoding. For metabarcoding with Cytochrome Oxidase subunit I (COI), we modified published invertebrate COI primers LCO1490 and HCO1777, which reduced host reads to 0.03%, and amplified Arachnida DNA without significant changing the recovery of other arthropod taxa. DNA metabarcoding retrieved all commonly camera‐recorded taxa. Overall, and in each replicate year (N = 3), the relative scaled biomass of prey taxa and COI read numbers correlated at R = .85 (95CI:0.68–0.94) at order level and at R = .75 (CI:0.67–0.82) at family level. Similarity in arthropod community composition between gizzard and intestines suggested limited digestive bias. This DNA metabarcoding validation demonstrates that quantitative analyses of arthropod diet is possible. We discuss the ecological applications for insectivorous birds.     

No effect of passive integrated transponder tagging method on survival or body condition in a northern population of Black‐capped Chickadees (Poecile atricapillus)

Passive integrated transponder (PIT) tags allow a range of individual‐level data to be collected passively and have become a commonly used technology in many avian studies. Although the potential adverse effects of PIT tags have been evaluated in several species, explicit investigations of their impacts on small (<12 g) birds are limited. This is important, because it is reasonable to expect that smaller birds could be impacted more strongly by application of PIT tags. In this study, we individually marked Black‐capped Chickadees (Poecile atricapillus), a small (circa 10 g) passerine, at the University of Alberta Botanic Garden to evaluate potential lethal and sublethal effects of two PIT tagging methods: attachment to leg bands or subcutaneous implantation. We used a Cox proportional hazards model to compare the apparent survival of chickadees with leg band (N = 79) and implanted PIT tags (N = 77) compared with control birds that received no PIT tags (N = 76) over the subsequent 2 years based on mist net recaptures. We used radio‐frequency identification (RFID) redetections of leg band PIT tags to evaluate sex‐specific survival and increase the accuracy of our survival estimates. We also used a generalized linear regression model to compare the body condition of birds recaptured after overwintering with leg band PIT tags, implanted PIT tags, or neither. Our analysis found no evidence for adverse effects of either PIT tagging method on survival or body condition. While we recommend carefully monitoring study animals and evaluating the efficacy of different PIT tagging methods, we have shown that both leg band and subcutaneously implanted PIT tags ethical means of obtaining individualized information in a small passerine.     

Fine‐scale ecological and anthropogenic variables predict the habitat use and detectability of sloth bears in the Churia habitat of east Nepal

Once widespread throughout the tropical forests of the Indian Subcontinent, the sloth bears have suffered a rapid range collapse and local extirpations in the recent decades. A significant portion of their current distribution range is situated outside of the protected areas (PAs). These unprotected sloth bear populations are under tremendous human pressures, but little is known about the patterns and determinants of their occurrence in most of these regions. The situation is more prevalent in Nepal where virtually no systematic information is available for sloth bears living outside of the PAs. We undertook a spatially replicated sign survey‐based single‐season occupancy study intending to overcome this information gap for the sloth bear populations residing in the Trijuga forest of southeast Nepal. Sloth bear sign detection histories and field‐based covariates data were collected between 2 October and 3 December 2020 at the 74 randomly chosen 4‐km² grid cells. From our results, the model‐averaged site use probability (ψ ± SE) was estimated to be 0.432 ± 0.039, which is a 13% increase from the naïve estimate (0.297) not accounting for imperfect detections of sloth bear signs. The presence of termite mound and the distance to the nearest water source were the most important variables affecting the habitat use probability of sloth bears. The average site‐level detectability (p ± SE) of sloth bear signs was estimated to be 0.195 ± 0.003 and was significantly determined by the index of human disturbances. We recommend considering the importance of fine‐scale ecological and anthropogenic factors in predicting the sloth bear‐habitat relationships across their range in the Churia habitat of Nepal, and more specifically in the unprotected areas.     

The stiffness‐controlled release of interleukin‐6 by cardiac fibroblasts is dependent on integrin α2β1

Cardiac fibroblasts are able to sense the rigidity of their environment. The present study examines whether the stiffness of the substrate in cardiac fibroblast culture can influence the release of interleukin‐6 (IL‐6), interleukin‐11 (IL‐11) and soluble receptor of IL‐6 (sIL‐6R). It also examines the roles of integrin α2β1 activation and intracellular signalling in these processes. Cardiac fibroblasts were cultured on polyacrylamide gels and grafted to collagen, with an elasticity of E = 2.23 ± 0.8 kPa (soft gel) and E = 8.28 ± 1.06 kPa (stiff gel, measured by Atomic Force Microscope). Flow cytometry and ELISA demonstrated that the fibroblasts cultured on the soft gel demonstrated higher expression of the α2 integrin subunit and increased α2β1 integrin count and released higher levels of IL‐6 and sIL‐6R than those on the stiff gel. Substrate elasticity did not modify fibroblast IL‐11 content. The silencing of the α2 integrin subunit decreased the release of IL‐6. Similar effects were induced by TC‐I 15 (an α2β1 integrin inhibitor). The IL‐6 levels in the serum and heart were markedly lower in α2 integrin‐deficient mice B6.Cg‐Itga2^{tm1.1Tkun/tm1.1Tkun} than wild type. Inhibition of Src kinase by AZM 475271 modifies the IL‐6 level. sIL‐6R secretion is not dependent on α2β1 integrin. Conclusion: The elastic properties of the substrate influence the release of IL‐6 by cardiac fibroblasts, and this effect is dependent on α2β1 integrin and kinase Src activation.     

The effects of taxonomy,diet, and ecology on the microbiota of riverine macroinvertebrates

Freshwater macroinvertebrates play key ecological roles in riverine food webs, such as the transfer of nutrients to consumers and decomposition of organic matter. Although local habitat quality drives macroinvertebrate diversity and abundance, little is known about their microbiota. In most animals, the microbiota provides benefits, such as increasing the rate at which nutrients are metabolized, facilitating immune system development, and defending against pathogenic attack. Our objectives were to identify the bacteria within aquatic invertebrates and determine whether their composition varied with taxonomy, habitat, diet, and time of sample collection. In 2016 and 2017, we collected 264 aquatic invertebrates from the mainstem Saint John (Wolastoq) River in New Brunswick, Canada, representing 15 orders. We then amplified the V3‐V4 hypervariable region of the 16S rRNA gene within each individual, which revealed nearly 20,000 bacterial operational taxonomic units (OTUs). The microbiota across all aquatic invertebrates were dominated by Proteobacteria (69.25% of the total sequence reads), but they differed significantly in beta diversity, both among host invertebrate taxa (genus‐, family‐, and order‐levels) and temporally. In contrast to previous work, we observed no microbiota differences among functional feeding groups or traditional feeding habits, and neither water velocity nor microhabitat type structured microbiota variability. Our findings suggest that host invertebrate taxonomy was the most important factor in modulating the composition of the microbiota, likely through a combination of vertical and horizontal bacterial transmission, and evolutionary processes. This is one of the most comprehensive studies of freshwater invertebrate microbiota to date, and it underscores the need for future studies of invertebrate microbiota evolution and linkages to environmental bacteria and physico‐chemical conditions.     

Genetic diversity and sex‐biased dispersal in the brown spotted pitviper (Protobothrops mucrosquamatus): Evidence from microsatellite markers

Dispersal plays a vital role in the geographical distribution, population genetic structure, quantity dynamics, and evolution of a species. Sex‐biased dispersal is common among vertebrates and many studies have documented a tendency toward male‐biased dispersal in mammals and female‐biased dispersal in birds. However, dispersal patterns in reptiles remain poorly understood. In this study, we explored the genetic diversity and dispersal patterns of the widely distributed Asian pitviper Protobothrops mucrosquamatus. In total, 16 polymorphic microsatellite loci were screened in 150 snakes (48 males, 44 females, 58 samples without sex information) covering most of their distribution. Microsatellite analysis revealed high genetic diversity in P. mucrosquamatus. Bayesian clustering of population assignment identified two major clusters for all populations, somewhat inconsistent with the mitochondrial DNA phylogeny of P. mucrosquamatus reported in previous research. Analyses based on 92 sex‐determined and 37 samples of P. mucrosquamatus from three small sites in Sichuan, China (Mingshan, Yibin, and Zizhong) consistently suggested female‐biased dispersal in P. mucrosquamatus, which is the first example of this pattern in snakes. The female‐biased dispersal patterns in P. mucrosquamatus may be explained by local resource competition.     

Phylogeography of sugar kelp: Northern ice‐age refugia in the Gulf of Alaska

Many Northeast (NE) Pacific fishes and invertebrates survived Pleistocene glaciations in northern refugia, but the extent that kelps survived in northern areas is uncertain. Here, we test the hypothesis that populations of sugar kelp (Saccharina latissima) persisted in the Gulf of Alaska during ice‐age maxima when the western margin of the Cordilleran ice sheet covered coastal areas around the NE Pacific Ocean. We estimated genetic diversities within and phylogeographical relationships among 14 populations along 2,800 km in the NE Pacific and Bering Sea with partial sequences of mitochondrial DNA 5′‐cytochrome oxidase subunit I (COI, bp = 624, n = 543), chloroplast DNA ribulose‐1,5‐bisphosphate carboxylase large subunit‐3′ (rbcL, bp = 735, n = 514), and 11 microsatellite loci. Concatenated sequences of rbcL and COI showed moderate levels of within‐population genetic diversity (mean h = 0.200) but substantial differences among populations (Φ_ST = 0.834, p < .0001). Microsatellites showed moderate levels of heterozygosity within populations (mean H _E = 0.391). Kelps in the same organellar lineage tended to cluster together, regardless of geographic origins, as indicated in a principal coordinate analysis (PCoA) of microsatellite genotypes. The PCoA also showed evidence of nuclear hybridizations between co‐occurring organellar lineages. Individual admixture plots with population clusters of K = 2, 6, and 9 showed increasing complexity with considerable historical admixture between some clusters. A time‐calibrated phylogeny placed divergences between rbcL‐COI lineages at 1.4 million years at most. The time frames of mutation in the rbcL‐COI lineages and microsatellite population clusters differed among locations. The existence of ancient lineages in the Gulf of Alaska, moderate levels of genetic diversity, and the absence of departures from neutrality are consistent with northern refugia during multiple Croll‐Milankovitch climate cycles in the Pleistocene Epoch.     

Modeling the effects of grassland management intensity on biodiversity

A growing food demand and advanced agricultural techniques increasingly affect farmland ecosystems, threatening invertebrate populations with cascading effects along the food chain upon insectivorous vertebrates. Supporting farmland biodiversity thus optimally requires the delineation of species hotspots at multiple trophic levels to prioritize conservation management. The goal of this study was to investigate the links between grassland management intensity and orthopteran density at the field scale and to upscale this information to the landscape in order to guide management action at landscape scale. More specifically, we investigated the relationships between grassland management intensity, floral indicator species, and orthopteran abundance in grasslands with different land use in the SW Swiss Alps. Field vegetation surveys of indicator plant species were used to generate a management intensity proxy, to which field assessments of orthopterans were related. Orthopteran abundance showed a hump‐shaped response to management intensity, with low values in intensified, nutrient‐rich grasslands and in nutrient‐poor, xeric grasslands, while it peaked in middle‐intensity grasslands. Combined with remote‐sensed data about grassland gross primary productivity, the above proxy was used to build landscape‐wide, spatially explicit projections of the potential distribution of orthopteran‐rich grasslands as possible foraging grounds for insectivorous vertebrates. This spatially explicit multitrophic approach enables the delineation of focal farmland areas in order to prioritize conservation action.     

Effect of rearing density on pecking behaviour and plumage condition of laying hens in two types of aviary

The objective of this experiment was to investigate the effect of rearing density on pecking behaviour and plumage during rearing and throughout the laying period in aviaries. Chicks were reared on sand at high (H; 13 m⁻²) or low (L; 6.5 m⁻²) density, in four rearing pens of 390 chicks and eight pens of 195 chicks, respectively, each pen measuring 30 m². Proportions of chicks per pen performing various types of pecking behaviour were recorded by scan sampling during 16 observation bouts in each rearing pen at 6 weeks of age and during 24 observation bouts at 12 weeks. Individual body weights and plumage condition were recorded. Later, these pullets were housed at 17 hens m⁻² in Tiered Wire Floor (TWF; 3 H and 3 L pens of 275 hens) and Laco-Volétage (2 H and 2 L pens of 275 hens) aviaries. At 35 weeks, two samples of eight hens from each aviary pen were observed for pecking behaviour in a test pen. Throughout the laying period, additional records were collected on pecking behaviour, body weight, plumage condition, egg production, and mortality. The L birds had better plumage condition at 6 weeks of age and throughout the laying period. These birds also ground pecked more frequently than H birds during rearing and the laying period. At 12 weeks, L birds feather pecked less than H birds, but no relationship was found between rearing density and feather-pecking behaviour during the laying period. Although TWF hens feather pecked more frequently than Volétage hens, there was no interaction between rearing density and type of aviary for the various pecking behaviours.     

Role of individual dispersal in genetic resilience in fluctuating populations of the gray‐sided vole Myodes rufocanus

Population densities of the gray‐sided vole Myodes rufocanus fluctuate greatly within and across years in Japan. Here, to investigate the role of individual dispersal in maintaining population genetic diversity, we examined how genetic diversity varied during fluctuations in density by analyzing eight microsatellite loci in voles sampled three times per year for 5 years, using two fixed trapping grids (approximately 0.5 ha each). At each trapping session, all captured voles at each trapping grid were removed. The STRUCTURE program was used to analyze serially collected samples to examine how population crashes were related to temporal variability, based on local‐scale genetic compositions in each population. In total, 461 and 527 voles were captured at each trapping grid during this study. The number of voles captured during each trapping session (i.e., vole density) varied considerably at both grids. Although patterns in fluctuations were not synchronized between grids, the peak densities were similar. At both grids, the mean allele number recorded at each trapping session was strongly, positively, and nonlinearly correlated with density. STRUCTURE analyses revealed that the proportions of cluster compositions among individuals at each grid differed markedly before and after the crash phase, implying the long‐distance dispersal of voles from remote areas at periods of low density. The present results suggest that, in gray‐sided vole populations, genetic diversity varies with density largely at the local scale; in contrast, genetic variation in a metapopulation is well‐preserved at the regional scale due to the density‐dependent dispersal behaviors of individuals. By influencing the dispersal patterns of individuals, fluctuations in density affect metapopulation structure spatially and temporally, while the levels of genetic diversity are preserved in a metapopulation.     

Interrupted incubation: How dabbling ducks respond when flushed from the nest

Nesting birds must provide a thermal environment sufficient for egg development while also meeting self‐maintenance needs. Many birds, particularly those with uniparental incubation, achieve this balance through periodic incubation recesses, during which foraging and other self‐maintenance activities can occur. However, incubating birds may experience disturbances such as predator or human activity which interrupt natural incubation patterns by compelling them to leave the nest. We characterized incubating mallard Anas platyrhynchos and gadwall Mareca strepera hens’ responses when flushed by predators and investigators in Suisun Marsh, California, USA. Diurnal incubation recesses initiated by investigators approaching nests were 63% longer than natural diurnal incubation recesses initiated by the hen (geometric mean: 226.77 min versus 142.04 min). Nocturnal incubation recesses, many of which were likely the result of predators flushing hens, were of similar duration regardless of whether the nest was partially depredated during the event (115.33 [101.01;131.68] minutes) or not (119.62 [111.96;127.82] minutes), yet were 16% shorter than natural diurnal incubation recesses. Hens moved further from the nest during natural diurnal recesses or investigator‐initiated recesses than during nocturnal recesses, and the proportion of hen locations recorded in wetland versus upland habitat during recesses varied with recess type (model‐predicted means: natural diurnal recess 0.77; investigator‐initiated recess 0.82; nocturnal recess 0.31). Hens were more likely to take a natural recess following an investigator‐initiated recess earlier that same day than following a natural recess earlier that same day, and natural recesses that followed an investigator‐initiated recess were longer than natural recesses that followed an earlier natural recess, suggesting that hens may not fulfill all of their physiological needs during investigator‐initiated recesses. We found no evidence that the duration of investigator‐initiated recesses was influenced by repeated visits to the nest, whether by predators or by investigators, and trapping and handling the hen did not affect investigator‐initiated recess duration unless the hen was also fitted with a backpack‐harness style GPS–GSM transmitter at the time of capture. Hens that were captured and fitted with GPS–GSM transmitters took recesses that were 26% longer than recesses during which a hen was captured but a GPS–GSM transmitter was not attached. Incubation interruptions had measurable but limited and specific effects on hen behavior.     

A multispecies approach to manage effects of land cover and weather on upland game birds

Loss and degradation of grasslands in the Great Plains region have resulted in major declines in abundance of grassland bird species. To ensure future viability of grassland bird populations, it is crucial to evaluate specific effects of environmental factors among species to determine drivers of population decline and develop effective conservation strategies. We used threshold models to quantify the effects of land cover and weather changes in "lesser prairie‐chicken" and "greater prairie‐chicken" (Tympanuchus pallidicinctus and T. cupido, respectively), northern bobwhites (Colinus virginianus), and ring‐necked pheasants (Phasianus colchicus). We demonstrated a novel approach for estimating landscape conditions needed to optimize abundance across multiple species at a variety of spatial scales. Abundance of all four species was highest following wet summers and dry winters. Prairie chicken and ring‐necked pheasant abundance was highest following cool winters, while northern bobwhite abundance was highest following warm winters. Greater prairie chicken and northern bobwhite abundance was also highest following cooler summers. Optimal abundance of each species occurred in landscapes that represented a grassland and cropland mosaic, though prairie chicken abundance was optimized in landscapes with more grassland and less edge habitat than northern bobwhites and ring‐necked pheasants. Because these effects differed among species, managing for an optimal landscape for multiple species may not be the optimal scenario for any one species.     

Can evolutionary theories of dispersal and senescence predict postrelease survival,dispersal, and body condition of a reintroduced threatened mammal?

1. Theories of dispersal and senescence (or aging) predict that dispersal, and ongoing survival and body condition, are influenced by evolutionary drivers, along with intrinsic and extrinsic factors. Such theories are relevant to translocations of animals where high mortality, loss of body condition, and dispersal beyond the area of release are commonly reported. However, these theories have rarely been tested using data from translocations.
2. We explore whether theories of dispersal and senescence, together with biological knowledge and management interventions, can predict rates of postrelease dispersal, survival and change in body condition of a translocated endangered meso‐predator, the eastern quoll Dasyurus viverrinus.
3. Captive‐bred quolls (n = 60) from three sanctuaries were translocated to an unfenced, predator‐managed reserve (Booderee National Park) over 2 years (2018, 2019). Survival, dispersal and body mass were monitored via GPS/VHF tracking and targeted trapping for 45 days postrelease.
4. We found support for the “social subordinate” hypothesis, with smaller quolls dispersing further. Consistent with theories of senescence and the biology of our species, survival was marginally greater for females, and females regained losses in body mass in both years following release. In contrast, males recovered body condition in the first but not the second release as this coincided with breeding. Quolls that originated from the mainland sanctuary were on average heavier at release and, after accounting for weight, dispersed further.
5. Synthesis and applications. Using theory to test outcomes of wildlife translocations can provide insights into patterns across taxa and under different conditions, enabling useful improvements to future fauna translocations. This allows for better predictions to be made about the likelihood of success from proposed translocations, changes to planning to improve outcomes (e.g., modifying sex ratios, individual selection and release cohort), and improved animal welfare as fewer animals are subjected to trials.

     

Litter decomposes slowly on shaded steep slope and sunny gentle slope in a typical steppe ecoregion

Plant litter decomposition is mainly affected by litter properties and environmental factors, but the influence of terrain on litter decomposition is not well understood. We studied the effects of terrain on litter decomposition over a period of 12 months at six locations in a typical steppe ecoregion and measured the concomitant release of carbon (C), nitrogen (N), and phosphorus (P). The study site has two aspects, shaded and sunny, each aspect having three slopes: 15°, 30°, and 45°. The same mixed litter was used at each location to exclude the influence of litter quality variation. Results showed that soil temperature and moisture, solar radiation, and plant species diversity varied by terrain, which in turn, affected the k‐value (standardized total effects, 0.78, 0.12, 0.92, 0.23, respectively) and the release of C (0.72, –0.25, 0.83, 0.24, respectively), N (0.89, –0.45, 0.76, 0.40, respectively) and P (0.88, 0.77, 0.58, 0.57, respectively). K‐value and C release decreased with increasing slope on shaded aspect, while increased with increasing slope on sunny aspect. The release of N and P decreased with increasing slope on the shaded aspect. K‐value and C, N, and P release were significantly higher on shaded than that on sunny aspect at 15° and 30°, while at 45°, it was higher on sunny than on shaded aspect. The litter mass loss was slower on shaded 45° and sunny 15°. So moderate grazing or mowing could be used to reduce litter accumulation and accelerate litter decomposition on these terrains. Structural equation modeling indicated that soil temperature and solar radiation had the greatest influence on k‐value and C, N, and P release, and these two factors were directly related to soil moisture and plant species diversity. Overall, our results emphasize the need to consider terrain for litter decomposition in typical steppe ecoregions.     

Secondhand homes: The multilayered influence of woodpeckers as ecosystem engineers

Ecosystem engineers alter, and can be influenced in turn by, the ecosystems they live in. Woodpeckers choose foraging and nesting sites based, in part, on food availability. Once abandoned, these cavities, particularly within areas of high forage, may be crucial to secondary cavity‐nesting birds otherwise limited by cavities formed through decay. Our study examined factors that influence the nesting success of primary cavity nesters and the subsequent impact on secondary cavity‐nesting birds. Using 5 years of point count data, we monitored the outcomes of cavity‐nesting birds in South Texas. We used logistic‐exposure models to predict daily survival rates based on cavity metrics and used woodpecker foraging trends and insect surveys to determine if nesting where woodpeckers actively forage benefits secondary cavity‐nesting birds. Both woodpeckers and secondary cavity nesters shared predictors of daily survival; nests were more successful in cavities with small openings in minimally decayed trees. All secondary cavity nesters had higher probabilities of success when nesting in an abandoned woodpecker cavity, opposed to ones formed by decay. Woodpeckers tended to forage in areas with higher‐than‐average levels of the insect orders Coleoptera, Hymenoptera, and Orthoptera, and secondary cavity nesters had higher rates of success when nesting in these areas. Our results suggest abandoned woodpecker cavities may be constructed in a way that directly benefit secondary cavity nesters. Additionally, we suggest an interplay between these ecosystem engineers, food availability, and secondary cavity nesters: Woodpeckers engineer superior nesting cavities in areas where food is more abundant, and the resultant cavities in areas of high forage may benefit local secondary cavity nesters. Our findings indicate that there is still much to be explored in the role of ecosystem engineers, and how they influence local communities on multiple trophic levels.     

Sex‐ and strain‐specific effects of mitochondrial uncoupling on age‐related metabolic diseases in high‐fat diet‐fed mice

Mild uncoupling of oxidative phosphorylation is an intrinsic property of all mitochondria and may have evolved to protect cells against the production of damaging reactive oxygen species. Therefore, compounds that enhance mitochondrial uncoupling are potentially attractive anti‐aging therapies; however, chronic ingestion is associated with a number of unwanted side effects. We have previously developed a controlled‐release mitochondrial protonophore (CRMP) that is functionally liver‐directed and promotes oxidation of hepatic triglycerides by causing a subtle sustained increase in hepatic mitochondrial inefficiency. Here, we sought to leverage the higher therapeutic index of CRMP to test whether mild mitochondrial uncoupling in a liver‐directed fashion could reduce oxidative damage and improve age‐related metabolic disease and lifespan in diet‐induced obese mice. Oral administration of CRMP (20 mg/[kg‐day] × 4 weeks) reduced hepatic lipid content, protein kinase C epsilon activation, and hepatic insulin resistance in aged (74‐week‐old) high‐fat diet (HFD)‐fed C57BL/6J male mice, independently of changes in body weight, whole‐body energy expenditure, food intake, or markers of hepatic mitochondrial biogenesis. CRMP treatment was also associated with a significant reduction in hepatic lipid peroxidation, protein carbonylation, and inflammation. Importantly, long‐term (49 weeks) hepatic mitochondrial uncoupling initiated late in life (94–104 weeks), in conjugation with HFD feeding, protected mice against neoplastic disorders, including hepatocellular carcinoma (HCC), in a strain and sex‐specific manner. Taken together, these studies illustrate the complex variation of aging and provide important proof‐of‐concept data to support further studies investigating the use of liver‐directed mitochondrial uncouplers to promote healthy aging in humans.     

Novel mitochondrial gene rearrangements pattern in the millipede Polydesmus sp. GZCS‐2019 and phylogenetic analysis of the Myriapoda

The subphylum Myriapoda included four extant classes (Chilopoda, Symphyla, Diplopoda, and Pauropoda). Due to the limitation of taxon sampling, the phylogenetic relationships within Myriapoda remained contentious, especially for Diplopoda. Herein, we determined the complete mitochondrial genome of Polydesmus sp. GZCS‐2019 (Myriapoda: Polydesmida) and the mitochondrial genomes are circular molecules of 15,036 bp, with all genes encoded on + strand. The A+T content is 66.1%, making the chain asymmetric, and exhibits negative AT‐skew (−0.236). Several genes rearrangements were detected and we propose a new rearrangement model: “TD (N\R) L + C” based on the genome‐scale duplication + (non‐random/random) loss + recombination. Phylogenetic analyses demonstrated that Chilopoda and Symphyla both were monophyletic group, whereas Pauropoda was embedded in Diplopoda to form the Dignatha. Divergence time showed the first split of Myriapoda occurred between the Chilopoda and other classes (Wenlock period of Silurian). We combine phylogenetic analysis, divergence time, and gene arrangement to yield valuable insights into the evolutionary history and classification relationship of Myriapoda and these results support a monophyletic Progoneata and the relationship (Chilopoda + (Symphyla + (Diplopoda + Pauropoda))) within myriapod. Our results help to better explain the gene rearrangement events of the invertebrate mitogenome and lay the foundation for further phylogenetic study of Myriapoda.     

Not a cakewalk: Insights into movement of large carnivores in human‐dominated landscapes in India

Large carnivores play an important role in the functioning of ecosystems, yet their conservation remains a massive challenge across the world. Owing to wide‐ranging habits, they encounter various anthropogenic pressures, affecting their movement in different landscape. Therefore, studying how large carnivores adapt their movement to dynamic landscape conditions is vital for management and conservation policy.A total of 26 individuals across 4 species of large carnivores of different sex and age classes (14 Panthera tigris, 3 Panthera pardus, 5 Cuon alpinus, and 4 Canis lupus pallipes) were GPS collared and monitored from 2014–19. We quantified movement parameters (step length and net squared displacement) of four large carnivores in and outside protected areas in India. We tested the effects of human pressures such as human density, road network, and landuse types on the movement of the species. We also examined the configuration of core areas as a strategy to subsist in a human‐dominated landscape using BBMM.Mean displacement of large carnivores varied from 99.35 m/hr for leopards to 637.7 m/hr for wolves. Tigers outside PAs exhibited higher displacement than tigers inside PAs. Moreover, displacement during day–night was significantly different for tigers inside and outside PAs. Similarly, wolf also showed significant difference between day‐night movement. However, no difference in day–night movement was found for leopard and dholes. Anthropogenic factors such as road length and proportion of agriculture within the home range of tigers outside PAs were found to be significantly different. All the habitat variables in the home range showed significant difference between the social canids. The core area size for tiger outside PA and wolf was found greater than PAs.The study on movement of large carnivore species across landscapes is crucial for conservation planning. Our findings can be a starting point for interlinking animal movement and landscape management of large carnivore conservation in the current Anthropocene.