Stochasticity, determinism, and contingency shape genome evolution of endosymbiotic bacteria.

Evolution results from the interaction of stochastic and deterministic processes that create a web of historical contingency, shaping gene content and organismal function. To understand the scope of this interaction, we examine the relative contributions of stochasticity, determinism, and contingency in shaping gene inactivation in 34 lineages of endosymbiotic bacteria, Sodalis, found in parasitic lice, Columbicola, that are independently undergoing genome degeneration. Here we show that the process of genome degeneration in this system is largely deterministic: genes involved in amino acid biosynthesis are lost while those involved in providing B-vitamins to the host are retained. In contrast, many genes encoding redundant functions, including components of the respiratory chain and DNA repair pathways, are subject to stochastic loss, yielding historical contingencies that constrain subsequent losses. Thus, while selection results in functional convergence between symbiont lineages, stochastic mutations initiate distinct evolutionary trajectories, generating diverse gene inventories that lack the functional redundancy typically found in free-living relatives.

Telemedicine-enabled biofeedback electropalatography rehabilitation (TEBER): A pilot study for patients treated with surgery for oral cavity carcinoma.

BACKGROUND: To address the rehabilitative barriers to frequency and precision of care, we conducted a pilot study of a biofeedback electropalatography (EPG) device paired with telemedicine for patients who underwent primary surgery +/- adjuvant radiation for oral cavity carcinoma. We hypothesized that lingual optimization followed by telemedicine-enabled biofeedback electropalatography rehabilitation (TEBER) would further improve speech and swallowing outcomes after "standard-of-care" SOC rehabilitation. METHOD: Pilot prospective 8-week (TEBER) program following 8 weeks of (SOC) rehabilitation. RESULTS: Twenty-seven patients were included and 11 completed the protocol. When examining the benefit of TEBER independent of standard of care, "range-of-liquids" improved by +0.36 [95% CI, 0.02-0.70, p = 0.05] and "range-of-solids" improved by +0.73 [95% CI, 0.12-1.34, p = 0.03]. There was a positive trend toward better oral cavity obliteration; residual volume decreased by -1.2 [95% CI, -2.45 to 0.053, p = 0.06], and "nutritional-mode" increased by +0.55 [95% CI, -0.15 to 1.24, p = 0.08]. CONCLUSION: This pilot suggests that TEBER bolsters oral rehabilitation after 8 weeks of SOC lingual range of motion.

INFLUENCE OF GROOMING ON PERMANENT ARTHROPOD ASSOCIATES OF BIRDS: CATTLE EGRETS, LICE, AND MITES.

Birds have a diverse community of "permanent" arthropods that complete their entire life cycle on the body of the host. Because some of these arthropods are parasites that reduce host fitness, birds control them by grooming, which consists of preening with the beak and scratching with the feet. Although preening is the primary component of grooming, scratching is essential for controlling arthropods on the head and neck, which cannot be preened. Several unrelated groups of birds have evolved comb-like pectinate claws on the middle toenail of each foot. We tested the role of these claws in the control of arthropods by experimentally removing teeth from the claws of captive western cattle egrets (Bubulcus ibis) infested with chewing lice (Insecta: Phthiraptera), feather mites (Acari: Sarcoptiformes), and nasal mites (Acari: Mesostigmata). After a period of 4 mo, we compared the abundance of arthropods on experimental birds to that of control birds with intact teeth. We used video to quantify the grooming rates of the captive birds, which groomed twice as much as wild birds. Experimental and control birds did not differ significantly in grooming time. Both groups virtually eradicated the chewing lice, but not feather mites or nasal mites. We found no support for the hypothesis that pectinate claws increase the efficiency of arthropod control by grooming. Experiments with wild birds are needed to test the hypothesis further under conditions in which birds devote less time to grooming.

Establishing peat-forming plant communities: A comparison of wetland reclamation methods in Alberta's oil sands region.

The Sandhill Wetland (SW) and Nikanotee Fen (NF) are two wetland research projects designed to test the viability of peatland reclamation in the Alberta oil sands post-mining landscape. To identify effective approaches for establishing peat-forming vegetation in reclaimed wetlands, we evaluated how plant introduction approaches and water level gradients influence species distribution, plant community development, and the establishment of bryophyte and peatland species richness and cover. Plant introduction approaches included seeding with a Carex aquatilis-dominated seed mix, planting C. aquatilis and Juncus balticus seedlings, and spreading a harvested moss layer transfer. Establishment was assessed 6 years after the introduction at SW and 5 years after the introduction at NF. In total, 51 species were introduced to the reclaimed wetlands, and 122 species were observed after 5 and 6 years. The most abundant species in both reclaimed wetlands was C. aquatilis, which produced dense canopies and occupied the largest water level range of observed plants. Introducing C. aquatilis also helped to exclude marsh plants such as Typha latifolia that has little to no peat accumulation potential. Juncus balticus persisted where the water table was lower and encouraged the formation of a diverse peatland community and facilitated bryophyte establishment. Various bryophytes colonized suitable areas, but the moss layer transfer increased the cover of desirable peat-forming mosses. Communities with the highest bryophyte and peatland species richness and cover (averaging 9 and 14 species, and 50%-160% cover respectively) occurred where the summer water level was between -10 and -40 cm. Outside this water level range, a marsh community of Typha latifolia dominated in standing water and a wet meadow upland community of Calamagrostis canadensis and woody species established where the water table was deeper. Overall, the two wetland reclamation projects demonstrated that establishing peat-forming vascular plants and bryophytes is possible, and community formation is dependent upon water level and plant introduction approaches. Future projects should aim to create microtopography with water tables within 40 cm of the surface and introduce vascular plants such as J. balticus that facilitate bryophyte establishment and support the development of a diverse peatland plant community.

Gender-Specific Differences in Preoperative Concerns in Patients Undergoing Endoscopic Sinus Surgery for Chronic Rhinosinusitis.

OBJECTIVES: Among patients with chronic rhinosinusitis (CRS), gender differences in epidemiology as well as quality of life have been reported. However, whether gender differences in endoscopic sinus surgery (ESS) preoperative concerns exist is unclear. METHODS: CRS patients undergoing ESS at 3 tertiary care centers in Los Angeles completed the validated Western Surgical Concern Inventory - ESS assessing ESS preoperative concerns. RESULTS: Of the 75 patients included, female patients expressed greater concern than male patients in regard to nasal packing, undergoing anesthesia, impact of surgery on daily activities, and pain and discomfort following surgery. CONCLUSION: This study suggests there are gender differences in ESS preoperative concerns and otolaryngologists should be aware of these possible concerns during preoperative discussions.

The fitness landscape of a community of Darwin's finches.

Divergent natural selection should lead to adaptive radiation-that is, the rapid evolution of phenotypic and ecological diversity originating from a single clade. The drivers of adaptive radiation have often been conceptualized through the concept of "adaptive landscapes," yet formal empirical estimates of adaptive landscapes for natural adaptive radiations have proven elusive. Here, we use a 17-year dataset of Darwin's ground finches (Geospiza spp.) at an intensively studied site on Santa Cruz (Galápagos) to estimate individual apparent lifespan in relation to beak traits. We use these estimates to model a multi-species fitness landscape, which we also convert to a formal adaptive landscape. We then assess the correspondence between estimated fitness peaks and observed phenotypes for each of five phenotypic modes (G. fuliginosa, G. fortis [small and large morphotypes], G. magnirostris, and G. scandens). The fitness and adaptive landscapes show 5 and 4 peaks, respectively, and, as expected, the adaptive landscape was smoother than the fitness landscape. Each of the five phenotypic modes appeared reasonably close to the corresponding fitness peak, yet interesting deviations were also documented and examined. By estimating adaptive landscapes in an ongoing adaptive radiation, our study demonstrates their utility as a quantitative tool for exploring and predicting adaptive radiation.

Co-parasitism in the face of predation: Effects of natural enemies on a neotropical mockingbird.

Co-parasitism is ubiquitous and has important consequences for the ecology and evolution of wild host populations. Studies of parasite co-infections remain limited in scope, with few experimental tests of the fitness consequences of multiple parasites, especially in natural populations. We measured the separate and combined effects of Philornis seguyi nest flies and shiny cowbirds Molothrus bonariensis on the fitness of a shared host, the chalk-browed mockingbird (Mimus saturninus) in Argentina. Using a two-factor experimental approach, we manipulated the presence of nest flies and cowbirds in mockingbird nests and assessed their effects on mockingbird haemoglobin levels, begging and provisioning rates, body size, and fledging success. We also monitored rates of nest predation in relation to parasitism by flies and cowbirds. Nest flies reduced the haemoglobin concentration, body size, and fledging success of mockingbirds, likely because mockingbirds did not compensate for parasitism by begging more or feeding their nestlings more. Cowbirds also reduced the fledging success of mockingbirds, even though they had no detectable effect on haemoglobin or body size. Nests with cowbirds, which beg more than mockingbirds, attracted more nest predators. There was no significant interaction between the effects of flies and cowbirds on any component of mockingbird fitness. The combined effects of nest flies and cowbirds were strictly additive. In summary, we show that nest flies and cowbirds both reduce host fitness, but do not have interactive effects in co-parasitized nests. Our results further suggest that predators exacerbate the effects of nest flies and cowbirds on their hosts. Our study shows that the fitness consequences of co-parasitism are complex, especially in the context of community-level interactions.

El co-parasitismo es ubicuo y tiene consecuencias importantes para la ecología y la evolución de las poblaciones de hospedadores silvestres. Los estudios de coinfecciones por parásitos poseen un alcance limitado, con pocos trabajos experimentales que analicen las consecuencias del parasitismo múltiple sobre la eficacia biológica, especialmente en poblaciones naturales. Medimos los efectos separados y combinados de las moscas de los nidos Philornis seguyi y el tordo renegrido (Molothrus bonariensis) sobre la eficacia biológica de un hospedador compartido, la calandria grande (Mimus saturninus) en Argentina. Utilizando un enfoque experimental de dos factores, manipulamos la presencia de moscas de nido y tordos en los nidos de calandrias y evaluamos sus efectos sobre los niveles de hemoglobina, las tasas de solicitud de alimento y aprovisionamiento, el tamaño corporal y el éxito de supervivencia de los pichones de calandria. También monitoreamos las tasas de depredación de nidos en relación con el parasitismo de moscas y tordos. Las moscas de los nidos redujeron la concentración de hemoglobina, el tamaño corporal y el éxito de supervivencia de los pichones de calandrias, probablemente porque las calandrias no compensaron el parasitismo solicitando más alimento o alimentando más a sus pichones. Los tordos también redujeron el éxito de supervivencia de las calandrias, aunque no tuvieron un efecto detectable sobre la hemoglobina o el tamaño corporal. Los nidos con tordos, quienes solicitaron más alimento más que las calandrias, atrajeron a más depredadores de nidos. El aumento de la depredación de nidos asociado a la alta intensidad de solicitud de alimento puede explicar por qué las calandrias en Argentina no solicitan más alimento en respuesta al parasitismo de las moscas. No hubo una interacción significativa entre los efectos de las moscas y los tordos en ningún componente de la eficacia biológica de las calandrias. Los efectos combinados de las moscas de los nidos y los tordos fueron estrictamente aditivos. En resumen, mostramos que las moscas de los nidos y los tordos reducen la eficacia biológica del hospedador, pero no tienen efectos interactivos en los nidos co-parasitados. Nuestros resultados sugieren además que los depredadores exacerban los efectos de las moscas de los nidos y los tordos sobre sus hospedadores. Nuestro estudio muestra que las consecuencias del co-parasitismo sobre la eficacia biológica son complejas, especialmente en el contexto de las interacciones a nivel comunitario.

Glossectomy for the treatment of oral cavity carcinoma: Quantitative, functional and patient-reported quality of life outcomes differ by four glossectomy defects.

OBJECTIVE: The goal was to characterize four clinically distinct glossectomy defects to establish significant quantitative cut points using functional metrics, the MD Anderson Dysphagia Index (MDADI) and speech intelligibility. METHODS: Population included 101 patients treated with surgery, adjuvant radiation per NCCN guidelines, and ≥ 12 months follow-up. RESULTS: Defect groups: subtotal hemiglossectomy (1), hemiglossectomy (2), extended hemiglossectomy (3) and oral glossectomy (4) were compared: All outcomes supported a four defect model. Intergroup comparison of outcomes with subtotal hemiglossectomy as reference (p value): Tongue Protrusion <0.001,<0.001,<0.001; Elevation <0.001,<0.001,<0.001; Open Mouth Premaxillary Contact Elevation <0.001,<0.001,<0.001; Obliteration 0.6,<0.001,<0.001; Normalcy of Diet, <0.3,<0.001,<0.001; Nutritional Mode, <0.9,<0.8,<0.001; Range of Liquids, <0.4,<0.016,<0.02; Range of Solids, <0.5,<0.004,<0.001; Eating in Public, <0.2,<0.002,<0.03; Understandability of Speech, <0.9,<0.001,<0.001; Speaking in Public, <0.4,<0.03,<0.001; MDADI, <0.4,<0.005,<0.01; Single Word Intelligibility, <0.4,<0.1,<0.001; Sentence Intelligibility, <0.5,<0.08,<0.001; Words Per Minute Intelligibility, <0.6,<0.04,<0.001; Sentence Efficiency Ratio, <0.4,<0.03,<0.002. Proportion of patients by 4 defect groups who underwent: tissue transplantation, 51%,93.9%,100%,100%.Radiation,24%,67%,88%,80%.Between hemiglossectomy and extended hemiglossectomy, the defect extends into the contralateral floor of the mouth and/or the anterior tonsillar pillar; resection of these subunits limits tongue mobility with an impact on functional outcome and MDADI. Between extended hemiglossectomy and oral glossectomy, the defect extends to include the tip of the tongue and appears to impact functional outcome and MDADI. CONCLUSIONS: Subtotal hemiglossectomy, hemiglossectomy, extended glossectomy and oral glossectomy are associated with quantitative (elevation, protrusion, open mouth premaxillary contact and obliteration), qualitative (speech and swallowing) and MDADI differences, suggesting that these 4 ordinal defect groups are distinct.

DOES PREENING BEHAVIOR REDUCE THE PREVALENCE OF AVIAN FEATHER LICE (PHTHIRAPTERA: ISCHNOCERA)?

Animals defend themselves against parasites in many ways. Defenses, such as physiological immune responses, are capable of clearing some infections. External parasites that do not feed on blood, however, are not controlled by the physiological immune system. Instead, ectoparasites like feather-feeding lice (Phthiraptera: Ischnocera) are primarily controlled by behavioral defenses such as preening. Here we test the hypothesis that birds able to preen are capable of clearing infestations of feather lice. We experimentally manipulated preening ability in a captive population of rock pigeons (Columba livia) that were infested with identical numbers of feather lice (Columbicola columbae or Campanulotes compar or both). We then monitored the feather louse infestations for 42 wk. Birds with impaired preening remained infested throughout the experiment; in contrast, the prevalence of lice on birds that could preen normally decreased by 50%. These data indicate that it is indeed possible for birds to clear themselves of feather lice, and perhaps other ectoparasites, by preening. We note, however, that captive birds spend more time preening than wild birds, and that they are less likely to be reinfested than wild birds. Thus, additional studies are necessary to determine under what circumstances wild birds can clear themselves of ectoparasites by preening.

Culture, Motivation, Self-Regulation, and the Impactful Work of Dennis M. McInerney.

This tribute celebrates the distinguished scholarship and extraordinary life of Dennis Michael McInerney, who passed away in Hong Kong on May 20th, 2022. It is a testimony of his impact on our professional and personal lives while highlighting the multitude and depth of his scholarly contributions. McInerney was one of those thinkers who invited us to reconsider how we conceptualize, assess, and apply scientific investigations in our teaching and learning practices. He authored and co-authored numerous widely used books and published numerous research articles in peer-refereed journals. During his remarkable career, McInerney dedicated a significant part to researching the problems associated with studying culture and uncovering how culture is a missing link in most motivation research. He believed there was a noteworthy need to conduct Indigenous educational research to understand the extent to which mainstream motivation theories apply to culturally diverse groups and stand up to cross-cultural testing scrutiny. McInerney's influence and impact will transcend future generations of research, given the gravity of his scholarly contributions.

Grooming Time Predicts Survival: American Kestrels, Falco sparverius, on a Subtropical Island.

AbstractAnimals have evolved a variety of adaptations to care for their body surfaces, such as grooming behavior, which keeps the integument clean, parasite-free, and properly arranged. Despite extensive research on the grooming of mammals, birds, and arthropods, the survival value of grooming has never been directly measured in natural populations. We monitored grooming and survival in a population of marked American kestrels (Falco sparverius) on San Salvador Island, Bahamas. We found a strong association between time spent grooming and survival over a 2-year period. The quadratic relationship we show is consistent with stabilizing natural selection on grooming time. To our knowledge, this is the first evidence for a correlation between grooming time and survival in a natural population. Grooming time may predict the survival of many animal taxa, but additional studies are needed to determine the shape and strength of the relationship among birds, mammals, and arthropods.

The High-Elevation Peatlands of the Northern Andes, Colombia.

Andean peatlands are important carbon reservoirs for countries in the northern Andes and have a unique diversity. Peatland plant diversity is generally related to hydrology and water chemistry, and the response of the vegetation in tropical high-elevation peatlands to changes in elevation, climate, and disturbance is poorly understood. Here, we address the questions of what the main vegetation types of peat-forming vegetation in the northern Andes are, and how the different vegetation types are related to water chemistry and pH. We measured plant diversity in 121 peatlands. We identified a total of 264 species, including 124 bryophytes and 140 vascular plants. We differentiated five main vegetation types: cushion plants, Sphagnum, true mosses, sedges, and grasses. Cushion-dominated peatlands are restricted to elevations above 4000 m. Variation in peatland vegetation is mostly driven be elevation and water chemistry. Encroachment of sedges and Sphagnum sancto-josephense in disturbed sites was associated with a reduction in soil carbon. We conclude that peatland variation is driven first by elevation and climate followed by water chemistry and human disturbances. Sites with higher human disturbances had lower carbon content. Peat-forming vegetation in the northern Andes was unique to each site bringing challenges on how to better conserve them and the ecosystem services they offer.

The terroir of the finch: How spatial and temporal variation shapes phenotypic traits in DARWIN'S finches.

The term terroir is used in viticulture to emphasize how the biotic and abiotic characteristics of a local site influence grape physiology and thus the properties of wine. In ecology and evolution, such terroir (i.e., the effect of space or "site") is expected to play an important role in shaping phenotypic traits. Just how important is the pure spatial effect of terroir (e.g., differences between sites that persist across years) in comparison to temporal variation (e.g., differences between years that persist across sites), and the interaction between space and time (e.g., differences between sites change across years)? We answer this question by analyzing beak and body traits of 4388 medium ground finches (Geospiza fortis) collected across 10 years at three locations in Galápagos. Analyses of variance indicated that phenotypic variation was mostly explained by site for beak size (η 2 = 0.42) and body size (η 2 = 0.43), with a smaller contribution for beak shape (η 2 = 0.05) and body shape (η 2 = 0.12), but still higher compared to year and site-by-year effects. As such, the effect of terroir seems to be very strong in Darwin's finches, notwithstanding the oft-emphasized interannual variation. However, these results changed dramatically when we excluded data from Daphne Major, indicating that the strong effect of terroir was mostly driven by that particular population. These phenotypic results were largely paralleled in analyses of environmental variables (rainfall and vegetation indices) expected to shape terroir in this system. These findings affirm the evolutionary importance of terroir, while also revealing its dependence on other factors, such as geographical isolation.

Long-distance dispersal of pigeons and doves generated new ecological opportunities for host-switching and adaptive radiation by their parasites.

Adaptive radiation is an important mechanism of organismal diversification and can be triggered by new ecological opportunities. Although poorly studied in this regard, parasites are an ideal group in which to study adaptive radiations because of their close associations with host species. Both experimental and comparative studies suggest that the ectoparasitic wing lice of pigeons and doves have adaptively radiated, leading to differences in body size and overall coloration. Here, we show that long-distance dispersal by dove hosts was central to parasite diversification because it provided new ecological opportunities for parasites to speciate after host-switching. We further show that among extant parasite lineages host-switching decreased over time, with cospeciation becoming the more dominant mode of parasite speciation. Taken together, our results suggest that host dispersal, followed by host-switching, provided novel ecological opportunities that facilitated adaptive radiation by parasites.

A Quantitative Analysis Examining Patients' Choice of Active Surveillance or Surgery for Managing Low-Risk Papillary Thyroid Cancer.

Background: It is important to understand patient preferences on managing low-risk papillary thyroid cancer (PTC). Methods: We prospectively followed patients with low-risk PTC <2 cm in maximal diameter, who were offered the choice of thyroidectomy or active surveillance (AS) at the University Health Network (UHN), in Toronto, Canada. The primary outcome was the frequency of AS choice (percentage with confidence interval [CI]). Univariate and multivariable analyses were performed to identify predictors of the choice of AS. Results: We enrolled 200 patients of median age 51 years (interquartile range 42-62). The primary tumor measured >1 cm in 55.5% (111/200) of participants. The AS was chosen by 77.5% [71.2-82.7%, 155/200] of participants. In a backwards conditional regression model, the clinical and demographic factors independently associated with choosing AS included: older age (compared with referent group <40 years)-age 40-64 years-odds ratio (OR) 2.78 [CI, 1.23-6.30, p = 0.014], age ≥65 years-OR 8.43 [2.13-33.37, p = 0.002], and education level of high school or lower-OR 4.41 [1.25-15.53, p = 0.021]; AS was inversely associated with the patient's surgeon of record being affiliated with the study hospital-OR 0.29 [0.11-0.76, p = 0.012]. In a separate backwards conditional logistic regression model examining associations with psychological characteristics, AS choice was independently associated with a fear of needing to take thyroid hormones after thyroidectomy-OR 1.24 [1.11-1.39, p < 0.001], but inversely associated with fear of PTC progression-OR 0.94 [0.90-0.98, p = 0.006] and an active coping mechanism ("doing something")-OR 0.43 [0.28-0.66, p < 0.001]. Conclusions: Approximately three-quarters of our participants chose AS over surgery. The factors associated with choosing AS included older age, lower education level, and having a surgeon outside the study institution. Patients' fears about either their PTC progressing or taking thyroid hormone replacement as well as the level of active coping style were associated with the decision. Our results inform the understanding of patients' decisions on managing low-risk PTC. Registration: Clinicaltrials.gov NCT03271892.

Cost-effectiveness Analysis of Submandibular Gland Preservation With Sialendoscopy for the Management of Sialolithiasis.

OBJECTIVE: To compare the cost-effectiveness of sialendoscopy with gland excision for the management of submandibular gland sialolithiasis. STUDY DESIGN: Cost-effectiveness analysis. SETTING: Outpatient surgery centers. METHODS: A Markov decision model compared the cost-effectiveness of sialendoscopy versus gland excision for managing submandibular gland sialolithiasis. Surgical outcome probabilities were found in the primary literature. The quality of life of patients was represented by health utilities, and costs were estimated from a third-party payer's perspective. The effectiveness of each intervention was measured in quality-adjusted life-years (QALYs). The incremental costs and effectiveness of each intervention were compared, and a willingness-to-pay ratio of $150,000 per QALY was considered cost-effective. One-way, multivariate, and probabilistic sensitivity analyses were performed to challenge model conclusions. RESULTS: Over 10 years, sialendoscopy yielded 9.00 QALYs at an average cost of $8306, while gland excision produced 8.94 QALYs at an average cost of $6103. The ICER for sialendoscopy was $36,717 per QALY gained, making sialendoscopy cost-effective by our best estimates. The model was sensitive to the probability of success and the cost of sialendoscopy. Sialendoscopy must meet a probability-of-success threshold of 0.61 (61%) and cost ≤$11,996 to remain cost-effective. A Monte Carlo simulation revealed sialendoscopy to be cost-effective 60% of the time. CONCLUSION: Sialendoscopy appears to be a cost-effective management strategy for sialolithiasis of the submandibular gland when certain thresholds are maintained. Further studies elucidating the clinical factors that determine successful sialendoscopy may be aided by these thresholds as well as future comparisons of novel technology.

Reclaiming to Brackish Wetlands in the Alberta Oil Sands: Comparison of Responses to Sodium Concentrations by Carex atherodes and Carex aquatilis.

The variation in sodium concentrations in waters of natural fens and marshes on the western Canadian landscape provides a background for choosing the appropriate plants for wetland reclamation. Broad tolerances to salinity are especially important for reclamation trials on saline-rich 'in-pits' that were left from open-pit oil sands mining. One such species, Carex aquatilis, has been identified as a key species in early reclamation attempts; however, at the Sandhill Wetland on the Syncrude Canada oil sands lease, this species has aggressively colonized, dominating parts of the wetland and limiting species diversity. A second species, also widespread on natural lake shores and marshes, is Carex atherodes, with field observations suggesting a broad tolerance to salinity. Here, we examine the responses of this species to a series of sodium concentrations and compare these to those of C. aquatilis. In particular, we addressed three questions: (1) How do structural attributes of C. atherodes respond to a series of Na+ concentration treatments? (2) Are different structural responses related to the functional attributes of photosynthesis, stomatal conductance, and/or transpiration rate? (3) How do these responses compare to those of C. aquatilis? We implemented a phytotron experiment to test the responses of these two species to either five or six concentrations of sodium, ranging from 20 to 3000 mg Na+ L-1. In general, structural responses of C. atherodes did not differ between 50 and 789 mg Na+ L-1, while performances of all attributes were reduced at 1407 mg L-1. Physiological attributes had high variation, but also had reduced performances at similar treatment levels. In comparison, a clear threshold was present for structural attributes in Carex aquatilis between 1650 and 2148 mg Na+ L-1, while physiological attributes were reduced between 1035 to 1650 mg Na+ L-1. These responses from C. aquatilis were similar to those previously reported. Na+ concentrations in porewater at the Sandhill Wetland in 2019 reached as high as 1200 mg Na+ L-1, with natural subsaline and sodic sites ranging much higher. Although all of the plants in the treatments remained viable at the end of the experiment, these results indicate that Na+ concentrations above 1500-2000 mg Na+ L-1 may inhibit the growth of these two species and decrease their competitive abilities.

Epigenetic effects of parasites and pesticides on captive and wild nestling birds.

Anthropogenic changes to the environment challenge animal populations to adapt to new conditions and unique threats. While the study of adaptation has focused on genetic variation, epigenetic mechanisms may also be important. DNA methylation is sensitive to environmental stressors, such as parasites and pesticides, which may affect gene expression and phenotype. We studied the effects of an invasive ectoparasite, Philornis downsi, on DNA methylation of Galápagos mockingbirds (Mimus parvulus). We used the insecticide permethrin to manipulate P. downsi presence in nests of free-living mockingbirds and tested for effects of parasitism on nestling mockingbirds using epiGBS, a reduced-representation bisulfite sequencing (RRBS) approach. To distinguish the confounding effects of insecticide exposure, we conducted a matching experiment exposing captive nestling zebra finches (Taeniopygia guttata) to permethrin. We used zebra finches because they were the closest model organism to mockingbirds that we could breed in controlled conditions. We identified a limited number of differentially methylated cytosines (DMCs) in parasitized versus nonparasitized mockingbirds, but the number was not more than expected by chance. In contrast, we saw clear effects of permethrin on methylation in captive zebra finches. DMCs in zebra finches paralleled documented effects of permethrin exposure on vertebrate cellular signaling and endocrine function. Our results from captive birds indicate a role for epigenetic processes in mediating sublethal nontarget effects of pyrethroid exposure in vertebrates. Environmental conditions in the field were more variable than the laboratory, which may have made effects of both parasitism and permethrin harder to detect in mockingbirds. RRBS approaches such as epiGBS may be a cost-effective way to characterize genome-wide methylation profiles. However, our results indicate that ecological epigenetic studies in natural populations should consider the number of cytosines interrogated and the depth of sequencing in order to have adequate power to detect small and variable effects.

Bog plant/lichen tissue nitrogen and sulfur concentrations as indicators of emissions from oil sands development in Alberta, Canada.

Increasing gaseous emissions of nitrogen (N) and sulfur (S) associated with oil sands development in northern Alberta (Canada) has led to changing regional wet and dry N and S deposition regimes. We assessed the potential for using bog plant/lichen tissue chemistry (N and S concentrations, C:N and C:S ratios, in 10 plant/lichen species) to monitor changing atmospheric N and S deposition through sampling at five bog sites, 3-6 times per growing season from 2009 to 2016. During this 8-year period, oil sands N emissions steadily increased, while S emissions steadily decreased. We examined the following: (1) whether each species showed changes in tissue chemistry with increasing distance from the Syncrude and Suncor upgrader stacks (the two largest point sources of N and S emissions); (2) whether tissue chemistry changed over the 8 year period in ways that were consistent with increasing N and decreasing S emissions from oil sands facilities; and (3) whether tissue chemistry was correlated with growing season wet deposition of NH4+-N, NO3--N, or SO42--S. Based on these criteria, the best biomonitors of a changing N deposition regime were Evernia mesomorpha, Sphagnum fuscum, and Vaccinium oxycoccos. The best biomonitors of a changing S deposition regime were Evernia mesomorpha, Cladonia mitis, Sphagnum fuscum, Sphagnum capillifolium, Vaccinium oxycoccos, and Picea mariana. Changing N and S deposition regimes in the oil sands region appear to be influencing N and S cycling in what once were pristine ombrotrophic bogs, to the extent that these bogs may effectively monitor future spatial and temporal patterns of deposition.

A MISIDENTIFICATION CRISIS PLAGUES SPECIMEN-BASED RESEARCH: A CASE FOR GUIDELINES WITH A RECENT EXAMPLE (ALI ET AL., 2020).

A recent paper in this journal concerning parasites of rock pigeons (Columba livia) published by Ali and colleagues exemplifies a growing trend of misidentified parasites in the literature, despite increased online resources that should help facilitate accurate identification. In the Ali et al. paper, a pigeon louse in the genus Columbicola (Phthiraptera: Ischnocera) is misidentified as Menopon gallinae, which is a parasite of chickens (Gallus gallus) and their relatives; moreover, this louse is from an entirely different suborder of lice (Phthiraptera: Amblycera). Another louse is misidentified as Goniodes dissimilis, another parasite of chickens and junglefowl. In addition, photographs of cestodes from pigeons in the same paper are not sufficient to confirm identification. Misidentifications are fueled, in part, by increasing pressure to publish coupled with a decrease in taxonomic expertise. We consider the downstream consequences of misidentification and suggest guidelines for authors, reviewers, and editors that could help to improve the reliability of specimen-based research.