Niche Evolution Along a Gradient of Ecological Specialization

The concept of the ecological niche is fundamental to understanding constraints on species distributions in space and time, and in explaining the origin and maintenance of biodiversity. A niche can be broadly defined to include all of the biotic and abiotic conditions that a species requires to persist. Niche breadth, or the degree of specialization, may influence how labile a species niche is, which can have broad implications for species ability to adapt to environmental change, and for explaining patterns of diversification. I investigated mechanism that facilitate or constrain niche evolution at multiple scales. First, I developed an index of specialization in bill morphology using museum specimens across a diverse New World Passerine clade. I used this index of specialization to evaluate the relative influence of geographic and ecological niche partitioning on speciation rates across islands and continents. I then examined evolutionary transition rates among generalist and specialist bill morphotypes to determine if specialization constrains further evolution over long time scales, thus creating an evolutionary dead end. My results suggest that specialization increases speciation rates, and that niche expansion allowing transitions from specialist back to a more generalist bill morphology were common. I further explored mechanisms that drive these broad scale patters by examining patterns of intraspecific niche partitioning in closely related tidal marsh passerines. I found that habitat characteristics that reflected a salinity gradient best explained parallel patterns of bill size divergence among populations of two closely related sparrow species. Lastly, I examined if the definition of specialization varies across niche axes. We found that niche breadth, or the degree of specialization, is correlated among functional, environmental, and competition axes among five species of Passerelid sparrows. By examining the influence of specialization on macroevolutionary patterns of diversification and patterns of niche partitioning within species we gain a more comprehensive understanding of how niches evolve across different temporal and taxonomic scales. I found specialization is associated with increased speciation rates that influence continental-scale patterns of diversification. I also provide evidence that specialists retain the potential for niche expansion at the species and population scale. Patterns of intraspecific niche partitioning along habitat gradient presented here also increase our understanding of how species might adapt to change at scales that are applicable to local conservation. My results suggest strategies to incorporate a diversity of habitat characteristics may be beneficial for conserving intraspecific variation and adaptive capacity of specialist species

Intraspecific variation in reproductive traits of burrowing owls

Abstract Reviews of hatching asynchrony in birds recommended more studies on intraspecific variation in the extent of hatching asynchrony. We examined intraspecific variation in clutch size, laying chronology, onset of incubation, incubation period, and hatching asynchrony in burrowing owls (Athene cunicularia) in the Imperial Valley of California. Mean clutch size was 7.4 eggs and owls averaged 0.5 eggs laid per day. Females varied considerably in laying interval and onset of incubation (range = 1st to 9th egg in the clutch). The mean incubation period was 21.9 days. Hatching interval also varied greatly among females (x = 0.8, range 0.1-2.0 days between successively hatched eggs). Past burrowing owl studies have largely overlooked the substantial intraspecific variation in these traits or have reported estimates that differ from ours. Future studies designed to identify the environmental factors that explain the large intraspecific variation in these traits will likely provide insights into the constraints on local abundance

Detection of local-scale population declines through optimized tidal marsh bird monitoring design

Evaluating the efficacy of monitoring designs is crucial for the successful monitoring and conservation of populations. For tidal marsh bird species of conservation concern, detecting population declines at local spatial scales within actionable time frames is a top priority. We examined and compared the effectiveness of alternative monitoring strategies for detecting local-scale population declines using count data from 1176 spatially-independent salt marsh sampling points throughout the northeastern United States (Maine to Virginia). We used abundance estimates that accounted for imperfect detection as initial conditions to simulate annual population declines of 5%, 10%, 30%, and 50% over a 5-year sampling period. Under an optimal monitoring design with biennial sampling, we were able to successfully detect annual population declines of ≥30% for each species and for all species combined. However, this required a minimum of 15–20 points per site being sampled. Power to detect declines, although low for detecting smaller annual declines (i.e., \u3c10%), improved substantially when points were visited twice per season, yet a third visit provided a reduced benefit. When testing factors that could potentially influence power to detect declines, we found that the power within sites was positively related to species abundance. Power was similar between biennial sampling (3 of 5 years) and annual sampling (5 of 5 years), suggesting a more cost-effective approach would be to sample every other year. We found that within most sites, detecting annual declines of 10% or less over a relatively short 5-year duration would be difficult. Hence, we recommend that salt marsh bird monitoring programs in the northeastern United States conduct two visits to each site per sampling year, include 15 or more sampling points per site (without confounding spatial independence), and conduct monitoring efforts every other year. This approach will maximize the efficacy of site-level monitoring of tidal marsh birds, which can aid in assessments of coastal wetland conservation and related habitat management efforts

An open-source device for measuring food intake and operant behavior in rodent home-cages

Feeding is critical for survival, and disruption in the mechanisms that govern food intake underlies disorders such as obesity and anorexia nervosa. It is important to understand both food intake and food motivation to reveal mechanisms underlying feeding disorders. Operant behavioral testing can be used to measure the motivational component to feeding, but most food intake monitoring systems do not measure operant behavior. Here, we present a new solution for monitoring both food intake and motivation in rodent home-cages: the Feeding Experimentation Device version 3 (FED3). FED3 measures food intake and operant behavior in rodent home-cages, enabling longitudinal studies of feeding behavior with minimal experimenter intervention. It has a programmable output for synchronizing behavior with optogenetic stimulation or neural recordings. Finally, FED3 design files are open-source and freely available, allowing researchers to modify FED3 to suit their needs

Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201

Sex Differences and the Role of IL-10 in Ischemic Stroke Recovery.

Females experience poorer recovery after ischemic stroke compared to males, even after controlling for age and stroke severity. IL-10 is an anti-inflammatory cytokine produced by T regulatory cells and Th2 CD4+ helper T cells. In ischemic stroke, an excessive IL-10 response contributes to post-stroke immunosuppression, which worsens outcomes. However, it is unknown if sex differences exist in IL-10 levels after ischemic stroke. In this study, we found that higher levels of IL-10 were associated with poor acute and long-term outcomes after ischemic stroke in female patients but not in males. After controlling for confounders, IL-10 was not an independent predictor of functional outcomes. This suggests that higher serum IL-10 levels may reflect factors that interact with sex such as age and stroke severity

Probability of major depression classification based on the SCID, CIDI, and MINI diagnostic interviews: A synthesis of three individual participant data meta-analyses

Introduction: Three previous individual participant data meta-analyses (IPDMAs) reported that, compared to the Structured Clinical Interview for the DSM (SCID), alternative reference standards, primarily the Composite International Diagnostic Interview (CIDI) and the Mini International Neuropsychiatric Interview (MINI), tended to misclassify major depression status, when controlling for depression symptom severity. However, there was an important lack of precision in the results. Objective: To compare the odds of the major depression classification based on the SCID, CIDI, and MINI. Methods: We included and standardized data from 3 IPDMA databases. For each IPDMA, separately, we fitted binomial generalized linear mixed models to compare the adjusted odds ratios (aORs) of major depression classification, controlling for symptom severity and characteristics of participants, and the interaction between interview and symptom severity. Next, we synthesized results using a DerSimonian-Laird random-effects meta-analysis. Results: In total, 69,405 participants (7,574 [11%] with major depression) from 212 studies were included. Controlling for symptom severity and participant characteristics, the MINI (74 studies; 25,749 participants) classified major depression more often than the SCID (108 studies; 21,953 participants; aOR 1.46; 95% confidence interval [CI] 1.11-1.92]). Classification odds for the CIDI (30 studies; 21,703 participants) and the SCID did not differ overall (aOR 1.19; 95% CI 0.79-1.75); however, as screening scores increased, the aOR increased less for the CIDI than the SCID (interaction aOR 0.64; 95% CI 0.52-0.80). Conclusions: Compared to the SCID, the MINI classified major depression more often. The odds of the depression classification with the CIDI increased less as symptom levels increased. Interpretation of research that uses diagnostic interviews to classify depression should consider the interview characteristics.</p