The macroecology of chemical communication in lizards: do climatic factors drive the evolution of signalling glands?

Chemical communication plays a pivotal role in shaping sexual and ecological interactions among animals. In lizards, fundamental mechanisms of sexual selection such as female mate choice have rarely been shown to be influenced by quantitative phenotypic traits (e.g., ornaments), while chemical signals have been found to potentially influence multiple forms of sexual and social interactions, including mate choice and territoriality. Chemical signals in lizards are secreted by glands primarily located on the edge of the cloacae (precloacal glands, PG) and thighs (femoral glands), and whose interspecific and interclade number ranges from 0 to >100. However, elucidating the factors underlying the evolution of such remarkable variation remains an elusive endeavour. Competing hypotheses suggest a dominant role for phylogenetic conservatism (i.e., species within clades share similar numbers of glands) or for natural selection (i.e., their adaptive diversification results in deviating numbers of glands from ancestors). Using the prolific Liolaemus lizard radiation from South America (where precloacal glands vary from 0-14), we present one of the largest-scale tests of both hypotheses to date. Based on climatic and phylogenetic modelling, we show a clear role for both phylogenetic inertia and adaptation underlying gland variation: (i) solar radiation, net primary productivity, topographic heterogeneity and precipitation range have a significant effect on number of PG variation, (ii) humid and cold environments tend to concentrate species with a higher number of glands, (iii) there is a strong phylogenetic signal that tends to conserve the number of PG within clades. Collectively, our study confirms that the inertia of niche conservatism can be broken down by the need of species facing different selection regimes to adjust their glands to suit the demands of their specific environments

Implementation of a quality improvement project on smoking cessation reduces smoking in a high risk trauma patient population

BACKGROUND: Cigarette smoking causes about one of every five deaths in the U.S. each year. In 2013 the prevalence of smoking in our institution’s trauma population was 26.7 %, well above the national adult average of 18.1 % according to the CDC website. As a quality improvement project we implemented a multimodality smoking cessation program in a high-risk trauma population. METHODS: All smokers with independent mental capacity admitted to our level I trauma center from 6/1/2014 until 3/31/2015 were counseled by a physician on the benefits of smoking cessation. Those who wished to quit smoking were given further counseling by a pulmonary rehabilitation nurse and offered nicotine replacement therapy (e.g. nicotine patch). A planned 30 day or later follow-up was performed to ascertain the primary endpoint of the total number of patients who quit smoking, with a secondary endpoint of reduction in the frequency of smoking, defined as at least a half pack per day reduction from their pre-intervention state. RESULTS: During the 9 month study period, 1066 trauma patients were admitted with 241 (22.6 %) identified as smokers. A total of 31 patients with a mean Injury Severity Score (ISS) of 14.2 (range 1–38), mean age of 47.6 (21–71) and mean years of smoking of 27.1 (2–55), wished to stop smoking. Seven of the 31 patients, (22.5 %, 95 % confidence interval [CI] of 10–41 %) achieved self-reported smoking cessation at or beyond 30 days post discharge. An additional eight patients (25.8 %, 95 % CI 12–45 %) reported significant reduction in smoking. CONCLUSIONS: Trauma patients represent a high risk smoking population. The implementation of a smoking cessation program led to a smoking cessation rate of 22.5 % and smoking reduction in 25.8 % of all identified smokers who participated in the program. This is a relatively simple, inexpensive intervention with potentially far reaching and beneficial long-term health implications. A larger, multi-center prospective study appears warranted. LEVEL OF EVIDENCE: Therapeutic Study, Level V evidence

Intra and inter-annual variation in the diet of Magellanic penguin (Spheniscus magellanicus) at Martillo Island, Beagle Channel

Knowledge of seabirds’ diet at each breeding site and its temporal variation is key to understanding and evaluating how changes in marine resources affect each seabird population. In this study, we determined the diet of Magellanic penguins (MP, Spheniscus magellanicus) at Martillo Island, accounting for sex, breeding stage and year. We analyzed a total of 144 stomach contents during three consecutive breeding seasons (2006–2007, 2007–2008 and 2008–2009) and stages (incubation, early and late chick-rearing). MP fed mainly on fuegian sprat (Sprattus fuegensis), which represented 75 % of the biomass consumed by birds during the entire study. The next important prey was squat lobster (Munida gregaria), followed by Patagonian squid (Loligo gahi). Both sexes consumed similar prey items. We observed variation in diet relative composition among breeding years and stages. Fuegian sprat consumption decreased throughout the years whereas squat lobster increased. Penguins consumed a higher proportion of squat lobster and Patagonian squid during the incubation stage than in the chick-rearing stages, whereas fuegian sprat was almost the only prey item consumed during the late chick-rearing stage. MPs show certain flexibility in the use of resources probably as a response to changes in prey populations. Variability in the diet among different reproductive stages could be related to changes in the distribution and abundance of their main prey near the colony during the breeding season together with changes in the energy requirements of seabirds.Fil: Scioscia, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Saenz Samaniego, Ricardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Florentin, Olga Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Schiavini, Adrian Carlos Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Macroevolutionary diversification with limited niche disparity in a species-rich lineage of cold-climate lizards

Background: Life diversifies via adaptive radiation when natural selection drives the evolution of ecologically distinct species mediated by their access to novel niche space, or via non-adaptive radiation when new species diversify while retaining ancestral niches. However, while cases of adaptive radiation are widely documented, examples of non-adaptively radiating lineages remain rarely observed. A prolific cold-climate lizard radiation from South America (Phymaturus), sister to a hyper-diverse adaptive radiation (Liolaemus), has extensively diversified phylogenetically and geographically, but with exceptionally minimal ecological and life-history diversification. This lineage, therefore, may offer unique opportunities to investigate the non-adaptive basis of diversification, and in combination with Liolaemus, to cover the whole spectrum of modes of diversification predicted by theory, from adaptive to non-adaptive. Using phylogenetic macroevolutionary modelling performed on a newly created 58-species molecular tree, we establish the tempo and mode of diversification in the Phymaturus radiation. Results: Lineage accumulation in Phymaturus opposes a density-dependent (or ‘niche-filling’) process of diversification. Concurrently, we found that body size diversification is better described by an Ornstein-Uhlenbeck evolutionary model, suggesting stabilizing selection as the mechanism underlying niche conservatism (i.e., maintaining two fundamental size peaks), and which has predominantly evolved around two major adaptive peaks on a ‘Simpsonian’ adaptive landscape. Conclusions: Lineage diversification of the Phymaturus genus does not conform to an adaptive radiation, as it is characterised by a constant rate of species accumulation during the clade’s history. Their strict habitat requirements (rocky outcrops), predominantly invariant herbivory, and especially the constant viviparous reproduction across species have likely limited their opportunities for adaptive diversifications throughout novel environments. This mode of diversification contrasts dramatically with its sister lineage Liolaemus, which geographically overlaps with Phymaturus, but exploits all possible microhabitats in these and other bioclimatic areas. Our study contributes importantly to consolidate these lizards (liolaemids) as promising model systems to investigate the entire spectrum of modes of species formations, from the adaptive to the non-adaptive extremes of the continuum