Heritable symbionts in a world of varying temperature

Heritable microbes represent an important component of the biology, ecology and evolution of many plants, animals and fungi, acting as both parasites and partners. In this review, we examine how heritable symbiont–host interactions may alter host thermal tolerance, and how the dynamics of these interactions may more generally be altered by thermal environment. Obligate symbionts, those required by their host, are considered to represent a thermally sensitive weak point for their host, associated with accumulation of deleterious mutations. As such, these symbionts may represent an important determinant of host thermal envelope and spatial distribution. We then examine the varied relationship between thermal environment and the frequency of facultative symbionts that provide ecologically contingent benefits or act as parasites. We note that some facultative symbionts directly alter host thermotolerance. We outline how thermal environment will alter the benefits/costs of infection more widely, and additionally modulate vertical transmission efficiency. Multiple patterns are observed, with symbionts being cold sensitive in some species and heat sensitive in others, with varying and non-coincident thresholds at which phenotype and transmission are ablated. Nevertheless, it is clear that studies aiming to predict ecological and evolutionary dynamics of symbiont–host interactions need to examine the interaction across a range of thermal environments. Finally, we discuss the importance of thermal sensitivity in predicting the success/failure of symbionts to spread into novel species following natural/engineered introduction

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

Patterns of Head Shape Variation in Lizards: Morphological Correlates of Foraging Mode

The relationship between cranial morphology, diet, and feeding performance has been explored in most vertebrate classes. In fact, key biomechanical elements and regions of the skull are known to be associated with various prey types in a wide range of species (Radinsky, 1981; Kiltie, 1982; Lauder, 1991; Zweers et al., 1994; Perez-Barberia and Gordon, 1999). Numerous examples in teleosts have linked form, function, and diet (Lauder, 1991; Turingan et al., 1995; Wainwright, 1996); in birds, beak morphology and lever mechanics have been correlated with various dietary patterns (Beecher, 1962; James, 1982; Barbosa and Moreno, 1999). In mammals, the rostrum (snout) often becomes narrower and incisor tooth structure changes as dietary selectivity increases (Radinsky, 1981; Solounias, 1988; Gordon and Illius, 1994; Biknevicius, 1996). In lizards (non-ophidian squamates), there are relatively few quantitative and comparative studies relating diet to skull morphology, especially with regard to foraging modes (McBrayer, 2004). Classic works provide descriptions of lizard skull and muscle morphology (see, for example, Haas, 1973; Gomes, 1974). Some functional morphological studies have detailed particularly interesting forms such as the outgroup to lizards, Sphenodon (Gorniak et al., 1982), durophagous species (Wineski and Gans, 1984; Gans et al., 1985; Gans and De Vree, 1986, 1987), carnivorous species (Smith, 1982, 1984; Throckmorton and Saubert, 1982), ovophagous species (Herrel et al., 1997b), and herbivorous species (Throckmorton, 1976, 1978, 1980; Herrel and De Vree, 1999; Herrel et al., 1999a)

Covariation Between Morphological and Behavioral Evolution in Lizards

Lizards (non-ophidian squamates) are an ecologically diverse, species rich clade of terrestrial vertebrates. Morphologically, lizards are also very diverse; they range over an order of magnitude in body size and numerous groups possess unique skeletal modifications (e.g. casques, horns, cranial kinesis, etc.). Like most vertebrate groups key aspects of skull form are correlated with diet. However, despite their ecological, morphological, and taxonomic diversity, most lizards are thought to employ one of two broad foraging styles or modes (ambush foragers and active foragers). In this study, we perform phylogenetically informed analyses testing for the degree of coevolution between skull morphology and foraging mode. This study differs from previous studies in several important ways. First, we use the most recently published phylogenetic hypotheses for comparison to previous results. Second, we use a combination of geometric morphometrics and traditional linear distance measures to better understand changes in skull shape throughout the history of this diverse clade. Third, we use species-specific behavioral (moves per minute, percent time moving) and morphological data rather than assigning a foraging mode state to an entire family. Therefore, this study is a rigorous attempt to test the adaptive significance of changes in skull form as they pertain to prey capture and processing

Data from: Linkage and trade-off in trophic morphology and behavioral performance of birds

1. Bill closing behaviour involves a complex suite of tissue types, kinematics, morphological states and muscle architectural arrangements that has been under the scrutiny of natural selection for millions of years. Hence, an evolutionary shift to specialize in closing force may come at a cost to closing velocity and vice versa. 2. Using field measurements on behavioural performance and morphological data from museum specimens, we tested predictions of the force–velocity trade-off hypothesis in 18 species of North American birds with diverse phylogenetic and ecological backgrounds. 3. Linear models revealed that size and shape are excellent predictors of both bite force and closing velocity. However, taken one at a time, they each have a somewhat unique set of morphological predictors. In-lever length, mandibular depth and bill width comprise the best model of prediction for force, while a combination of out-lever length and total skull length provides the best prediction of closing velocity. Additionally, in our sample, only force is size-dependent. Hence, the predicted trade-off is revealed only after correcting bite force for head size. 4. Various modes of predation and decoupled morphological prediction models for performance suggest that specialization towards one strategy (e.g. increase force) may not necessarily come at a cost to the other. towards one strategy (e.g. increase force) may not necessarily come at a cost to the other

Morphology and Bite Force as Guild Predictors in Caribbean Birds

This talk was given during the International Congress of Vertebrate Morphology

Data for FE-2013-00888.R2

Appendix I. Bill closing velocity for 18 species of North American birds. First columns include: AOU Species Codes, vernacular and latin binomials. Other columns include: BC = bill closing velocity in cm/s (for analyses, I used the maximum value for each individual). Location: 1= Private residence in Pittsburgh, PA (PPA), 2 = Beechwood Farms Nature Reserve (PPA), 3 = North Park Latodami Nature Center (PPA), 4 = Bloomsburg University campus, Bloomsburg, PA, 5 = National Aviary in Pittsburgh, (PPA). Sex, M = Male, F = Female, “.” = unknown. Appendix II. Bite-force for 18 species of North American birds. First columns as in appendix I. Band # = USGS aluminum band number for each individual. Asterisk next to four-letter code denotes bite-force inferred by regression from a larger data set (Corbin, et al. in prep). Recap = recaptured individual; the highest value for captured or recaptured bird was used in analysis. Bite-force (N); these are the calibrated amplifier readings. Location = 1 Bloomsburg University campus, Bloomsburg, PA. 2 = private residence in Orange Township, Columbia County, PA, 3 = taken from a data set on netted birds in Coconino Forest, AZ in 2011 (Corbin, et al. in prep). Appendix III. Skull/jaw morphological measurements for 18 species of North American birds. Measurements are in mm. First columns as Appendix I, M = male, F = female. Museum specimen numbers available upon request from CEC (BAHS, Bloomsburg University, Bloomsburg, PA 17815, [email protected], 570-389-4134