About this blog
Newest kudos -- Paul De Luca's work is IN PRESS!; Leann and John Confer's works is accepted; Jean, Maki, Andy, and Peter's work is published!
Friday, December 5, 2014
2014 De Luca, PA, Stoltz, JA, Andrade, MCB & Mason, AC. Metabolic efficiency in courtship favors males with intermediate mass in the Australian redback spider, Latrodectus hasselti. Journal of Insect Physiology. In press.
Recent studies have suggested that metabolic efficiency may be an important factor in male mating success when females require vigorous and/or prolonged courtship. In capital breeding animals in which a male’s resource pool is fixed at adulthood the relationship between energy expenditure and courtship performance may be especially important, as males are expected to utilize their finite resources efficiently when soliciting mates. Males may benefit from being efficient, i.e., achieving a sufficiently high level of courtship signaling at low energetic cost, if it enables them to acquire mates before their limited energy reserves are depleted. We investigated the relationship between metabolic efficiency and courtship vibrational signaling in the Australian redback spider, Latrodectus hasselti, a semelparous capital breeder where males invest heavily in courtship to secure a mating. We assessed metabolic rate in a sample of males and measured two courtship components (duty cycle and amplitude) that reflected the energy content of web-borne vibrations. We then calculated two indices of metabolic efficiency for these courtship properties. There was a quadratic relationship between mass and duty cycle such that the highest duty cycle signals were performed by males having intermediate mass. Furthermore, intermediate-mass males were also the most metabolically efficient. Prolonged courtship is necessary in L. hasselti for successful mating, and the results of this study suggest that intermediate-mass males are superior courters because they utilize their finite resource pool most efficiently to produce high energy vibrational signals.
Friday, March 14, 2014
John Confer, Leann Kanda, and Ireyena Li (recent ENVS graduate). Accepted March 2014. “Northern Saw-whet Owl regional patterns for fall migration and demographics revealed by banding data” accepted for publication in the Wilson Journal of Ornithology.
Monday, November 4, 2013
Jean C. Hardwick, Shannon E. Ryan (’12), Eric Beaumont, Jeffrey L. Ardell, E. Marie Southerland, Dynamic remodeling of the guinea pig intrinsic cardiac plexus induced by chronic myocardial infarction, Autonomic Neuroscience, Available online 31 October 2013, ISSN 1566-0702, http://dx.doi.org/10.1016/j.autneu.2013.10.008.
Wednesday, July 3, 2013
Melcher P, and Zwieniecki MA. (2013). Functional analysis of embolism induced by air injection in Acer rubrum and Salix nigra. Frontiers in Plant Biophysics and Modeling. Link to more information here.
Maciej A. Zwieniecki, Peter J. Melcher, and Eric T. Ahrens (2013). Analysis of spatial and temporal dynamics of xylem refilling in Acer rubrum L. using magnetic resonance imaging (MRI). Frontiers in Plant Biophysics and Modeling. doi: 10.3389/fpls/2013.00265.
Thursday, March 28, 2013
M. Braun (Biology ’11), M. Menges (Biology '10), F. Opoku (Biochemistry ’13) and A. M. Smith. 2013. The relative contribution of calcium, zinc and oxidation-based cross-links to the stiffness of Arion subfuscus glue. The Journal of Experimental Biology 216, 1475-148. View the article here.
Metal ions are present in many different biological materials, and are capable of forming strong cross-links in aqueous environments. The relative contribution of different metal-based cross-links was measured in the defensive glue produced by the terrestrial slug Arion subfuscus. This glue contains calcium, zinc, manganese, iron and copper. These metals are essential to the integrity of the glue and to gel stiffening. Removal of all metals caused at least a fifteen-fold decrease in the storage modulus of the glue. Selectively disrupting cross-links involving hard Lewis acids such as calcium weakened the glue, while disrupting cross-links involving borderline Lewis acids such as zinc did not. Calcium is the most common cation bound to the glue (40 mmol L-1), and its charge is balanced primarily by sulfate at 82 to 84 mmol L-1. Thus, these ions likely play a primary role in bringing polymers together directly. Imine bonds formed as a result of protein oxidation also contribute substantially to the strength of the glue. Disrupting these bonds with hydroxylamine caused a 33% decrease in storage modulus of the glue, while stabilizing them by reduction with sodium borohydride increased the storage modulus by 40%. Thus, a combination of metal-based bonds operates in this glue. Most likely, cross-links directly involving calcium play a primary role in bringing together and stabilizing the polymer network, followed by imine bond formation and possible iron coordination.