Life Sciences Commons^™

The Contributions Of Evolutionary Divergence And Phenotypic Plasticity To Geographic Variation In The Western Fence Lizard, Sceloporus Occidentalis, Christine R. Buckley, Duncan J. Irschick, Stephen C. Adolph

Biology Department Faculty Publication Series

Local genetic adaptation and phenotypic plasticity are two mechanisms that can have marked effects on the morphology, performance, and behaviour of animals, producing geographic variation among populations. However, few studies have examined how these mechanisms interact during ontogeny to shape organismal phenotypes. We incubated eggs of the western fence lizard, Sceloporus occidentalis, from four populations (representing two latitudes and altitudes) in either a warm or cool environment in the laboratory. We then raised the hatchlings under common laboratory conditions, measured morphological and performance traits until 5 weeks of age, and compared juvenile morphology with that of field-caught adults from …

A Performance Based Approach To Distinguish Indices From Handicaps In Sexual Selection Studies, B Vanhooydonck, R Van Damme, A Herrel, Dj Irschick

Biology Department Faculty Publication Series

1. Central to theories of the evolution of conspicuous secondary sexual traits is that sexual traits honestly reflect at least one aspect of an individual's quality. In general, the reliability of sexual traits can be explained in two ways. Either sexual traits are reliable indicators of individual quality because they are costly and the costs in terms of survival are higher for an individual of low quality as compared to an individual of high quality (i.e. handicap principle) or sexual traits are reliable because of physical constraints and thus cost-free (reliability by design).
2. The distinction between indices and handicaps thus centres …

A Functional Approach To Sexual Selection, Duncan J. Irschick, Anthony Herrel, Bieke Vanhooydonck, Raoul Van Damme

Biology Department Faculty Publication Series

1. Sexual selection theory is a robust and dynamic field within evolutionary biology, yet despite decades of research, remarkably little is known of the mechanistic bases of mate choice and male competition.
2. Because many aspects of sexual selection involve dynamic movements, and are physically challenging, the limits of sexual selection may be defined by key functional and physiological variables (i.e. the ‘functional approach’).
3. We advocate the functional approach for providing mechanistic resolution on the adaptive basis of sexual structures and signals, the nature of mate choice and how males compete, among other issues.
4. An overview of recent work, highlighted in this …

Effects Of Temperature And Sex On Jump Performance And Biomechanics In The Lizard Anolis Carolinensis, Sp Lailvaux, Dj Irschick

Biology Department Faculty Publication Series

1. Temperature is known to affect whole-organism performance capacities significantly in ectotherms, but may potentially alter performance kinematics as well. Locomotor performance is a multivariate phenomenon, hence changes in temperature are probably reflected in multiple aspects of locomotion.
2. We studied the thermal sensitivity of several kinetic and kinematic jump variables, including acceleration and power output, in male and female green anole lizards, Anolis carolinensis Voigt 1832. We hypothesized that temperature would have similar effects on kinetic and kinematic variables.
3. We also tested the hypotheses that males and females would differ in jump performance, but only because of sexual dimorphism for body …

The Quick And The Fast: The Evolution Of Acceleration Capacity In Anolis Lizards, Bieke Vanhooydonck, Anthony Herrel, Raoul Van Damme, Duncan J. Irschick

Biology Department Faculty Publication Series

Although of prime ecological relevance, acceleration capacity is a poorly understood locomotor performance trait in terrestrial vertebrates. No empirical data exist on which design characteristics determine acceleration capacity among species and whether these design traits influence other aspects of locomotor performance. In this study we explore how acceleration capacity and sprint speed have evolved in Anolis lizards. We investigate whether the same or different morphological traits (i.e., limb dimensions and muscle mass) correlate with both locomotor traits. Within our sample of Anolis lizards, relative sprint speed and acceleration capacity coevolved. However, whereas the variation in relative acceleration capacity is primarily …

The Effects Of Gape Angle And Bite Point On Bite Force In Bats, Elizabeth R. Dumont, Anthony Herrel

Biology Department Faculty Publication Series

Models of mammalian mastication predict that bite force is affected by both the degree of mouth opening (gape angle) and the point along the tooth row at which force is transferred to a food item (bite point). Despite the widespread use of these models in comparative analyses, experimental data documenting bite force in non-human mammals are extremely limited. The goal of this study is to document variation in non-stimulated bite force associated with change in gape angle and bite point in a broad range of species. We focus on plant-visiting bats because they exhibit a relatively primitive cranial morphology and …