Life Sciences Commons^™

To What Extent Do Physiological Tolerances Determine Elevational Range Limits Of Mammals?, Jay F. Storz, Graham R. Scott

School of Biological Sciences: Faculty Publications

A key question in biology concerns the extent to which distributional range limits of species are determined by intrinsic limits of physiological tolerance. Here, we use common-garden data for wild rodents to assess whether species with higher elevational range limits typically have higher thermogenic capacities in comparison to closely related lowland species. Among South American leaf-eared mice (genus Phyllotis), mean thermogenic performance is higher in species with higher elevational range limits, but there is little among-species variation in the magnitude of plasticity in this trait. In the North American rodent genus Peromyscus, highland deer mice (Peromyscus maniculatus …

Plant Species’ Capacity For Range Shifts At The Habitat And Geographic Scales: A Trade-Off-Based Framework, Bailey H. Mcnichol, Sabrina E. Russo

School of Biological Sciences: Faculty Publications

Climate change is causing rapid shifts in the abiotic and biotic environmental conditions experienced by plant populations, but we lack generalizable frameworks for predicting the consequences for species. These changes may cause individuals to become poorly matched to their environments, potentially inducing shifts in the distributions of populations and altering species’ habitat and geographic ranges. We present a trade-off-based framework for understanding and predicting whether plant species may undergo range shifts, based on ecological strategies defined by functional trait variation. We define a species’ capacity for undergoing range shifts as the product of its colonization ability and the ability to …

Gene Regulatory Changes Underlie Developmental Plasticity In Respiration And Aerobic Performance In Highland Deer Mice, Rena M. Schweizer, Catherine M. Ivy, Chandrasekhar Natarajan, Graham R. Scott, Jay F. Storz, Zachary A. Cheviron

School of Biological Sciences: Faculty Publications

Phenotypic plasticity can play an important role in the ability of animals to tolerate environmental stress, but the nature and magnitude of plastic responses are often specific to the developmental timing of exposure. Here, we examine changes in gene expression in the diaphragm of highland deer mice (Peromyscus maniculatus) in response to hypoxia exposure at different stages of development. In highland deer mice, developmental plasticity in diaphragm function may mediate changes in several respiratory traits that influence aerobic metabolism and performance under hypoxia. We generated RNAseq data from diaphragm tissue of adult deer mice exposed to (1) life-long …

To What Extent Do Physiological Tolerances Determine Elevational Range Limits Of Mammals?, Jay F. Storz, Graham R. Scott

School of Biological Sciences: Faculty Publications

A key question in biology concerns the extent to which distributional range limits of species are determined by intrinsic limits of physiological tolerance. Here, we use common-garden data for wild rodents to assess whether species with higher elevational range limits typically have higher thermogenic capacities in comparison to closely related lowland species. Among South American leaf-eared mice (genus Phyllotis), mean thermogenic performance is higher in species with higher elevational range limits, but there is little among-species variation in the magnitude of plasticity in this trait. In the North American rodent genus Peromyscus, highland deermice (Peromyscus maniculatus) …

Life Ascending: Mechanism And Process In Physiological Adaptation To High-Altitude Hypoxia, Jay F. Storz, Graham R. Scott

School of Biological Sciences: Faculty Publications

To cope with the reduced availability of O2 at high altitude, air-breathing vertebrates have evolved myriad adjustments in the cardiorespiratory system to match tissue O2 delivery with metabolic O2 demand. We explain how changes at interacting steps of the O2 transport pathway contribute to plastic and evolved changes in whole-animal aerobic performance under hypoxia. In vertebrates native to high altitude, enhancements of aerobic performance under hypoxia are attributable to a combination of environ- mentally induced and evolved changes in multiple steps of the pathway. Additionally, evidence suggests that many high-altitude natives have evolved mechanisms for attenuating maladaptive acclimatization responses to …

Predators Modify The Temperature Dependence Of Life-History Trade-Offs, Thomas M. Luhring, Janna M. Vavra, Clayton E. Cressler, John Delong

School of Biological Sciences: Faculty Publications

Although life histories are shaped by temperature and predation, their joint influence on the interdependence of life-history traits is poorly understood. Shifts in one life-history trait often necessitate shifts in another—structured in some cases by trade-offs— leading to differing life-history strategies among environments. The offspring size–number trade-off connects three traits whereby a constant reproductive allocation (R) constrains how the number (O) and size (S) of offspring change. Increasing temperature and size-independent predation decrease size at and time to reproduction which can lower R through reduced time for resource accrual or size-constrained fecundity. We investigated how O, S, and R in …

Energy Demand And The Context-Dependent Effects Of Genetic Interactions Underlying Metabolism, Luke A. Hoekstra, Cole R. Julick, Katelyn M. Mika, Kristi L. Montooth

School of Biological Sciences: Faculty Publications

Genetic effects are often context dependent, with the same genotype differentially affecting phenotypes across environments, life stages, and sexes.We used an environmental manipulation designed to increase energy demand during development to investigate energy demand as a general physiological explanation for context-dependent effects of mutations, particularly for those mutations that affect metabolism. We found that increasing the photoperiod during which Drosophila larvae are active during development phenocopies a temperature-dependent developmental delay in a mitochondrial-nuclear genotype with disrupted metabolism. This result indicates that the context-dependent fitness effects of this genotype are not specific to the effects of temperature and may generally result …

Parasitoid Infestation Changes Female Mating Preferences, Oliver M. Beckers, William E. Wagner

School of Biological Sciences: Faculty Publications

Females often adjust their mating preference to environmental and social conditions. This plasticity of preference can be adaptive for females and can have important consequences for the evolution of male traits. While predation and parasitism are widespread, their effects on female preferences have rarely been investigated. Females of the cricket Gryllus lineaticeps are parasitized by the parasitoid fly Ormia ochracea. Infestation with fly larvae substantially reduces female life span and thus reproductive opportunities of the cricket. Both female G. lineaticeps and flies orient to male song and both prefer male songs with faster chirp rates to songs with slower chirp …

Variation In Leaf Stomatal Traits Of 28 Tree Species In Relation To Gas Exchange Along An Edaphic Gradient In A Bornean Rain Forest, Sabrina E. Russo, Whitney Logan Cannon, Christian Elowsky, Sylvester Tan, Stuart J. Davies

School of Biological Sciences: Faculty Publications

Premise of the study: Quantifying variation in functional traits associated with shifts in the species composition of plant communities along resource gradients helps identify environmental attributes important for community assembly. Stomates regulate the balance between carbon assimilation and water status in plants. If environmental attributes affecting photosynthetic water-use efficiency govern species distribution along an edaphic gradient, then adaptive variation in stomatal traits of plant species specializing on different soils should reflect belowground resource availability.

Methods: We tested this hypothesis by quantifying stomatal trait variation in understory saplings of 28 Bornean tree species in relation to gas exchange and …

Repeatability Of Maximal Aerobic Performance In Belding’S Ground Squirrels, Spermophilus Beldingi, M. A. Chappell, Gwendolyn C. Bachman, J. P. Odell

School of Biological Sciences: Faculty Publications

1. The repeatability of a trait is a critical factor in determining how that trait is affected by natural selection. We examined the repeatability of a key physiological trait, maximum oxygen consumption (VO_2max), in a wild population of Belding’s Ground Squirrels, Spermophilus beldingi. VO_2max is an integrated measure of organismal metabolic performance. It can be intuitively related to fitness because it sets an upper limit to sustainable power output during ecologically important activites such as locomotion and thermoregulatory heat production.

2. We used respirometry to determine VO_2max during exercise and thermogenesis. Exercise VO …