Life Sciences Commons^™

Temperature Has A Unimodal Effect On The Functional Response Of Wolf Spiders, John Delong, Stella F. Uiterwaal, Alondra Magallanes

School of Biological Sciences: Faculty Publications

The response of biotic interactions to changes in temperature will play a large role in determining the impact of climate change on ecological communities. In particular, how warming alters predator-prey interactions will influence population stability, food web connectivity, and the movement of energy across trophic levels. The functional response relates predator foraging rates to prey availability, and it is often predicted to increase monotonically with temperature, at least within the limits of predator function. However, some studies suggest that functional responses peak and then decline, and such a difference has critical implications for the effect of warming on ecological communities. …

Quantifying Predator Functional Responses Under Field Conditions Reveals Interactive Effects Of Temperature And Interference With Sex And Stage, Kyle E. Coblentz, Amber Squires, Stella Uiterwaal, John Delong

School of Biological Sciences: Faculty Publications

1. Predator functional responses describe predator feeding rates and are central to predator–prey theory. Originally defined as the relationship between predator feeding rates and prey densities, it is now well known that functional responses are shaped by a multitude of factors. However, much of our knowledge about how these factors influence functional responses is based on laboratory studies that are generally logistically constrained to examining only a few factors simultaneously and that have unclear links to the conditions organisms experience in the field.
2. We apply an observational approach for measuring functional responses to understand how sex/stage differences, temperature and predator densities …

Functional Responses Are Maximized At Intermediate Temperatures, Stella F. Uiterwaal, John Delong

School of Biological Sciences: Faculty Publications

Functional responses describe how consumer foraging rates change with resource density. Despite extensive research looking at the factors underlying foraging interactions, there remains ongoing controversy about how temperature and body size control the functional response parameters space clearance (or attack) rate and handling time. Here, we investigate the effects of temperature, consumer mass, and resource mass using the largest compilation of functional responses yet assembled. This compilation contains 2,083 functional response curves covering a wide range of foragers and prey types, environmental conditions, and habitats. After accounting for experimental arena size, dimensionality of the foraging interaction, and consumer taxon, we …

Gravid Tetragnathid Spiders Show An Increased Functional Response, Mary E. Boswell, John P. Delong

School of Biological Sciences: Faculty Publications

Spiders in the genus Tetragnatha feed on emerging aquatic insects, including mosquitoes and midges, but there is little known about the foraging behavior of these spiders. We hypothesized that female spiders actively developing egg sacs would increase food consumption to provide more energy to produce and provision their eggs. We tested this hypothesis by measuring foraging rates of Tetragnatha spiders kept in jars and provisioned with different levels of midges. We then tested for a difference in the functional response of spiders that did or did not lay egg sacs in their jars. Egg-laying and non-egg-laying spiders showed significantly different …

Fueling Defense: Effects Of Resources On The Ecology And Evolution Of Tolerance To Parasite Infection, Sarah A. Budischak, Clayton E. Cressler

School of Biological Sciences: Faculty Publications

Resource availability is a key environmental constraint affecting the ecology and evolution of species. Resources have strong effects on disease resistance, but they can also affect the othermain parasite defense strategy, tolerance. A small but growing number of animal studies are beginning to investigate the effects of resources on tolerance phenotypes. Here, we review how resources affect tolerance strategies across animal taxa ranging from fruit flies to frogs to mice. Surprisingly, resources (quality and quantity) can increase or reduce tolerance, dependent upon the particular host-parasite system. To explore this seeming contradiction, we recast predictions of models of sterility tolerance and …

Temporal Variation In Predation Risk May Explain Daily Rhythms Of Foraging Behavior In An Orb-Weaving Spider, J. Colton Watts, Thomas C. Jones, Ashley Herrig, Madeleine Miller, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Daily rhythms occur in numerous physiological and behavioral processes across an immense diversity of taxa, but there remain few cases in which mechanistic links between rhythms of trait expression and organismal fitness have been established. We construct a dynamic optimization model to determine whether risk allocation provides an adaptive explanation for the daily foraging rhythm observed in many species using the orb-weaving spider Cyclosa turbinata as a case study. Our model predicts that female C. turbinata should generally start foraging at lower levels of energy reserves (i.e., should be less bold) during midday when predators are most abundant. We also …

Displaying To Females May Lower Male Foraging Time And Vigilance In A Lekking Bird, Sarah A. Cowles, Robert M. Gibson

School of Biological Sciences: Faculty Publications

Males of many species use courtship behavior to attract mates. However, by doing so males may face the associated costs of increased energetic expenditure, reduced foraging time, and elevated predation risk. We investigated the costs of display in lekking male Sharp-tailed Grouse (Tympanuchus phasianellus). We used lek-wide scan sampling to study how males allocated time among courtship display (‘‘dancing’’), agonism, foraging, and inactivity in relation to female numbers both within and across days. We also addressed the limited attention hypothesis and estimated visual attentiveness by videotaping 13 males and scoring head turns during these different activities. We found that the …