Radford University
Research
How do ecological community contexts influence disease outcomes?
One basic but unresolved question is how do other species present in the larger community, besides the parasite/pathogen and its host themselves, influence the transmission of diseases? We use field studies, experiments, and models to address questions like: Do diverse arrays of hosts dilute or amplify disease? How often do predators actually consume enough disease propagules to matter? Can predators of disease hosts act to stabilize or reduce disease prevalence?”
Supported by NSF Award 0918656, 0918960.
Gajewski Z, McElmurray P, Wojdak J, ^McGregor C, ^Zeller L, ^Cooper H, Belden L, Hopkins S. Accepted. Nonrandom foraging and resource distributions affect the relationships between host density, contact rates, and parasite transmission. Ecology Letters.
Hopkins S, ^McGregor C, Belden L, Wojdak J. 2022. Host preferences inhibit transmission from potential superspreader host species. Proceedings of the Royal Society B. 2892022008420220084 http://doi.org/10.1098/rspb.2022.0084
Hopkins S, Fleming-Davies A, Belden L, Wojdak J. 2020. Systematic review of modelling assumptions and empirical evidence: Does parasite transmission increase nonlinearly with host density? Methods in Ecology and Evolution 11: 476–486. https://doi.org/10.1111/2041-210X.13361
^ denotes undergraduate researcher
Predators and their prey, in pairs and beyond
Predators affect prey by killing them, clearly, but also by changing their behavior (e.g., hide more, eat less!) and their morphological traits (e.g, induced trait-changes like these tadpole’s camouflaging pigment, and well, more direct changes like having their tails removed by predators!)
Ecologists have long struggled with a fundamental trade-off when trying to understand how nature works because the whole ecosystem is much too complex to understand. We begrudgingly proceed by isolating parts, circumscribing some interactions in a window of space and time, in hopes of peeling back the mechanisms that make things work. Yet, in doing so, we excise species from their full context, fundamentally changing things in the process. Much of my research has been working at the inflection point as we move from the simplest isolated species interactions – a predator and a prey species – to add back in more complexity, in the form of alternate prey, other predators, or parasites. Besides discovering a lot of interesting ecology, we end up needing to be careful and thoughtful with our accounting – the math we use to keep track of (and ideally predict!) how predators might influence the behavior, traits, and abundance of their prey. We also end up needing jargon like “trait-mediated indirect interactions” and “non-linear functional responses” to understand basic ecological questions like: What happens to the relationship between one predator and its prey when another predator is also feeding? …or when that second predator changes the behavior or habitat use of the prey?
Supported by an ROA supplement to NSF Award 0717220 to James Vonesh, and NSF Awards 1556729, 1556686, 1556743.
McCoy M, Hamman E, Albecker M, Wojdak J, Vonesh J, Bolker B. 2022. Incorporating nonlinearity with generalized functional responses to simulate multiple predator effects. PeerJ 10:e13920 https://doi.org/10.7717/peerj.13920
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Touchon J, Wojdak J. 2014. Plastic hatching timing by Red-Eyed Treefrog embryos interacts with larval predator Iientity and sublethal predation to affect prey morphology but not performance. PLoS ONE 9(6): e100623. https://doi.org/10.1371/journal.pone.0100623