Clayton E. Cressler's research while affiliated with University of Nebraska at Lincoln and other places

Publications (54)

Article
Full-text available
Biological rhythms mediate important within‐host processes such as metabolism, immunity, and behavior which are often linked to combating disease exposure. For many hosts, exposure to pathogens occurs while feeding. However, the link between feeding rhythms and infection risk is unclear because feeding behavior is tightly coupled with immune and me...
Article
Stochastic processes such as genetic drift may hinder adaptation, but the effect of such stochasticity on evolution via its effect on ecological dynamics is poorly understood. Here we evaluate patterns of adaptation in a population subject to variation in demographic stochasticity. We show that stochasticity can alter population dynamics and lead t...
Article
Chronic antibiotic exposure impacts host health through changes to the microbiome. The detrimental effects of antibiotic perturbation on microbiome structure and function after one host generation of exposure have been well-studied, but less is understood about multigenerational effects of antibiotic exposure and subsequent recovery. In this study,...
Article
Hosts can avoid parasites (and pathogens) by reducing social contact, but such isolation may carry costs, e.g. increased vulnerability to predators. Thus, many predator–host–parasite systems confront hosts with a trade-off between predation and parasitism. Parasites, meanwhile, evolve higher virulence in response to increased host sociality and con...
Article
Full-text available
Parasites exploit hosts to replicate and transmit, but overexploitation kills both host and parasite. Predators may shift this cost–benefit balance by consuming infected hosts or changing host behaviour, but the strength of these effects remains unclear. Here we use field and lab data on Trinidadian guppies and their Gyrodactylus spp. parasites to...
Article
Host-associated microbial communities are impacted by external and within-host factors, i.e., diet and feeding behavior. For organisms known to have a circadian rhythm in feeding behavior, microbiome composition is likely impacted by the different rates of microbe introduction and removal across a daily cycle, in addition to any diet-induced change...
Article
Circadian rhythms enable organisms to mediate their molecular and physiological processes with changes in their environment. Although feeding behavior directly affects within-organism processes, there are few examples of a circadian rhythm in this key behavior. Here, we show that Daphnia have a nocturnal circadian rhythm in feeding behavior that co...
Article
The incidence of zoonotic diseases is increasing worldwide, which makes identifying parasites likely to become zoonotic and hosts likely to harbour zoonotic parasites a critical concern. Prior work indicates that there is a higher risk of zoonotic spillover accruing from closely related hosts and from hosts that are infected with a high phylogeneti...
Article
A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites...
Preprint
Full-text available
Parasites exploit hosts to replicate and transmit, but overexploitation kills host and parasite ( 1 ): predators may shift this cost-benefit balance by consuming hosts ( 2–4 ) or changing host behavior, but the strength of these effects remains unclear. Modeling both, we find a primary, strong effect: hosts group to defend against predators ( 5 ),...
Preprint
Genome size varies ∼ 100,000-fold across eukaryotes. Genome size is heavily shaped by transposable element accumulation, the dynamics of which are increasingly well understood. However, given that traits like cell size and rate of development co-vary strongly with genome size, organism-level trait evolution likely shapes genome size diversity as we...
Preprint
Full-text available
Background: Chronic antibiotic exposure impacts host health through changes to the microbiome, increasing disease risk and reducing the functional repertoire of community members. The detrimental effects of antibiotic perturbation on microbiome structure and function after one host generation of exposure have been well-studied. However, much less i...
Article
Full-text available
Host-associated microbes contribute to host fitness, but it is unclear whether these contributions are from rare keystone taxa, numerically abundant taxa, or interactions among community members. Experimental perturbation of the microbiota can highlight functionally important taxa; however, this approach is primarily applied in systems with complex...
Preprint
The significant variation in host specificity exhibited by parasites has been separately linked to evolutionary history and ecological factors in specific host-parasite associations. Yet, whether there are any general patterns in the factors that shape host specificity across parasites more broadly is unknown. Here we constructed a molecular phylog...
Preprint
Host-associated microbes contribute to host fitness, but it is unclear whether these contributions are from rare keystone taxa, numerically abundant taxa, or interactions among community members. Experimental perturbation of the microbiota can highlight functionally important taxa; however, this approach is primarily applied in systems with complex...
Article
Full-text available
• Food ingestion is one of the most basic features of all organisms. However, obtaining precise—and high‐throughput—estimates of feeding rates remains challenging, particularly for small, aquatic herbivores such as zooplankton, snails, and tadpoles. These animals typically consume low volumes of food that are time‐consuming to accurately measure. •...
Article
Full-text available
The keystone zooplankton Daphnia magna has recently been used as a model system for understanding host-microbiota interactions. However, the bacterial species present and functions associated with their genomes are not well understood. In order to understand potential functions of these species, we combined 16S rRNA sequencing and shotgun metagenom...
Article
Full-text available
Predicting how organisms respond to climate change requires that we understand the temperature dependence of fitness in relevant ecological contexts (e.g., with or without predation risk). Predation risk often induces changes to life history traits that are themselves temperature dependent. We explore how perceived predation risk and temperature in...
Article
The loss of appetite that typically accompanies infection or mere exposure to parasites is traditionally considered a negative byproduct of infection, benefitting neither the host nor the parasite. Numerous medical and veterinary practices directly or indirectly subvert this 'illness-mediated anorexia'. However, the ecological factors that influenc...
Article
Full-text available
Temporary but substantial reductions in voluntary food intake routinely accompany parasite infection in hosts ranging from insects to humans. This 'parasite-mediated anorexia' drives dynamic nutrient-dependent feedbacks within and among hosts, which should alter the fitness of both hosts and parasites. Yet, few studies have examined the evolutionar...
Preprint
Full-text available
Background: The keystone zooplankton Daphnia magna has recently been used as a model system for understanding host-microbiota interactions. However, the bacterial species present and functions associated with their genomes are not well understood. In order to understand potential functions of these species, we combined 16S rRNA sequencing and shotg...
Article
Over a billion people on earth are infected with helminth parasites and show remarkable variation in parasite burden and chronicity. These parasite distributions are captured well by classic statistics, such as the negative binomial distribution. But the within-host processes underlying this variation are not well understood. In this study, we expl...
Article
Full-text available
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 other main parasite defense strategy, tolerance. A small but growing number of animal studies are beginning to investigate the effects of resources on tolerance phe...
Preprint
Full-text available
Parasite-mediated anorexia is a ubiquitous, but poorly understood component of host-parasite interactions. These temporary but substantial reductions in food intake (range: 4-100%) limit exposure to parasites and alter within-host physiological processes that regulate parasite development, production, and survival, such as energy allocation, immune...
Article
Full-text available
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–num...
Article
Full-text available
What drives the evolution of parasite life-history traits? Recent studies suggest that linking within- and between-host processes can provide key insight into both disease dynamics and parasite evolution. Still, it remains difficult to understand how to pinpoint the critical factors connecting these cross-scale feedbacks, particularly under non-equ...
Article
Resources are a core currency of species interactions and ecology in general (e.g., think of food webs or competition). Within parasite-infected hosts, resources are divided among the competing demands of host immunity and growth as well as parasite reproduction and growth. Effects of resources on immune responses are increasingly understood at the...
Article
Full-text available
Resources are a core currency of species interactions and ecology in general (e.g., think of food webs or competition). Within parasite-infected hosts, resources are divided among the competing demands of host immunity and growth as well as parasite reproduction and growth. Effects of resources on immune responses are increasingly understood at the...
Data
Interferon gamma (IFNg), interleukin 10 (IL10), and interleukin 17 (IL17) concentrations were higher in infected mice than uninfected mice (Wilcoxon tests; IFNg: W = 506, p = 0.046, IL10: W = 483, p = 0.010, IL17: W = 441, p = 0.0036), but did not vary with diet (IFNg: W = 843, p = 0.67, IL10: W = 929, p = 0.13, IL17: W = 899, p = 0.28).
Article
Individual differences in genetics, age, or environment can cause tremendous differences in individual life-history traits. This individual heterogeneity generates demographic heterogeneity at the population level, which is predicted to have a strong impact on both ecological and evolutionary dynamics. However, we know surprisingly little about the...
Article
Full-text available
Parasites vary widely in the diversity of hosts they infect: some parasite species are specialists?infecting just a single host species, while others are generalists, capable of infecting many. Understanding the factors that drive parasite host-generalism is of basic biological interest, but also directly relevant to predicting disease emergence in...
Article
Full-text available
Why is it that some parasites cause high levels of host damage (i.e. virulence) whereas others are relatively benign? There are now numerous reviews of virulence evolution in the literature but it is nevertheless still difficult to find a comprehensive treatment of the theory and data on the subject that is easily accessible to non-specialists. Her...
Article
Full-text available
Phylogenetic comparative analysis is an approach to inferring evolutionary process from a combination of phylogenetic and phenotypic data. The last few years have seen increasingly sophisticated models employed in the evaluation of more and more detailed evolutionary hypotheses, including adaptive hypotheses with multiple selective optima and hypot...
Article
Full-text available
Hosts are expected to incur several physiological costs in defending against parasites. These include constitutive energetic (or other resource) costs of a defence system, facultative resource costs of deploying defences when parasites strike, and immunopathological costs of collateral damage. Here, we investigate the evolution of host recovery rat...
Article
Full-text available
Parasites often induce life-history changes in their hosts. In many cases, these infection-induced life-history changes are driven by changes in the pattern of energy allocation and utilization within the host. Because these processes will affect both host and parasite fitness, it can be challenging to determine who benefits from them. Determining...
Article
Full-text available
The interaction between the immune system and pathogens is often characterised as a predator-prey interaction. This characterisation ignores the fact that both require host resources to reproduce. Here, we propose novel theory that considers how these resource requirements can modify the interaction between the immune system and pathogens. We deriv...
Conference Paper
Background/Question/Methods Individual variation in growth, reproduction, and mortality is widespread, even in asexual organisms. Analysis of this variation reveals the existence of strong positive and negative correlations among life history traits. These correlations often run counter to the predictions of simple theory. For example, a strong p...
Chapter
There is increasing evidence that the structure and functioning of ecological communities and ecosystems are strongly influenced by flexible traits of individuals within species. A deep understanding of how trait flexibility alters direct and indirect species interactions is crucial for addressing key issues in basic and applied ecology. This book...
Article
Full-text available
Trade-offs are fundamental to understanding the origin and maintenance of biological diversity. In particular, phenotypic evolution is predicted to depend critically on the shapes of the trade-off functions relating fitness costs and benefits to trait expression. Existing studies have focused on understanding the evolution of single traits. This ap...
Article
Inducible defense, which is phenotypic plasticity in traits that affect predation risk, is taxonomically widespread and has been shown to have important ecological consequences. However, it remains unclear what factors promote the evolution of qualitatively different defense strategies and when evolution should favor strategies that involve modific...
Conference Paper
Background/Question/Methods Understanding how ecological and evolutionary processes feed back on one another is essential for understanding trait expression. Previous theory has shown that different curvatures of the foraging--predation risk tradeoff lead to the evolution of qualitatively different predator defense strategies. Linear tradeoffs are...

Citations

... Adaptive prey responses to predation risk (i.e. anti-predator responses) have an overall net positive effect to the prey as compared to not responding, which is consistent with the basic tenet of plasticity, wherein trait changes reflect a balance between benefits and costs (Abrams, 2010; Lind & Cresswell, 2005;Peacor & Cressler, 2012). Yet there is a great deal of evidence and focus on the associated costs that risk-induced trait changes have on prey fitness components (given its usefulness in estimating population growth rate, Transition 2; Figure 1). ...
... Immune cells are also regulated by circadian clocks, which can affect the risk of infection. Though the exact relation is yet to be identified, studies have revealed a significant association between the timing of exposure and the risk of developing infection [40]. One of the major immune cells expressing intrinsic circadian rhythm are macrophages. ...
... B 289: 20222131 low-predation environments to demonstrate evidence for rapid parallel evolution in microbiome composition in response to the change in environmental conditions. Walsman et al. [23] use an eco-evolutionary model, inspired by a guppy system, to explore how behavioural responses of prey to predation risk may lead to increased prevalence and virulence of parasites owing to changes in grouping behaviour. Kanwal & Gardner [24] modelled the role of population viscosity on kin selection, finding that if dispersal is conditional upon local density, individuals in more altruistic neighbourhoods disperse more frequently and kin competition is relaxed, leading to a negative correlation between dispersal and altruism. ...
... Both male [40] and female [41,42] guppies prefer more active mates. Similarly, host grouping behaviour, such as shoaling in guppies, has fitness benefits, including access to mates, foraging efficiency and defence against predators [43][44][45][46][47]. Therefore, guppies are an ideal system with which to test whether the skin microbiome is associated with fitness-relevant behaviours. ...
... Second, many of the dietary items returned (e.g., hemichordates, mollusks, flatworms, annelids, nematodes, and scalidophorans) could have been picked up from the midwater as larvae or parasites, entangled in marine snow, or ingested secondarily. In particular, Tomopteris has a proboscis ideally suited for attaching to and sucking up portions of gelatinous prey [85] and has been reported to feed on pelagic tunicates, chaetognaths, and sometimes, diatoms [86], yet we found primarily crustacean and phytoplankton sequences as their likely prey items. It may well be that crustaceans were secondarily ingested after being concentrated in the gut of a ctenophore or cnidarian. ...
... In addition to the daily locomotor behavior, D. dentifera exhibit a circadian rhythm in feeding behavior (Pfenning-Butterworth et al., 2021), which may directly modulate differences in pathogen exposure and infection outcomes. For the wide array of hosts, including Daphnia, that encounter infectious agents while foraging, changes in feeding rates serve as a first line of defense, reducing the infective dose and sequestering resources away from pathogen (Adamo et al., 2010). ...
... Mutation and host switch of agents from animals to human host could be investigated more actively [54,55]. The world has been and is changing at a rapid pace, and a recent assessment of biomass on Earth estimated the wild mammal biomass to be 0.007 Gt C (gigatons of carbon), while that of humans was 0.06 Gt C and livestock 0.1 Gt C [56]. ...
... The final three possible sources of bias concern underlying parasite and host population dynamics. First, parasites with multiple hosts in their life cycle (heteroxenous) are more vulnerable than parasites that require only one host (Farrell et al., 2021;Koh et al., 2004). For example, mites and digenean trematodes require multiple host species in their life cycle (chironomids, fish, or birds [Molloy et al., 1997]), which may also be endangered given the threatened state of freshwater ecosystems generally (e.g., Desforges et al., 2021). ...
... In this manner, key specialized functional microbiota (composed of a functional core microbiome and/or microbial hubs) can be identified, and stable synthetic communities can be assembled in order to mediate plant health. Using this approach, host plants can be used to recruit and self-identify desirable microorganisms that could later be used as inoculants to transfer functional core microbiota, or whole microbiota, in order to obtain healthy plants for subsequent generations (vertical transmission [165], Figure 4). For example, Cooper et al. (2021) recently showed that HMME strategy can be used to improve wheat plant growth under drought stress [165]. ...
... Mercury tolerant Pseudomonas-10 reduces mercury concentration in the medium and also enhances D. magna tolerance to mercury and increases its survival and fecundity (Fong et al., 2019). Several studies about the effects of antibiotics on Daphnia observed reduced growth and survival due to alteration of microbiota (Zalewski et al., 2011;Akbar et al., 2020;Cooper et al., 2021). ...