Biology subjects

Vannatta, J. T.

Publications and source records attributed to Vannatta, J. T..

4 recordsLinked to original sources

bioRxiv2021

Lack of Host Reproductive Trade-offs Associated with Fecundity Compensation Response to Parasitic Castration

Host-parasite coevolution may result in life-history changes in hosts that can limit the detrimental effects of parasitism. Fecundity compensation is one such life-history response, occurring when hosts increase their current reproductive output to make up for expected losses in future reproduction due to parasitic infection. However, the potential trade-offs between quantity and quality of offspring produced during fecundity compensation are relatively unexplored. This study uses the trematode, Schistosoma mansoni, and its snail intermediate host, Biomphalaria glabrata, to better understand the impacts of this host life-history response. Measures of host reproductive output as well as offspring hatching success and survival were collected to assess the reproductive consequences of infection. Infected snails exhibited fecundity compensation (increase in the number of eggs laid compared to controls) and had a higher probability of laying any eggs at all. Infection status did not play a significant role in hatching or offspring survival to maturity. However, the age of the parental snail had a significant impact on hatching success, as offspring from older parents demonstrated a higher hatching success rate. Overall, the lack of an apparent trade-off between quantity and quality of offspring suggests that infected parental snails invest more resources towards reproduction in order to maintain the fitness of their offspring, possibly at the expense of their own longevity.

evolutionary biology↗

bioRxiv2021

Opportunity or catastrophe? Effect of sea salt on host-parasite survival and reproduction

Seawater intrusion caused by anthropogenic climate change may affect freshwater species and their parasites. While brackish water certainly impacts freshwater systems globally, its impact on disease transmission is largely unknown. This study examined the effect of artificial seawater on host-parasite interactions using a freshwater snail host, Biomphalaria alexandrina, and the human trematode parasite Schistosoma mansoni. Four components were analyzed to evaluate the impact of increasing salinity on disease transmission: snail survival, snail reproduction, infection prevalence, and the survival of the parasite infective stage (cercariae). We found a decrease in snail survival, snail egg mass production, and snail infection prevalence as salinity increases. However, cercarial survival peaked at an intermediate salinity value. Our results suggest that seawater intrusion into freshwaters has the potential to decrease schistosome transmission to humans. Author SummaryClimate change will have numerous impacts on many systems, including host-parasite systems. One mechanism by which climate change with impact host-parasite interactions is by rising sea levels flooding coastal regions, increasing salinity in many freshwaters. Host-parasite interactions are a key component of freshwater ecosystems, but the effects of sea water intrusion on host-parasite dynamics are largely unknown. In this study, we quantify the effects of sea salt concentration on the model host-parasite system, Biomphalaria alexandrina and Schistosoma mansoni. We demonstrate a significant, negative relationship between sea salt concentration and host-parasite survival and reproduction. The increase in freshwater salinity associated with sea level rise has the potential to decrease parasite transmission and disease burden in humans and wildlife. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/446887v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@529bd5org.highwire.dtl.DTLVardef@174cc80org.highwire.dtl.DTLVardef@11e0912org.highwire.dtl.DTLVardef@e5ab7a_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗

bioRxiv2020

Downstream Effects: Impact of Antibiotic Pollution on Aquatic Host-Parasite Interactions

The global increase in antibiotic use has led to contamination of freshwater environments occupied by parasites and their hosts. Despite the identified impacts of antibiotics on humans and wildlife, the effect of antibiotics on host-parasite life cycles is relatively unexplored. We utilize the trematode parasite Schistosoma mansoni, and its snail intermediate host Biomphalaria glabrata to investigate the influence of an ecologically relevant antibiotic concentration on the life history characteristics of both parasite and host. Our results demonstrate that antibiotics not only accelerate parasite development time, but also increase host reproduction and delay parasite-induced host castration. We propose that antibiotic exposure alters host microbiome composition, leading to increased host susceptibility and higher parasite production. Using a mathematical model, we suggest that life history alterations associated with antibiotics are likely to increase parasite transmission and disease burden. Our study suggests that antibiotic pollution could impact freshwater ecosystems by influencing host-parasite dynamics and potentially increase the burden of schistosomiasis in endemic regions.

ecology↗

bioRxiv2020

Helminth infection in a suburban ungulate population is driven more by age than landscape variables

Wildlife are increasingly common in suburban environments as towns and cities spread into surrounding rural areas. Many wildlife species have adapted to these new environments; however, we know comparatively little about how parasites respond urbanization of host habitats. Parasites are important members within ecological communities and alterations to transmission dynamics are known to alter host population dynamics. For complex life cycle parasites (parasites that use multiple different host species), suburban environments are thought to decrease transmission. Here, infection metrics of two parasites of white-tailed deer, giant liver flukes and thin-necked bladderworms, are examined to determine how successful these parasites are in a suburban environment. Additionally, land cover variables within suburban deer hunting areas are used to test if infection prevalence is associated with certain landscape level metrics. Results indicate that both parasites are common across the suburban landscape and are commonly found coinfecting the same hosts. Prevalence of neither parasite was strongly related to landscape variables within deer hunting areas, but fluke intensity was negatively correlated with the proportion of human development on the landscape. Overall, the scale of transmission events and host-parasite biology may explain why landscape metrics are weak predictors of infection risk in this system.

ecology↗