Biology subjects

Minchella, D. J.

Publications and source records attributed to Minchella, D. J..

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

Snail host parental investment throughout a Schistosoma mansoni infection

Parental investment theory describes the ability of organisms to respond to an environmental challenge by increasing the fitness of future offspring. Utilizing life history changes, organisms can maximize fitness by increasing their total reproductive output or by investing more into the success of fewer offspring. In cases where parasitic infections result in castration of their host, increased reproductive effort known as fecundity compensation has been demonstrated in a variety of organisms. This response appears predictive of expected future reproductive losses. Organisms struggling with an environmental pathogen, may attempt to better prepare their offspring for the environment they are experiencing through transgenerational immune priming (TGIP). In immune priming, primary infection lowers the prevalence and intensity of a subsequent infection by the same pathogen. Transgenerational immune priming carries pathogen resistance into further generations without genotypic changes. The focus of this study was to determine whether invertebrate parental investment into offspring parasite resistance varies over the course of an infection. Utilizing the snail host Biomphalaria glabrata and its trematode parasite Schistosoma mansoni, offspring were reared from specific time intervals in the parents infection and subsequently exposed to the same pathogen when each cohort reached the same age- 12 weeks. Differences in infection prevalence and intensity were expected based on when the offspring were born during their parents infection. A trade-off was predicted between the number of offspring produced in a cohort and offspring resistance to future infections. Offspring born during the period of fecundity compensation were predicted to exhibit lower resistance due to a dilution of individual investment by parents into a larger offspring pool. While our results did not support TGIP, there were differences in offspring prevalence, as well as an indication that parent health may interact with genetics in offspring resistance. Results suggest that parental condition can influence resistance of B. glabrata offspring to S. mansoni but that TGIP may not be operating in this system.

evolutionary biology↗