Biology subjects

Wanamaker, S.

Publications and source records attributed to Wanamaker, S..

3 recordsLinked to original sources

bioRxiv2025

Male songbirds show higher coccidia oocyst burdens than femalesfollowing anthelmintic treatment

In wildlife research, wild-caught vertebrates are often given anti-parasitic drugs when brought into captivity to protect animal health and reduce confounding effects of parasitic infection on research outcomes. However, the impacts of antiparasitic drugs on non-target parasite taxa are understudied, especially regarding host sex. To help address this gap, we investigated the impact of an anthelmintic medication on a protozoan gut parasite by quantifying coccidia oocyst burden in the feces of wild-caught dark-eyed juncos (Junco hyemalis) before and after two oral doses of ivermectin. Prior to treatment, males showed higher oocyst burdens than females. Following treatment, ivermectin-treated males showed larger increases in oocyst burden compared to both control males and ivermectin-treated females, while there was no difference in baseline and post-treatment oocyst burden in treated females. Our results suggest that wild-caught songbirds should be housed separately by sex during ivermectin treatment and that male enclosures should be cleaned at a relatively higher frequency due to excessive oocyst shedding. It is unclear whether increases in oocyst burden among males were attributable to helminth removal or a direct impact of ivermectin on host immune function. Further work investigating sex differences in the impact of antiparasitic drugs on non-target parasite taxa is warranted.

ecology↗

bioRxiv2025

Building an epigenetic clock: Utilizing whole genome DNA methylation patterns to predict age in haddock, Melanogrammus aeglefinus

Age-based population models are a gold standard approach to estimate stock size and sustainable catch recommendations for effective fisheries management. Traditional ageing by counting annuli on their ear stones (otoliths), is labor-intensive, lethal, and can be inaccurate for long-lived fishes. In this study, we present an accurate, non-lethal epigenetic clock method for predicting age in haddock, Melanogrammus aeglefinus, one of the most valuable commercial fisheries in the north Atlantic Ocean. Pectoral fin tissue (n=140 individuals) was collected during Fall 2022 and Spring 2023 bottom trawl surveys in the Georges Bank-Gulf of Maine region, and whole-genome bisulfite sequencing was conducted to measure CpG loci DNA methylation levels. The most age-predictive loci were identified using a three-step modeling approach: a Bayesian generalized linear mixed model with length and sex as random factors followed by machine learning models with a 70/30 train-test split. The final model used 111 loci to predict age within 1-year at 93% accuracy. Hypo- and hyper-methylated age-related loci were found throughout the genome and were enriched in intragenic regions with functions related to immunity, transcriptional regulation, and signal transduction. This study provides an accurate, cost-effective, and scalable epigenetic tool for fisheries management to predict the age of haddock.

genomics↗

bioRxiv2020

Artificial light at night amplifies seasonal relapse of haemosporidian parasites in a widespread songbird

Urban habitats can shape interactions between hosts and parasites by altering not only exposure rates but also within-host processes. Artificial light at night is common in urban environments, and chronic exposure can impair host immunity in ways that may increase infection. However, studies of causal links between this stressor, immunity, and infection dynamics are rare, particularly in migratory animals. Here, we experimentally tested how artificial light at night affects cellular immunity and haemosporidian parasite intensity across the annual cycle of migrant and resident subspecies of the dark-eyed junco (Junco hyemalis). We monitored an experimental group exposed to light at night and a control group under natural light/dark cycles as they passed through short days simulating early spring to longer days simulating the breeding season, followed by fall migration. Using generalized additive models, we show that artificial light at night increased inflammation, and leukocyte counts were greatest in early spring and fall. At the start of the experiment, few birds had active infections based on microscopy, but PCR revealed many birds had chronic infections. Artificial light at night increased parasitemia across the annual cycle, with strong peaks in spring and fall that were largely absent in control birds. As birds were kept in indoor aviaries to prevent vector exposure, this increased parasitemia indicates relapse of chronic infection during costly life history stages (i.e., reproduction). Although the immunological and parasitological time series were in phase for control birds, cross-correlation analyses also revealed artificial light at night desynchronized leukocyte profiles and parasitemia, which could suggest a general exaggerated inflammatory response. Our study shows how a common anthropogenic influence can shape within-host processes to affect infection dynamics.

ecology↗