University of Illinois Urbana-Champaign

Intestinal helminth infections, distributions, and associations with health parameters of spring-migrating female Lesser Scaup in the upper Midwest

England, Jamison Conner

Content Files
ENGLAND-THESIS-2016.pdf

Permalink

https://hdl.handle.net/2142/90624

Description

Title
Intestinal helminth infections, distributions, and associations with health parameters of spring-migrating female Lesser Scaup in the upper Midwest
Author(s)
England, Jamison Conner
Issue Date
2016-04-22
Director of Research (if dissertation) or Advisor (if thesis)
  • Hagy, Heath M.
  • Levengood, Jeffrey M.
Department of Study
Natural Res & Env Sci
Discipline
Natural Res & Env Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2016-07-07T19:57:46Z
Keyword(s)
  • Lesser Scaup
  • Aythya affinis
  • Helminths
  • Parasitism
  • Midwest
  • Health
  • Habitat Quality
Abstract
The continental breeding population of Lesser Scaup (Aythya affinis) reached a record low of 3.2 million in 2006 and has since remained below the goal of 6.3 million set by the North American Waterfowl Management Plan. Although many factors have been identified as possible contributors to the decline, the Spring Condition Hypothesis proposes reduced recruitment resulting from females in reduced condition as the most influential cause. Since 2002, infections with non-native trematodes transmitted by the invasive Faucet Snail (Bithynia tentaculata) have resulted in the deaths of tens of thousands of Lesser Scaup in the upper Midwest, USA during migrations. To determine if parasitic intestinal helminths were associated with reduced body condition and health, I collected 130 apparently healthy female Lesser Scaup and identified and enumerated helminths within their intestinal tracts. I also measured a suite of health parameters to identify associations between intestinal helminth infections and their sub-lethal effects on Lesser Scaup. Forty helminth taxa (20 trematodes, 14 cestodes, 4 nematodes, and 2 acanthocephalans) were identified, including one digenean (Plenosoma minimum) for the first time in Lesser Scaup and in the Midwest. Helminth species diversity and mean total helminth abundance were greatest in northern portions of the study region along the Mississippi River, and mean total helminth abundance was less in 2015 than in 2014. Host age and body size were not associated as factors contributing to helminth assemblage, which may be due in part to physiological changes experienced during migration. The intestinal helminth infracommunities of Lesser Scaup were found to vary across the four regions and two years of the study. Variations in helminth infracommunity structure were likely due to geophysical variation within the study area, prey item (intermediate host) diversity, and weather pattern variations that occurred between years thus affecting migration chronologies and prey abundance. Varying associations were detected between 11 health parameters and seven response variables of differing helminth metrics. Most notably were the relationships observed between helminth species diversity and body fat, albumin, glucose, and percentage of white blood cells that were monocytes. Total trematode abundance was negatively related to the plasma metabolite concentrations of non-esterified fatty acids and albumin. Total nematode abundance showed a strong negative association with plasma bilirubin concentrations. The daily lipid dynamic index, a ratio of blood metabolites used as an index of foraging habitat quality, showed a negative association with total cestode abundance and Sphaeridiotrema spp. intensity. Cestode total abundance was also negatively associated with the heterophil:lymphocyte ratio, an indicator of long-term stress, but displayed a strong, positive relationship with plasma bilirubin concentrations. The introduced trematodes responsible for annual die-offs of Lesser Scaup in the upper Midwest displayed varying relationships with health parameters. While a positive relationship was detected between the introduced Cyathocotyle bushiensis and basophil white blood cells, negative associations were observed between Sphaeridiotrema spp. and bilirubin concentrations, packed cell volumes, and habitat quality variables. These biochemical and hematological measurements are important to physiological homeostasis and serve as indicators of condition at a critical period of the Lesser Scaup annual cycle. The associations between the health parameters, helminth metrics, and habitat quality measurements reported herein provide additional evidence for possible mechanisms underlying the Spring Condition Hypothesis in the upper Midwest, USA.
Graduation Semester
2016-05
Type of Resource
text
Permalink
http://hdl.handle.net/2142/90624
Copyright and License Information
Copyright 2016 J. Conner England

Owning Collections

Graduate Dissertations and Theses at Illinois PRIMARY
Graduate Theses and Dissertations at Illinois
Dissertations and Theses - Prairie Research Institute
Dissertations and Theses by Institute staff or students advised by Institute staff
Theses and Dissertations -- Illinois Natural History Survey
Dissertations and theses authored by INHS staff or advised by INHS staff.