The Suprapopulation Dynamics of Acanthocephalus Dirus in a Definitive Host, Etheostoma Squamiceps, & Two Intermediate Hosts, Lirceus Fontinalis & Gammarus Minus

• Main Author: Weimorts, Mary
• Format: Others
• Published: TopSCHOLAR® 1983
• Subjects: Biology; Life Sciences
• Online Access: https://digitalcommons.wku.edu/theses/2947; https://digitalcommons.wku.edu/cgi/viewcontent.cgi?article=3961&context=theses

The suprapopulation dynamics of Acanthocephalus dirus were studied in the definitive host, Etheostoma squamiceps, and two intermediate hosts, Lirceus fontinalis and Gammarus minus, from Lick Creek, Warren County, Kentucky. The study was conducted from December 1981 through January 1983. A total of 448 isopods, L. fontinalis, was examined for larval A. dirus and 9 (2.01%) were infected. Infected isopods were observed from September through December 1982. There was no correlation between the presence of larvae and lack of pigmentation. A total of 441 amphipods, G. minus, was examined. Of these, 21 (4.76%) were infected. Infected amphipods were observed in all months except May, June, July, and September 1982. In both intermediate hosts, ovarian balls were present in the pseudocoelom of female cystacanths. This suprapopulation was unique in that it utilized two intermediate hosts, of different orders, within a single ecosystem. This is the first time that an amphipod has been reported to play a substantial role in propagating the life cycle of an acanthocephalan of the genus Acanthocephalus. A total of 180 E. squamiceps was examined, and 118 (65.5%) were infected with A. dirus. No significant difference in prevalence of infection or in the mean intensity of infection was observed between male and female hosts. No seasonal periodicity of the parasites in E. squamiceps was observed. There was, however, d significant difference in the attachment sites of the parasites in the gut of the fish during different months and seasons. This was associated with recruitment periods of the parasite by the definitive host. All parasites were sexually mature, and the overall ratio of males to females was 1:1. Acanthocephalus dirus were overdispersed in E. squamiceps, and there was a positive correlation between host total length and density of parasites.