Assessment of the helminth fauna in northern bobwhites (Colinus virginianus) occurring within South Texas.

S.A Shea,A.M Fedynich,D.B Wester

doi:10.1017/s0022149x20001029

Abstract

Populations of northern bobwhites (Colinus virginianus; hereafter bobwhite) have been declining across their geographic range in North America, prompting consideration of the role parasites may play. We conducted this study to learn about the helminth fauna in South Texas, a region that supports a sustainable bobwhite population. Helminths were examined from 356 bobwhites collected during the 2014-2015 (n = 124) and 2015-2016 (n = 232) hunting seasons, when increasing trends in precipitation were observed in comparison with the previous two years. Ten helminth species were found, consisting of 14,127 individuals. Of these, all are heteroxenous parasites and three are pathogenic (Dispharynx nasuta, Tetrameres pattersoni and Oxyspirura petrowi). Aulonocephalus pennula numerically dominated the component community (81% prevalence, 99% of the total helminths found), whereas each of the remaining species occurred rarely (≤9% prevalence) and contributed few individuals (≤0.4%) to the helminth community. Prevalence and abundance of A. pennula were not influenced by host age, sex or body mass, but abundance was higher during the 2014-2015 than the 2015-2016 hunting season. Our findings indicate that the helminth community in bobwhites from South Texas can vary during long-term, highly variable precipitation conditions and these communities are more similar to those found in the Rolling Plains of Texas than those found in the eastern part of the bobwhite's geographic range in the US.

Highlights

The northern bobwhite (Colinus virginianus; hereafter bobwhite) is a prized upland game bird across its geographic range in the US that is experiencing a long-term population decline
This study examined the helminth community in bobwhites during a severe drought period (NOAA, 2020), representing the decline phase of the host’s boom-and-bust cycle
Species found that are known to be pathogenic in bobwhite included O. petrowi, Tetrameres pattersoni and D. nasuta, which occurred in 4%, 1% and

Summary

Introduction

The northern bobwhite (Colinus virginianus; hereafter bobwhite) is a prized upland game bird across its geographic range in the US that is experiencing a long-term population decline. Some studies have focused on species likely to cause pathology such as the eyeworm (Oxyspirura petrowi; Villarreal et al, 2012; Bruno et al, 2015; Dunham et al, 2016, 2017; Henry et al, 2017) and the caecal worm (Aulonocephalus pennula; Henry et al, 2017), whereas other studies have used a community survey approach (Olsen & Fedynich, 2016; Villarreal et al, 2016; Bruno et al, 2018, 2019) Findings from these studies have shown that geographic location, season, year and variation in precipitation can influence helminth species richness, prevalence and abundance in bobwhites, highlighting the importance of temporal helminth surveys in regions characterized by stochastic environmental conditions. The objectives of our study were to determine helminth community structure (prevalence and abundance) and patterns (distribution patterns, diversity, numerical dominance) in bobwhites occurring within South Texas during a wet period and relate our findings to the host boom-and-bust cycle within the region and from distinctly different physiographic environments

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