“Weight of evidence” as a tool for evaluating disease in wildlife: An example assessing parasitic infection in Northern bobwhite (Colinus virginianus)

Abstract

The potential of parasites to affect host abundance has been a topic of heated contention within the scientific community for some time, with many maintaining that issues such as habitat loss are more important in regulating wildlife populations than diseases. This is in part due to the difficulty in detecting and quantifying the consequences of disease, such as parasitic infection, within wild systems. An example of this is found in the Northern bobwhite quail ( Colinus virginanus ), an iconic game bird that is one of the most extensively studied vertebrates on the planet. Yet, despite countless volumes dedicated to the study and management of this bird, bobwhite continue to disappear from fields, forest margins, and grasslands across the United States in what some have referred to as “our greatest wildlife tragedy”. Here, we will discuss the history of disease and wildlife conservation, some of the challenges wildlife disease studies face in the ever-changing world, and how a “weight of evidence” approach has been invaluable to evaluating the impact of parasites on bobwhite in the Rolling Plains of Texas. Through this, we highlight the potential of using “weight of the evidence” to better understand the complex effects of diseases on wildlife and urge a greater consideration of the importance of disease in wildlife conservation.

Implications of Treating Parasitic Infection in Northern Bobwhite (Colinus virginianus) on Overall Helminth Life Cycle

“…Extraction was performed following the manufacturer's recommendations except for the final elution step, which was done using 50 ll of nuclease-free water (NFH 2 O). Polymerase chain reaction (PCR) was done following the protocol described in Henry et al (2019Henry et al ( , 2020a, minus the addition of bobwhite DNA to the solution, to amplify the cytochrome c oxidase subunit 1 (CO1) of A. pennula and the internal transcribed spacer 1 (ITS1) of O. petrowi. Table I shows the primer sequences used.…”

“…Although drought, temperature extremes, habitat degradation, and habitat fragmentation are all factors that have been attributed to declines in bobwhite (DeMaso et al, 2014;Tri et al, 2016), populations continue to decrease even in intensely managed areas and under favorable environmental conditions (Thogmartin et al, 2017;Rollins, 2018;Texas Parks and Wildlife Department, 2019). There is compelling evidence that the eyeworm Oxyspirura petrowi and the cecal worm Aulonocephalus pennula are negatively affecting wild bobwhite populations (Brym et al, 2018;Henry et al, 2020a). This evidence comes from observations of parasite epidemics coinciding with documented bobwhite population crashes.…”

“…Eyeworms were found in a greater diversity of hosts than cecal worms, suggesting that cecal worms are more host specific than eyeworms (Henry et al, 2023). However, the eyeworms were still predominately found in Orthopterans rather than insects from other orders (Almas et al, 2018;Henry et al, 2020aHenry et al, , 2023. Additionally, bobwhite became infected with O. petrowi after being fed experimentally infected field crickets and L3 larvae recovered from a wild-caught plains lubber grasshopper (Brachystola magna) (Kistler et al, 2016;Kalyanasundaram et al, 2019).…”

Validation of an LC–MS/MS method for assessment of fenbendazole sulfone drug residue in northern bobwhite liver

“…However, parasites have garnered increased interest over the past couple of decades as researchers continue to document instances where parasites do indeed affect wildlife populations in a regulatory manner, for instance, by impacting survival and fecundity (Watson, 2013; Pedersen & Fenton, 2015). Despite this, identifying the consequences of parasitic infection in free‐living hosts remains challenging because of the many factors that interact to affect wildlife populations (Henry et al, 2020; Pedersen & Fenton, 2015; Rose et al, 2014).…”

“…fecundity (Watson, 2013;Pedersen & Fenton, 2015). Despite this, identifying the consequences of parasitic infection in free-living hosts remains challenging because of the many factors that interact to affect wildlife populations (Henry et al, 2020;Pedersen & Fenton, 2015;Rose et al, 2014).…”