EXPLORING A PLANT-DIVERSITY HYPOTHESIS TO EXPLAIN HELMINTH PREVALENCE IN NORTHERN BOBWHITE (COLINUS VIRGINIANUS) IN TEXAS, USA.

Abstract

Helminths, in particular eyeworms (Oxyspirura petrowi) and cecal worms (Aulonocephalus pennula), may be a factor influencing northern bobwhite (Colinus virginianus) populations in Texas. Previous research has shown a discrepancy in helminth infections between the Rolling Plains and Rio Grande Plains of Texas, US, potentially caused by differences in intermediate host distribution and abundance. We explored an alternative hypothesis centered on plant diversity, given that many plants possess phytochemicals with anthelmintic properties. We predicted that plant diversity would be greater and bobwhite diet more diverse in the Rio Grande Plains than the Rolling Plains, which in turn would potentially expose bobwhites to more plants with anthelmintic properties and therefore result in lower parasite prevalence and intensity. We conducted a literature review of plant diversity, anthelmintic plants, and bobwhite diet in Texas to explore this hypothesis. We also quantified the relationship between helminth prevalence in bobwhites and latitude. We documented trends for higher plant species richness, greater number of anthelmintic plants, and more diverse bobwhite diet in the Rio Grande Plains compared to the Rolling Plains. In addition, we documented a trend for increasing helminth prevalence with latitude for eyeworms but not cecal worms. Our study provides circumstantial evidence supporting the plant-diversity hypothesis and warrants experimental testing.