Carrion Beetles in Orchards and Ranches in Oklahoma and Investigation of Genes Associated with Antimicrobial Production
Abstract
Family Silphidae, the carrion beetles, is a highly evolved family of Coleoptera that has members with unique social behaviors and physical abilities that allow them to utilize decaying vertebrate matter for sustenance and larval rearing. Two investigations were conducted to elaborate on the habitat association and gene expression of certain members of in the subfamily Nicrophorinae (burying beetles). The first investigation tested the effect of two forms of agricultural production on populations of Silphidae in eastern Oklahoma, with particular focus on the endangered American Burying Beetle (Nicrophorus americanus Olivier/ABB). Between 2017 and 2018, 10 weeks of field sampling was conducted in pecan orchards and cattle pastures of eastern Oklahoma, capturing a total of 2,338 Silphidae. Ultimately, no statistically significant differences were found between median capture values of Silphidae in either land usage (pecan orchard: [8]; cattle pasture [4]) in a majority of examined species, including the ABB. This finding suggests an overall trend toward generalism of habitat use by Silphidae in Oklahoma. The second investigation tested the nature of antimicrobial secretions used by Subfamily Nicrophorinae (burying beetles) in the preservation of carrion and the expression of genes in response to food availability. Using two species of burying beetle, Nicrophorus orbicollis Say, which has a typical life cycle, and Nicrophorus pustulatus Herschel, a brood parasite, gene expression of excised salivary glands was analyzed through RNA sequencing of beetles exposed to and denied ground beef as food. N. orbicollis had higher expression of innate immunity compounds when fed (6.58% of characterized sequences) than did N. pustulatus (5.19%) and a higher percentage of expression overall (7.14%/4.22%). These findings suggest the active bactericidal compounds in burying beetle secretions to be antimicrobial proteins produced by individual beetles in response to feeding. Together, these findings suggest that ABB can use areas of Oklahoma that are converted for pecan and ranching operations and that burying beetles have the potential to provide novel compounds for antibiotics or preservation of meat at room temperature.
Collections
- OSU Theses [15752]