Odor masking of a vertebrate carcass by a burying beetle (Nicrophorus marginatus)

Burying beetles of the genus Nicrophorus (Coleoptera: Silphidae) use small vertebrate carcasses as food in raising their young with bi-parental care. These carcasses are stripped of hair and treated with oral and anal secretions by both males and females. Here, I report on whether Nicrophorus marginatus, a widely distributed species in North America, masks the odor of decomposing carcasses, and if so, how it accomplishes the masking. First, I compare the volatiles emitted by mouse carcasses from six different treatments, including mouse carcasses that are processed by male and female pairs of N. marginatus. The release of volatiles is assessed both by human subjects and by chemical analyses, employing solid phase extraction. Second, I examine the chemical composition of the anal secretions of both N. marginatus and N. carolinus by solid phase microextraction to gain insight into which compounds, if any, are involved in odor masking. The solid phase extraction and solid phase microextraction analyses were subsequently characterized by gas chromatography and mass spectrometry. The results of the solid phase microextraction analyses showed the commonalities and differences of several compounds between the two sexes and genders of burying beetles, but shed no light on whether any of them aids in odor masking. The solid phase extraction analyses showed an increase in an anal secretion of N. marginatus, methoxy-phenyl-oxime, with the increase in decomposing mouse carcass volatiles, suggesting that odor masking is taking place.