Evidence of Wolbachia infection in five sympatric species of nicrophorine burying beetles including the endangered American burying beetle

Bacteria in the genus Wolbachia are found in gonadal tissue of arthropods and are estimated to be prevalent in 66% of all insects, with pervasiveness in coleopterans. Wolbachia bacteria employ several strategies to ensure vertical transmission, all of which select for increased numbers of host females. Nicrophorus beetles, including the endangered Nicrophorus americanus (Olivier) (Coleoptera: Silphidae), have a unique life history in which they sequester a small vertebrate carrion source to use as a food source and provide bi-parental care for developing offspring and have experienced a great habitat loss in the last 100 years. Field data revealed that the population of Nicrophorus americanus at The Nature Conservancy’s Tallgrass Prairie Preserve in Osage County, Oklahoma (N36.8456, W 96.4189; latitude, longitude) is skewed toward a female-biased sex ratio. A population skew toward a female-bias is one indicator of Wolbachia presence. QPCR analysis using ftsz primers indicated that Wolbachia is present in N. americanus as well as sympatric species, N. marginatus, N. tomentosus, N. pustulatus, and N. orbicollis. Future work will focus on identification of specific bacterial symbionts in Nicrophorus spp. and the evolution of behaviors that could have evolved as a response to infection, as well as the conservation implications bacterial presence may have.