American Burying Beetle (Coleoptera: Silphidae) Occurrence at Reservoir Shoreline and Hand-Planted Forest at the Western Limit of Their Range

ABSTRACT: The largest North American Silphidae, the American burying beetle (ABB), Nicrophorus americanus Olivier, has been extirpated from ∼90% of its historic range and is federally threatened. Two distinct populations in the Southern (Oklahoma and Arkansas) and North-Central United States (Nebraska and South Dakota) persist at the western edge of the ABB's former range. In Nebraska, the western limits of occurrence are associated with Merritt Reservoir and linked irrigation canals. ABBs are also found at the nearby hand-planted McKelvie National Forest. While habitat alteration and fragmentation are likely the primary reasons for ABB decline, few studies have examined their response to human habitat modifications unrelated to urbanization or agricultural conversion. Through five-day sampling periods with carrion-baited pitfall traps, ABB were captured and recorded in June and August from 2015 to 2017 at Merritt Reservoir and McKelvie National Forest in Cherry County, Nebraska. Traps were placed in transects (N = 4) at each location with reservoir traps set at the shoreline, transition, and upland habitats and forest traps set in the prairie, transition zone, and pine forest. At Merritt Reservoir, 651 ABB were captured, with significantly more collected at the shoreline. Concurrently, 23 ABB were captured at McKelvie Forest, with more ABB found within the forest compared to nearby prairie. These findings support previous suggestions that the western distribution of ABB is limited by moisture. Further investigation may indicate that reliable soil moisture associated with altered habitats in Nebraska could support ABB and potentially allow western range expansion.