Threatened American Burying Beetle (Nicrophorus americanus) Consumed by Northern Short-Tailed Shrew (Blarina brevicauda) and Trap Avoidance by Silphidae

Abstract

During the last century, the range of the American burying beetle (Nicrophorus americanus Olivier) has been reduced by >90%. Only isolated, extant populations of this federally threatened species now exist, primarily in the Great Plains. Although the primary reason for this decline remains unclear, anthropogenic changes to habitat and vertebrate food sources used for reproduction have played a significant role. Other factors may be contributing to the decline, but little research has been conducted on understanding predators of N. americanus and how the beetle avoids them. Herein, we document a new predatory species for N. americanus, the northern short-tailed shrew (Blarina brevicauda Say), and report anecdotal evidence that beetles may avoid the musky scent of this predator. In June 2019, we observed the death of at least 2 N. americanus in the presence of a male B. brevicauda in a baited pitfall trap in Tripp County, South Dakota. In August 2020, we observed predation of carrion beetles by a female B. brevicauda that did not produce any noticeable scent. In 2019, after predation and with the presence of the male's musky scent, we noted avoidance of the baited trap by carrion beetles (Silphidae) for the remainder of the 5-day sampling period. Understanding potential predators of and predator avoidance by N. americanus will help aid recovery efforts and improve trapping protocols.