Natural history data for Nicrophorus orbicollis

Burying beetles of the genus Nicrophorus have become a model for studying
the evolution of complex parental care in a laboratory. Nicrophorus
species depend on small vertebrate carcasses to breed, which they process
and provision to their begging offspring. However, vertebrate carcasses
are highly sought after by a wide variety of species and so competition is
expected to be critical to the evolution of parental care. Despite this,
the competitive environment for Nicrophorus is rarely characterized in the
wild and remains a missing factor in laboratory studies. Here, we
performed a systematic sampling of Nicrophorus orbicollis living near the
southern extent of their range at Whitehall Forest in Clarke County,
Georgia, USA. We determined the density of N. orbicollis and other
necrophilous species that may affect the availability of this breeding
resource through interference or exploitation competition. In addition, we
characterize body size, a key trait involved in competitive ability, for
all Nicrophorus species at Whitehall Forest throughout the season.
Finally, we compare our findings to other published natural history data
for Nicrophorines. We document a significantly longer active season than
was observed twenty years previously at Whitehall Forest for both N.
orbicollis and Nicrophorus tomentosus, potentially due to climate change.
As expected, the adult body size of N. orbicollis was larger than N.
tomentosus, the only other Nicrophorus species that was captured in 2022
at Whitehall Forest. The other most prevalent insects captured included
species in the families Staphylinidae, Histeridae, Scarabaeidae, and
Elateridae, which may act as competitors or predators of Nicrophorus
young. Together, our results indicate significant variation in intra- and
interspecific competition relative to populations within the N. orbicollis
range. These findings suggest that the competitive environment shows
extensive spatiotemporal variation, providing the basis to make
predictions for how ecology may influence parenting in this species.