Spatiotemporal variation in the competitive environment, with implications for how climate change may affect a species with parental care

Abstract

Burying beetles of the genus Nicrophorus have become a model for studying the evolution of complex parental care in laboratory studies. 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 20 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.

takeout gene expression is associated with temporal kin recognition

“…Nicrophorus orbicollis used in this study were part of an outbred colony that we supplemented regularly with beetles from Whitehall Forest in Athens, GA [ 22 ]. We designed housing with the goal of reducing stress and maximizing the animals' welfare.…”

The Occurrence of the American Burying Beetle (Nicrophorus americanus) and Associated Silphid Beetle Community in South Dakota: Implications for Managed Relocation

“…Using the Peterson method, Backlund et al [34] reported a doubling in population between June and August. This difference may be explained by climate factors, including variation in precipitation, nighttime temperatures, or shifts in activity patterns associated with warmer average temperatures or more variation in precipitation [49]. The weekly or bi-weekly monitoring of a population [29,49] and population sampling after emergence from overwintering and again after breeding in more areas would be valuable for documenting shifts and interpreting population stability.…”

“…Temporal and spatial tactics to limit interspecific competition are important for ephemeral resources like carrion [11,56]. However, there is still seasonal and preferred carcass-size overlap among the collective silphid community in most regions, where resource partitioning is further influenced by biotic and abiotic gradients [31,49,54].…”

“…Competition, activity patterns, and niche partitioning among closely related Nicrophorus recently revealed the effects of temperatures on seasonal activity, allowing the coexistence of Nicrophorus [28,30,31]. In warming climates, shifts in activity patterns increase overlap among these closely related species [49]. Additionally, in the study of the montane species, Nicrophorus nepalensis revealed that populations at different elevations relied on thermal tolerance and reproductive photoperiodism to shape breeding phenology.…”

takeoutgene expression is associated with temporal kin recognition

“…Nicrophorus orbicollis used in this study were part of an outbred colony that we supplemented regularly with beetles from Whitehall Forest in Athens, GA (Potticary et al, 2023). We maintained all virgin beetles in an incubator (Percival, model no.…”