How will insect communities respond to a novel chemical cue introduced by a range-expanding beetle?

Climate change is facilitating northward range expansion of the southern pine beetle (Dendroctonus frontalis Zimm.; SPB). In the beetle’s native range, the SPB-associated insect community includes predators, parasitoids, and competitors. Some of these insects are known to respond to SPB pheromones in the southern U.S., which could be evidence of co-evolutionary dynamics between SPB and its associates. Prior to SPB outbreaks in New England, we explore the response of forest beetles to the SPB aggregation pheromone, frontalin--a novel chemical cue in this region. We also identify beetle community responses to pheromones of native Ips bark beetles, α-pinene, and unbaited funnel traps. Traps captured beetles in 18 pine forests throughout New England in 2020 and 2021. We identified over 90,000 insects to 149 taxa, including SPB predators and co-colonizing bark beetles to species. We analyze beetle diversity and abundance across lure types and in association with pine host species present at each site (white pine, Pinus strobus L.; or pitch pine, Pinus rigida Mill). We hypothesized that pine host species may act as an ecological filter for the forest beetle community, and we find evidence for this via ordination of community data and in the abundance of key taxa. Frontalin-baited traps captured less beetle diversity than Ips or α-pinene traps, and many bark beetle predators were most abundant in the Ips traps.