Through the canopy and across the landscape: Native Cerambycidae species assemblages and richness in diverse sites in Michigan

Many native Cerambycidae play important roles in nutrient recycling and decomposition by colonizing dying or newly dead trees, but often little is known about the distribution or host range of cerambycid species. From 2017-2023, we deployed two cross-vane panel traps baited with a broadly attractive sex-aggregation pheromone at 15 sites for 3-7 years. Within each site, a “canopy” trap was suspended from a low to mid canopy branch (3-5 m) and a “ground” trap was supported on rebar, 1.5 m aboveground. Sites varied from small urban parks with relatively few trees to large forests surrounding campgrounds or recreation areas. At each site, we assessed overstory tree species and coarse woody debris ( >10 cm diam) in fixed radius plots and linear transects, respectively, centered on the traps. Land use classes within a 1 km radius were identified to quantify potentially available Cerambycidae brood material. Between 2017 and 2023, a total of 10,215 cerambycids representing 89 unique species were captured. Annual mean species richness ranged from 6.7 ± 0.9 to 20.5 ± 2.2 species per site. The most captured species was Neoclytus m. mucronatus representing 2,837 individuals. Singletons and doubletons represented 19% and 6% of the total species captured, respectively. Canopy traps captured 4,705 individuals representing 81 species while ground traps captured 5,510 individuals representing 71 species. Indicator Species Analysis showed that Astylopsis sexguttata, and Molorchus b. bimaculatus were indicators of canopy traps while Xylotrechus colonus and Asemum striatum were indicators of ground traps.