365 Urban Species. #100: Ground Beetle
photo by cottonmanifesto
Urban species #100: Ground beetle: Pterostichus melanarius
As we have seen in this journal with the Canadian nightcrawler, various kinds of woodlouse, and the woodlouse spider, transatlantic trade in dirt has provided North America with several urban animals originally native to Europe. To this list I add the ground beetle. While there are over 2000 species of ground beetle in North America, the most common urban species is Pterostichus melanarius, from Europe.
Ground beetles are nocturnal predators, feeding on other soil organisms such as slugs, crane fly larvae and millipedes. Though they are an introduced species, it is not known if their effect on the ecosystem is negative--they seem to feed on as many pests as they do beneficial species. Many overwinter as larvae, appearing as adults in summer, but some (like the individual pictured) overwinter as adults.
