Nightcrawler (Lumbricus terrestris) is an anecic earthworm that constructs burrows up to 2.5 m (ca 8 feet) deep. Photograph by Jack Kelly Clark.
	Middens of nightcrawler (Lumbricus terrestris) in an organic walnut orchard. Middens are turret-like structures of mud and vegetational litter, and sit atop burrows that can be as deep as 2.5 m (ca 8 feet). Photo by Robert L. Bugg.
	Middens of nightcrawler (Lumbricus terrestris) in a citrus orchard. Photo by Robert L. Bugg.
	As observed in San Joaquin and Solano counties, densely shaded sprinkler- or flood-irrigated walnut orchards appear especially conducive to the establishment and spread of nightcrawler (Lumbricus terrestris). Photo by Robert L. Bugg.