The Slender Dung Beetle, Ataenius cognatus, is a small scarab beetle measuring 4.2 to 5.5 mm in length. It belongs to the Aphodiinae subfamily of dung beetles and is part of the strigatus-group within the genus Ataenius. This species closely resembles A. strigatus and A. spretulus but is distinguished by the absence of posterior femoral lines and shallower pronotal punctures.

Adults are typically shiny black with a slender, elongated body suited for burrowing in soil near dung. They are found across a range from California to Indiana and Mississippi, extending into northeastern Mexico. These beetles inhabit pastures, grasslands, and areas with livestock where fresh dung is available.

Ataenius cognatus plays a role in nutrient recycling by breaking down mammal dung. Adults fly to fresh droppings, burrow beneath them, and provision tunnels with dung fragments for larval development. The life cycle includes egg, larva, pupa, and adult stages, all occurring in or near dung pats. Larvae feed on organic matter within the dung, aiding decomposition.

Specimens are ideal for entomology studies, insect collections, and educational displays. Check it out on BugGuide! http://bugguide.net/node/view/351305