A member of the Erotylidae family of beetles, they are fungivorous beetles, meaning they eat fungi. Megalodacne species feed on harder bracket fungi, such as Ganoderma tsugae (Hemlock Varnish Shelf). Adult beetles of the genus Megalodacne range in size from 9 to 22 mm, making them among the larger members of the family. Distinguishing characteristics of the genus along with other members of the subfamily Megalodacninae include large eyes and a lack of depressions in the club joint of the antennae. The first three tarsomeres are also cylindrical and of similar shape and size, while the fourth is significantly shorter. Primarily black with orange/red banding.
Often found in coniferous forest where there are hemlock trees, and thus also the hemlock varnish shelf fungus.