Darkling Beetles

Darkling beetles are some of the largest invertebrates in the park, reaching up to 1.5 inches (3.8cm) long.

NPS Robb Hannawacker

 

Scientific Name

Tenebrionidae Family (27 species found in the Park)

 

Identification

• As the name suggests, darkling beetles are completely black in color. The shell of their abdomen can be either smooth or textured with ridges or bumps, depending on the species.
• They are some of the largest insects in the park. Adults can be up to 1.5 inches (3.8cm) in length.
• They walk with their heads down, so that the end of their abdomen is lifted higher than their head.

 

Habitat

• Darking beetles are found across the United States, but are most commonly found in arid regions.
• They are found throughout the Grand Canyon. No matter where you are in the park, you are not far from at least one of the 27 species of darkling beetles that call the Grand Canyon home.
• They prefer open sandy areas, surrounded by pinyon-juniper forest or desert scrub. Because of their size, it is easier for these beetles to move through sandy or rocky terrain, rather than thick grass or fallen leaves.

 

Behavior

• Darkling beetles are ground dwellers that are active during the day and night. During the hottest part of the day, they burrow under sand to stay cool.
• Unlike most other beetles, darkling beetles cannot fly. Their wings are fused together and are useless.
• They are scavengers that feed on fungus, decaying vegetation, animal feces, and occasionally live plants.
• After they hatch, they begin their lives as worm-like larvae. When they grow large enough, they burrow under the soil and pupate, remaining motionless until they have metamorphosed as adult beetles.
• Darkling beetles of the genus Eleodes have a powerful defense against predators: they can squirt a foul-smelling liquid from the back of their abdomen into the face of attackers. This has earned them the nickname of "skunk beetle." 13 species of this subgroup of darkling beetles are found in Grand Canyon National Park.