Ground beetles vs darkling beetles - what's the difference?

Shiny, dark predatory beetles with well-defined mouthparts and antennae are often ground beetles.

Two groups of beetles that often get confused with each other are ground beetles and darkling beetles.  Initially, they look similar.  Both tend to be dark, often black, can often be found under stuff (turn over a board or rock and you may find one), and definitely look like beetles.  However, if you take a few moments, you will find there are significant differences.

• Ground beetles are shiny, often with glossy surfaces.  Darkling beetles are dull with little sheen.
• Ground beetles have thread-like antennae, while darkling beetles have beaded/clubbed antennae.
• Ground beetles have visible jaws.  Darkling beetles don't.
• Ground beetles are predatory, both as larvae and adults.  Darkling beetles are mainly detritivores, scavengers or herbivores.
• Ground beetles can move quickly and have longer legs, while darkling beetles are more sedentary with shorter legs.
• Ground beetles have 5 tarsal segments on the last pair of legs; darkling beetles have only 4.

Bugeric has a blog on the subject that you can find here.

The above photo is of a flower Lebia beetle.  I photographed this individual in August.  The shiny, dark exoskeleton, long, beaded antennae, visible mouthparts, and 5 tarsal segments on the last pair of legs (hard to see, but they're there) all point to this being a type of ground beetle.

I hope you learned something from this.  I mostly find ground beetles rather than darkling beetles, but while visiting my brother in Texas, I discovered a huge darkling beetle.  It had all the classic signs, as pointed out above.  

Thanks for reading.

Eric Svendsen     www.ericspix.com