What’s the beetle doing to its companion?

This brief video (about 7 seconds long) captures a pair of beetles, apparently “Darkling Beetles” (family Tenebrionidae). It shows one beetle touching the other with its antennae.  The video was shot September 5 on Fatman’s Loop trail (Mt. Elden area of Flagstaff, Arizona).  I removed the sound track and edited out most of the effects … More What’s the beetle doing to its companion?