|Photo by Honey-Matt Ball 5/23/2014|
Big evidence of a Mesquite Girdler Beetle. (Click on the photo to see the scratch on the left, just to the left of the bump on the lower side of the branch.) You can see why the female MGB cuts a ring into the branch and lays her eggs in the scratch beyond the cut (on this branch, that's left). If she hadn't made the cut, all the sap that pooled (and hardened) would have washed away her eggs.
As you'd expect, mesquite sap is sweet. You can actually see the sugar crystals on this sap ball, if you look closely.
Thanks to Ken for sending this video made by the Park Service, A day in the desert. Watch it inside : -)