We found these butterflies in Mexico while following a cracking noise. Crack, crack, crack in rapid succession. It turned out that these were the culprits and I think they might have been calling their brethren to this tree. Out of small wounds was leaking a red sap that butterflies and bees were eagerly ingesting. I suspect there was a high sugar content but it was an interesting discovery.
Canon 1D X, Canon 100/f2.8L IS
100mm, f4, 1/640 sec @ 100 ISO