Epic wasp battle! This series of photos, with that title, was sent in by reader Mark Sturtevant. His notes are indented:
I had recently sent some pictures about insects attracted to wind-fallen apples in our yard. Among the insects were downy yellowjackets (Vespula flavopilosa), which are social insects—but that does not mean they always got along. Yes, some tolerated each other, perhaps recognizing a nest-mate, but other encounters between them were not friendly. When rival wasps met, one would generally shoo away the other turning toward them, jaws agape, and with slightly raised wings. The other was then supposed to flee.
The first picture shows how encounters between rivals would generally start. The wasp on the right is clearly signaling the other to scram. But in this case, the other wasp just would not get the message. Perhaps the interloper had come to believe that it owned this apple as well. What followed was what I like to call an Epic Wasp Battle. I watched several of these encounters between these two wasps, but I never did see if they ever resolved their differences.
The next five pictures shows the resulting battle that began with the first picture. Here, the aggressor charges in but is met with resistance by its opponent, and so the two roll around for a couple seconds. Shortly after they would move apart. But the aggressor wasp would soon notice the interloper, and the whole sequence would repeat, as shown in the last photo.
Just some final comments. First, neither wasp seemed willing to escalate by actually harming the other. I never saw one bite the other, nor did I see any stingers come out. Second, I expect that all of us have noticed this sort of conflict between wasps over sugary sources such as an open soda can. I for one never gave them more than a glance. But seen up close, these battles do look pretty dramatic!