Paper wasps scour milkweed leaf tops, hungry for aphid “honeydew” frass
(noted in this 2017 post) dropped from leaf bottoms above.

Clockwise from top left:
Guinea wasp (Polistes exclamans),  Northern paper wasp (Polistes fuscatus), Metricus paper wasp (Polistes metricus), European paper wasp (Polistes dominula).

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