Large milkweed bugs (Oncopeltus fasciatus) on narrow-leaf milkweed. There is a brood of immature bugs (nymphs) in the opening seed pod, between the two adults. The aposematic red-orange color tells predators the insects taste bad. Adults probably benefit from staying on a plant with the nymphs, because collectively the defensive display is more effective.
The adjacent photograph of immature milkweed bugs (from Photography on the Run) is being used by the Denver Museum of Nature and Science as part of their “Awesome Adaptations” station educational program.