Immature Harlequin Bugs

Red and black beetle congregations
Hello dear bug folks,
I’ve paged through all your beetle pages and couldn’t find them: It’s that time of year again – these beetles like to congregate in piles (see photo) at the edge of the woods. Each pile will have beetles of all different sizes and shades of red. Who are they and what are they doing? yours,

Hi Debbie,
Your error was in mistaking them for beetles. They are Hemipterans, True Bugs, more specifically Shield Bugs or Stink Bugs. Nymphs, the immature insects, are more difficult to accurately identify, but our money is on the Harlequin Bug, Murgantia histrionica. There is a visual match on BugGuide. Before opening your photos, we were positive they would be Boxelder Bugs, another red and black Hemipteran that aggregates.

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