In the Common Whitetail and Blue Dasher dragonflies (Plathemis lydia and Pachydiplax longipennis), males display the pruinescence on the back of the abdomen to other males as a territorial threat.
NYPD Blue | Toronto Blue Jays | Blue Peter | Blue | Blue Ridge Mountains | Blue Öyster Cult | Blue Note Records | Blue Heelers | Pokémon Red and Blue | Winnipeg Blue Bombers | Blue Nile | Blue's Clues | ''Pokémon Red'' and ''Blue'' | Blue Man Group | Vida Blue | The Blue Danube | Rhapsody in Blue | blue plaque | Blue Mountain State | Blue Cheer | Blue Bloods | Blue Beetle | Ateneo Blue Eagles | Project Blue Book | Blue Hill, Maine | Operation Blue Star | Kind of Blue | Blue Bloods (TV series) | Blue Angels | Three Colors: Blue |