Banded Net-Winged Beetle

Calopteron reticulatum — the banded net-winged beetle — is one of about 4,000 species in family Lycidae (the net-winged beetles) and one of the most striking small beetles in eastern North America. The species is widespread across the eastern US from southern New England south through the eastern US to northern Florida and west to Texas. Adults are 8-15 mm long, oval-shaped, with the species' two diagnostic features: (1) BRIGHT ORANGE-YELLOW ELYTRA marked by TWO BROAD BLACK CROSS-BANDS — a wide black band across the middle of the elytra and another wider black band at the wing tips; (2) A UNIQUE RAISED NETWORK OF VEINS across the elytra (the 'net-winged' family name) — the wing-covers have a distinctive lattice texture created by raised ridges that form a network pattern across the elytra surface, looking like miniature orange ironwork. The lattice texture is unique to family Lycidae and is one of the most distinctive elytral surface patterns in NA Coleoptera. The species is one of the most-cited examples of MÜLLERIAN MIMICRY in NA Coleoptera. Müllerian mimicry differs from Batesian mimicry: in BATESIAN mimicry, a harmless species mimics a toxic species (the harmless species benefits from predator avoidance learned by predators experience with the toxic model — but the model species doesn't benefit from the mimic's existence); in MÜLLERIAN mimicry, MULTIPLE UNPALATABLE species share the same warning coloration, providing collective protection — predators that learn to avoid the warning pattern after one species encounter benefit from avoiding all members of the mimicry ring, including all the toxic species. The orange-and-black banded pattern of the banded net-winged beetle is shared by MULTIPLE UNRELATED BEETLE SPECIES in eastern North America, including: end band lycid (Calopteron terminale), false net-winged beetle (Cucujus clavipes), banded soldier beetle (Chauliognathus pensylvanicus), and several lycid (Lycus) species. The mimicry ring also includes some moth species and true bugs that have evolved similar orange-and-black patterns. The species is CHEMICALLY DEFENDED — adults contain TOXIC CARDIAC GLYCOSIDES and other deterrent compounds that make the beetles unpalatable to bird and small-mammal predators. The orange-and-black warning coloration alerts predators to the toxic chemistry; predators that have learned the pattern from one Müllerian-ring species avoid all Müllerian-ring species. The species is harmless to humans (no bite, no sting, no aggressive behavior) and one of the most-photographed beetles in eastern NA macro nature photography.