Hummingbird Clearwing

Hemaris thysbe — the hummingbird clearwing — is one of about 17 species in genus Hemaris (the clearwing hawk moths) and one of the most extraordinary cases of vertebrate mimicry by an insect. The species is widespread across all of eastern North America from southern Canada south through the eastern US to northern Florida and west to the Great Plains. Adults are 4-5 cm wingspan with a fat olive-green-and-burgundy body coloration that closely resembles the body shape and color pattern of a small hummingbird. The species' identifying feature is the 'CLEARWING' wing pattern — large central wing patches that are completely TRANSPARENT (the wing scales fall off during the moth's first flight, leaving the bare wing membrane visible), framed by a narrow border of dark scales around the wing margins. The transparent wing patches allow the wings to beat at HUMMINGBIRD-LIKE FREQUENCIES (~70 Hz, similar to ruby-throated hummingbird wing beats) without producing visible wing motion — the wings appear as a translucent blur in flight, very similar to a hummingbird's wing blur. The species is one of the most successful examples of VERTEBRATE MIMICRY BY AN INSECT. Even experienced birders consistently misidentify hummingbird clearwings in flight as hummingbirds — the combination of hovering posture, similar body shape, fuzzy 'feather-like' thoracic vestiture, similar size (the moth is somewhat smaller than a ruby-throated hummingbird but in the same general size range), wing-blur appearance, and DAYTIME flight (most hawk moths are crepuscular or nocturnal — Hemaris is one of the few day-flying hawk moth groups) make for an exceptionally convincing hummingbird mimic. The mimicry function is debated: it may provide protection from bird predators (which avoid attacking small hummingbirds), or it may be an example of CONVERGENT EVOLUTION on similar foraging biology (long-proboscis hovering nectar feeding from long-tubed flowers selects for similar body morphology and flight kinematics in both moths and hummingbirds). Adults feed on nectar from a wide range of long-tubed flowers (especially honeysuckle, bee balm, phlox, and butterfly bush) using a 2-3 cm extended proboscis. The species is a major beneficial pollinator in eastern North American gardens and is one of the most-photographed insects in NA macro nature photography because of the dramatic visual impact of the hummingbird-mimic flight.