Moth Mimic

You can see these moths, these hummingbird moths, all summer.  They hover, move from flower to flower and sip nectar.  They are unusual for moths because they fly during the day time.  This group of moths has a bewildering number of names: hummingbird moth, hawk moth, bumblebee moth, sphinx moth.  With a casual glance these moths can be mistaken for a hummingbird or a bee and that mistaken identity gives them a couple of their common names.  There are three species of hummingbird moths in Eastern North America.  This summer we hosted a group of Hemaris diffinis. These moths fed on beebalm, milkweed, lantana and other flowers in our yard. 

 

The hummingbird moth Hemaris diffinis feeding on Lantana camara in North Carolina

Hemaris diffinis, besides being called all these other names has yet another common name, snowberry clearwing.  Snowberry (Symphoricarpos) is a member of the honeysuckle family and Hemaris diffinis uses this plant as a host for its eggs and larvae.  The clearwing part of the name comes from the transparent areas on the moth’s wings.  Hemaris diffinis has a large body with a golden thorax and a black abdomen.  This yellow and black pattern is like that of several species of bumblebees.  At the tip of the abdomen, this hummingbird moth has a fan of bristles that resemble the tail of a hummingbird.  Hemaris diffinis does not flap as fast as a hummingbird but the clear areas of the wings make them appear to be a blur, just like the wings of a hummingbird.  Hemaris diffinis has an extendible mouthpart, called the proboscis, which it uses to sip nectar from flowers.  The proboscis even resembles the beak of a hummingbird.  

The video above shows Hermaris diffinis, with its yellow body and black abdomen, hovering as it feeds on Lantana.  This is similar to the color pattern of the Common Bumblebee Bombus impatiens in the next section of the video.  Finally a male Ruby-throated Hummingbird perched on and hovering near a hummingbird feeder shows a similar flight and feeding pattern to the moth. 

Hemaris diffinis is a mimic and it is mimicking both hummingbirds and large bees.  The question is, why?  It is easy to explain mimicking a bee.  Bees are able to sting and they advertise this fact by bold patterns and colors of yellow and black.  This yellow and black pattern is a well know warning to potential predators.  A number of insects including flies and beetles mimic bees and enjoy protection from bird predators.  But why would a moth mimic a hummingbird?   The birds that prey on moths do not hunt hummingbirds, so being mistaken for a hummingbird is a second level of protection. 

Summer is still going and the hummingbird moths are still flying.  Go out and enjoy these double mimics in fields and gardens.