Vampire Moths

Vampire moths may sound like something out of European folklore, but they exist and they suck blood.

Male vampire moth (Julia L. Snyder) CC BY-SA 4.0

The vampire moth family

Vampire moths have an entire genus of their own with 17 known species. Ten of them drink blood. Originally from Malaysia, the Urals, and southern Europe, Calyptra have expanded their range to include northern Europe, Sweden, and Finland. Due to international shipping and travel and climate change, it is expected that these moths will continue to expand their range. The Canadian owlet or meadow rue owlet moth (Calyptra canadensis) is the only New World member of this group.

Moth proboscises

Many adult moths do not eat. Some of them do not even have mouths. Those that do often have a surprisingly long, slender straw, called a proboscis. Moths keep their proboscis curled up in a flat, vertical spiral. The proboscis is generally used to drink nectar. The hawk moth has a proboscis that is over one foot long. In the case of the vampire moth, the end of that straw has a serrated edge that is sharp enough to cut through elephant skin. I don’t know how long it is.

Hawk moth with proboscis extended (Charles J. Sharp) CC BY-SA 4.0

Vampire moth diet

Male and female vampire moths eat the nectar of meadow rue and other members of the buttercup family (Thalictrum). They also suck the juices from fruits, such as strawberries. Vampire moth caterpillars feed on leaves.

Unlike mosquitoes, where it is the females who must drink blood to provide for their offspring (obligate), blood-sucking vampire moths are male and they drink blood because they like it (facultative). Some scientists suspect that male vampire moths drink blood for the salt, which they then pass on to the female in their sperm to provide for their offspring. No one knows for sure just yet.

Male vampire moths pierce the skin of vertebrates, including us, to drink blood. They do this by using  a proboscis that is divided into two parts. They use a back-and-forth sawing motion to pierce the skin of their victims with these dual tubes.

Once attached, vampire moths are not easily removed and they may remain in place for up to 50 minutes. They do not technically “suck your blood”. Instead, they use their victims’ blood pressure to do that work for them. If you are the victim of a vampire moth, you will not turn into a vampire or a moth, but the site will be red and sore for several hours with an itchy rash. Vampire moths are not believed to carry or spread any diseases.

Canadian owlet caterpillar (Judy Gallagher) CC BY 2.0

Vampire moth identification

Vampire moths are relatively plain. They are broad-winged moths with yellowish-brown or pinkish-brown forewings and dull brown hindwings. The wingspan is 1.25 to 1.5 inches wide. You may be able to see dark brown bands, but these can be faint.

​Larvae are chubby, pale green to black caterpillars with yellow or red heads, depending on the species and location. The green specimens have spotted black and yellow longitudinal lines. The black caterpillars have yellow bellies and white bands arranged in groups of four or they may be solid black with tiny yellow spots. They have three pairs of prolegs. These moths are most active in summer, and they are attracted to lights.

Chinese vampire moths (Calyptra orthograpta) look like dead leaves while at rest.

​It is believed that vampire moths evolved from purely fruit-sucking species. I can’t help wondering what my tomato plants are planning…

Chinese vampire moth (LiCheng Shih) CC BY 2.0