Polka-dot wasp moth nectaring on saw palmetto.

Polka-dot wasp moth

by Elora Pfriender

“Know your native pollinators” is a series of articles that will help you identify and appreciate Florida’s varied pollinators, including bees, wasps, butterflies, moths, beetles, flies, birds and bats. Pictured above: Polka-dot wasp moth (Syntomeida epilais) on Saw palmetto (Serenoa repens) by Alan Cressler.

Contrary to its appearance, the harmless Polka-dot wasp moth isn’t a wasp — but it’s not your typical moth, either.

CLASSIFICATION

Class: Insecta
Order: Lepidoptera
Family: Erebidae
Genus species: Syntomeida epilais

FUN FACT

While other moths and butterflies release pheromones to attract mates, Polka-dot wasp moths instead produce ultrasonic clicking sounds to communicate during courtship. Males and females each produce unique, sexually dimorphic click patterns, with males homing in on female clicks. Studies suggest the acoustic images created by these click patterns may also confuse or deter predatory bats by interfering with echolocation.

IDENTIFICATION

Polka-dot wasp moth nectaring on Saw palmetto.
Polka-dot wasp moth (Syntomeida epilais) on Saw palmetto (Serenoa repens) by Alan Cressler.

These harmless wasp lookalikes are strikingly iridescent, with teal wings and bodies ending in a bright red-orange abdomen that signals their toxicity to predators. Both males and females are covered in white spots — hence the common name “Polka-dot wasp moth” — and are similar in appearance, with a wingspan of 45–51 mm. Their slender wings and bodies mimic the shape of stinging wasps, likely as a defense mechanism to ward off predators.

FORAGING PREFERENCES

The Polka-dot wasp moth’s preference for the non-native oleander (Nerium oleander) as a host plant has earned its larvae the common name “oleander caterpillar” and a reputation as a voracious pest. However, their original host plant in Florida is believed to be the native Devil’s potato (Echites umbellatus), a vine found in coastal hammocks and dunes of South Florida and the Keys. While larvae are sometimes observed on other non-native ornamentals like Frangipani (Plumeria spp.) and Rocktrumpet (Mandevilla spp.), these are not natural host plants. Adult Polka-dot wasp moths nectar on a variety of flowers, including Florida privet (Forestiera segregata) and species in the aster and dogbane families.

HABITAT

Native to Neotropic areas, the polka-dot wasp moth is commonly found throughout Florida, especially in warmer months. Many individuals found year-round in Florida belong to the North American subspecies Syntomeida epilais jucundissima, which is also found throughout the southeastern United States and into Mexico. Unlike most moths, the Polka-dot wasp moth is diurnal (active during the daytime) and are frequently found fluttering through sunny pastures and gardens.

DID YOU KNOW?

Polka-dot wasp moth larvae, or oleander caterpillars, are known to ravenously feed on oleander. Rather than leaving noticeable bite marks, they consume the leaf tissue and leave the veins intact, leaving a skeletonized leaf behind. However, this defoliation does not kill the plant.

LIFE CYCLE

Orange Polka-dot wasp moth caterpillar with black bristles.
Polka-dot wasp moth caterpillar (Syntomeida epilais). Photo by Alan Cressler

Polka-dot wasp moths use ultrasonic signals to find mates in the hours before dawn. After mating, females lay clusters of small, spherical, pale yellow eggs on the undersides of their host plants’ leaves. Larvae are bright orange with sparse clumps of long black hair. While they are toxic to predators, they are harmless to humans and do not sting, unlike many other hairy caterpillars. During metamorphosis, several caterpillars may come together to form a shared cocoon made of silk and their own hairs. Inside, each pupa is shiny and brown.

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