The oleander caterpillar, Syntomeida epilais Walker, a bright orange caterpillar with tufts of long black hairs, is a common sight on and around oleanders in Florida.
In South Florida, the oleander caterpillar can cause considerable defoliation. In the Panhandle, this is rarely a problem but this caterpillar can cause other headaches for homeowners, especially on the beach.
Like all butterflies and caterpillars, this Halloween-colored worm undergoes complete metamorphosis and creates a cocoon in which to transform. The caterpillars often leave their host plant and look for a protected place to undergo their change. For some reason, the base of siding is a preferred site. Especially in the fall, horrified homeowners may find their driveway, or the slab beneath a stilt house, overrun with these whiskery worms as they migrate toward the structure.
An application of most over-the-counter pesticides labeled for outdoor use, and a broom or leaf blower, should solve the problem. These mass migrations are usually short-lived.
This caterpillar transforms into an unusual moth that flies during the day and resembles a large, brightly colored wasp. This stage is commonly referred to as the polka dot wasp moth or the Uncle Sam bug because it is bright red and blue with starry white spots.
When mating, females contact male polka-dot wasp moths by means of ultrasonic signals that travel through a branch. The male follows the sound to his new mate, and when he reaches her, emits an answering signal.
The eggs, found in clusters on the underside of oleander leaves, are pale cream to light yellow spheres, and measure less than 1 mm in diameter. One method of control is to remove and destroy foliage with eggs. You can also handpick the larvae from oleander plants but wear gloves and wash your hands afterwards.
This moth is an invasive imported from the Caribbean by Spanish settlers during the 17th century, probably carried to the mainland on ornamental oleander plants.
In its native range, it is believed to have fed on a relatively rare vine in the dogbane family also found in Florida.
Because it feeds on oleander, which is poisonous, this insect also contains poisonous compounds called glycosides. These are similar to the toxins found in milkweed and sequestered by monarch butterflies. Just as birds and small mammals avoid feeding on monarchs, they avoid the oleander caterpillar. Natural enemies include predatory stinkbugs, parasitic tachinid flies and wasps, and ants including the red imported fire ant.