Bill Dunson, born in rural Georgia, skipped 12th grade and went directly to Yale. Bill subsequent-ly received a PhD in Zoology from the University of Michigan, studying softshell turtles. Bill is Professor Emeritus of Pennsylvania State University thanks to a career spent entirely at that institution, teaching and doing research on the physio-logical ecology and ecotoxiciology of reptiles, amphibians and fish. Always curious about nature, Bill has dedicated his life to learning and sharing his knowledge with others. He has served on many advisory boards here in Southwest Florida to preserve the water that gives life to our region.

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click for a larger view: background polka-dot wasp moth inset top: spotted oleaner moth
inset bottom: spotted caterpillar

The Bizarre Oleander Wasp-Moths

If you travel or live in southern states or in California you will have noticed the exotic oleander plant (dogbane family) which is widely planted for its beautiful flowers and attractive foliage. It is used a lot due to its ability to grow in difficult sites, and general resistance to herbivores. You may not be aware that this is one of the most poisonous plants known and can be very dangerous to children. I have been tempted to remove them from my yard but have not done so because of the interesting moth caterpillars that feed on it. There are two moths in Florida, the much more common polka-dot wasp-moth, and the more southerly spotted oleander moth, shown in the attachments. The adult moths in these two photos are feeding on nectar from Mexican flame vine and Florida privet, respectively. These moths prove the rule that no matter how well defended a plant is by toxins, something will evolve to eat it.

The moths and their caterpillars are brightly colored, but in different ways, reflecting their protection by toxins obtained from their larval food. The fact that these moths, normally nocturnal in habits, fly so freely in the daytime also indicates the high degree of protection they obtain from their food. However a rather interesting aspect of their behavior and coloration is that they also resemble wasps (hence the name wasp-moths), providing a second, independent line of defense against predatory birds and lizards.

So watch for these beautiful and amazing wasp-moths around their larval food plant (oleander) and in the vicinity of nectar-bearing flowers, but do not eat them!

Bill Dunson
Englewood, FL & Galax, VA