This is a moth larva/caterpillar.

We can tell by the plant it is eating.

Every caterpillar becomes either a butterfly or a moth. It can be difficult to tell what they will become if you aren't someone who studies this stuff (a lepidopterist for example). The most precise way to discover whether a caterpillar will become a butterfly or a moth involves some detective work.

The two most significant clues

The two biggest clues are 1. location and 2. host plant.

Location is important because butterflies and moths have ranges where they live. If you secure the location, you eliminate everything that doesn't live within that region.

It helps to know plants because caterpillars and plants are inseparable. Each type of butterfly caterpillar is fairly picky and can only eat a certain type of plant. Most types of moth caterpillars are far more indiscriminate and can eat any number of plants. All of that to say, if you can identify the plant that your caterpillar is eating, you have a much better chance of identifying it.

Detective Work to Tell the Difference

In the preceding photo, the caterpillar is eating my Desert Rose, but it is commonly called the "oleander caterpillar" (Syntomeida epilais) and will eat many other plants in South Florida too. It is often found on oleanders (duh). It resembles the caterpillars of the Gulf Fritillary (Agraulis vanillae) butterfly, so many people confuse the two. One difference is that the moth caterpillar has bristles instead of singular spines down its back. Both caterpillars (the Gulf Fritillary and the Oleander Moth) are orange with black (painful looking) pokey parts so it can be confusing. Oddly, neither can sting.

Here is a photo of a Gulf Fritillary caterpillar for comparison.

Since both caterpillars are orange and spiny, and difficult for novices to tell apart, they are best identified by knowing the plant they are feeding on. Butterflies will only eat the leaves of one genus or species of plant, in most cases. Moths, however, are typically able to eat all sorts of plants (which is how caterpillars get a bad reputation). Since I know that Gulf Fritillaries don't eat Desert Roses, I know that the caterpillar eating it is not a juvenile Gulf Fritillary.

What's the Difference Between Butterfly and Moth?

Scientifically speaking, there is no true difference between butterflies and moths. Basically, butterflies are day flying moths. They are both in the order Lepidoptera (scaly winged insects). All caterpillars are always juveniles and they grow up to be either butterflies or moths (not beetles or mosquitoes or ants). Both serve the same ecological purposes: they are the bottom of the food chain, they pollinate, they can indicate a healthy eco-system.

There are some general differences between butterflies and moths, but none that hold true across the board. Typically moths have larvae that can eat many different plants, are nocturnal, have thicker bodies and more "hair" scales (this is because they fly at night when it's cold), have feathery antennae and rest with their wings open rather than folded above their thorax. Yet, there are ALWAYS exceptions. Since moths fly at night, their wings aren't usually as colorful as butterflies'. Since moths are nocturnal, they often drink nectar from white flowers which are fragrant and easier to see in the dark.

Can Moths or Butterflies Sting?

In their adult (winged) stage, they are harmless. But SOME caterpillars, mostly moth ones, can sting.

Can Caterpillars Hurt?

Most butterfly caterpillars don't sting. Some moth caterpillars do sting. Of course, this is not useful information if you aren't sure which type it is.

As a general rule, be careful if you find a spiny caterpillar. These can be dangerous.

Some have venomous spikes or hairs and can sting. They can't kill a human, but they may be painful.

Some caterpillars look like they can sting, but they can't. They are tricky.

If you aren't completely sure what species it is, you should not handle it. Recall that the plant it is eating (if you are lucky enough to find it doing so) is a strong clue to help you identify what kind it is because certain kinds eat certain plants. It helps to know about plants if you want to study butterflies.

If you find a caterpillar on a sidewalk or a fence, you will have a harder time identifying it. You can look around you, within about twenty feet or so and if there are plants being eaten it could be a clue, but this isn't always easy to do. Most caterpillars don't wander too far away from the plant they were eating, but if a predator or something else relocated them, you wouldn't know.

That Oleander Caterpillar grows up to be a polka-dot wasp moth (it's actually a moth but looks like a wasp). They are beautiful and harmless. One is pictured below.

The Most Famous American "Moth" Is a Butterfly

Another commonly misidentified species in Florida and beyond is the Cabbage White Butterfly (Pieris rapae). People often call it the "cabbage moth" but it's actually a day-flying butterfly. This species isn't usually in south Florida but it is very common in most of the rest of the continental U.S.

People are familiar with the Cabbage White because it eats cruciferous vegetables like kale and other garden plants that humans grow for food. Generally people don't like it and so they assume it's a moth. This is a bad assumption. There may be dozens of green caterpillars on your cabbage and if so, this lovely white butterfly is probably the culprit.

Identifying the plants that a caterpillar is eating will go a long way in butterfly or moth identification.

A Common Stinging Caterpillar

The Io moth (Automeris io) can also be found in Florida and across the central and eastern US. They can feed on many plants including willow, hackberry, redbud, currant, blackberry, pear, mesquite and more.

Once they are adults, Io moths are harmless. I raised the female below from the time she was a stinging little caterpillar (but I only touched her once she emerged with wings). Males have different coloration than females of this species.

There are many more moths on earth than there are butterflies. Therefore, most caterpillars on earth will become moths. With over a hundred thousand species, there are many options. Learning the plants in your area is the best place to start.

Have A Fluttery Day,

Jessica Morgan McAtee