Tortoise Beetle
Tortoise beetles are small, rounded leaf-eating beetles whose wide, flat shells make them look like tiny tortoises or turtles. Some are so shiny they look like drops of gold or living jewelry.
Tortoise beetle Quick Facts
| Common name | Tortoise beetle |
| Type | Insect (leaf beetle subfamily) |
| Diet | Leaves of plants such as morning glory, sweet potato, thistle and palms |
| Habitat | Gardens, fields, meadows and forests |
| Native range | Worldwide, most species in the tropics |
| Size | Mostly 4-12 mm long |
| Special feature | Shield-like shell that hides the head and legs |
They belong to the subfamily Cassidinae in the leaf beetle family, Chrysomelidae. There are about 3,000 kinds of tortoise beetles, found around the world but most common in the tropics.
What Do Tortoise Beetles Look Like?
Most tortoise beetles are about 4 to 12 mm long. Their wing covers and the plate behind the head (the pronotum) spread out sideways and forward into a wide, flat rim. From above, this shield hides the head and legs completely, just like a tortoise hiding inside its shell.
The edges of the shield are often see-through, like a window. Many species are green, gold, orange, red or brown, and some have spots or patterns. A few tropical species are among the most colorful beetles in the world.
The larvae are flattened and spiny, with a fork-shaped tail that plays a very strange role in protecting them.
Where Do Tortoise Beetles Live?
Tortoise beetles live on plants in gardens, fields, meadows and forests across much of the world, from North and South America to Europe, Africa and Asia. Each species usually feeds on just one plant family. Many feed on morning glories and sweet potatoes, while others feed on thistles, mints, beets or palms.
What Do Tortoise Beetles Eat?
Both adults and larvae eat the leaves of their host plants. They chew small round holes in the middle of the leaves or nibble the edges. A few beetles do little harm, but large numbers can damage young plants.
Clever Defenses
When a predator such as an ant comes close, an adult tortoise beetle pulls in its legs and antennae and clamps its flat shell down tightly against the leaf. With no edges to grab, the predator usually gives up.
The larvae have an even stranger trick. As they feed, they collect their own droppings (frass) and old shed skins on the fork at the end of their body. They hold this pile over their back like an umbrella. This fecal shield helps keep away ants, spiders and other small predators, and some species even use chemicals from the plant they ate to make it taste worse.
Life Cycle
Tortoise beetles go through complete metamorphosis: egg, larva, pupa and adult. Females lay small eggs on the leaves or stems of the host plant, either one at a time or in groups. Some species cover each egg with a protective coating, and in a few tropical species the mother even guards her eggs and young.
The eggs hatch in about one to two weeks. The spiny larvae feed and molt several times, usually going through about five stages. Then they attach themselves to a leaf and turn into a pupa. In warm weather, the whole cycle from egg to adult may take only about a month. In cooler northern areas, there is often just one generation a year, and adults spend the winter hidden in leaf litter.
Types of Tortoise Beetles
Golden Tortoise Beetle
Golden Tortoise Beetle – Photo by: Ilona Loser.
The golden tortoise beetle (Charidotella sexpunctata) is a tiny beetle, about 5 to 7 mm long, that lives in North and Central America. It looks like a drop of shiny gold, which is why people sometimes call it a “goldbug.”
Amazingly, it can change color. When it is disturbed or stressed, it changes the amount of moisture in the layers of its shell, and within minutes it can turn from gleaming gold to a dull reddish-brown with dark spots. It feeds on morning glories, bindweed and sweet potato leaves.
Its larvae carry fecal shields to protect themselves, but they still have enemies, such as assassin bugs, stink bugs, ladybugs and tiny parasitic wasps and flies.
Green Tortoise Beetle
Green Tortoise Beetle – Photo by: Ton Rulkens.
The green tortoise beetle (Cassida viridis) lives in Europe and Asia. It is bright green, which helps it hide on the leaves of mint and related plants that it feeds on. Its larvae also carry shields made of droppings and old skins, holding them over their backs whenever they are disturbed.
Thirteen-spotted Tortoise Beetle
Thirteen Spotted Tortoise Beetle – Photo by: G. Bohne.
The thirteen-spotted tortoise beetle (Laccoptera tredecimpunctata) lives in warm parts of Asia. As its name suggests, its shell is marked with dark spots. It feeds on sweet potato and related plants, and its slow-moving larvae hold their old shed skins over their bodies for protection.
Palmetto Tortoise Beetle
Palmetto Tortoise Beetle – Photo by: Mary Keim.
The palmetto tortoise beetle (Hemisphaerota cyanea) lives in the southeastern United States, where it feeds on saw palmetto and other palm tree leaves. It is a dark, shiny blue-purple, almost round beetle.
It is famous for its incredible grip. Each of its feet is covered with thousands of tiny bristles. When an ant or other predator attacks, the beetle presses all of its bristles against the leaf and releases an oily fluid, sticking itself down so tightly that predators cannot pry it off.
Thistle Tortoise Beetle
Green Thistle Beetle – Photo by: Lairich Rig.
The thistle tortoise beetle (Cassida rubiginosa) is a green tortoise beetle from Europe and Asia, common in Britain. It feeds on thistles. It was accidentally brought to North America more than a hundred years ago, and it has also been released on purpose in places like Virginia and New Zealand to help control Canada thistle, a troublesome weed.
Tortoise Beetles as Pests
Most tortoise beetles do little harm, but a few species can damage crops like sweet potatoes and beets. Gardeners can usually manage them without chemicals:
- Hand-pick adults and larvae and drop them into a bucket of soapy water.
- Check the undersides of leaves for eggs and remove them.
- Remove nearby weeds such as bindweed and wild morning glories, where the beetles breed.
- Cover young plants with light garden fabric until they are strong.
- Encourage natural enemies like ladybugs, assassin bugs and birds by avoiding insecticides.
Healthy, older plants can usually lose a few leaves to tortoise beetles without any real harm.
Tortoise beetle FAQs
Are tortoise beetles harmful?
Tortoise beetles do not bite or sting and are harmless to people and pets. A few species chew holes in garden plants like sweet potatoes, but most cause little damage.
Why does the golden tortoise beetle change color?
When disturbed, it changes the moisture in the layers of its shell. This changes how light reflects, so it can switch from shiny gold to dull reddish-brown in minutes.
What is a fecal shield?
It is a pile of a larva’s own droppings and old shed skins, held over its back on a fork at the tail end. It helps protect the larva from ants and other small predators.
What do tortoise beetles eat?
Adults and larvae eat leaves. Each species usually feeds on one group of plants, such as morning glories and sweet potatoes, thistles, mints, beets or palms.
How do you get rid of tortoise beetles naturally?
Hand-pick beetles and larvae into soapy water, remove eggs from leaves, pull out nearby weeds like bindweed, and cover young plants with garden fabric.
Randi Jones is the owner and founder of the Nature Gift Store, an online retailer specializing in nature-themed gifts, educational science projects, live animal nature kits and real butterfly artwork. A biology graduate who fell in love with insects, she founded the company in 2001 to make active learning about nature fun, accessible and engaging for children and adults. Her store offers real butterfly frames, home and garden decor and educational live animal kits, including ant farms, worm farms, tadpoles, ladybugs and hermit crabs, and she runs a bug museum in Washington featuring live animals like Eddie the Iguana alongside other reptiles and insects.
