Discover what makes these curious-looking treehoppers stand out.

The Brazilian treehopper (Bocydium globulare) is a small, curious-looking insect from the family Membracidae that inhabits many tropical rainforests in South America. Related to cicadas and leafhoppers, the nearly 3,300 Membracidae treehopper species have evolved distinctive forms of mimicry to support their survival, including faux thorns, helmets, wings, and leaf-like shapes.

But even among its thousands of showy relations, the Brazilian treehopper stands out because of the curious cluster of balls it wears around its head. Why such an ornate display? Find out this and other fascinating facts about this bizarre and wonderful creature. 

1. Brazilian Treehoppers Wear a “Helmet” of Tiny Hairy Balls

Check out any image of a Brazilian treehopper and you'll enjoy the kaleidoscope of color, shapes, and among the most outlandish insect appendages you’ve ever seen. The most distinctive feature of treehoppers is the pronotum, a plate-like structure in many insects that typically covers the thorax.

On treehoppers, however, the pronotum grows up and out in endless variations depending on the species. The Brazilian treehopper is no exception. Its pronotum is impressively ornamented with tiny balls and bristly hairs that extend in a circle around its head like helicopter propellers.

2. Wing Genes May Be Responsible for Their Helmets

Scientists long pondered why the Brazilian treehopper has this remarkable globular helmet. It wasn't likely to be ornamentation that males used to attract a mate, because both males and females have it.

One hypothesis states that it could be a decoy for predators. In 2011, a study even proposed that it could even be an extra set of wings.1 Other researchers refuted this last hypothesis, although wing genes may be responsible for Brazilian treehopper helmets.

In 2019, a research team asserted that treehopper helmets were not wings but simply outgrowths of the insect’s thorax. However, they found that helmet growth depended on wing genes: For some reason, the pronotum was turning on certain genes otherwise used for growing wings.2 The precise process by which that happens remains a mystery, however, as does the reason for the helmet. 

3. ...Or, The Helmets Might Mimic a Fungus to Ward Off Predators

Another hypothesis for why the Brazilian treehopper has such unique ornamentation is that it might be intended to mimic a parasitic fungus.

This deadly fungus infiltrates the bodies of ants and then pushes out of them in shapes that resemble the Brazilian treehopper’s globular helmet. Mimicking that shape might provide protection to the treehopper since predators want nothing to do with a killer fungus.

4. Brazilian Treehoppers Are Only About the Size of a Pea

Microphotography has made it possible to see an extraordinary degree of detail on these tiny creatures. These photos can make treehoppers seem like miniature monsters. Encountering a Brazilian treehopper in real life is a bit less exciting. They are only about 5 or 6 millimeters long, so you might need a magnifying glass to clearly see the details of its extraordinary pronotum.

5. They Are Sapsuckers

Treehoppers suck sap out of plants and trees similar, in some respects, to the way mosquitos suck blood. Treehoppers have a mouthpiece with two sharp straw-like tubes: one that punctures a plant stem or leaf to inject saliva, and the other to suck out the plant’s phloem (sap). Brazilian treehoppers are frequently found under glory bush leaves. 

6. They Feed Other Insects While Feeding Themselves.

Treehoppers can feed on a single plant repeatedly because their saliva keeps the plant from closing up the puncture site. Once they find a suitable plant, they often stay put for several weeks, excreting a sugar-rich substance known as honeydew as they feed. This, in turn, feeds ants and other insects, which often reciprocate by protecting treehoppers against predators in order to defend their food source.

7. Female Brazilian Treehoppers Sit on Their Eggs

Female treehoppers are fiercely protective of their offspring. They lay their eggs in the stem of their food source. Then, unlike many other insects, they sit on their eggs to shield them from predators. They also create little punctures in the plant stem so that the hatched nymphs have ready access to food. 

8. They Communicate Through Subtle Vibrations

These humming sounds don’t travel through the air but through plants. Researchers have been able to record the vibrations of some treehopper species using a variety of highly sensitive equipment. They believe that treehoppers use these vibrations to alert each other to predators, attract mates, and signal a good place to feed.

University of Missouri biologist Rex Cocroft, who has studied treehoppers for decades, captured some species’ courtship calls and those of nymphs and believes treehopper communication to be more complex than is currently understood by science.

9. An Insect Sculptor Created a Remarkable Brazilian Treehopper Model

For 25 years between 1930 and his death in 1955, the sculptor Alfred Keller worked at the Berlin Museum of Natural History building incredible scientific models of insects and their larvae. One of his most remarkable creations is a 3-D model of B. globulare magnified to 100 times its actual size. The model was highlighted in the journal Nature.3

Looking at Keller’s exquisitely detailed model, it’s uncanny to see how similar the Brazilian treehopper is (sans helmet, of course) to the cicada, even if it is considerably smaller.