"Waxy" backflip

These bugs use wax ‘tails’ to stabilize their ultrafast jumps

 

Ricania sp. nymph jumping with intact wax structures

These tiny jumping clouds are planthoppers (Fulgoromorpha). They are found in tropical environments around the world and when they are juveniles, they produce remarkable wax ‘tails’ – cottony tufts to filamentous jets extending from their rear. Many scientists have theorized what the wax is for, including defense from hungry predators, protection from the sun’s UV rays, or even a deterrent against parasites. But how these waxy structures affect the planthopper’s ultrafast jump remains unclear. Our study looks at how these wax structures affect the planthopper’s namesake — hopping.

Planthoppers rank among some of the fastest jumpers in the insect world – with some reaching nearly 6 m/s. We traveled to the Philippines and worked with local scientists to collect planthopper nymphs and record their ultrafast jumps under high-speed video. Our experiment looks at whether
the presence of wax aids in gliding and aerial righting during their hops.

Real time recording of Ricania sp. nymph hopping.

Planthopper nymphs from Asia, the U.S., South America, and Australia. Images A–F, H are unmodified and used under a Creative Commons Attribution License (CC BY or CC BY-NC)

 
 

Major questions

  1. How do wax tails influence body orientation during planthopper jumps?

  2. Do wax tails help planthoppers land successfully?

  3. What are the implications for evolutionary history for how features
    evolved for aerial righting led to powered flight?

 

What we’ve discovered

Wax Tails Enable Rotational Stability and Reduce Velocity

We recorded jumps using high-speed cameras with wax on and wax off. Wax-intact nymphs experienced significantly reduced body rotations during jumps compared to those with wax removed. Wax structures contribute to a greater reduction in velocity from takeoff to landing, helping nymphs achieve more controlled descents.

Planthopper Wax ‘Tails’ Help in Successful Landing

Nymphs with intact wax tails successfully land on their feet 98.5% of the time, whereas those without wax achieve only a 35.5% success rate – less than a 50-50 change. This is likely due to the reduced rotation rate, velocity at impact, and body orientation at impact.

Wax Structures May Contribute to Transitional Forms in Evolving Flight

Aerial righting strategies and jumping in wingless animals are considered precursors to powered flapping flight. How did organisms make the jump to winged insects when there are no clear transitional forms in the fossil records? We theorize that wax structures, which utilize strategies for jumps initiating aerial righting, may play a role in the evolutionary development of powered flight.

 

Read the paper

 

Wax “tails” enable planthopper nymphs to self-right midair and land on their feet. ICB (2024).

 

We thank Jaime Nina for permission to use his photograph of a planthopper nymph, used in the cover image and on this webpage.

Saad Bhamla