“…and today we’re talking about a bug that sounds like a power tool… but more on that later.”
Early on a Saturday morning is no time to start hearing machinery going in the neighborhood… but what if you hear that same sound in Australia’s open heath habitats and woodlands? Did someone put gravel in their didgeridoo? No, that’s the song of the sandgrinder cicada… and to other cicadas it’s the sweet music of Life, Death, and Taxonomy.
Description of the Sandgrinder Cicada
- Looks like someone crossed a housefly, a grasshopper, and a tiny military helicopter.
- Medium-sized cicada with a chunky body and broad head.
- Usually mottled brown, tan, gray, and black, helping it disappear against sandy ground.
- Covered in a hard, glossy exoskeleton rather than fur or scales.
- Transparent wings with delicate lace-like veins that fold neatly over the back.
- Large bulging eyes sit on either side of the head like built-in surveillance cameras.
- Short bristly hairs cover parts of the body, giving it a slightly dusty appearance.
- Strong digging legs help it emerge from sandy soils after spending years underground.
- Compared to many tropical cicadas, it’s fairly modest in size, but it makes up for that with attitude.
Measure Up
Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com.
Body Length
Adult sandgrinders are about 33 mm (1.3 inches) long.
The Australian 20-cent coin features a platypus. The coin is one of the largest circulating coins in Australia and is famous for being accidentally mistaken for foreign currency in vending machines.
True or False — 1.2 sandgrinder cicadas go into the diameter of an Australian 20-cent coin.
Answer:
True.
The coin is 28.65 mm across. A 33 mm sandgrinder is about 1.15 times the coin’s diameter.
Wingspan
A sandgrinder’s wingspan is about 90 mm (3.5 inches).
The legendary Australian snack known as a Tim Tam was created in 1964. Australians have developed the “Tim Tam Slam,” in which the cookie is used as a straw before rapidly disintegrating.
True or False — Three sandgrinder cicada wingspans laid end-to-end are longer than a standard Tim Tam.
Answer:
False.
A Tim Tam is roughly 6 cm (60 mm) long. Three wingspans would be about 270 mm (10.6 inches).
Fast Facts about the Sandgrinder Cicada
- Range: Found in coastal dune systems and sandy regions of southern Australia, particularly around South Australia and Western Australia.
- Habitat: Prefers loose sandy soils, dunes, and scrublands where its underground nymphs can easily burrow among plant roots.
- Diet: Like other cicadas, adults sip plant fluids using a straw-like mouthpart, while nymphs spend years feeding on root sap underground.
- Lifespan: Like other cicadas, most of its life is spent underground as a nymph, often for several years, while the adult stage may last only a few weeks.
- Social Behavior: They’re generally solitary, but large numbers can emerge during favorable conditions, turning a quiet dune into anarchy.
- Predators: Birds, reptiles, spiders, and small mammals all enjoy cicadas.
- Defense Strategy: Their camouflage blends remarkably well with sand and dry vegetation, helping them avoid becoming somebody else’s lunch.
- Weird Fact: After molting, the empty exoskeleton remains clinging to plants and sticks.
- Even Weirder Fact: Their underground tunneling helps aerate sandy soils, making them accidental landscapers that never send an invoice.
Major Fact: Grinds My Gears
While many cicadas produce rhythmic songs with distinct phrases, the sandgrinder’s song is often described as a continuous, harsh, grinding buzz that can seem almost mechanical.
How does it make the sound?
Like other cicadas, the male uses a pair of structures called tymbals located on the sides of his abdomen. Each tymbal is a ribbed membrane that acts a bit like the lid of a metal can.
When specialized muscles contract:
- The tymbal buckles inward with a click.
- It snaps back into shape when the muscles relax.
- This happens hundreds of times per second.
- The clicks merge into a continuous buzz.
The abdomen itself acts as a resonating chamber, amplifying the sound much like the body of a guitar amplifies vibrating strings.
How loud is it?
Precise measurements for Arenopsaltria fullo are scarce, but Australian cicadas are among the loudest insects in the world. Some species exceed 100 decibels at close range—comparable to:
- A motorcycle
- A chainsaw
- A loud sporting event
The sandgrinder isn’t generally cited as Australia’s absolute loudest cicada, but its continuous nature makes it especially noticeable. A less-loud but unbroken drone can feel more overwhelming than a louder sound that comes in short bursts.
Why make so much noise?
The loud song serves several purposes:
Attracting females
A female listens for males and may move toward the most attractive caller. A louder, more persistent call can advertise a healthy male.
Competing with rivals
In areas with many calling males, volume helps an individual stand out from the chorus.
Predator dilution
One insect calling loudly would be easy to locate. Hundreds calling at once create a wall of sound that can make it difficult for predators to pinpoint any single cicada.
A strange consequence
The louder a cicada calls, the harder it can be to locate. Humans use differences in sound arriving at each ear to determine direction. When a loud, high-frequency cicada call reflects off trees, shrubs, and the ground, the sound can seem to come from everywhere at once.
That’s why people often spend several minutes staring into a tree looking for a sandgrinder that’s only a few feet away.
Ending
So aerate your local patch of sand, sip some delicious plant fluids, and drum it out on the dunes like the sandgrinder cicada here in LDT.