Locusts, cicadas, and crickets each produce sounds that are distinct enough to tell apart once you know what to listen for, but similar enough that people routinely mix them up. Locusts make a dry, crackling or buzzing rasp; cicadas produce a loud, continuous, almost electric drone or whine; and crickets deliver a rhythmic, musical chirp with a surprisingly pure tone. These differences arise because each insect uses a completely different body part and mechanism to generate sound, and understanding those mechanisms makes it easy to identify who is singing on a summer evening.
How Locusts Make Sound
Locusts are grasshoppers that can form swarming phases, and like their non-swarming relatives, they produce sound primarily by rubbing their hind legs against their forewings. This process is called stridulation. A row of tiny pegs on the inner surface of the hind femur scrapes across a thickened vein on the wing, and the result is a short, scratchy rasp or buzz. It sounds a bit like running your fingernail across the teeth of a comb, fast and rough with no clear musical pitch. Some species also produce sound in flight by crepitation, snapping their hindwings open in a way that creates audible clicks or crackling noises.
The character of locust sound varies by species and context. Grasshoppers and locusts communicate with species-specific and situation-specific songs used to attract mates, signal reproductive readiness, or fend off rivals, with the selection and timing of these signals coordinated by a brain region called the central complex.1Europe PMC / Frontiers in Neuroscience. Reproduction-related sound production of grasshoppers regulated by internal state and actual sensory environment In practical terms, this means a locust in courtship mode may produce a more structured, rhythmic series of rasps, while a disturbed locust may crackle its wings in a brief, erratic burst. Either way, the overall quality stays dry and percussive rather than tonal or melodic.
How Cicadas Make Sound
Cicadas use a mechanism entirely different from leg-on-wing scraping. Males have a pair of ribbed, hardened membranes called tymbals on the sides of their first abdominal segment. Large muscles attached to these membranes contract and relax rapidly, causing the ribs to snap inward one after another from back to front. Each snap produces a click, and the rapid succession of clicks generates a broadband acoustic signal that the cicada’s body then shapes and amplifies.2PubMed Central. The tymbal of a cicada: nature’s sound-generating metastructure The abdomen itself is largely hollow, acting like a resonating chamber that boosts the volume.
The result is one of the loudest sounds in the insect world. Individual cicadas of some species can exceed 100 decibels at close range, which is comparable to a power tool or a motorcycle. What most people notice, though, is not a single cicada but the collective effect. When hundreds or thousands of males sing together, they produce a wall of sound that can dominate an entire landscape. These mass choruses are not random; studies have shown that cicada choruses self-organize, with the volume fluctuations of the group responding to local conditions like ambient light levels. Brighter illumination was associated with faster, larger, and more spatially synchronous fluctuations in chorus volume.3PubMed Central. Self‐organizing cicada choruses respond to the local sound and light environment That pulsing, rising-and-falling drone that fills summer afternoons in many parts of the world is the acoustic signature of this self-organizing behavior.
To human ears, a cicada chorus sounds mechanical or electronic. People often compare it to a power line buzzing, a table saw running in the distance, or a science-fiction sound effect. The pitch varies by species, with some producing a high, shrill whine and others a lower, pulsating drone, but the quality is always sustained and continuous rather than rhythmic and interrupted.
How Crickets Make Sound
Crickets also stridulate, but their method is fundamentally different from a locust’s. Instead of leg against wing, a cricket rubs one forewing across the other. The underside of the right wing typically has a hardened scraper, and the top of the left wing has a row of teeth called the stridulatory file. As the wings close, the scraper catches on successive teeth, and the vibration that results is transmitted across the wing surface.
What makes cricket song special is its purity. Research on field crickets has demonstrated that during stridulation, both wings resonate together at a single identical frequency, with the left wing dominating the amplitude. The stridulatory file acts as a constant resonator, showing no variation in its natural frequency along its length during sound production. The two wings function as coupled oscillators that together control the mechanical vibrations, producing a remarkably pure, species-specific tone.4The Company of Biologists (Journal of Experimental Biology). Sound radiation and wing mechanics in stridulating field crickets (Orthoptera: Gryllidae) This is why a cricket’s chirp sounds so clean and musical compared to a locust’s rasp. A cricket produces something closer to a single sustained note than a band of noise.
Cricket song also has a characteristic temporal pattern: the familiar “chirp-chirp-chirp” with regular pauses between each pulse. The speed of this chirping changes with conditions. Temperature has a positive correlation with pulse rate and a negative correlation with the interval between chirps, meaning crickets chirp faster when it is warmer and slower when it cools down.5Canadian Journal of Zoology. Natural variation in the temporal patterning of calling song structure in the field cricket Gryllus pennsylvanicus: effects of temperature, age, mass, time of day, and nearest neighbour This relationship is regular enough that counting cricket chirps has long been used as a rough thermometer, and while the folk versions of that formula are imprecise, the underlying correlation is real and well documented.
A Side-by-Side Comparison
Putting the three side by side clarifies how different they really are, even though all three fall under the umbrella of “bug noises” in casual conversation:
- Locusts: Short, dry, scratchy rasps or buzzes produced by leg-on-wing friction, sometimes punctuated by wing-snap crackles in flight. Low to moderate volume. Rhythmic but not musical.
- Cicadas: Loud, sustained, buzzing or whining drones produced by vibrating tymbal membranes on the abdomen. Easily the loudest of the three. Continuous and often pulsating rather than broken into discrete chirps.
- Crickets: Clean, tonal chirps produced by wing-on-wing friction. Moderate volume. Delivered in a regular, rhythmic cadence with clear pauses between each chirp or trill.
The confusion between these insects is partly cultural. In American English, “locust” is commonly used to refer to periodical cicadas, the species that emerge in massive broods every 13 or 17 years. This usage dates back centuries and has nothing to do with actual locusts, which are swarming grasshoppers. So when someone says “the locusts are deafening this summer,” they almost always mean cicadas. True locusts are relatively quiet individually and are far more famous for their eating habits than their singing.
Why Each Sound Exists
All three groups produce sound primarily for mating, but the details differ. Male crickets sing to attract females from a distance, and females approach silently, using ears on their front legs to locate the caller. The purity of the cricket’s tone is not an accident; a clean signal at a single frequency is easier for a female to locate in a cluttered acoustic environment. Male cicadas chorus together for the same basic reason, though the extreme volume likely serves a dual purpose: attracting females from farther away and potentially deterring some predators. Locusts use their songs for mate attraction as well, but also to coordinate behavior during close-range courtship and to assert dominance over nearby rivals.
The seasonal and daily timing of these sounds also differs. Crickets are overwhelmingly nocturnal singers, filling the evening and nighttime hours with their chirps. Cicadas are daytime callers, peaking during the hottest hours of the afternoon. Locusts are less predictable, calling during the day when conditions are warm enough to be active. So in many parts of the world, there is an acoustic handoff: cicadas dominate the afternoon, and crickets take the night shift.
Where Their Ears Are
One of the stranger details of insect acoustics is that these animals hear with body parts that no vertebrate would recognize as ears. Unlike mammals, whose ears are always on the head, insect tympanal organs show up in different places depending on the species.6Annual Reviews. Tympanal hearing in insects Crickets and katydids have their ears on their front tibiae, the equivalent of hearing with your shins. Locusts and grasshoppers have their tympanal organs on the sides of the first abdominal segment, roughly at the waist. Cicadas also hear through abdominal structures, though their hearing is tuned to the frequencies of their own species’ calls.
This diversity of ear placement reflects the fact that insect hearing evolved independently many times. These organs arose from ancestral proprioceptive structures, essentially internal stretch sensors, that were gradually repurposed to detect airborne vibrations. The result is that each group’s hearing system is optimized for its own acoustic world rather than for sound perception in general.
The Evolutionary Roots of Insect Song
The differences in how these three groups produce sound are not just mechanical curiosities; they reflect deep evolutionary history. Crickets belong to the suborder Ensifera, which also includes katydids and their relatives. Phylogenomic analysis has found that wing-on-wing stridulation likely evolved in the common ancestor of all living Ensifera lineages, making it an ancient innovation. A few families subsequently lost this ability, but usually because they lost their wings entirely, not because they abandoned acoustic communication. In families that did lose wing stridulation while retaining other limbs, alternative methods evolved, like rubbing the abdomen against the legs to produce defensive sounds.7Nature Communications. Phylogenomic analysis sheds light on the evolutionary pathways towards acoustic communication in Orthoptera
Locusts and grasshoppers belong to the suborder Caelifera, where the story is more scattered. Stridulatory structures evolved at least ten times across the group, involving many different body parts. However, the ability of most of these structures to actually produce functional sound for communication remains unconfirmed for many species. Definitive sound-producing organs used for mating evolved at least three times in Caelifera, each using a different mechanism, from abdominal rubbing to specialized leg-and-wing systems.7Nature Communications. Phylogenomic analysis sheds light on the evolutionary pathways towards acoustic communication in Orthoptera The hearing organs in this group also arose independently multiple times, with abdominal tympana evolving on at least three separate occasions.
Cicadas sit in an entirely different branch of the insect tree. They belong to the order Hemiptera, not Orthoptera, which means they are more closely related to aphids and leafhoppers than to crickets or grasshoppers. Their tymbal system evolved independently of any orthopteran stridulation. This is a case of convergent evolution at a broad level: unrelated lineages arrived at the strategy of using sound for mating, but each invented its own hardware to do it.
How the Physical Environment Shapes What You Hear
The sounds you hear from these insects on any given evening are filtered through the environment before they reach you. Vegetation, structures, temperature, and even the height at which an insect is calling all affect how well sound propagates. Research in orthopteran acoustics has shown that physical structures like walls and floors in vegetated fields can either enhance or hinder sound transmission depending on the species’ acoustic traits. Ground-level crickets in the subfamily Nemobiinae had their song detection improved by nearby structures, likely because hard surfaces reflected their sound. But katydids in the subfamily Conocephalinae showed reduced detection near the same structures, possibly because their higher-frequency songs were scattered or absorbed differently.8Ecological Entomology. Of walls and floors: how physical structures affect mating song detection in stridulating orthopterans
Temperature is a recurring theme across all three groups. Warmer air tends to enhance both the production and the transmission of insect sounds. Crickets chirp faster and more continuously. Cicada choruses intensify during the warmest parts of the day. Locusts are more vocally active when the air is warm enough to support sustained flight and leg movement. Even the detection of insect songs by microphones in field studies improves in warmer conditions and at elevated listening positions, which mirrors the experience of anyone who has noticed that insect sounds seem louder and more pervasive on hot summer nights compared to cool ones.8Ecological Entomology. Of walls and floors: how physical structures affect mating song detection in stridulating orthopterans
Katydids and Other Sources of Confusion
Beyond the locust-cicada-cricket trio, katydids are another frequent source of acoustic confusion. Katydids are close relatives of crickets and produce sound by the same wing-on-wing mechanism, but their songs tend to be higher-pitched, more buzzy, and less cleanly tonal than a cricket’s chirp. Some katydid species produce sounds in the ultrasonic range, well above what humans can hear, while others make a rapid, raspy shuffling noise that could easily be mistaken for a small locust. Unlike crickets, many katydids sing from elevated positions in shrubs and trees, which gives their sound a different spatial quality and makes it carry differently through the landscape.
The key distinction for the listener is rhythmic structure. Crickets produce regular, evenly spaced chirps. Katydids produce irregular, buzzy phrases that are less predictable. Cicadas produce continuous drones. And locusts produce brief, scratchy rasps or clicks. Once you learn to attend to the rhythm and tonal quality rather than just the volume or location, sorting them out becomes surprisingly intuitive.
Insect Acoustics as Engineering Inspiration
The miniaturized sound systems of insects have attracted serious interest from engineers, particularly in the field of microelectromechanical systems. One well-known example involves a parasitic fly called Ormia ochracea, which hunts crickets by homing in on their calls with extraordinary directional accuracy despite having ears separated by less than two millimeters. The mechanical coupling between its two tympanal membranes allows it to detect the direction of incoming sound with a precision that should be physically impossible at that scale. This mechanism has inspired the design of microscale directional microphones that could drastically reduce the need for signal post-processing.9Current Opinion in Insect Science. Insect-inspired acoustic micro-sensors
More broadly, the acoustic strategies of insects from locusts to moths to crickets and mosquitoes have all been reviewed as potential templates for solving small-scale engineering challenges in acoustic detection.10PubMed. Review of the applications of principles of insect hearing to microscale acoustic engineering challenges The cricket’s ability to produce a pure tone from a structure the size of a fingernail, the cicada’s trick of amplifying a tymbal click into a deafening drone using its hollow body, and the locust’s capacity to detect flight sounds in a swarm all represent elegant solutions to physics problems that engineers working on hearing aids, drones, and surveillance equipment are still trying to replicate at comparable scales.