Most grasshoppers are some shade of green or brown, and for good reason: their survival depends on blending into the vegetation or soil where they live. But grasshopper color is far more varied and dynamic than a simple green-or-brown split suggests. Depending on the species, the habitat, and even the individual’s life stage, grasshoppers can be yellow, black, red, pied, or strikingly blue. The mechanisms behind these colors range from diet-dependent pigments to light-scattering nanostructures, and the evolutionary pressures shaping them include predation, temperature, fire, altitude, and sex.
How Green Happens at the Molecular Level
Green is not produced by a single pigment. In grasshoppers and their relatives, green body color results from a combination of two very different pigments layered together: a blue-green pigment called biliverdin (or its close relative mesobiliverdin) and yellow carotenoids, likely beta-carotene or a similar compound. The blue and yellow together read as green to the eye, much the way mixing paint works.
Research on the grasshopper Paulinia acuminata confirmed that green morphs carry both mesobiliverdin and a yellow carotenoid, and that the insects appear to need a diet of green plant material to synthesize the biliverdin component. Without it, the green color does not develop properly.
Recent gene-expression work on the club-legged grasshopper Gomphocerus sibiricus has added detail to this picture. In green individuals, a gene coding for beta-carotene-binding protein is expressed at higher levels than in brown individuals. The hypothesis is that this protein grabs carotenoids from the diet, transports them into the body tissues, and creates the yellow layer that, combined with biliverdin, produces green. Brown morphs, which express less of this protein, end up without enough yellow pigment to overlay the blue, and their default cuticle pigments (browns, tans) dominate instead.
Brown, Pied, and Everything in Between
Green gets the attention, but brown is just as common, and in many populations more so. Surveys of the alpine grasshopper G. sibiricus across 42 sites found that green and brown morphs co-occurred at virtually every site, with the proportion of green individuals ranging from zero to about 70 percent depending on location. A third category, “pied” individuals with mottled or patchy coloration, appeared at every site too, making up anywhere from 3 to 75 percent of the local population.
These ratios are not random. The proportion of green grasshoppers tended to rise in drier areas with lower summer and winter precipitation, while pied morphs showed a geographic cline, increasing in frequency from east to west and becoming less common at higher altitudes and cooler temperatures. Pied morphs were also more frequent on grazed sites, where patchy vegetation and bare soil create a mosaic background that a mottled body matches well.
When Color Develops and Whether It Can Change
Grasshoppers do not hatch fully colored. A study tracking two green-brown polymorphic species from hatching through adulthood found that color morph differences begin to appear during the second nymphal stage, become clearly defined by the third stage, and then remain stable for the rest of the individual’s life.
That stability, though, applies to the basic morph (green vs. brown). Brightness and shade are a different story. A color-changing grasshopper species studied in the lab adjusted its body brightness over several weeks to better match whatever substrate it was sitting on, and individuals exposed to simulated predation risk (being disturbed repeatedly by hand) shifted their brightness even further toward the background color. The degree of camouflage, in other words, appears to be under the animal’s active control, tuned upward when the threat level is higher.
Separate from this behavioral plasticity, temperature during development influences how light or dark an individual ends up. In the Senegalese grasshopper Oedaleus senegalensis, rearing at a low temperature (25°C) produced dark, near-black individuals, while a high temperature (40°C) produced pale, nearly white ones, and an intermediate temperature gave a grayish brown. A similar pattern appeared in the meadow grasshopper Conocephalus maculatus, where higher rearing temperatures produced lighter, paler individuals overall. Temperature seems to tune the intensity of coloration rather than switching which morph an individual becomes.
Black Grasshoppers and Fire
One of the most dramatic color variants is the melanistic, or all-black, form. Pygmy grasshoppers (Tetrix subulata) offer a striking case. In areas that had burned the previous year, roughly half of all pygmy grasshoppers were black, compared with far lower frequencies in unburned habitats nearby. Over the following years, as vegetation regrew and the charred ground was covered, the frequency of black individuals dropped from about 50 percent one year after a fire to around 30 percent by year four. Genetic analysis confirmed that these shifts were evolutionary, not just individuals changing color: the populations were actually evolving in response to fire-altered landscapes.
The selective advantage is camouflage. When researchers used human “predators” searching for grasshoppers against photographic backgrounds with varying amounts of charred ground, survival time for black grasshoppers climbed steadily as the proportion of black substrate increased. On heavily burned backgrounds, black grasshoppers were detected much more slowly and missed entirely more often. On green, unburned backgrounds, green and brown morphs had the advantage. The result is a geographic mosaic of selection: fire creates patches where dark morphs thrive, and succession erodes that advantage over a few years as vegetation returns.
Darker at Higher Altitudes
Fire is not the only reason to be dark. High-altitude grasshoppers tend to be darker than their lowland counterparts, a pattern that has been documented across multiple species and fits with what ecologists call the thermal melanism hypothesis. The idea is straightforward: darker bodies absorb solar radiation faster, which helps cold-blooded animals warm up in cool environments where basking time is limited.
Laboratory tests on the wingless grasshopper Phaulacridium vittatum confirmed the physics. Darker unstriped morphs warmed more rapidly and reached a higher equilibrium temperature than lighter ones, with body darkness significantly predicting how quickly individuals heated up. Field data from the same species showed that grasshoppers were darker at higher altitudes, even though body size did not change with elevation. In the meadow grasshopper Pseudochorthippus parallelus, brown morphs increased at higher altitudes relative to green morphs, and researchers suspect the thermal advantage of darker coloration explains the sharp transition.
The trade-off, though, is real. At lower, warmer elevations, being too dark could mean overheating. The result is an altitudinal cline: darker morphs dominate the mountaintops, and greener or lighter morphs are more common in the valleys.
The Cost of Being Pale
The link between melanin and temperature has a hidden twist involving the immune system. The enzyme phenoloxidase drives both the production of melanin in the cuticle and a key part of the insect innate immune response, the ability to encapsulate and kill fungal invaders. When grasshoppers (Melanoplus sanguinipes) were reared at higher temperatures, they became paler, had lower phenoloxidase activity, and were more vulnerable to infection by the fungus Beauveria bassiana compared with grasshoppers reared in cooler conditions.
This means color is not just about camouflage or temperature. A grasshopper that reduces its melanin to avoid overheating in a warm habitat may simultaneously be weakening its defenses against pathogens. The evolutionary “decision” about how dark to be involves balancing at least three pressures: predation risk, thermoregulation, and disease resistance. That complexity helps explain why color polymorphism persists in so many grasshopper populations rather than a single “best” color winning out.
The Rare Blue Grasshopper
Blue grasshoppers are among the rarest and most visually striking variants. The best-studied example is the chameleon grasshopper of the Australian Alps, Kosciuscola tristis, which can shift between blue and black depending on temperature. The blue color is not produced by a pigment at all. Instead, it arises from Tyndall scattering, a physical phenomenon in which tiny granules suspended beneath the cuticle scatter short-wavelength (blue) light. These granules, made largely of uric acid and a pteridine compound, are white when isolated. Seen against the dark background of deeper pigment layers, the scattered light reads as vivid blue.
When the grasshopper cools down, black pigment granules migrate toward the surface, mingling with the scattering particles and quenching the blue. The animal turns dark, which helps it absorb heat. As it warms, the black granules retreat and the blue reappears. This rapid, reversible color change is unusual among grasshoppers and is driven by physical rearrangement of granules rather than by production or destruction of pigment.
Warning Colors and the Shift to Camouflage
Not all grasshopper coloration is about hiding. Some species advertise their presence with bright, high-contrast patterns, a strategy called aposematism. The South American grasshopper Chromacris psittacus illustrates an unusual ontogenetic shift between two color strategies. As nymphs, these grasshoppers are black and red, a classic warning color combination that signals chemical defenses and stands out against green foliage. The nymphs also cluster together in groups, reinforcing the warning signal.
As they mature into adults, the same individuals become green and yellow, blending into their surroundings. The adults are less gregarious and rely on camouflage and evasive flash coloration rather than bold warning patterns. Both the nymphal and adult color strategies appear to work with chemical defense, but the mode of protection flips from “look at me, I’m toxic” to “you can’t see me.”
Males and Females in Different Colors
In a number of grasshopper species, males and females are not the same color. This sexual dichromatism is common in the genus Sphenarium, where it appears linked to the environmental conditions each species inhabits. Males and females differ in chromatic properties, and these differences correlate with local precipitation levels, suggesting that the sexes have diverged in how they respond to their visual environment.
Field studies of two neotropical grasshopper species found that males tend to be more disruptive in their color pattern, meaning their coloration breaks up the body outline, while females show higher background matching with fewer disruptive elements. The explanation may lie in behavioral differences: males are generally more mobile, moving around to find mates, and a disruptive pattern works better for an animal in motion across varied micro-habitats. Females, which tend to stay in one place longer, benefit more from closely matching the local background. Different selective pressures on the two sexes, including predation risk that varies with mobility, may drive the color divergence.
City Grasshoppers Matching Urban Pavement
One of the more surprising recent findings involves grasshoppers living in cities. Researchers studying grasshoppers on different types of urban pavement found that individuals approximately matched the color of their local substrate, whether that was light concrete or dark asphalt. The mechanism, though, was not what most people would guess. It was not natural selection picking off poorly matched individuals, because observed mortality rates on these urban surfaces were too low for that to work. And it was not color-change plasticity, because experiments showed negligible color shifts in response to substrate.
Instead, the grasshoppers were actively choosing substrates that matched their own body color. By experimentally manipulating grasshopper color and tracking movement, researchers confirmed that individuals preferentially used surfaces resembling their own coloration. This biased movement, rather than differential survival or developmental plasticity, was the main driver of the local color-substrate match. It is a form of habitat choice that effectively creates the appearance of adaptive coloration without requiring either evolution or color change in any given individual.
Why So Many Colors Persist
A natural question, given all of this, is why grasshopper populations do not converge on a single “best” color. The answer is that there is no single best color. The fitness payoff of any color morph depends on the local substrate, the season, the altitude, the fire history, the predation pressure, the temperature regime, the pathogen load, and even whether the individual is male or female. Green is excellent camouflage in lush meadows. Brown is better on dry ground or dead vegetation. Black is advantageous on charred soil or at cold, high-altitude sites. Pied patterning works where the ground is patchy.
On top of that, the mechanisms maintaining color diversity operate at different scales. Large-scale geographic clines in precipitation or altitude shape morph ratios across a species’ range. Small-scale habitat heterogeneity, like a meadow with both bare soil and thick grass, can maintain multiple morphs within a single field. Genetic variation, developmental plasticity, temperature-dependent pigmentation, and behavioral substrate choice all contribute simultaneously, making grasshopper color one of the more layered examples of how organisms manage to look the way they do.
Locust Phase Change and the Most Extreme Color Shift
Locusts are grasshoppers that have an additional dimension of color variation tied to population density. When certain species, like the desert locust Schistocerca gregaria or the migratory locust Locusta migratoria, transition from their solitary phase to the gregarious swarming phase, their coloration changes dramatically. Solitary individuals are typically green or brown and cryptic. Gregarious individuals can become bright yellow, orange, or black-and-yellow, a shift so stark that early entomologists classified the two phases as separate species.
This phase polyphenism is triggered by crowding. Physical contact, particularly stimulation of the hind legs, initiates a cascade of hormonal and neurochemical changes that alter not just color but behavior, body shape, and metabolism. The swarming phase coloration likely functions as a combination of warning signal (gregarious locusts accumulate toxins from their food plants) and social signal. The color shift can occur within a single generation and is partially reversible if crowding decreases, making it one of the most extreme examples of environmentally induced color change in any insect. The carotenoid-binding proteins involved in normal grasshopper coloration play a role here too: in Schistocerca gregaria, beta-carotene-binding protein facilitates the yellow pigmentation of gregarious adults, and in Locusta migratoria, the same protein family modulates carotenoid dynamics during the phase transition.