Georgeous photograph of a rare pink grasshopper in a sandbox.

PINK GRASSHOPPERS

They are not rare genetic mutants!




Why do people call them genetic mutants?

Photo of a northern green-striped grasshopper with a pink head.

After finding another pink grasshopper in my yard, I went to the internet to find out what causes them to become pink and everywhere I looked, I found the same information repeated over and over...that it was a rare genetic mutation.

I scoured the internet to find the original source of that information and the oldest article so far was from 2012.

To be clear, the 2012 article by Crystal Cockman at The UNC Charlotte Urban Institute describes pink katydids and says "Erythrism is a unique reddish pigmentation, usually the result of a genetic mutation, similar to the recessive gene found in albinos". The keys here are the lack of certainty and lack of specificity. It was just a hypothesis, and the phenomenon is addressed generically, not being specific to grasshoppers.

Somehow, credulous writers erroneously twisted this into something else!

So down the rabbit hole I went. I looked for the scientific evidence - you know, some real research on how pink pigment occurs in grasshoppers. This page is the result.

Are they really that rare?

A quick search for “pink grasshopper” at the BugGuide.net (an online catalog of north American insects) produces dozens of images for many different species including multiple subspecies of green-striped grasshoppers, slant-faced grasshoppers, round-headed katydids, bird grasshoppers, spur-throat toothpick grasshoppers and many more. So, it seems that while they are strikingly beautiful pink insects, they are not particularly rare.

If we go global, and look at certain orthopteran species, such as the leaf-like katydids from Borneo (Eulophophyllum species), we will discover that all of the females that have ever been collected for those species happen to be pink with green stripes, while the males are uniformly green. For those species, pink coloration may be influenced by genetics, but it is not rare at all! However, one thing that I think is more important to note is that species normally not associated with pinkishness are sometimes pink anyway.

I was surprised to discover that adult locusts (yes, those ones from the bible) are pink at first, and then slowly change color as they mature. So, in that situation, finding a locust with a pink hue definitely is not rare, and if you simply kept it alive for a while longer, it would stop being pink! I hope I will always continue to be excited to find a pink grasshopper or katydid, but I will no longer consider it to be particularly rare.

SUMMARY: They are not that rare!

Are they genetic mutants?

Maybe…I was once gifted an entire book on pygmy grasshopper genetics by a retiring professor. His career was devoted to the biochemistry of how the exoskeleton of insects becomes pigmented and hardened. The book was from 1929. I don’t recall anything about pink grasshoppers in that book!

Now, grasshopper genetics isn’t all that hot of a topic, but I managed to compile an array of sources on grasshopper coat color variants. Suffice to say, none of them address “pink” grasshoppers, but one comes close.

In the migratory grasshopper (Melanoplus sanguinipes), one group found a genetic mutant they called “bloody” which has variable splotches of pink on the face, legs and wings. The pattern was likened to that of the young locusts. The bloody trait appears to be inherited as a single autosomal recessive gene.

SUMMARY: Mutations have not been verified.

If it isn’t genetic, is it environmental?

Maybe. There is clear evidence for two main possibilities: 1) environmental stress, 2) the color of their surroundings.

Stress is a major component of morphological differentiation in locusts. The two main stressors are humidity and crowding. High humidity promotes more greenish forms and low humidity promotes brownish forms of the nymphs. Solitary nymphs develop coloration that helps hide them within their environment and crowding results in gregarious forms that are more pigmented as nymphs, pink when first molted, and become conspicuously yellow over time. While this phenomenon was known in locusts for a long time, similar color morph differences can occur in other grasshopper species in response to crowding, temperature differences or diet.

Grasshoppers reared on different colored substrates or in different colored containers will grow up to partly match their surroundings!

SUMMARY: It might be environmental.



Pink grasshoppers – THEY ARE NOT GENETIC MUTANTS!

Rare mutations that induce erythrism have never been demonstrated to exist in grasshoppers, but the internet is riddled with stories about rare mutations creating pink grasshoppers. Let's throw that myth in the garbage.

Colorful photo of a Blue Death Feigning Beetle - Asbolus verrucosus - eating a carrot.