The Colorful World of Grasshoppers
Updated: Mar 15
These days you don’t have to look hard for a grasshopper fly pattern with pink, purple, or even lime green. Are fly tyers using these colors just to mix things up, or is there evidence from the natural world that these bright colors mimic the natural coloration of grasshoppers?
Fish that are seeking out terrestrials are searching for the largest meal possible while avoiding unnecessary risks -- a major one being an angler's fly! So when we’re all out on the water tossing cleanly-tied, foam segmented hoppers, the trout learn to ignore those offerings, especially after being hooked by these impostors. Instead, fish might favor an unfamiliar tattered pink fly pattern simply because they have no reason to assume it is anything BUT food. This is the conventional wisdom, and probably explains things well enough for 90% of anglers.
I’m not satisfied with that answer though. Hopefully, you aren’t either, because there is more to this post!
Luckily, I didn't have to dig too deep to find evidence from the natural world that supports another explanation as to why a fish would take a seemingly bizarre-colored hopper. Within the fly-fishing literature, Boots Allen, author of Snake River Flies: Eighty Years of Proven Patterns for Fly Fishing Around the Globe, offers this insight. He notes that a grasshopper's coloration often matches their surrounding environment and that these insects even have the ability to change colors with the season. Changing from the greens of late spring to match emergent grasses, to oranges, tans, and yellows, as foliage ripens and cures. As far as pinks and purples go, Allen suggests that some hoppers exhibit these colors in an attempt to match the coloration of specific plant species. It may be camouflage, it may be tied to a grasshopper’s diet, or it may be both.
Next, I took a dip into the scientific literature and found several details that complicate and enrich Allen’s explanation. Many studies have examined the effects of temperature on grasshopper color changes, technically referred to as color polymorphism. Temperature seems to have a strong influence on hopper body color, more so than other factors, such as the color of the surrounding environment, hopper population density, or relative humidity. These results suggest that temperature changes over the course of a season (rising in spring, warmest in summer, and falling in autumn) influence coloration. This evolved to help these cold-blooded critters thermoregulate (stay comfortable). As previously mentioned, this color matching also offers camouflage in accordance with these insect’s surroundings. Tanaka (2008) even noted that the timing of the color change may be different between males and females. Surprisingly, Valverde & Schielzeth (2015) specifically make note that grasshopper color changes do in fact include pinks, purples, yellows, and even blues.
Now, consider that there are about 400 species of grasshoppers in the Western United States, each with varying abilities to change colors, sex-specific colorations, varying diets and habitats, and even different colorations during nymph life stages. That’s a whole lot of potential for color variation!
Now a caveat. These insects are still prey items and have to blend into their environment to avoid being eaten. So the likelihood of seeing a strikingly pink grasshopper may be a bit far fetched, most are tan, gray, cream, yellow, green, brown, or even red in places with ferric soils (at least on their bellies, the viewpoint most important to trout and fly tyers).
There is still diversity in grasshopper coloration though, mainly in what I call, accent colors. Every angler who has fished to picky trout can attest that sometimes they just key into these details like stripes, spots, banding, and brightly colored legs. After examining the University of Wyoming’s guide to western grasshoppers, several coloration trends became apparent. I categorized the common hopper colors into primary (abdomen) color, secondary (head and thorax) colors, and hind leg (not the femur) colors. Yes, it is subjective, but I stayed true to the field guide’s color descriptions. Based on their field guide descriptions, the following colors are most common in western grasshoppers.
Abdominal colors are fairly conservative (mainly tan, brown, green and yellow), but hind leg colors offer some striking colors, notably red and blue. How many hopper patterns do you see with the skinny hind leg segments in blue? Maybe there should be some...
Maybe the trout aren’t really all that picky about hopper patterns, and they just get bored of seeing the same old, tired patterns, knowing there is a more colorful hopper to be munched on; that’s just a theory at this point, and a hard one to justify.
Nonetheless, next time I tie hoppers, I'll keep these colors in mind. And when I go terrestrial fishing, I’ll be paying close attention to the color of the surrounding stream-side environment and time of year before I pick up my go-to terrestrial pattern.
Boots Allen. 2014. Snake River Flies: Eighty Years of Proven Patterns for Fly Fishing Around the Globe.
Valverde & Schielzeth. 2015. What triggers colour change? Effects of background colour and temperature on the development of an alpine grasshopper. BMC Evolutionary Biology.
Tanaka. 2008. Effects of temperature on body color change in the grasshopper Atractomorpha lata (Orthoptera: Pyrgomorphidae) with reference to sex differences in color morph frequencies. Entomological Science.
Don Roberts. Accessed 2019. Grasshoppers: The Only Kosher Insect. Northwest Fly Fishing Magazine.
P. Dieker, et al. 2018. Spatial analysis of two color polymorphism in an alpine grasshopper reveal a role of small-scale heterogeneity. Ecology and Evolution.
Anthony Joern. 2011. Grasshoppers. Encyclopedia of the Great Plains. University of Nebraska-Lincoln.
University of Wyoming. Accessed 2019. Field Guide to Common Western Grasshoppers. http://www.uwyo.edu/entomology/grasshoppers/facttoc.htm#Gomphocerinae