Entomology

Hello everyone!

I decided to take a little break from fishing today to look for some of our aquatic friends. There are three photos of aquatic insects below which are staples at one of our local fisheries.

Can you tell me what each insect is? Extra points awarded for both the Latin and common names for each of these!😊

Bonus question… Based on seeing what I found, can you guess where I was fishing today?

Have fun!

Scott

Hesperoperla pacifica. Hesperoperla pacifica, the golden stonefly, is a species of common stonefly in the family Perlidae. It is found in North America. Its nymph is distinguished from other perlids by a pale, hourglass-shaped mark on its head.

Great job, Paul!

One of these photos is indeed Hesperoperla pacifica... the Golden Stonefly, in its nymph stage!

One down... Two to go!

Well done, Paul!

Here are a couple of hints for our mystery suspects shown in photo one and three!

Photo 1:

While we learned about the Hexagenia at Lake Almanor this year, I am not a Hex... but I am a mayfly! This large mayfly is known for its erratic flight patterns and is often seen darting around near rivers in late summer and fall. In its adult form, it can have a wingspan of two full inches and is a seasonal highlight for many fly fishers.

Photo 3:

This large aquatic nymph is one of the largest stonefly species in North America and serves as a key player for fly fishers. It finds its home in clean, flowing rivers and is known for its robust size and uncanny ability to frighten children and even some small pets.

While it may look a bit ugly, it doesn’t bite—our friend here eats decaying plant material and other organic matter (also known as detritus) and plays an important role as a food source for fish, making it a popular target for us.

Can you now guess what we are?

Have fun!

Scott

The bottom one almost looks like a Hellgrammite but it’s missing those bigger mandibles 😳

Hi Paul.... The hellgramite is an interesting bug and is actually the larval form of the Dobson Fly. I may do a write up on that one at a later date as we do have some around in our Sierra Nevada watersheds.

Here is another hint... The Latin name of Mr. Ugly down there has something to do with the State you live in. 😀

Happy Thursday everyone!

Here are the answers to this little riddle:

1. Isonychia velma – Commonly called “Iso’s” or sometimes the "Slate Drake", among many other names depending on the region. Our specific Isonychia is easy to identify as I. velma is the only species of “Iso” we have in California.

• Fun fact: Isonychias are incredibly strong swimmers! Catching a live one is tough—they’ll swim away quickly unless you use a catch net.

• Often, what you'll find are their husks (exoskeletons) left over after they’ve hatched into adults (like the one in this photo). These husks give us clues about their presence in the water.

2. Hesperoperla pacifica – The "Golden Stonefly"

• These insects are a staple in trout diets, especially during their nymph stage when they dwell under rocks in faster-moving waters.

• Known for their golden color, they’re great indicators of clean, well-oxygenated water, as they thrive only in high-quality streams and rivers.

3. Pteronarcys californica – The "California Giant Salmonfly"

• As one of the largest stonefly species, this "giant" is a favorite meal for trout and steelhead.

• They’re sensitive to pollution, making their presence a sign of a healthy river ecosystem, much like the Golden Stonefly above.

• When we use flies like the “Pat’s Rubberlegs,” we’re often imitating the Pteronarcys californica nymph, as it closely resembles this large stonefly that calls many of our local waters home.

While these bugs are often found in several of our local watersheds, this trifecta of life is a good hint of where I was fishing last Saturday…. The Trinity River.

If you all liked this exercise, please let me know and I’ll do similar for you with some of our other watersheds as I get some time to get out and explore.

Understanding what lives in these waters can help you select fly imitations which can help increase your chances of success.

Plus… bugs are just super cool!

Hope you enjoyed!

Scott