These beautiful stoneflies are widespread, and the trout love them.
[by Nadica and Igor Stacev]
YELLOW SALLY STONEFLIES, which are members of the genus Isoperla, inhabit most clean rivers, especially oxygen-rich chalk streams containing stony bottoms. Yellow sallies are probably the most beautiful stoneflies, and anglers can easily spot these brightly colored insects flittering over the water. Trout eagerly feed on yellow sallies when the spent insects fall to the river’s surface. As with other members of the order Plechoptera (stoneflies), the yellow sally has an incomplete life cycle, which is called hemimetabolism. The hemimetabolism life cycle includes three stages: the egg, nymph, and adult (imago). There is no pupal stage of development in the hemimetabolism life cycle. The nymphs of aquatic insects that have incomplete metamorphosis live in the water; the adults live on the stream bank. Insects that have a hemimetabolism life cycle include Plechoptera (stoneflies), Ephemeroptera (mayflies), and Odonata (dragonflies and damselflies).
More Isoperla Facts
An Isoperla imago is lemon yellow colored. The body of the female measures up to 14 millimeters (about half an inch); the male is a little shorter. A female is longer because it carries precious cargo—the eggs. The adult has two tails, two long antennae, and two sets of wings that fold along the top of the body when the insect is at rest. When yellow sallies appear on the water in larger numbers, fish strike them readily, sometimes even selectively. Insects called the little yellow sally are very similar to the common yellow sally. Little yellow sally genera and species include Chloroperla torrentium, Siphonoperla, and Xanthoperla. These are widely distributed in fast streams, especially those containing stony beds.
Little yellow sallies are pale yellow, and they hatch from April until July. The female measures up to eight millimeters (about 1 /3 inch), and once again, the males are a little shorter. As with all other stoneflies, these insects have two pairs of wings, two of tails, and two antennae. For comparison, Isoperla gramatica, which is considered a midsize stonefly, has a body that is 14 millimeters long. On the other hand, Perla grandis is the largest stonefly; its body is almost 40 millimeters long (1 1 /2 inches). Leuctra fusca, sometimes called the needle fly, is the smallest stonefly; the body of the female is only eight millimeters long, and the male is even shorter. The females lay their eggs by flying over the surface, dipping the tips of their abdomens into the water and releasing their eggs. The eggs fall to the bottom of the stream and begin a new life cycle. The entire life cycle, from egg to adult, takes approximately one year. The females end their lives on the surface “spent” with spread wings, helplessly floating on the water and becoming easy prey for the fish.
Isoperla nymphs are easy to recognize. They have no gills,and they obtain oxygen from the water through their tough exoskeletons. The outer exoskeletons also support and protect the insects’ bodies. Before hatching, the fully grown, mature nymphs migrate from the faster parts of the river toward the bank. They crawl out of the water onto streamside rocks and vegetation at dusk or dawn; the low light protects the insects from marauding birds and small animals. The nymphs cling to these rocks and vegetation, and the adult insects struggle free of their immature skins. The newly emerged adults hide in the shoreline vegetation.
STANCEV YELLOW SALLY
Hook: Tiemco TMC100 or TMC5212, size 16 or 14.
Thread: Yellow or cream, size 12/0 or another extremely ﬁne thread.
Body: Mix of yellow-cream polypropylene dubbing with a pinch of pearl Ice Dub.
Legs: Cock grizzly hackle dyed yellow.
Underwing: Cul de canard.
Wings: Yellow-colored Medallion Sheeting or a similar product, rafﬁa, or Swiss straw.
Tying the Stancev Yellow Sally
A Better Yellow Sally Imitation
Our yellow sally imitation is not difficult to tie. It looks semi-realistic, and we have used it for many years to catch brown trout on different waters all over Europe. Tie the body using fine polypropylene dubbing mixed with a small amount of pearl dubbing. The wings are yellowish and semitransparent, and we tie them with a slight spread angle to make them appear more realistic. The legs are not too dense and are pointed out from the sides of the fly. All these elements create an excellent effect, even when presenting the fly on slower, calmer parts of the river, where the fish have more time to inspect our pattern, and when the trout are picky and extremely difficult to catch. Fishing with the Yellow Sally is most productive when the real Isoperla stoneflies are hatching. Emergence generally begins in April and lasts until July, but in some higher altitudes, it will extend into August. On warmer spring days, they might hatch during the middle part of the day. We think you will enjoy tying and fishing our Yellow Sally, but if you choose another pattern, try maintaining the correct size, shape, and yellowish color, the trademarks of this beautiful stonefly.
Nadica and Igor Stancev are serious students of aquatic entomology. They are also masters at tying realistic imitations designed for real-world fishing. Nadica and Igor live in Macedonia. To see examples of their flies and much more, go to their website, www.fishingflies.com.mk.