This Skwala nymph still has a couple months left to go before hatching, but it's still a good representative of its species, which was extremely abundant in my sample for a stonefly of this size. It's obvious why the Yakima is known for its Skwala hatch.
Taxon on Jun 26, 2006June 26th, 2006, 10:22 am EDT
Jason-
Wow, believe these are the first photos I've seen of winged Baetisca. They certainly have a stout abdomen, don't they. Guess that shouldn't be a particular surprise given the shape of the nymphs, but must admit it startled me.
Troutnut on Jun 26, 2006June 26th, 2006, 4:51 pm EDT
I was surprised, too, when I first collected one. I almost instantly knew it had to be Baetisca, but it was still very neat to see. Interestingly, the males are quite a bit less robust -- about half-way between the female Baetiscas and the typical sulphur spinners.
The pretty wing patterns of the duns aren't carried over into the spinners, which have unmarked hyaline wings. Since the spinners are the stage to imitate, people should take note of this difference.
Another interesting thing about Baetiscas is that the males, at least in the spinner stage, aren't as stout as the females. They're still more robust than other mayflies, but it takes a close look to notice the difference.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist