Pair of stoneflies mating.

Yesterday's blog (click here) was on stoneflies with an image I shot of a nymph feeding on another insect larva. Today's blog features the adults, a male and female, involved in mating. The male is smaller and is riding on the back of the female. If you look closely, you can see his abdomen wraps underneath the female's where the copulatory process is taking place.

What I found interesting about this was that the pair was still ambulatory. The male hung on tight but the female could move about using her legs; flying was out of the question. There were many individual stoneflies about and numerous mating pairs. They were heavily distributed in the vegetation alongside of the river. They seem to have emerged at once, or at least within a very narrow time period. I did not go down to the rocks by the river as it was dangerous, but I am sure I would have found quite a few discarded ecdyses - the last molt leading to adult emersion.

The adults were very large, the males being around one and a half inches and the females being closer to two inches. These are among the largest stonelfies in existance. They belong to the Pteronarcyidae, more commonly called giant stoneflies. This particular species is the golden stonefly (I think - not validated) and is sometimes called a salmonfly. I have to say it was quite a find and they were amazing to watch.

Thanks for reading.     Ericspix     Eric Svendsen