Note: This post contains the answer to a clue, part of a Pacific Northwest Blogger Scavenger Hunt devised and organized by Patricia Lichen. For a full explanation and list of participants, visit her blog, starting 9 AM PDT, Saturday August 27.
The slough at Terra Nova Rural Park, Richmond BC, was scraped from an abandoned field a few years back. Decades before that, a natural slough was diked, drained and filled to create a field. The more things change, the more they almost get back to what once was there. I was thinking this as I stared into the murky water, which now is ringed by emergent vegetation, and is home to waterfowl, stickleback, and numerous invertebrates, such as....hey! What’s that?
A stick with legs is slowly resolving, like a zombie through the fog. A water scorpion!
Not really a scorpion, of course. It is a true bug, Order Hemiptera, Family Nepidae. This stick-bug shaped version is in the genus Ranatra. It's about 2.5 inches (~6cm) long. The front pair of legs are closer in form and function to the predatory appendages of mantids than the cheliped-like pincer of a scorpion. There are two more pairs of legs that are used, somewhat inefficiently it appeared, as oars.
Here comes another one!
The "tail" is really a pair of caudal appendages that together function as a breathing tube, allowing gas diffusion to and from a bubble of air that is trapped beneath the body.
Taking a breather.
Adults can fly, which is how they arrived at a relatively recently created watercourse. I think the bugs in these pictures are sub-adults, nymphs. There are two short, narrow flap-like appendages midbody, what should develop into large wings that will extend to the base of the tail.
Looking closer, on and between those winglets, there are orange spheres. These bugs have passengers, aquatic mites (Hydracarina). These are parasitic larval stages; adults move around independently and are predatory.
Anyone who lives in a pond should be permanently itchy.