Survivors?!

with 1.5" of rain over two days, the wetland bounces back... briefly, September 23, 2021

I stopped by the wetland today and discovered that after 1.5" of rain over the past two days, the aquatic phase of the wetland is back in business. I don't expect it to last long, but after everything was dry on Monday, I thought the aquatic phase of the wetland cycle was over for the summer and most of the Fall. Surprise! On Monday as I noted in that day's blog post, "Death... and Life," there were no living aquatic creatures visible. There were plenty of frogs still hopping around, but thousands of dead tadpoles and hundreds of dead dragonfly naiads.

Not surprisingly there were no signs of tadpole life today; however, there were many dragonfly naiads exploring the edges of the big puddle or scooting through it. Like the tadpoles, dragonfly naiads are completely aquatic and breathe through gills. With so many of them dead on Monday, these must have burrowed down deeply enough into the mud to have managed to survive and then resurfaced with the return of the water. Almost all of them, were darner naiads, almost certainly the common green darner, which is the only darner I have seen reproducing at the wetland. Although they managed to survive a day or two with no water in the wetland, my exploration of the wetland in early Spring this year leads me to believe that they will not manage to survive the expected months of dry coming soon. But we will see. Repopulation of the dragonfly inhabitants of the wetland, with the exception of the meadowhawk species, is entirely dependent on adults coming from elsewhere.

Darner (Dragonfly) Naiad with Snails, September 23, 2021

In addition to the darner naiads and a couple of other dragonfly naiads, there were an abundance of snails that also must have survived by burrowing deep enough into the mud to survive the lack of water. Unlike the darner naiads, however, a good number of them should be able to survive the coming months of dryness burrowed deep into the mud and be present to repopulate the wetland when it is wet again. It's a good thing for them since, in contrast to the adult dragonflies, snails cannot travel long distances to recolonize wetlands.

Also present in the reconstituted wetland were backswimmers, which are capable of flight and may have gone away and returned or perhaps more likely still been in the area. Like most of the insects that inhabit the wetland, backswimmers breathe air, so the drying of the wetland is not as life-threatening for them as it is for dragonfly naiads and snails. Similarly there were small shiny water beetles, giant water bug nymphs (below), horsefly or deerfly larvae and a water scorpion (below).  All of these also breathe air.  Adult water bugs can fly and would have had no problem moving to a permanent body of water, but the nymphs are not yet mature and not yet capable of flight so were no doubt still present when the water returned.  

Water scorpions are "true bugs" like the giant water bugs with sucking mouthparts and capable of flight when adults. The one pictured below is preying on a small fly of some type that it snatched from the surface of the water. There is another one of these flies on the water's surface just in front of the water scorpion. The long tube at the back of the water scorpion functions as a snorkel to provide it's air supply when needed.
Giant Water Bug Nymph Refilling Air Supply at the Surface, September 23, 2021


Water Scorpion with Prey, September 23, 2021


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