Posting may be light today as it’s a busy day: I have to feed the dorm ducks, giving them extra water because it’s going to be hot (93° F, 34° C), and then we have to meet with Facilities this afternoon to see what the fate of Botany Pond is. I’m worried as they mentioned “duck deterrents” during the mating season. No baby ducks? Unthinkable! Besides, since the pond will be full of water there is no way in hell to keep ducks away from it.
Today sees the return of regular Mark Sturtevant, insect and arthropod photographer extraodinaire. His captions are indented and you can enlarge his photos by clicking on them.
Here are more pictures that are mainly from the previous summer. The first two pictures are nymphs of a predatory Hemipteran known as the Masked Hunter (Reduvius personatus). As nymphs, they decorate themselves with dirt or sand for concealment. The third picture shows an adult Masked Hunter. Although the nymphs are normally very difficult to find, both the nymph and the adult were found at my porch light at night. Most members of this family (Reduviidae, or assassin bugs) are slow and plodding, but Masked Hunters are surprisingly quick on their feet.
A “fen” is a special kind of wetland that is a bit different from what one might call a bog or a marsh. I have learned that defining these things is a delicate matter, but as I understand it a fen is sustained by water that percolates up from limestone, resulting in an alkaline pH. Fens are characterized by an array of specific and interesting plants (and insects, as we shall see). There is a park about 15 minutes from my house called Seven Lakes State Park, and it has several fens. One of them can only be accessed by a Secret Path through the woods, and I’ve never seen a trace of anyone else there so it is now “Sturtevant’s Fen”.
Once out of the woods, the higher ground surrounding Sturtevant’s Fen is sprinkled with a lovely orchid called the Grass Pink Orchid, Calopogon tuberosus, as shown in the next picture. This orchid is famously described as the “upside down orchid”, but that is all part of a great deception. Orchid flower anatomy is a bit different from other flowers, and I hope I get this right (feel free of course to correct me, someone). In orchids, the sepals and petals tend to look like petals, and male and female reproductive organs are fused into a single structure called the column that can be seen in this orchid as the curved structure at the bottom. But what about those bright yellow thingies on the top-most sepal that look like male anthers? They are the deception part of the story, and also why this is the upside- down orchid. What appears to be a flashy set of anthers that promise a rich pollen reward are actually lures, aimed at tricking bees. When a bee visits this flower, it will likely go after the false anthers, and this causes the sepal they are on to suddenly hinge down and whack the bee against the column. This results in sticky and inaccessible pollen sacs attaching to the back of the bee. The bee flies off, and if it visits another of these orchids it will likely make the same mistake by going after the false anthers (bees are not smart). It will get whacked again, and this results in the pollen sacs being transferred. Darwin would have loved this orchid!
Out on the fen proper, the ground becomes firm sand that is always under about a quarter inch of water. Your shoes will get wet. And among the dense stands of coarse sedge grasses are three different species of carnivorous plants! Most obvious among them are the numerous Pitcher Plants, Sarracenia purpurea, which are shown in the next two pictures. Early in the season, these have tall flower stalks with weird flowers. A feature of carnivorous plants is that they do not want to eat their pollinators, so they keep their flowers well away from their insect traps. I wonder if the weird shape of the flowers themselves are also designed to keep their pollinators from falling to their doom. Of course, the watery trap in each pitcher plant holds syrupy water with digestive juices and often lots of dissolved insects. Once I found a live maggot living inside one that was evidently there to feed on trapped insects.
Crowding around the bases of the pitcher plants are Sundews, another insect-eating plant shown in the next picture. They of course trap and digest insects with sticky hairs on their leaves. The Sundew here I think is Drosera rotundiflora. They too try to not kill their pollinators with flowers on tall stalks, but I have yet to see those.
How those two carnivorous plants trap prey is pretty obvious and well known. The third carnivorous plant is more subtle about it. Dotting the fen landscape are much scarcer but very distinct flowers, one of which is shown in the next picture. These belong to the horned bladderwort (Utricularia cornuta). Bladderworts are more aquatic, and they have tiny specialized vessels among their roots that trap and digest small aquatic prey.
But for me, the real attraction of my private fen is a very special little dragonfly. These are Elfin Skimmers (Nannothemis bella), and they are by far the smallest dragonfly in the U.S. The world’s smallest dragonfly is a close relative found in China, and it is not much smaller! Elfin Skimmers abound in Sturtevant’s Fen, which is as it should be. First, here is a female. These are suspected to be wasp mimics. Next is a male.
Although those tiny dragons were perched on grass blades, it may still be hard to convey how incredibly tiny these are for a dragonfly. So just for this post, I made a special trip back to Sturtevant’s fen with a butterfly net and very carefully captured the young female shown in the last picture. Look at your index finger. The body of that little dragon will hardly stretch across the width of your finger!