Saturday, March 5, 2016
Creepy Crawly Exotica: Astounding Temperate Rainforest Invertebrates on Roan Mountain
Some people in Eastern North America believe that in order to experience the most amazing wildlife and nature, they need to travel abroad. This isn't true. Along with coral reefs, South American jungles and other exotic places, the Southern Appalachian region is one of the places dubbed a biodiversity hotspot. Roan Mountain is especially diverse. Two kinds of northern temperate rainforest mingle with southern nature, creating a haven for plants and animals, especially the small, overlooked ones. Invertebrates make up most of the world's species, and Roan Mountain's. But since the biodiversity of Roan Mountain includes many "bugs", some of these bugs are very large, impressive, or just plain amazing. Just take a look at some of them!
The monstrous creature above is powerful, large and its pattern tells that it is full of deadly toxins. Luckily, it is a peaceful detrivore which leaves other species alone. You can see these animals inching across gravel, burrowing through rotten wood, or crawling out of rocks on damp mornings and evenings. Their enormous size deters small predators, and their coloration deters large ones. They actually can't harm you if you only touch them. Their mouths are small and built for nibbling detritus the consistency of pudding, so bites aren't a problem. Their poisonous insides are kept inside by a calcareous armor of shell, and no stingers, pincers, or anything else of that sort are present on this creature. It is the North American Giant Millipede (Narceus americanus), and is very vulnerable to humans indeed. You can see them mashed by the tire of a bicycle or car, or squashed by the heel of a foot in the afternoon, after their crepuscular perambulation. They can be held, but not petted. This is because of tiny beneficial mites that help regulate the millipede's external membranes, and roughly handling one of these animals can expel these mites and eventually kill the millipede. It doesn't have a million or even a thousand legs, but around two hundred. If you watch one walk, its legs ripple like a wave along its body. Sometimes, several "waves" of legs will be traveling simultaneously up the millipede's underside if it's larger. They aren't common, so if you see one, you'll know it. This millipede also has an African relative, which is sought after as a pet because of its unique behavior, puzzling build and peaceful disposition.
A spout of orange mush bursting from a tunnel in a red oak log is a telltale sign of the Northern Patent Leather Beetle (Ododontotaenius disjunctus), "Jerusalem Beetle", or "Bessbug" on the move. If you turn over many red oak logs, you will see many things. Oriental cockroaches (an introduced species) scuttle or flutter away from the sunlight. Blind soil centipedes slowly but slyly disappear down holes, a few metallic green cuckoo bees may spread their wings and zoom buzzing away, but the real show-stopper is the occasional inch-and-a-half black, glossy beetle sitting in the rotten wood. Upon closer inspection, its legs and wings are fringed with long, bronze fur strips, and seersucker grooves decorate its back. On its belly, pink-red parasitic mites scramble over regal black plates extending the length of the bessbug. If you look inside the log under which you found the bug, you may find many more of its kind. They will make a remarkably audible squeaking commotion as the stumble and fall over each other in surprise if you come close. Some will be large and glossy black, but others are scarcely an inch, possess a slight maroon tint, and have a larger horn on their heads. The latter is the male, and the first is the female. Males prefer the deeper burrows in the log. Bessbugs are friendly to each other and other organisms. Their strength and labor provide tunnels large enough to easily be shared with smaller wood-dwelling insects (such as click beetles), and in cold-weather, may save the lives of warmth-loving insects such as bees. Their abandoned burrows can become homes for little furry creatures as well as snakes and salamanders. They settle down after being caught, and go about their business. Curiously enough, bessbug larvae cannot fend for itself, in fact, it can't even eat by itself. Parents must shove food in its mouth for it to be able to feed. Orphaned bessbug grubs are rarely left to starve in a colony. Instead, other parent bessbugs, male and female, will gather extra food to feed them. Yes, they live peaceful lives, most of the time at least. Their most frightening predator is the great Pileated Woodpecker (Dryocopus pileatus). It will swoop upon a colony and hack at a whole log with a bessbug colony residing within. It determinedly drills into the log until a storm of clay-colored wood chips lash through the woods with echoing drumming that rivals the grouse in ferocity. Once the woodpecker is done, it flies away, hardly leaving a previous Bessbug inhabitant. Bessbugs, since they are beetles, have many relatives across the world.
The remarkable Northern Walkingstick (Diapheromera femorata), or "Stick Bug" is a well-known and beautiful insect. They are often seen in late fall, even after the frost sets. The reason for this appearance is their late breeding period, when they congregate to outdoor buildings such as sheds and campsite bathhouses. Though they don't have wings, they follow glowing lights to these buildings, where they meet with other stick bugs. Then they will depart and lay a single egg in the leaf litter. But the egg is cloned. Male stick bugs are extremely rare, maybe one in a hundred stick bugs is a male, in optimal conditions. So female stick bugs have been recorded to clone themselves, though they sometimes mate. They feed on foliage, usually of hickory or oak, and live peacefully high in the canopy outside of breeding season. Nymphs just look like small adults, and are only about an inch long. Some walkingsticks grow up to three and a half inches long. The giant walkingsticks, the Northern's larger relatives, live in tropical to subtropical environments and are more vibrantly colored. That''s another fact; Northern Walkingsticks can be green, yellow, red-streaked, brown, striped or any number of colors and shades, all for the purpose of camouflage. They also have a unique quirk about them. When it feels threatened, a stick bug will rock side to side on its spindly legs, making it almost invisible to predators with bad eyesight, and making it seem larger to creatures with better vision. When resting, a stick bug will hang upside-down with its front legs and antennae pointing in front of it, and its two pairs of back legs symmetrically stretched out beside it.
With an unseen swoop and a precise landing, the hulking, inch-long body of the Bee Killer (Promachus fitchii) or Giant Robber Fly is a bold and imposing sight to forest insects. Almost as fierce and effective as the dragonfly in its hunting methods, robber flies don't hesitate to attack the most dangerous, stinging bees, and with their maneuverability and powerful bite, they can fly away with a tasty new meal. With their raccoon-striped tail, dusky, hairy back, as well as their neatly folded wings and obsidian-black eyes, these bugs are easily recognized. Robber fly larvae live underground and feed on burrowing insects and decaying matter, rarely noticed. But when they emerge from the earth, they are a fearful sight to other insects. When hunting, a robber fly may sit in ambush at a favorite perch, snatching unsuspecting prey as it goes by, especially bees and wasps. Piles of insect bodies with their insides removed gather under a favorite bee-killer perch. The adults fly mainly in late summer, but larvae hatch out in spring to devour June Beetle larvae before they turn into adults. Robber flies have many fascinating relatives, including a nectar-drinking pollinator and even a dancing robber fly.
So this spring and summer, look for the four insects above. You may see them, their relatives, or even discover a whole new species!
-Happy Trails, Critter Cade