Blue Ridge Ramble Late May – 2011

An ironic twist to the lore about secret places where naturalists find interesting critters is that often one will find a wonderful sight just at the back door or in the parking lot. Thus I always look around the doorway in case a strange visitor from the night before has lingered. That was the case when I went outside recently and noticed a large crane fly, which you might mistake for an enormous mosquito! But these giant flies are harmless to humans and have maggot-like larvae that may live in water or soil. There is only one pair of wings and just behind the wings is a pair of short rods with a bulb on the end. These organs are called halteres and are thought to have evolved from the original ancestral second pair of wings. They are moved in opposition to the wings and are thought to function as a means of gyroscopic orientation during flight. For those flies that mimic bees I always look for the lack of a second pair of wings and the halteres to confirm that this bug will not sting.

Along a pathway I noticed an unusual aggregation of tiger swallowtail butterflies. This behavior is usually referred to as “puddling” since it is sometimes occurs around small seeps or pools, especially on damp mud. But it can also be seen on animal dung or on carcasses of vertebrates. What seems to be happening is that these butterfly vegetarians lack some of the salts, mainly sodium, that are common constituents of the vertebrate body and excrement. Thus they seek out and imbibe fluids from urine, feces, and decaying bodies to gain salts. What was unusual in this case was the large numbers of butterflies of mainly the same species and the fact that there was no obvious source of salts on the ground where they were clustered. My theory is that an animal urinated in this spot.

A natural wonder of a very different kind along another the path was the so-called “earth star.” This is a type of puffball fungus which un-furls radiating points of tissue to reveal a round central structure containing spores. When mature, the spores are released from the hole in the center.

A female musk turtle appeared on a pathway apparently looking for a suitable place to lay her eggs. These turtles spend most of their lives in water and have glands in the edges of their shell which emit a fluid that smells very bad, hence the name musk turtle. They are rather similar to mud turtles but have a reduced lower shell which reflects their more aquatic nature. It is interesting that turtles which are so ancient have never evolved the capacity for live birth even when they are thoroughly aquatic. So they must always return to the land to lay their eggs.

Finally I observed a number of red-spotted newts swimming around in the shallow water of a nearby pond; they are predatory on many small creatures and even the eggs of other amphibians. This appears to be a male based on the enlarged hind legs for grasping the female and a large tail fin. Newts are famous for their extreme toxicity based on the presence of tetrodotoxin in their skin and organs, and this allows them to swim boldly in the presence of fish. The adults and early juveniles are aquatic, but there is a terrestrial phase that is red/orange called the red eft. The bright color advertises the eft’s toxicity and is the basis for mimicry by a number of salamanders such as the northern red salamander.

Once again a simple ramble reveals a multitude of life forms of surpassing beauty and complex ecological interactions.

Bill Dunson, Englewood, FL & Galax, VA
wdunson@comcast.net