Blue Ridge Ramble Early September- 2011

As the summer comes to a close and the first chill of fall begins to intrude on our consciousness, there are still a few warm weeks left to enjoy the flowers and insects and watch for migrating birds. I am always interested to learn a few more butterflies and had the opportunity recently to practice one of the more difficult choices between great spangled and aphrodite fritillaries. These two large and showy butterflies are “sibling species” that are closely related and difficult to tell apart. The great spangled is the default identification since it is far more common in most locations. However when you are at a higher elevation, the aphrodite becomes a possibility. The photo of an aphrodite shown here was taken along the Blue Ridge Parkway and illustrates the presence of a tiny dark spot on the medial area of the forewing that is distinctive if cryptic. Such closely related but different species illustrate evolution in action- the very gradual divergence of two populations that differ perhaps in their choice of habitat. In Florida I encounter a very similar conundrum in distinguishing between the widespread common buckeye and the coastal mangrove buckeye.

One of my favorite beetles, the locust borer, becomes obvious this time of year when it is often seen searching for nectar on the late-blooming flowers of the boneset. It is a remarkable mimic of a yellow jacket wasp and although tasty to birds, seems to know that it is relatively immune from their attacks. In late summer there are many colonies of yellow jackets around in holes in the ground and I get reminded too often of how painful their stings are. One of the main allies we have in our battle against yellow jackets is the striped skunk which digs up their nests and eats the larvae. I came across this skunk in our field ambling along with little concern for people and gave it proper respect. I formerly persecuted skunks because they can be very aggravating at night due to their release of their defensive stink in their nocturnal wanderings. But I have learned from experience that my farmer neighbor was correct in warning me to leave the skunks alone and let them make war on the wasps.

As I walk along our numerous woods trails I never know what might turn up. This strange black wasp with a long abdomen was an unexpected treat since this pelecinid wasp has a very unusual life cycle. This is a female which uses the long abdomen to lay eggs on beetle grubs in the soil. Yet there are few or no males in the US and it appears that the females reproduce parthenogenetically. Such a method of “virgin birth” is convenient since no males are needed, but there will be limited genetic variation present and thus potential problems in adapting to changing conditions.

It is relatively rare that I see snakes so I can get excited even about a common garter snake seen here crossing a trail. This illustrates an interesting phenomenon about hu mans- we tend to ignore things we are familiar with. In this case we see a striped snake with lines running parallel to the long axis of the body and we say so what. But shouldn’t this color pattern have a specific function? I think so and I like the theory that striped snakes have evolved this pattern to confuse predators- as they move the lines flow by the eyes of a potential predator and make it very difficult to focus on one spot to attack before the snake slips away.

Many folks put out sugar water for hummingbirds and enjoy their antics. I greatly prefer to plant flowers to accomplish this more naturally and this time of year there is such an abundance of flowers (especially jewelweed) that hummers find lots of food. But as I looked o ut the back door I saw a hummingbird nectar ing on a small penta plant that my wife had planted. Pentas originated in eastern African and are popular in Florida as attractants for butterflies and hummingbirds. We tried one in VA and it did not grow well but as you can see it attracted a hummer with its red tubular flowers.

For those of you in northern climes, this is your last chance before frost to get out there and revel in the wonderful end of summer abundance of critters. It is a fabulous time of year but change is definitely coming on the wind.

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

Please follow and like us: