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.
In the world of insects, it can be difficult to distinguish choices such as the one between the great spangled and aphrodite fritillaries. These large, showy butterflies are sibling species, which means they are closely related and difficult to tell apart.
The great spangled is the default identification since it is far more common in most locations. At higher elevations such as the Blue Ridge Parkway the aphrodite fritillary shows its tiny dark spot on the medial area of the forewing. Distinctive if cryptic.
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A hummingbird nectaring on a small pentaplant. Pentas originated in eastern African and are popular in Florida as attractants for butterflies and hummingbirds.
Such closely related but different species illustrate evolution in action - the gradual divergence of two populations that differ in their choice of habitat.
In Florida exists a 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 am 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.
Fact Box
William Dunson, Ph.d., professor emeritus of biology at Penn State University, splits time between Southwest Florida and his farm in Connecticut. He can be reached at wdunson@comcast.net.
I formerly persecuted skunks because they can be aggravating at night due to the release of their defensive stink during nocturnal wanderings. But my farmer neighbor was correct in saying to leave the skunks alone and let them make war on the wasps.
Walking along numerous woods trails I never know what might turn up. This strange black wasp with a long abdomen was an unexpected treat - a pelecinid wasp with an unusual life cycle. This female uses the long abdomen to lay eggs on beetle grubs in the soil. Yet there are few or no males in the United States and it appears 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.
Coming across a common garter snake crossing a trail illustrates an interesting phenomenon about humans - we tend to ignore familiar things. But I saw a striped garter snake with lines running parallel to the long axis of the body and this color pattern likely has a specific function. I like the theory 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.
Folks put out sugar water for hummingbirds and enjoy their antics. I greatly prefer to plant flowers to accomplish this more naturally and there is such an abundance of flowers, especially jewelweed, that hummers prefer for food this time of year. Out the back door I can watch a hummingbird nectaring on a small pentaplant my wife had planted. Pentas originated in eastern African and are popular in Florida as attractants for butterflies and hummingbirds. We tried one in Virginia, and it did not grow well, but 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 in the wind.
