A Dazzling Nature Ramble in Early September

September 10, 2014

Nature Notes by Bill Dunson

Although many of our favorite birds have migrated south by late August and early September, there is a great profusion of insect life in the fields and meadows. Thus this time of year I spend a great deal more time walking in grasslands than in the woods, which comparatively have much less life than open areas. On our 107 acre farm we have about 40 acres of former pasture which are now managed as grasslands which have been mowed, burned and planted in a heterogeneous fashion to yield a diversity of habitats.

Our common milkweeds were mowed along with the hay on July 11, but by Sept. 3 had re-grown and were even blooming. Adult monarchs were nectaring on the flowers and laying eggs on the tender young leaves. Our goal is to maximize the number of caterpillars such as this large one shown feeding on common milkweed. Monarch caterpillars can sometimes be difficult to find so I look for chewed leaves and frass (caterpillar poop). The caterpillars tend to hide when not feeding perhaps to minimize predation. One unexpected potential predator was a large wheel or assassin bug on a milkweed plant; these bugs are infamous for their painful bites so do not touch!

Some butterflies in the field were the beautiful sleepy oranges which fly low and often sit on the ground, and a variegated fritillary sipping nectar from a purple coneflower. A somewhat unusual sight was a pair of mating yellow collared scape tiger moths. Ours are more orange collared than yellow, and appear to be mimicking wasps as a means of defense. Of course moths generally fly at night and are not usually attacked by day-feeding birds unless these avian predators can find the moths while they are resting on vegetation. Tiger moths which fly in daytime may be either wasp mimics or have hind-wing flash colors to intimidate birds or warn them of toxicity.

Another invertebrate predator often found in the fields is a dragonfly, in this case a female widow skimmer. The females are duller in color than the males and are often found away from water, thus avoiding competition for food with the males which maintain territories around ponds. I also encountered a young pilot black snake prowling in the grass, looking possibly for a mouse or young bird to eat.

Except for migrants passing through and a few hardy residents, our birds have abandoned us and have become “snowbirds” heading to southern climates. This is a great time to learn the butterflies and some of the other myriad of insects that still throng the sunny meadows.

Bill Dunson

About Bill Dunson

Bill Dunson, born in rural Georgia, skipped 12th grade and went directly to Yale. Bill subsequent-ly received a PhD in Zoology from the University of Michigan, studying softshell turtles. Bill is Professor Emeritus of Pennsylvania State University thanks to a career spent entirely at that institution, teaching and doing research on the physio-logical ecology and ecotoxiciology of reptiles, amphibians and fish. Always curious about nature, Bill has dedicated his life to learning and sharing his knowledge with others. He has served on many advisory boards here in Southwest Florida to preserve the water that gives life to our region.

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