Summer Pond Life

August 17, 2015

Nature Notes by Bill Dunson

Nothing expresses summer time more than the whirl of life around a pond. There is an intensity of competition and predation, but also great beauty among the intricate web of life that revolves around a small body of water.

The fishing spider lives at the intersection of air and water by running across the surface tension and also diving under the water to capture tadpoles and small fish. Dragonflies are completely aerial predators as adults but live as nymphs underwater. Although relatively primitive insects, they have complex behavioral patterns governing their reproductive patterns. The eastern pond hawk illustrates the striking difference in color between the male and female. One day I caught a pair of green darners in the process of laying eggs with the male (on right with bluish abdomen) contact guarding the female (holding her behind her head) while she laid. This insures the male that his sperm will fertilize the eggs.

Frogs insure their paternity by external fertilization of the eggs as they are laid. The male bullfrog maintains a territory in part by calling loudly and the external ear drum of the male is much larger than that of the female, the better to evaluate the quality of the call of rivals. Compare the size of the ear drum in males and females against the size of the eye. Green frogs occur in the same ponds and can be distinguished from bullfrogs by a lateral fold in the skin; the male also has an ear drum larger than its eye.

A top predator in most ponds is the snapping turtle which will eat almost anything it can catch. They roam widely to reach remote ponds and are ubiquitous inhabitants of fresh water. Their shell is greatly reduced in comparison with a box turtle since their defensive capabilities are considerable. They often bask to raise their body temperature to accelerate digestion.

The northern water snake is also wide spread and often feared by humans due to its resemblance to the water moccasin, which does not occur in the mountains and northern latitudes. It is primarily seen while basking on rocks and logs. This large female likely enhances the development of her young by raising her body temperature.

Try sitting by a small pond for a while and enjoy the show! It is a fascinating illustration of how one tiny habitat can provide a home for a myriad of creatures that are each dependent in some way on aquatic habitats. I find it especially interesting how this web of life fluctuates on both a daily and seasonal basis, and varies depending on whether fish are present.

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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