A September Nature Ramble

September 19, 2016

Nature Notes by Bill Dunson

As summer draws to a close, there is still a great deal of animal activity and a different group of late blooming flowers. I seem to appreciate the sunrises and sunsets more in part because I am tired of working on the yard and want to sit and enjoy the view!

One of my favorite late blooming flowers is the monkshood, which is a classic blue, bumblebee pollinated, flower. Its shape, downwards orientation and color tells us that it specializes in attracting bumblebees. In contrast the upwards facing and easily accessible yellow flowers of wing stem attract a wide variety of insects such as this yellow/orange collared scape moth. This day-flying moth is believed to be protected against predation by its resemblance to a wasp. It also reminds me of the distasteful lightning bug/beetle. Such a variation in strategy of pollination between extreme specialization and generalization is quite remarkable and illustrates how evolution seems to explore all options that could be possible.

Fruits are appearing on many plants and this nannyberry virburnum is a good illustration of how some plants advertise their ripe fruits by color changes to black. The plant does not want its unripe fruits eaten since the seeds are not mature, so they protect them with toxins and show birds they are not ready by the green color.

We had a period of very wet weather and one result was a profusion of fungi in the woods. This Jack o-lantern is a spectacular example that not only is colored like a pumpkin but glows at night with bioluminescence. The purpose of such light production is unknown but the resulting “foxfire” is mysterious and impressive on a very dark night. But do not eat these surface fruiting bodies of the underground mycelium, since they are poisonous.

Goldfinches are looking for seeds on many plants, including this Maximillian sunflower which we planted in our fields. The males are losing their bright yellow color after breeding season is over making them less visible to predators. Such a “bright male” phenomenon usually indicates that the females are choosing mates based on the brilliance of their colors, which could indicate health and vigor which they would want to impart to their offspring.

As herbivores, butterflies are often deficient in sodium salts which are more common in animal prey than in plant food. So when I hung out my sweaty socks after a long hot hike, this pearl crescent landed on the sock and started drinking the salty fluid ! Butterflies must detect the odor of such garments since they target them so quickly. This is a variant of puddling behavior in which butterflies drink fluids from feces or salty damp soil.

I came across this spectacular viceroy butterfly sunning on a gravel path on a cool day. Two things are interesting about this- the sunning behavior to raise its body temperature, and the fact that it did not fear predation when so exposed. The viceroy is partially protected by the toxins it caterpillar ingested from its larval food of willow. But it also gains protection by its mimicry of the even more toxic monarch butterfly.

One of the reliable seasonal changes in late summer is the southern migration of the large common green darner dragonfly from our ponds. They are replaced by an equally large shadow darner (shown here) which is quite tolerant of cool weather in the fall and seems to assume the role of large insect predator patrolling the pond edges. This is an excellent example of temporal partitioning of the habitat by species that otherwise would compete with one another.

For many months now the predominant sound from our ponds has been the booming call of the bullfrog. But now these dominant amphibians are virtually silent. I still see them around the ponds, especially finding a sunny spot to enjoy the warmth before the advent of frosts to come. This is a male as shown by its very large eardrum and the yellow throat. In the bullfrog world, bigger is better and the larger you are and the deeper your call, the better your territory can be and the more females you can attract to lay eggs.

Although fall is upon us, there is still a very active natural world out there. But in many cases the flowers and animals that are now most active are a different group than we would have observed in previous months. Bird migration is in full swing and there is no doubt that other striking seasonal changes are occurring. So go forth into the natural world and enjoy the spectacle!

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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