Questions That Arise During Nature Study in SW Florida During Late Spring

Most things in nature intrigue and often mystify me. I like to paraphrase the saying that nature is not rocket science, it is far more complicated !

In addition to the intrinsic beauty of flowers, biologists find evolutionary meaning in variable colors and form. For example look at the flower of a Cassia fistula which we planted to attract egg laying by sulphur butterflies. It has five large yellowish petals, short male stamens, and the inner structure is open to insects such as this large carpenter bee; the female style curves around to the outside where it could intercept pollen packets attached to incoming bees. In contrast, the Jamaican caper we planted has very long stamens and even longer styles. It is whitish and emits a strong scent at night, presumably to attract sphinx moths. These moths have a very long tongue, they hover while feeding, and the arrangement of the flower’s sexual parts seems designed to fit this insect anatomy and behavior. Thus we can see how insect pollinators and their flowers co-evolved for mutual benefit.

A very young gopher tortoise seen in Manasota Scrub is a rare find. Why is that – are they truly rare or just secretive to avoid predation? Probably the latter since these tiny turtles have soft shells and could easily be crushed by a mammalian predator, including domestic dogs. Fortunately gopher tortoises live a long time so survival of the young may be slim but sufficient for maintenance of the population, unless adverse human influences intervene.

In the past week I came across two large yellow rat or chicken snakes, something I do not often see. The warmer weather has likely increased their movements. These large climbing predators on birds and mammals are colored very differently when young when they are blotched. Their close relatives, the corn snakes, are brightly colored in orange and black, and their northern relatives are blackish. Why so many different colors is not clear, but the lined adult pattern is believed to make it more difficult for a predator to focus on one spot to attack. These are of course harmless to humans and beneficial when they eat rats.

Neotropical bird migration is nearly finished and I was surprised to see three migrants in our yard this week, a spotted sandpiper, a thrush (a veery), and a northern waterthrush (a warbler). It is usually argued that the latest migrants are waiting for their far northerly breeding spots to warm up. This may apply to the spotted sandpiper since we saw one a few days ago in NC where it had fewer spots than this individual still in FL. The range map shows that this species has a very wide breeding range extending from the Blue Ridge mountains of NC to northern Alaska and Canada. So it seems likely that the tardy migrators are the most northerly populations.

A conundrum I have noticed lately is that manatees are regularly seen along our dock next to the neighbor’s bulkhead. The photo shows a young individual but there have been numerous others of larger size. They push up against the bulkhead in a determined manner so that I suspect that fresh water, possibly from a sprinkler system, may be leaking into the sea water attracting the manatees for a drink.

So let us not simply enjoy the wonders of nature but remain alert to their patterns and possible rational explanations.

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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