Sunday, May 15, 2011

Red-eared Turtle - common resident of ponds

Red Ear Slider hiding as it migrates in search of another pond. Note the red marking.
Common among Southeast Texas forests are small bodies of water known as "ponds". Inhabiting these ponds are the Red Ear Slider turtles. Typically there are plenty of plants and food for these amusing creatures to flourish. Like other reptiles, they require the sun, which warms and dries them. Their common name comes from their shyness and ability to "slide" off of rocks and tree limbs. Their anatomy includes papillae which function as gills to allow them to remain underwater for long periods of time, and a shell, which covers their vital parts to protect them from enemies such as a snake. Unique to the turtle is its ability to live for an extended time. Its vital organs do not deteriorate like other creatures over time. Longevity of the human body is being studied relative to this phenomena.  A turtle can be eaten but beware of salmonella, which it is known to carry. Their eggs can also be eaten, but it is made from a different protein than that of a bird. Note that it is generally not a good idea to eat something taken from a pond  located in a human residential neighborhood.
Red Ear Sliders ready to slide off of the floating wood

This particular turtle has been a resident of our forests for ages. Trachemys scripta elegans) is the most likely species to be seen in this part of the country and has been long long before man inhabited this continent. Eggs are laid in the soft sandy dirt of low-lying ponds and hatch without parental care. In fact, adults will eat their own young. Sliders will eat about anything from plants and animals to worms and fish. They will gorge themselves on fish waste (remains after cleaning for human consumption). Freshly hatched babies are popular as pets because they can be easily handled by a human without any consequences. I would not stick my finger however in its mouth. It can bite, if provoked, but it is not inclined to be defensive with its mouth. Its defense to withdraw its head into its shell. This strategy has worked some 215 million years to protect it from harm.

This Red Ear was in the street migrating from one pond to another
You might notice that the reptile is not seen much in cold weather. It goes to the bottom of the pond and waits it out, like a bear retiring for the winter into a cave. It is affected also by drought. In a pond, there is usually a balance of numbers.  It's population in a pond is founded on volume of water, which affects the ability of the pond to sustain life in general. The food chain dwindles with the reduction of water volume. Therefore, the turtle migrates from one pond to another to seek that balance instinctively. At the time of this article, I personally am experiencing an unusual frequency of sightings off the pond in abnormal places. Turtles can also migrate in order to find a mate or in search for an appropriate place to lay eggs. This year, the water's edge has retreated about six feet or more in the pond near my home, causing the normal vegetated shore to dry up and crust, removing the nesting habitat that normally exists. I expect to see attrition of our Red Ears during the current drought. There is nowhere to migrate to either lay eggs or to redistribute the current population.

Sunday, May 1, 2011

In search of the Pawpaw Butterfly - a strange beauty

Zebra Swallowtail  (Eurytides marcellus) drinking from dung after a short rain
To start the month of May, I joined a group of Butterfly enthusiasts to search for specific species and in general to count butterfly species in one of the great national forests of East Texas, The Big Thicket National Preserve near Beaumont, Texas, a short day trip from the Houston area.  When you see the Zebra Swallowtail, (Eurytides marcellus), you have no doubt whatsoever what you have seen. It is one of the easiest butterflies to identify.  But seeing and watching are two different things with this species. With its size, it easily escapes your presence instantly with the speed of a race car and the aloof attributes of a Turkey. Often all one gets is a rather short glimpse of this species unless it is feeding. On this day we were lucky. We happened on a male feeding on dung after a rain. Yes, in order to mate effectively, the male feeds on urine, dung residue and rotten fruit to enable it to impregnate the eggs.
PawPaw plant

Pawpaw fruit

Eggs are laid on its host, the interesting Pawpaw plant, abundant in the woodlands of the south. In a butterfly count, we expect to see the Pawpaw Butterfly, but not observe it. This day we watched it for 10 minutes as it feasted on its sperm food, then it returned again and again. It posed for the camera.

A member of the Kite family - note the tail
    This large butterfly inhabits only places where species of the Pawpaw plants exist. The larvae gets important nutrients from the plant that is found throughout its life cycle other than the egg. It is believed the survival of the fittest theory plays a role in this, because the chemical nature of the plant provides a "birdicide". It wards off attacks by birds, thereby enabling it to survive in the forest.

+ Wikipedia