Thursday, August 29, 2013

Heating and Cooling

Dragonflies are dependent on ambient temperature to warm or cool their bodies. On cool days dragonflies will align themselves perpendicular to the sun's rays in order absorb as much of the sun's energy as possible.This Slaty Skimmer perches with it's thorax and abdomen perpendicular to the sun in order to collect the maximum warmth needed for it's activities.

On hot sunny days dragonflies will point their abdomen directly at the sun in order to minimize the surface area of their bodies exposed to the sun.
This Blue Dasher is in the position called OBELISKING in order to expose the least amount of surface area to the sun and lowering it's body temperature.
Fox Island County Park, Allen Co., Indiana.

Wednesday, August 28, 2013

The Emperor's New Clothes

This Chinese Praying Mantis poses against the needles of a Blue Spruce after becoming too big for it's "britches"' and molting.  The remains of the mantis' skin is to the right of the mantis.  The male Praying Mantis may molt as many as 7 times and the female will molt another 2 times, in most cases. Mantids have excellent eyesight utilizing their 5 eyes.  They are also the only insect that can rotate their heads 180 degrees in order to track their prey.  It's a common myth that mantids are federally protected and illegal to kill.  The truth is that no state or the U.S. Government has a law protecting the Praying Mantis and it's been shown that mantids are their own worst enemy. Most males are eaten by their mate immediately after mating accounting for the greatest threat to mantis longevity.
Photograph by Sue Peters, Allen Co., IN

Sunday, August 25, 2013

Stream Damsels

                                                      Male, American Rubyspot
A damselfly with long legs preferring stream and river banks.  The wing beats of the Rubyspot are relatively slow, similar to that of a butterfly.

Female, American Rubyspot.

                                                Male, Stream Bluet
These three damselflies were photographed near the beginning of the Little River in Allen County.  The Little River is a slow moving stream at this point with heavy siltation and Reed Canary Grass lining the banks. There are many small fish (Green Sunfish, Top Minnows)at this location. The water is primarily runoff from local quarries but of high in dissolved oxygen and low in pollutants.
41 01' 12.94" N         85 12' 27.63" W

Saturday, August 24, 2013

Damsels Not Distressed

Female, Eastern Forktail Damselfly

Damselflies, like dragonflies, are members of the order Odonata.  Unlike dragonflies, damselflies are weak fliers and fly near the ground and surface of the water.  The eyes of Damselflies are separated and Damselflies fold their wings back along their body.

Male, Eastern Forktail Damselfly

Immature. Eastern Forktail Damselfly
This damselfly is newly molted from the nymph stage.  It's colors are not yet developed and flying abilities not well established. Odonata are very vulnerable to predation at this stage in their development.

Male, Fragile Forktail Damselfly
Perches low, horizontally on vegetation of small well vegetated ponds.

Nature Center Pond, Fox Island Co. Park
Allen Co., Indiana.

Sunday, August 18, 2013

The Eastern Pondhawk (male)  Erythemis simplisicollis
The only North American Pondhawk to inhabit Indiana.  The habitat of this dragonfly is ponds, lakes and streams which is the subject of this blog.
The black spots on the leading edges of the forewing and hind wing, near the tip, are called the Stigma.  They are thickened parts of the wings that minimize vibration of the wing when the dragonflies are gliding.  This along with the ability of the dragon fly to rotate the angle of the forewing, creating more lift on the hindwing, allows the dragonfly to glide on wings too small for that occur, in theory.  Dragonflies have had 250 million years to perfect their flying abilities tracing their ancestry back to the Carboniferous Era when their wingspan was 28".

Blue Dasher, male.