Pond life Revisted

The subjects of my interests about microscopy changes from time to time.  I have been crazy about rocks and minerals this summer.   The temperature here has been dipped down to mid 40s degree F (7 degree C) in the early morning although the mid day temperature is still comfortably at mid 70s.  I got to go out to collect some pond specimens for observation before it is too cold for any organism to be active.  I choose different collection site, Briscoe Park Located at Snellville, GA.

The number and variety have been drastically reduced from my early summer observation.  Again, I found seed shrimp (Ostracod) in my collection.

Seed Shrimp (Ostracod)

First time, I observed a dinoflagellate (Ceratium Furca). It is a flagellate protist. I can barely see the flagella because the flagella are relatively transparent.

Diatom

filamentous Green Algae

Unidentified Algae Colony

The specimen was collected in 60 mL tube and split into a several 7 mL tubes and centrifuged in my homemade centrifuge.

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Dragonfly

Dragonflies belong to the Odonata order.  It is characterized by very large mutifaceted eyes, two pair of strong transparent wings and elongated wings.  Dragonflies are similar to damselflies, but the adults can be differentiated by the position of their wings while resting.  Dragonflies’ wings are held to the side and perpendicular to the body while the damselflies held their wings in verticle position.

Dragonflies usually has a life span of more than a year.  The adult dragonflies mate in the air.   After them mate, the female dragonflies lay eggs on the plant in the water.  If they can’t find a suitable plant, they will just drop them in water.  The nymph stage begin after the egg hatches. Dragonfly lives in the water while they grow and developed into dragonfly.   The nymph stage can take up to four years to complete.  The dragonfly nymph will come out of water and turn into adult, once the dragonfly nymph fully grown and the temperator is warm.   They will hunt and start to mate.  The adult stage typically lasts less then two month.

You should not have trouble finding in near by pond during summer since dragonflies are aquatic insects.  We collected a Eastern Amber Wing dragonfly (Perithemis tenera) near a pond at little mulberry park located in Dacula, GA, USA on Jun 26, 2010.

Photos of dragon under microscope

Dragonfly (the end of the abdomen was chewed off by a Katydid whiling fighting in the collecting jar)

Mouth part of a dragonfly (This is a stacked photo from 3 photos)

Dragonfly's head

The front edge of the wing of a dragonfly

Wing of dragonfly

Front leg and compound of a dragonfly

Photos are taken with Tuscen 3.0 MP CMOS microscope camera through the eyepiece of Ample Scientific SM Plus Stereo Microscope.  The amplificion is either 20 x or 40x.

Related post:

My first attempt of making insect slides with common household chemicals at my new blog at http://practical-microscopy.blogspot.com.  The pictrue below is an aphid’s head and thorax. 

The head and thorax of an aphid

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Damselfly

Damselfly is an aquatic insect.  Their naiads live in water. They develop through 10 to 12 immature stages (instars), depending on the species and habitat. The last immature stage crawls out of the water onto vegetation before the adult emerges.   The adults emerge  from water and live for a few weeks to a few months. Mating is unusual: males deposit sperm in a secondary genitalia structure on the second and third abdominal segment by bending the abdomen forward. The male then clasps the female behind the head with claspers on the tip of his abdomen and mating pairs can be seen flying in tandem. The female then loops her abdomen forward and picks up the sperm from the male. Eggs are deposited in emergent plants or floating vegetation or directly into the water. 

Nymph picture: 

damselfly naiad - picture was taken at 40X through the eyepiece of Nexcope CM701 microscope with Tucsen microscope camera

 Adult damselfly (Turquois Bluet damselfly – Enallagma divagans) under microscope 

Damselfly Adult head

damselfly abdomen - anal appendges

Damselfly thorax and the first two segment of the abdomen

 This damselfly appears to be a female.  There are two spikes on the anal appendges but it seems to be too short to hold the female for mating.  The second segment of the abdomen does not have the structure for dispensing the sperms. 

Part of damselfly forewing

Part of damselfly forewing

Damselfly thorax side view

Damselfly thorax top view

Damselfly are closely related to anothe aquatic insects, dragonfly. The damselfly has: 

• long and slender body
• eyes are clearly separated
• all wings are in similar shape and size
• when rest the wings are held close and upright on the top of the abdomen
• The naiad are also slender and breath through gills

The dargonfly: 

• usually stocky
• eyes are touched and on the top of  the head
• Dissimilar wing pairs
• when rest, the wing held open, horizontally or downward
• The naiad has stock body and breath through rectal tracheal gill

You are are living in Georgia, USA or southeast georgia.  Here are the website for our local dragonfly and damselfly websites: 

Dragonfly and Damselfly in Georgia 

Dragonfly and Damselfly of Georgia and southeast by Giff Beaton

Books:
Dragonflies And Damselflies of Georgia And the Southeast (A Wormsloe Foundation Nature Book) (A Wormsloe Foundation Nature Book) (A Wormsloe Foundation Nature Book)

Dragonflies through Binoculars: A Field Guide to Dragonflies of North America (Butterflies and Others Through Binoculars Field Guide Series)

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Copepods

Copepods are a group of small crustacean, ranges from 1 to 2 mm.  They were commonly found in fresh water ponds.  The shape of copepods are like rain drops.  They are characterized by a single simple eye in the middle of the head.  The female copepods sometime carry the some eggs in clusters of egg sacs that are attached to the base of the abdomen.

Copepods female

Copepod egg sacs

Copepod and eggs scattered around it

copepod nauplius

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Molting Daphnia

While experimenting with my home made dark field.  I captured a molting Daphnia.

A molting Daphnia is still in its old outfit.

a molting Daphnia is trying to shack off its old shell.

This Daphnia shell is finally came off.

Daphnia and its old shell (exposure compensation -1)

Daphnia and its old shell (exposure compensation -2)

Related Article: Home-made dark field microscopy

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ostracod – seed shrimp

Ostradcods are a common crustacean, sometime also known as seed shrimp.  Like their names imply, they are very small.  Their typical size ranges from 0.2 mm to 30mm.    Seed shrimps are protected by a bivalve-like shell.  The hinge of the two valves are fused on the top of dorsal region of the body.      

While looking into the recent pond water sample, I can clearly see some little creature clinging to the side of the container occasionally jumped and swam like copepods.  Curiously about what this is, I syphon one of this little creature and place it on a 96 well plate.  It looks like a clam but some tentacle and appendages coming out of the shell.  With the help from the friends from yahoo amateur_microscope group (http://groups.yahoo.com/group/Amateur_Microscopy/message/4713) .  It is identified as ostracod. 

Ostracod at 40x. The size of this ostracod is about 650 um. Legs and tentacles are coming out of the shell.

ostracod at 100x - top view

ostracod side view

The shell of the seed shrimp was crushed. It revealed that there is a crusacean inside rather than Mollusca.

See Shrimp Eggs

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