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Article- Arthropod/Insect/Dragonfly basics (1 Viewer)

Forcreeks

If you want to see something new in nature, take t
Dragonfly 101 - the basics
By Birdforum member Steve Berliner

Apparently, upon registering at Birdforum.net I was quickly recognized as one who bugs people, for I was invited to write about bugs for this new forum area. After several weeks of well thought delay, here it is:

Pulitzer Prize winning biologist Edward O. Wilson has often called invertebrates "The little things that run the world" because of their huge influence on the world's environment. I remember one PBS Nature program about bees that said there are 1,000 species of fig trees in the world, and every one has just one distinct species of wasp responsible for its pollination.

If you combine the weight of all land animals, arthropods comprise over 85% of the total mass. So you see, elephants and hippos aren't as significant in the weighty department as we might think. And in sheer numbers, Arthropods are said to compose 94 percent of all animal species! (though I'm suspicious that this figure may be for terrestrial animals, also.)

Want another amazing numerical fact? Ninety-nine percent of human and animal waste is thought to be decomposed by invertebrates. Add to this that most agricultural and wild food crops are pollinated by insects; that the food chain largely depends on consumption of invertebrates at the bottom levels, especially for fish and birds, but even people (don't forget food-invertebrates such as Crustaceans, Mollusks, and yes insects); and their natural pest control role (well, yes they're sometimes pests too, but always food), and you can see why human life as we know it would probably not last a year beyond a day in which all invertebrate life ceased.

I'm a birder; but I also love dragonflies and respect and wonder in awe at all invertebrates, most of which are insects. I'm a Birdforum member, and a stream steward directing one watershed group here in Portland, OR… but I'm not a scientist, just a fascinated amateur naturalist. In stream stewardship we recognize the vast importance of aquatic invertebrates, otherwise known as "fish food!" That's how I came to appreciate and adore dragonflies, which spend most of their lives underwater in their larval, naiad stage, though some larva are semi-terrestrial, crawling through bogs, etc.

But lets back up, past even the Class Insecta, to the larger group or Phylum of Arthropods. Now there are other invertebrates (animals without spinal columns) such as worms and mollusks (clams, snails, slugs, squid, etc.), and of course all the single and simple-celled animals too small to see, with unaided eye.

Of all known animals, Arthropods are by far the most numerous in distinct species. In fact, while the class Insecta comprises about 95 percent of Arthropod species, insects also compose over 50% of all known living plants and animals! You might keep in mind that unlike Mollusks, Crustaceans (crabs lobsters, sow bugs, etc.) are also arthropods. Arthropod means "jointed foot", and we typically refer to arthropods' segmented bodies, and hard exoskeletons.

Interestingly the entire Arthropod phylum is thought to have evolved from an annelid (earthworm) type ancestor, evident in the fossil record. Within arthropod species the remaining 5+% which are not insects are found primarily in the Classes of: Crustaceans, Arachnids (spiders, mites, scorpions and kin), Centipedes, and Millipedes, and there are at least another five Classes of Arthropods with relatively few total species. Just as insects compose one Class of the Phylum Arthropods (Arthropoda)... Mammals, Birds, Fish, Amphibians, and Reptiles compose five different classes of the Phylum Vertebrates (Chordata). There, how's that for putting the Animal kingdom into some sort of perspective?

Below Class, are the different animal Orders, such as Rodent within the Mammal class, and beetles within the Insect class. Note that beetles (Order: Coleoptera) is prominent as the most species-diverse Order within Class Insecta, with its over 300,000 beetle species. Perhaps a total of around 1 million insect species have been identified, so beetles occupy about 30% of them all.

Order Lepidoptera, containing Butterflies, moths, and kin does very well, with about 200,000 species. A poor third are the bees, wasps, and ants (Order Hymenoptera) with species numbering in the low 100,000+ range. Slightly behind them are the many Flies species (Order Diptera), after which no other order of insects really comes close at all in species count, though there were still twenty-five other orders in my (admittedly 1980's) insect reference book. Taxa, and species grouping are part of an ever changing catalogue of life forms. (added May 9, 2003: The current edition of Smithsonian's guide to insects also shows 29 Insecta orders.. this is a small, extremely informative, and beautifully presented, book well worth the nominal purchase price.)

"Today I saw the dragon-fly
Come from the well where he did lie…
Thro' crofts and pastures wet with dew
A living flash of light he flew"
-Alfred Lord Tennyson

Oh yes, my favorites, the Dragonflies! Weighing in at just about 5700 species worldwide (still well over the known count of Mammal sps.), they are widely thought of as the flying jewels of the insect world, just as hummingbirds are so for the bird world. Where they may fall short of the beauty within the hugely more diverse Order of butterflies, they make up for it with their glistening sparkling colors, gossamer wings, and absolutely astounding flight capabilities.

A dragon can go from 0-30-0 mph in a second or so, change directions on a dime and triangulate it's prey's flight path in order to intercept it without the victim ever knowing it was pursued. The Order Odonata means, literally "the toothy ones", named for the larva's amazing extendable lower lip which can jut forward (as much as one third of body length) to grab prey in the merest fraction of a second.

Keep in mind that "Dragonfly" meaning the entire Order of Odonates includes two main sub-Orders: the larger bodied dragonflies which I'll elaborate on, and also the damselflies, their far more delicate cousins who hold their wings back over their bodies tent-like, instead of out to the sides like the dragonflies (notice the uncapitalized "d"). Their species counts are similar though the dragons are thought to outnumber the damsels at about 3,000 vs. 2600+ worldwide identified species.

Other differences between these two sub-Order Odonates are that dragonfly eyes often touch together while damselfly eyes are always at least an eye-width apart; the larva have two different means of locomotion (only dragonfly larva have "jet-propulsion", by expelling water); different number of abdominal appendages for clasping the female when mating (three vs. four), and dragonflies clasp the female at rear of head, while damselflies grasp female at front of thorax (middle segment). However both kinds of Odonate have head, thorax and 10 abdominal segments, two proportionately large compound eyes, and of course the six legs as with all insects.

There's a wonderful new field guide to North American dragonflies (no damsels in it), by Sidney Dunkle called Dragonflies through Binoculars, in paperback of 300 pages of which 47 pg. are color plates of the insects with opposite page giving range map, season and brief description. Then the forward 248 pgs. give elaborate species descriptions and information. Dunkle has divided our 307 species into seven proper Families (the next nomenclature level down from an Order): Petaltails; Darners; Clubtails; Spiketails; Cruisers; Emeralds; and Skimmers.

In ponds near my home (urban area!) I find quite a few Skimmer species and several Darner sp., some photos of which I've posted in the Insects Gallery. I mostly digiscope them while they perch between hunting forays; but darners often won't land all day long on a sunny day, and you have to net them. It's strictly catch and release for me. It's a bit of a thrill holding in your hand a flying wonder that has changed little in 300+ million years!

I'd love to read in the forum of different family classifications in UK and elsewhere, and other differences and unusual Species or Families of Odonates outside North America. Does anyone else attempt to net them, and if so do you photograph them? Does anyone collect (kill) specimens, or attempt to raise them from larva? Does anyone know the species counts for Europe, Africa, Australia, etc.? Any unusual or memorable experience with dragonflies? Did your parents misinform you that they bite or sting, and to avoid them? How about that darners will stitch your mouth shut during sleep? A horrid folktale, and I hope they added, "if you're bad!"
 
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Surreybirder

Ken Noble
One extra fact that I found fascinating:
apparently a fossil dragonfly has been found with an 67 cm wing span!
 
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Forcreeks

If you want to see something new in nature, take t
I tried the link and couldn't find the article. Please give link name once at above site...
My gawd! I'd heard the fossil record indicates the early ones "approached" 2-foot wingspans, but that's only 60 cm!!! "Fascinating" is understatement. We often note how Dragonflies are pretty harmless, not being stingers, and rarely biting anything too big to eat. I had a small skimmer take a bite at my finger and the tiny pinch surprised the heck out of me, but is hardly noteworthy as an animal bite, even for an insect. But those suckers you mention probably could've taken your hand off! Wouldn't you just love to see a living example or good accurate model of a live one, bright eyes and all? Thanks!
 
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Cindy M

Guest
well done Steve, very well written and well thought out piece on odonata- I too have a great passion for odes and all of the wonderful & fascinating insects we share our world with. Dragonflies are a good indicator species, allowing us to monitor the state of the environment. Insects like dragonflies can be of special concern and some species have become rare or endangered.
I use the 'Dragonflies Through Binoculars' guide, but the small Stokes 'Beginners Guide to Dragonflies' is a little gem of a guide too in that it shows some of our more common damselflies, which most guides do not cover & it's great for learning the basic families of odes. 'Dragonflies of Indiana' is reportedly a great guide that covers most of the species in N. America, but I haven't had the opportunity to check that one out yet.
Happy dragon-hunting :)
 

Forcreeks

If you want to see something new in nature, take t
"it shows some of our more common damselflies, which most guides do not cover " -Cindy M

So true, and I definitely need a good guide to damselflies. We do have a complete little paperback of both suborders for Ore. and Washington, but not of N. Americal overall. Thanks for both references. Different guides give us additional field mark tips and insights, don't they?
Surreybirder's suggested web site above has some really nice photos on it, and other not as good ones, but a nice visit for an American web tourist. -Steve
 

Cindy M

Guest
I think someone could do an entire guide on bluet damselflies alone :)
I belong to Great Lakes Odonata group, which has been very helpful with alot of my questions and identifications. Way over my head though, they trap/catch & net odes, but really nice folks. I've been asked to send in species along with my images to document them in my county, but I really don't have time to do that. Same with moths and butterflies, I use my camera instead of a net :)
 

steve_nova

Well-known member
An excellent and informative read. I really love Dragonflies and find it amazing too that huge species once existed. They must have sounded like helicopters!
One group that you have touched upon, the Acari or Mites are a very diverse group even though not insects. I read somewhere that they (as a group) have new species being discovered all the time, especially in the tropics and might even match the insects for sheer range of lifestyle and form.
Thanks again for an excellent read.
 

sparroweye

Well-known member
Damsel Fly

I did not even know what a damsel fly was. Then yesterday
I was describing this beautiful insect to my niece which had wings straight up the color of turquoise hovering over my gold fish
pond. She immediately told me I had described a damsel fly.
She said on her last kayak trip that she had damsel flys just
clinging to her jacket like lightening bugs. I would have liked to
have seen that. I had never seen a damsel fly over my pond, only
common dragon flys. We sometimes have this large species of
dragonfly that dive bombs our mobile home. I love both of these
species, both dragon fly and damsel fly. I shall try and take a
photo of the next damsel fly visitor and post here.
 

Forcreeks

If you want to see something new in nature, take t
Like many of you, I can hardly wait for the Odonates to start emerging in good numbers, counting and comparing species to my previous two yrs at this, and taking their photographs.. posting some to our gallery of course. Steve
 

Screech

Well-known member
Steve, great discourse on "Insect Basics", you opened my eyes to a new world. While birding you see dragons all the time, but when you think about the vatiety of species its mind boggling!
Oh, and really enjoy your pics!
 

jayhunter

Well-known member
Nice one Steve, last weekend took the Grandsons down to the riverbank for a picnic, and tried to get them interested in the dragon and damsel flies that abounded there. I couldn't afford too much time in my own pleasure, as two 5 and 6 year olds on a river bank could be quite dangerous!
 

Surreybirder

Ken Noble
Forcreeks said:
I tried the link and couldn't find the article. Please give link name once at above site...
My gawd! I'd heard the fossil record indicates the early ones "approached" 2-foot wingspans, but that's only 60 cm!!! "Fascinating" is understatement. We often note how Dragonflies are pretty harmless, not being stingers, and rarely biting anything too big to eat. I had a small skimmer take a bite at my finger and the tiny pinch surprised the heck out of me, but is hardly noteworthy as an animal bite, even for an insect. But those suckers you mention probably could've taken your hand off! Wouldn't you just love to see a living example or good accurate model of a live one, bright eyes and all? Thanks!

Steve,
I don't know where there is a pic of the giant dragonfly but I saw a reference in a book on our local (county) dragonflies. In case it's of any interest, I'm attaching an article I wrote for a local bird newsletter(!). I'm sorry that some of the references will not mean much to anyone who doesn't live in Surrey, but I hope that there may be a few interesting snippets in it:
Ken

East Surrey's odos

When pterodactyls first took wing, some 200 million years ago, there were other flying creatures that had already been around for 100 million years. And their descendants are with us today, little changed, the odonata (dragonflies and damselflies). The largest known fossil dragonfly had a wingspan of 67 cm, similar to that of a kestrel.
Some of the odonata fossils found in Surrey date back over 125 million years. Valdaeshna surreyensis (dubbed 'the Surrey dragonfly') is the best preserved Cretaceous odonatan found so far in southern England and looks remarkably like a modern dragonfly.
Dragonflies are amazing insects. They can fly forwards, backwards or upwards with equal ease, like a helicopter. Their huge compact eyes, each of which may have 28,000 lens cells, give them all-round vision which they use to capture their insect prey in mid-air. For most of their lives they live underwater, the larger species taking up to five years to develop from egg to flying insect. The larvae are voracious predators, eating tadpoles, sticklebacks and smaller larvae. Periodically they shed their skins and emerge as the next stage larva. In due course the final stage larva crawls out of the water and clings to a suitable perch. The skin cracks open and the dragonfly emerges. Once its wings have inflated and hardened, the immature odo-as enthusiasts tend to call them-flies away from its natal pond or stream. After a week or so it returns as a mature adult to breed. Mating odos adopt an extraordinary 'wheel' position, and they can sometimes be seen flying like this.
Dragonflies of Surrey, by Peter Follett (Surrey Wildlife Trust, 1996), is the main source of information about the distribution of Surrey's odos. He lists 13 damselflies and 23 dragonflies but one (White-faced Darter) has recently become extinct but the discovery of a few Scarce Chasers in 1996 offset the loss. A 19th century of another species is considered doubtful. The Small Red-eyed Damselfly recently colonised south-east England and has been expanding rapidly so it is likely to be found in Surrey soon. It is very similar to the Red-eyed, so care needs to be taken with its identification.
There is a much smaller number of dragonfly enthusiasts than birders, so there is scope for new discoveries. In my brief involvement with odos I have seen several species that are new 'tetrad' records, including White-legged Damselfly (at Coltsford Mill, Hurst Green, and near Townland Pond, Old Oxted) which was almost unknown in north-east Surrey when Follett's book appeared.
Good places to see odos in our area are Bay Pond, Godstone, which has the hyperactive metallic-coloured Downy Emerald, and the small pond by the traffic lights on the A22 in Blindley Heath. I have seen Downy Emerald, Emperor Dragonfly, Four-spotted Chaser (another species almost unrecorded in our area in Follett), Black-tailed Skimmer, Red-eyed and several other damselflies at the latter site. Hedgecourt and Wire Mill Lakes and the fishery between should be productive.
My interest in odos was sparked after we dug a small pond in our garden. Almost immediately damsels started moving in and my garden list now stands at eight species, including the spectacular Southern Hawker, Broad-bodied Chaser, Beautiful Demoiselle and, to my surprise, a single White-legged Damselfly.
So when the weather turns warm and the birds are not showing, I would recommend a lazy hour watching odos by a local pond or stream.
©Kenneth Noble, 2003
 

Surreybirder

Ken Noble
PS
Since writing the above, I have now seen small red-eyed damselflies in Surrey (at the Blindley Heath site mentioned, but not found by me).

Also, there is actually a third sub-order of Odonata which only has two species, I believe, relics of earlier, more wide-spread genera. Steve will no doubt have the info?
 

Forcreeks

If you want to see something new in nature, take t
Great Article Ken. My interest and time involved parallels yours. I too have read of this third Suborder; being Anisozygoptera, a word combination of the other two Suborder names. I believe these Asiatic "Living Fossils" (two species) have features common to both Damselflies and Dragonflies, though I don't have any good accounts of them in my materials. Thanks for adding to the depth of good common Odonate knowledge Birdforum enthusiasts can pick up right here. -Steve
 
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sparroweye

Well-known member
It seems like we have less dragonflies and lightening bugs in
Florida than we had 20 years ago. I often wonder if the fear
of disease and the spraying for mosquitoes has hurt all of the insect population. In Gainsville Florida they say they spray with
something that just interrupts the incubation of mosquito's but
would not that affect all insects which use the waterways for larvae and eggs? There must be another answer to control
harmful insects like mosquito, ticks and fleas.
 

Forcreeks

If you want to see something new in nature, take t
In my urban area here, around Portland, OR, the natural pathogin BT, a bacillus "germ" is the choice treatment of open waters for mosquito larva. Once the larva pupates, it's not effective, an that's where "Mosquito fish" Gambuzia? come in handy. They are said not to survive well in free flowing waters, however in sedentary water they should do well.
I too wonder at side effects of BT treatment, and would love to hear from a biochemist, or other qualified opinion about potential dangers. I'm sure many of you are already aware of the undesirable effects on butterflies of the genetically altered BT Corn, and that such corn had been "inadvertantly" distributed to restricted locations worldwide. I'm pretty well out of my element, but have read a few articles. -Steve
 

loggah

Well-known member
I'll drop in my two cents worth, too, Steve.

I am a newbie dragon/damselfly enthusiast. Even though I have seen them all of my life (Yes - my parents told me about "darning needles" that would sew up the mouths of naughty children), I had never really SEEN them until last summer. Now my head turns at every flash of wings! They are exciting to watch and identify. I do wish there were more and better field guides. Unless I find one with exactly the same markings as illustrated, it is tough to ID them, especially females and juveniles. And, of course, there is the problem of geographic variation in color and pattern. If only Sibley would do a dragonfly guide ....

Oh well, I guess if it was easy, it wouldn't be so much fun!

Thanks for this article. I am going to send you a private message with a meadowhawk I am having trouble with. If you have a minute, will you take a look?

Thanks

Cheryl
 

jvhigbee

Keep trying to improve. If you succeed, try again.
loggah said:
I'll drop in my two cents worth, too, Steve.

Oh well, I guess if it was easy, it wouldn't be so much fun!

Thanks for this article. I am going to send you a private message with a meadowhawk I am having trouble with. If you have a minute, will you take a look?

Thanks

Cheryl

Cheryl,
I want to try also.
Joe
jvhigbee
 

brianfm

Botanical Birder
I have just read this thread. Great read for someone like me who has almost nil knowledge in this area. I have recently stated in another thread that this autumn and winter, my reading is generally going to be devoted to insects etc. I am a birder, but always envy those with a much wider knowledge of natural history. Well having read this thread my interest has been heightened. I shall be reading it again to ensure I have taken it in. Thanks a lot.
 

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