Forcreeks
If you want to see something new in nature!
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!"
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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