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Author | Topic: Winter Project | |||||||||||||||||||||||||||||||||||||||||||
Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 9.8
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At the moment I am taking a break from mowing my lawn, but on most days I am observing & photographing the development of embryos inside a clutch of 180 dragonfly eggs oviposited on Nov. 1, 2020. This is the 6th species within a group of closely related species I have worked with in this project that I started in 2017.
All eggs in the first 5 species were quite closely synchronized (within each species) in the timing of all developmental stages and hatching occurred in each group within just a couple days of each other. All the eggs were reared under the same conditions of temperature and photoperiod. The species I am working with now is completely un-synchronized. The eggs all entered diapause (delayed development) after about 4 weeks, but then one egg recommenced development in January and hatched in early February. There was just a steady trickle of a couple a couple a day getting ready to hatch. There are still a few eggs that have not come out of diapause yet and at the same time I have nymphs that are in their 5th instar (molt). There may be between 10 and 17 instars depending on species and environmental conditions. The species I have reared out so far can all share the same general habitat. I am trying to understand what kids of selective pressures would bake these developmental strategies into their genes. When they hatch from their eggs they immediately shed their exoskeleton (the first molt) and become tiny little predators about 2mm long. They are partly transparent so I can see their internal structure and watch their respiratory contractions. Lots of things will eat them but they are fearless and routinely take on prey larger than themselves. Until now, only a few species have had the development of eggs and nymphs documented, but an addition positive aspect of these projects is, for me, the development of very specialized photographic equipment and technique, to capture the details of this fascinating and complex process. CheersWhat if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq
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AZPaul3 Member Posts: 8654 From: Phoenix Joined: Member Rating: 6.8 |
Yeah, so you say, but it didn't happen until you show us pictures.
Lots and lots of pretty pictures.Eschew obfuscation. Habituate elucidation.
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 9.8 |
I sent you a PM.
What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq
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AZPaul3 Member Posts: 8654 From: Phoenix Joined: Member Rating: 6.8 |
I can appreciate your concerns. Too many crazies in this world.
I do have a q? You said your first batch was synchronised while the second was not. Is the difference your selection process, luck of the draw or is there something else that accounts for the difference?Eschew obfuscation. Habituate elucidation.
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 9.8
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You said your first batch was synchronised while the second was not. I'm sorry, I was unclear. There were 4 prior batches or species. Each species was unique and synchronized only with itself. The 1st Species, Aeshna palmata oviposited more than 1200 eggs on 9-Oct-2017. The eggs were kept at a constant 68F with diffused daylight. They developed for 4-5 weeks and entered diapause. The 1st embryo resumed development 1-Jan-2018 and all the eggs had resumed within a week. The sign that development has restarted is each embryo actually switches ends inside the egg in a process called katatrepsis. The embyos continued development and began hatching in about 5 weeks and were all completed in 3 days. The 2nd and 3rd species were both oviposited on 8-Aug-2018. The 2nd species was Rhionaeschna multicolor and it gave me 750 eggs that went through very rapid development and the eggs all hatched in 16 days. The 3rd species, Aeshna interrupta developed for 4-5 weeks and seemed to be in diapause. Diapause ended in March and the nymphs all hatched within the same week in April. In 2019 I was not able to get any of the Aeshna/Rhionaeschna females I collected to lay eggs for me. This family, the Aeshnidae, all oviposit endophytically, that is, into vegetation or other soft material like wet floating wood. I induce oviposition by placing a female in a gallon sized container with wet unbleached coffee filter papers on the bottom. stored in a dim cool place for a day or so and the coffee filters will be riddled with eggs, that I have to very carefully under a microscope extract the eggs from the paper without getting fiber stuck all over them. Tedious work, but I can also have sets of images or videos shooting and some classic rock or an audiobook and I an in the zone. I did get eggs from a bunch of dragonflies that were kind enough to actually drop their eggs into a vial of water if you tap the tip of their abdomen on the water surface. In May of 2020 I got about 500 eggs from a female Rhionaeschna californica that also went through rapid development and they all hatched on day 21 and 22. And now I am watching the 5th species, Aeshna umbrosa, that is asynchronous in development. My hypothesis is that each species has a unique embryo development genetic program. Each of these species has a flight season that is months long so there has to be some plasticity built in depending on when the eggs are laid. Development is accelerated or delayed depending on species, but triggered by photoperiod. In other orders of insects photoperiod and temperature are the determining stimuli.What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq
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AZPaul3 Member Posts: 8654 From: Phoenix Joined: Member Rating: 6.8
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So the asynchronous nature of Aeshna umbrosa is natural while the other four are all synchronous by nature. Are there major differences in environmental niche the 4 inhabit vis-a-vis Aeshna umbrosa? Seems it would have to be if the photoperiod is the determinant.
Unless ... What is the timeline in the natural habitat for each species? Do they develop at different times during the season? Timed with predation? What of the possibility that Aeshna umbrosa was late to the evolutionary party and this asynchronous timing was advantageous due to competition? I'm just spouting. I'm not a bug guy. I have no idea what I'm talking about. But this is interesting. Edited by AZPaul3, : No reason given.Eschew obfuscation. Habituate elucidation.
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 9.8 |
So the asynchronous nature of Aeshna umbrosa is natural while the other four are all synchronous by nature. Are there major differences in environmental niche the 4 inhabit vis-a-vis Aeshna umbrosa? Seems it would have to be if the photoperiod is the determinant. Unless ... The microhabitat of A. umbrosa nymphs seems to be pretty much the same, and I have never seen an analysis that compares the microhabitats. Beyond 4th instar all dragonfly nymphs will prey on other nymphs if they come in range of their prehensile labium (lower lip). The flight seasons of adults of all these species are different but some of them overlap quite a bit. They are all large strong flying insects that are habitat generalists rather than specialists. The nymphs of these species are all prey stalkers rather than lying in wait and ambushing their prey. They hunt primarily by vision but are also very sensitive to vibrations.
What of the possibility that Aeshna umbrosa was late to the evolutionary party and this asynchronous timing was advantageous due to competition? Avoiding competition with conspecifics could certainly be a factor and with other species to a lesser extent. Edited by Tanypteryx, : No reason given.What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 9.8
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The oldest A. umbrosa nymph is now in instar 6 and there are still 3 eggs out of 180 that are in diapause and about a dozen that have completed katatrepsis and will hatch within the next 2 weeks. The asynchronous development pattern of these eggs has continued. All the eggs developed normally and entered diapause and then a couple months later 1-4 eggs per day would end diapause by going through katatrepsis, continue developing for 2 weeks and then hatch.
Every other species I have reared were quite synchronized in embryo development and hatching and that would plot against time in a steep, narrow bell curve, this includes closely related species in the same genus. In the early 80's I reared 2 species that each took 5 years to develop from egg to adult, Cordulegaster dorsalis and Tanypteryx hageni. After 5 years I had a dozen or so surviving C. dorsalis nymphs. Several weeks before they are ready to emerge the nymphs would crawl out of the water onto twigs to explore. I placed a dry woody shrub branch in their habitat to crawl out on and got my camera all set up ready to record metamorphosis into adults. All week end I waited.... Monday morning I had to go to work at 4:00 AM, at 5:00 my wife called and said, "they are hatching!" I told her to shoot them and she got a wonderful series of shots that show all the stages of metamorphosis. So, after 5 years they all emerged within minutes of each other. The Tanypteryx eggs were spread over 3 days but that's still incredibly tight.What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq
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dronestar Member Posts: 1459 From: usa Joined:
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Hi Tanypteryx,
Not sure if this is the best place to add this, sorry in advance if this is too off-topic for the thread, but I found the most interesting site of infographics that included the moving wing pattern of a dragonfly:Tabletop Whale I expected the wings to move symmetrically, at least in pairs, (as all other insects, and birds?). However, while the poster cautions that this isn't a fully accurate scientific representation, the animation does seem to show that the wings move in a rotational style, almost like a rotary asynchronous piston engine pointed upward. I've always marveled at how quick and maneuverable the dragonfly can fly, and if the movement's depiction is correct, I was just wondering if you could give more/any information about its evolved wing pattern. Or debunk it. : ( thanks
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 9.8
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It's always interesting to see these kinds of demonstrations and comparisons, so thanks.
There are some high quality, high speed videos of dragonflies in flight these days that really show the patterns of movement for different kinds of flight. Dragonflies and damselflies are unique among the insects because their flight muscles attach directly to the bases of the wing and each wing can move independently. Your diagram isn't showing normal wing movement because it shows the hindwings following the forewings. In normal flight and hovering, the forewings and hindwings move opposite each other, when the fore wings are up the hindwings are down and vice versa. The forewings create turbulence and the hindwings use those vortices for lift, speed and maneuverability. The wings can all rotate and twist around their longitudinal axis and are incredibly flexible. All other flying insects fly by muscles attached to the walls of the thorax flexing them and moving the wings. The odonates split from the other insects shortly after flight evolved. Now for every general rule there may be exceptions. In Costa Rica I encountered some huge damselflies, Megaloprepus caerulatus that fly with both wings synchronized, up and down together. I think this is the largest living odonate as far as body length and wingspan. There are a fairly large group of damselflies in the neo-tropics that have long abdomens for ovipositing in various kinds of treeholes that have water and mosquito larvae for prey. They are often called helicopter damselflies. The wings of many odonates are also colored and banded or spotted with every color imaginable and are used for all sorts of display for possible mates and rivals. Many years ago I met a fellow at a meeting from Germany named Georg Rüppell who was doing fantastic high speed filming of dragonflies in flight in the 70's and 80's and 90's. Some of his stuff may be on YouTube.What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq
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dronestar Member Posts: 1459 From: usa Joined:
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Thanks for the info Tanyp, verrry interesting.
At the moment I am interested in the early history of flight when man tried to authentically copy birds, with usually disastrous results. Kind of understandable, birds DO make flight look easy, . . . go figure. But scientists today have shown how really complicated their flight is. For example, until recently, I never knew that birds obtain lift when their wings move FORWARD. The infographic kind of shows this. Back to the dragonflies, thanks for confirming, their wings can move independently and longitudinally, but normally move synchronously in pairs. They are a marvel to watch when flying. Perhaps the humming bird is the only other magnificent flyer to compare. I know in prehistoric times, dragonflies were enormous. So I had to google Megaloprepus caerulatus to see how big we have them now: I've quickly googled Georg Rüppell. Found his name but didn't find his films. In my travels, I've seen some amazing insects. I remember seeing a wickedly cool looking metallic purple bumblebee in Uganda. Colorful beetles in the Amazon rain forest. For some reason I often see a single praying mantis during a visit. The mantis are good photo subjects. You can get really close, they are not fidgety or scared. But dragonflies . . . never once did I ever photograph a dragonfly, closeup. It amazes me that you do this for a living. You must be a 'dragonfly whisperer.'
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Percy Member Posts: 22940 From: New Hampshire Joined: Member Rating: 6.9 |
dronestar writes: I know in prehistoric times, dragonflies were enormous. Prehistoric is when humans existed but were not recording events. Giant insects existed in the Paleozoic more than 250 million years ago, which is approximately 250 million years before humans. I was wondering if the prehistoric mislabeling originated on the Internet and found that Google listed a couple of similarly malformed questions: "Why were insects bigger in prehistoric times?" and "How big were bugs in prehistoric times?". Check out this webpage at the usually technically savvy EarthSky website: Why were prehistoric insects so big? --Percy
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dronestar Member Posts: 1459 From: usa Joined:
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Hello again Tanypteryx,
I think I am rapidly becoming a dragonfly enthusiast. Can I come with you on your next research trip? I could help carry the gear, scout photo locations, and make strawberry daiquiris when back at the research tent. I found the following web site as an example of dragonfly flight (sorry, not sure how to embed video into this forum): https://youtu.be/m5XUdvBO_TE Do dragonflies see in slow motion? | The Kid Should See This The website shows examples of slowed motion videos of dragonflies in flight. It shows the wings operating, at least temporarily, autonomously/out of sync as you reported. Extremely interesting. But the reason I am posting is because I have found another interesting aspect. According to this BBC video, the dragonfly can supposedly see in "slow motion." While humans can see at about 60 frames per second, dragonflies can see about 200 frames per second. (Houseflies can see about 250 frames per second). So I am curious, . . . a four-propellor drone helicopter sometimes has on-board 6-axis gyro to steady it's flight. I am presuming the dragonflies high frame rate of sight also helps the dragonfly in flight, particularly when chasing (and catching) its prey. The microprocessor of a 'brain' that links its individual wings and 360 degree sight in nanoseconds is a wonder. Can you comment?
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 9.8
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Hey dronestar, thanks for the great video. I sent the link to my friends. We talk about these sorts of things whenever we're in the field together, and of course the rest of the time too. We're starting to make lots of video clips in the field and whenever we slow them down we can see new high speed behavior. I have shot lots of subject in flight with my still camera also and one interesting observation is that they maintain the position of their head parallel to the horizon even when their body is rotated 90 degrees in a high G turn.
So I am curious, . . . a four-propellor drone helicopter sometimes has on-board 6-axis gyro to steady it's flight. I am presuming the dragonflies high frame rate of sight also helps the dragonfly in flight, particularly when chasing (and catching) its prey. The microprocessor of a 'brain' that links its individual wings and 360 degree sight in nanoseconds is a wonder. Humans could not pilot a quadcopter drone anywhere near the speeds and high G maneuvers that dragonflies perform. We clearly cannot process visual information that rapidly. The flight to capture prey is quite slow and mostly just short sprints because most prey probably doesn't see the dragonfly. This is also true with the dragonflies that are on the wing continuously, just a short spurt for prey. The real high performance flight is when males are clashing with rivals or pursuing mates. They can follow their targets and track them through and against incredibly complex visual backgrounds. And it's not just rapid 360 vision, but also broken into many more distinct bands of color as well as ultraviolet. Humans have 3 opsins to see red, blue and green, whereas dragonflies may have 30 or so opsins.
I think I am rapidly becoming a dragonfly enthusiast. Can I come with you on your next research trip? I could help carry the gear, scout photo locations, and make strawberry daiquiris when back at the research tent I will PM you with some info you may find interesting.What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq
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dronestar Member Posts: 1459 From: usa Joined:
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Thanks for the reply and info Tany,
"dragonflies may have 30 or so opsins." Wow, I had thought only a few other animals had more opsins than man (some octopus have a dozen?). But an insect with 30? Amazing. A 10-bit HDTV can show a range of 1.07 billion possible colors. IF we divide that by the six primary and secondary colors, we get about 166,666,666 shades of orange. I presume most humans could not discern that many shades of orange. And as a designer, I can confidently state humans only need about . . . three, maybe four shades of oranges in life. And yet, nature has given a dragonfly the advantage to possibly discern even more, . . . exponentially more, . . . shades of orange? The dragonfly is pretty impressive. Many thanks for the PM, I replied.
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