time-lapse, part 5: frog spawn

[posted: ]  [11 comments]

i’ve done a new time-lapse project on frog spawn, because i spotted some in my pond.
the first post about this can be found here.

[skip all of that and download the video]
 

the phase i wanted to capture, was from the egg until slacking.
it would be too hard to record a pollywog’s growth in time-lapse – too much effort and clearly not ethical.
you’d have to give them tiny living space so they wouldn’t jet around all the time, or even slow them down somehow. there would have to be a special (=unnatural) way of feeding. water cleanness and oxygen problems would arise, and of course plants etc. would give them unwanted hiding places…
and i don’t presume to do that. (the environmentalist is shining through again ;-))

anyway, i did some internet research and found out the duration of my project would be about 2 weeks. in springlike-pond-climates, of course. it turns out, at room-temperature those little creatures leave their gelatinous eggs in less than 2 days!

 
the eggs would float around a lot, so i needed to fixate them somehow.
i had the idea of using single-hair-loops, because they’re thinner than any thread i could find, and they were there, sitting right next to me.

    i remembered a glimpse of the “lord of the rings, special extended version” audio commentary, where john rhys-davies (playing gimli) mentioned problems with the scene in lothlorien where gimli asks for three hairs from galadriel. the issue was that you couln’t really see a single hair on a tv screen (that’s why they didn’t show that particular scene and made up a little flashback-storytelling dialog).

sandra kindly played along and gave me three of her hairs, which were perfect because they’re long and blond (almost elvish ;-)) if you look closely you can see one of them in the bottom-right third of the image (on the very left part of that third).

 
the setting was a little different, this time:

  • i used continuous artificial lighting this time, to ensure brightness constance (because i was only using my dlink dsc-350 webcam >> lower level of light sensitivity).
  • i didn’t cover the whole window with soft tissue, but instead built up a little screen with double-layered tissue, so there would (hopefully) only be very scattered light and no shadows (i didn’t even want soft ones).

 
what’s that, you want a time-table? there you go!


date hours description
2005-03-23 17:00
-124
noticed frog spawn on the ground of my pond *
2005-03-28 22:00
0
took about 1/4 of the egg-cluster and set everything up in my room. eggs still perfectly globated
2005-03-29 08:00
10
two poles (different in size) are clearly noticeable
2005-03-29 11:00
13
“black blobs” start wiggling, still elongating; head and tail ends are distinguishable
2005-03-30 04:00
30
pollywogs now have their typical shape
2005-03-30 11:00
37
wiggling at full speed, real-time watchable
2005-03-30 15:00
41
first individuals hatch out
2005-03-30 20:00
46
most pollywogs have emerged, staying close to the cluster


* the pond had been ice free for at most 5 days then, so the spawn couldn’t have been very old.

also note the worm that was roaming the upper left portion from 13:00 to 23:00 on day 1.

***UPDATE***
the pollywogs that “grew naturally” in my pond hatched close to april 5th, so the 2-week breeding-time does apparently apply in natural conditions.

 

so here’s the video:


frog-spawn
(download video)


date:
starting time:
interval:
total time:

2005-03-29
05:00
5 minutes
43 hours

camera:
D-Link DSC-350
video data:
mpeg4/xvid – one pass: quality – 20 fps – qual: 85% (get the codec | help)
video length:
34 sec.
speedup:
x 4500 (1 second in the video equals 75 minutes in real-time)
file size:
3,5 MB

update: you might want to see this one, too:

 

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    [categories: nature, time lapse, video] [tags: , ]

    11 comments on “time-lapse, part 5: frog spawn

    1. I am a geography professor at Sam Houston State University in Huntsville TX, USA. I teach an online weather class and would appreciate you giving me permission to make use of your frozen dew photo ( http://markus.nolf.org/pic.php?s=180&img=1627 ) on my class website. I would of course provide credit on the photo. Appreciate your consideration. Jim Tiller Professor of Geography
    2. Hi, im a biology teacher from the Black Country, near Birmingham in the UK. At the moment i am teaching the life cycle of organisms. I have considered covering the frog, and setting up this experiment. I was wondering if you could send me information about how to setup this experiment, including the equipment and method. Naturally, i will credit you work Thanks alot, and i hope to hear from you soon Greg
    3. Hello, I'm student on middle school and I'm asking if I can use this video in my presentation. Thanks in advance, you are doing very good work...
    4. Hello Markus, i'm a student teacher & i need short video clips on life cycles of a frog for my school presentation. Juz wondering f u have 1? Wud really appreciate it n ofcoz will provide credit on the presentation. tQ!
    5. have u received my comment?
    6. got your message and will contact you by email.
    7. Dear Marcus, I am trying to obtain a photo of Lesser bird of Paradise to paint from. Can you help me? If yes, I need as sharp detail as possible. Thankyou! Laurie
    8. Dear Marcus, I'm invovled in organising an event on Tadpoles for the Nature Live events program at the Natural History Museum, London, and I was wondering if you could grant us permission to use your frogspawn video? Either the full length or the youtube would be great. It would be part of a session with one of our zoologist, would be show to a live audience, and the event would also be webcast on our website. It may possibly also be archived if permission is allowed for that too. We would of course credit the footage. Many thanks Aoife
    9. My son is working on a project/presentation on frogs. Would you grant permission to use this video in his project? Thanks for your consideration. Laura
    10. Hi, I have a question. Not sure if you can help but wanted to ask. I live on a fresh water river which has recently flooded. We had approx. 3 feet of water in our yard for about 2 weeks. When all of the water disappeared we had thousands of tiny frogs which were the size of a fingernail. My question is were the eggs present before the flood or were they deposited as a result of the flood? We rarely saw or heard frogs previously.
    11. hi kathy, it depends on the species of frog. some have very short development times, where 2 weeks could already be enough. after growing legs, young frogs usually spend a few years in grasslands or forests - away from bodies of water - so they could have already been in the vicinity before the flood.

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