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 Heleomyzidae on the snow
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| Lukasz Mielczarek |
Posted on 10-01-2010 14:13
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 Member Location: Poland, Krakow Posts: 498 Joined: 27.09.06 |
Thanks Andrzej, Ruud and Jorge. It is something special or common fly? I collected it first time  Greetings, Lukasz |
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| Andrzej |
Posted on 10-01-2010 14:16
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Member Location: Poland Posts: 2412 Joined: 05.01.06 |
Here, in Poland the most common Orbellia species !
dr. A. J. Woznica, Institute of Environmental Biology, Wroclaw University of Environmental & Life Sciences |
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| rvanderweele |
Posted on 10-01-2010 14:16
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Member Location: Leiden, the Netherlands Posts: 1988 Joined: 01.11.06 |
Jorge, perhaps the subject how these flies can stand these low temperatures is off topic. Well, so be it. I was always surprised to find Heleomyzidae such as Oldenbergiella vary active on snow. They are skilled in hovering. Also Schroederella hungarica, I collected them only on snow. I am not a biologist, but chemist. I was always fascinated how these animals could cope with the low temperatures. Correct me if I am wrong, but are not very often these winter active animals giving these strange copper green threads on needles a while after keeping them in a collection? Always Heleomyzidae, Scatophagidae, Sphaeroceridae, I believe as well. I wondered whether these animals have something in their blood, which reacts with the insect pins, but which may have a function as an anti-freeze??It is a big question to me. ruud van der weele rvanderweele@gmail.com |
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| Andrzej |
Posted on 10-01-2010 14:24
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Member Location: Poland Posts: 2412 Joined: 05.01.06 |
Hi Ruud, Some larvae and probably imagines too have some chemical antifreezing glicerine- or glicerol-like substances which protect the body before freezing ! see plz, an article about xylomannan: http://www.popularmechanics.co.za/content/news/singlepage.asp?key=893 . dr. A. J. Woznica, Institute of Environmental Biology, Wroclaw University of Environmental & Life Sciences |
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| jorgemotalmeida |
Posted on 10-01-2010 14:26
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 Member Location: Viseu - PORTUGAL Posts: 9296 Joined: 05.06.06 |
certainly it is not off-topic.  Maybe there are already studies on their blood content to know it. I will go for an anti-freeze product so the blood remains fluid.. |
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| jorgemotalmeida |
Posted on 10-01-2010 14:31
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Member Location: Viseu - PORTUGAL Posts: 9296 Joined: 05.06.06 |
found this interesting abstract: "Heleomyza borealis Boh. (Diptera, Heleomyzidae) overwinters as larvae in Arctic habitats, where they may experience winter temperatures below − 15°C. The larvae freeze at c.− 7°C but in acclimation experiments 80% survived when exposed to − 60°C. Of the larvae exposed to between − 4 and − 15°C, only 3% pupated. However, when cooled to − 20°C this increased to 44%, with 4% emerging as adults. Larvae maintained at 5°C contained low levels of glycerol, sorbitol and trehalose, which did not increase with acclimation to low temperatures. However, levels of fructose increased from 6.1 μg mg−1 fw in control animals to 17 μg mg−1 fw when exposed to − 2°C for 1 week. Larval body water (2.2 ± 0.1 g/g dw, mean ± SD, n = 100) and lipid content (0.22 ± 0.002 g/g fw, mean ± SE) showed no significant change during acclimation to low temperatures. Larvae maintained at a constant 5°C survived for over 18 months with little loss of body mass (from 7.5 ± 1.2 to 7.0 ± 1.2 mg fw, mean ± SD, n = 20), but none pupated. Heleomyza borealis larvae appear to feed and grow until they reach a body mass of about 7.5 mg and then become dormant. They remain in this state until they experience a low temperature stimulus (< − 15°C) followed by a warm period (≈ 5°C). This ensures that the larvae pupate and adults emerge in early summer, allowing the maximum growing period before the following winter. Heleomyza borealis are adapted to survive long winters in a dormant larval state. They have a low metabolic rate, can conserve body water even at subzero temperatures but do not synthesize large quantities of cryoprotectants. " |
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| Andrzej |
Posted on 10-01-2010 14:32
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Member Location: Poland Posts: 2412 Joined: 05.01.06 |
Indeed, I know this article
dr. A. J. Woznica, Institute of Environmental Biology, Wroclaw University of Environmental & Life Sciences |
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| rvanderweele |
Posted on 10-01-2010 14:32
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Member Location: Leiden, the Netherlands Posts: 1988 Joined: 01.11.06 |
As far as I know glycerine or glycerine derivates do not form complexes with Cu. Looking at the peculiar colour of the threads, which look like to come out of the insect on a pin, it is copper complex. But, of course, these structures have perhaps nothing to do with the "anti freeze". A very interesting article! It is a nice subject. ruud van der weele rvanderweele@gmail.com |
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| jorgemotalmeida |
Posted on 10-01-2010 14:34
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Member Location: Viseu - PORTUGAL Posts: 9296 Joined: 05.06.06 |
here more info: http://www.scienc...93bb7ca057 |
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| rvanderweele |
Posted on 10-01-2010 14:37
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Member Location: Leiden, the Netherlands Posts: 1988 Joined: 01.11.06 |
great info! Thanks a lot.
ruud van der weele rvanderweele@gmail.com |
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| jorgemotalmeida |
Posted on 10-01-2010 14:39
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Member Location: Viseu - PORTUGAL Posts: 9296 Joined: 05.06.06 |
Andrzej wrote: Hi Ruud, Some larvae and probably imagines too have some chemical antifreezing glicerine- or glicerol-like substances which protect the body before freezing ! see plz, an article about xylomannan: http://www.popularmechanics.co.za/content/news/singlepage.asp?key=893 . at the moment I would like to have an anti-freezing product in my blood to avoid heaters! grrr... Edited by jorgemotalmeida on 10-01-2010 14:40 |
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| jorgemotalmeida |
Posted on 10-01-2010 14:44
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Member Location: Viseu - PORTUGAL Posts: 9296 Joined: 05.06.06 |
isn't copper (Cu) good to protect the metals^?? |
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| rvanderweele |
Posted on 10-01-2010 14:47
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Member Location: Leiden, the Netherlands Posts: 1988 Joined: 01.11.06 |
jorgemotalmeida wrote: isn't copper (Cu) good to protect the metals^?? well, it rather easily forms copperoxide, so I actually doubt it. We should ask someone, who is selling insect pins. Perhaps they know. ruud van der weele rvanderweele@gmail.com |
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