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Hi Bev and other respondents re. winter insects, Thanks for the lead to your nice site, again (last time it was to your asilid Dioctria). Endorsing Angus' comments, some really interesting photos. I guess it's a simple gap in personal knowledge, but I didn't know that the adults of several 'advanced' flies like Ephydridae could be found as active adults in the depths of winter (some of this family also are littoral flies in seaweed). The flies that we keep in culture like Drosophila and Calliphora live only for a month or so as adults even in protective custody, and particular species that I catch in a garden trap here likewise appear only for a few weeks each year, usually starting with beeflies in May. If the same applies to the species you are seeing as adults in the dated January photographs on your site, emerging then would seem to be a wasted endeavour for them genetically unless the flies are actually breeding then and contributing to the next generation: raises the possibility that species that do this get a jump by having an extra generation in the year, though likely slowed down by the cold. Regarding the comments about the thermally protected micro-environment in the air spaces under stuff like washed-up seaweed, fully agreed, but not in the case of the adults if they come out and cavort on the snow where their bodies will rapidly equilibrate to ambient temperatures (probably in seconds). So could it be that these are simply occasional doomed escapees that didn't ought to be there (the Scots), while the real adult action is going on happily above zero but in fermenting vegetation under the protective snow cover (the Amundsens)? Or maybe these again are a few accidental escapees warmed up inadvertantly from an adult population that is natural dormant and hibernating? So the focussed question would be, are adult-flies-in-January of no real biological significance, or part of an interesting natural cycle? On a half related technical question, it is difficult to capture colours effectively if the insect/bird is photographed with a brilliant white background filling most of the frame, presumably because the camera automatically integrates in much of the background in setting the exposure, and so underexposes the insect itself. Snow in sunlight seems to be a particular challenge. Is there a known solution to this? Even switching to a centre spot focus doesn't always seem to help a lot in my limited tries on this. Presumably a filter up front would not be much help either because the troublesome background radiation has such a broad spectrum (looks 'white'), but has anybody tried this, e.g. using a UV filter? Photographers of birds must meet this all the time in winter. Any suggestions? Steve, Halifax Quoting bev wigney <bev@magickcanoe.com>: > On 20-Feb-07, at 10:32 PM, Stephen Shaw wrote: >> As a sort of reference point, I recall reading that the UK >> low-temperature record for an insect "behaving" was -5°C for a bristletail >> (wingless insect) that someone observed sitting on a seaside rock in Wales, >> whereupon it promptly ran away. > > * I've been photographing snow surface invertebrates here in Ontario > for a couple of winters. > Around -5C is about the lowest temperature that I would find active > insects or spiders. > This page of my collection of snow surface insects has several of the > flies that I've found > out and about on the snow. > http://www.pbase.com/crocodile/snow_creatures&page=2 > > Bev Wigney > (easter Ontario) >
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