At college we recently did a experiment involving C. vicina (blow-fly) larvae. The experiment was to analyse the effect of environmental temperature on the rate of activity among the larvae. The results showed that as the temperature increases the rate of activity among the C. vicina larvae increases.

In writing up and discussing the experiment I discovered that, not only is their activity affected by temperature, their rate of development and adult size is also affected by temperature. They develop faster in warmer conditions [1], however larvae cultured at higher temperatures tend to produce smaller adults [2].

Then I discovered that C. vicina thrive during the winter [3] and their flight activity threshold is lower than most other blow-flies [4].

This got me wondering how it is that an organism which develops faster, and is more active when the environmental temperatures are higher is actually more adapted to thrive in colder conditions. My initial thought (which I discussed in my write up) was that it was advantageous for C. vicina to thrive during the winter time because there is far less competition (because a lot of it's relatives thrive during the spring/summer), and thus increased activity/development rate was traded for the opportunity to thrive with much less competition. I also thought that perhaps it had something to do with the fact that larvae which develop at higher temperatures tend to produce smaller adults, perhaps there is some advantage in C. vicina being large? This might explain why they thrive in cooler climates because if they tend to be larger when they develop at cooler temperatures, and this was an advantage for some reason then it would make sense (wouldn't it?)

Anyway I thought I would put the question to you guys; why is it that despite being more active/developing faster in warmer environments, C. vicina tend to thrive in cooler climates?

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1. http://onlinelibrary.wiley.com/doi/10.1 ... 0600.x/pdf
2. http://www.nhm.ac.uk/nature-online/spec ... index.html
3. http://www.scielo.cl/scielo.php?script= ... en&nrm=iso
4. http://en.wikipedia.org/wiki/Calliphora_vicina

Maybe they thrive in cooler climates because there is less competition for food from other flies. You could test that by putting blow-fly larvae on an enclosed corpse that no other types of fly can get to and see how they do at different temperatures.

Yeah that's the initial thought I had. According to the paper I cited there's only one other species of fly (Sarconesia chlorogaster) which is abundant in winter. So the competition would be much less. So I figure being a bit sluggish and slow to develop as a larvae was a small price to pay for being able to thrive with little competition for food.