Wednesday, 21 November 2007

Temperature impact on Flies and Mosquitoes

Last week we bought one of those plastic bottle fly traps that you put a packet of pre-mixed stuff and water into, and thought we'd give it a go on the farm. About a fortnight before this I'd noticed how at sunrise there was no flies, but by mid morning they were pretty active - and suspected that they needed temperatures of around 15 degrees C to get them going. The instructions that came with the new fly trap set me straight. Flies get active when the temperature reaches 18 degrees, and begin feeding at 20 degrees C.

I decided to see whether temperature has a similar impact on mosquitoes. A quick surf of the internet took confirmed this is the case. Their activity kicks in at 7-8 degrees
C (Alaskan research). Curiously they don't function well in temperatures above 43 degrees C but neither do we! A couple of other things that were of interest - mosquitoes are very slow flyers (1-2 km/hour) and can thus be kept at bay using an electric fan; and mosquito screens on windows were first introduced in the 1880's.

Back on the fly trap - the instructions also suggested that the container would need to be emptied every 2 weeks or so. In our experience, try 1.5 days. This then begs the question of what the natural predators of flies are and what the ecological impact would be of us using the trap. Maybe I'll research this one day as well.

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