Blowflies are the main invaders of carrion in most parts of the world, including south-eastern Australia. The 5,512 blowflies in this conical flask were reared from maggots that had infested dead pigs in an ICB project examining whether blowflies prefer sunlit or shaded carcasses. The answer to this question appears to depend on the species of fly concerned. The flask in this photograph contains blowflies of three different species.