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 24 Calliphoridae competitor DHJanzen100478.jpg high resolution
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Please return to the newly dead duiker in the snare in image DHJanzen100472.jpg above. Here a close look at the head reveals the actors at work. This animal has been dead for less than an hour, and is hanging in a heavy rainstorm in the middle of the night. It was raining so hard that I did not want to try to change film, which is why I have only a few pictures of it. Under the neck of the duiker in flight is the calliphorid fly species in image DHJanzen100477.jpg above. The face is covered with the cream-colored newly laid larvae of this fly, larvae that the fly has been carrying in its abdomen in anticipation of finding such a carcass to scavenge. The eye is packed with eggs, laid by some other species of fly, eggs that will hatch within hours. In short, this is a scavenging fly community under strong selection for speed, speed to beat the mammalian scavengers that once roamed these forests (lions, leopards, canids, perhaps even forest hyenas, and even primates). Within hours these flies will be converting this large lump of food to something potentially less and less interesting to the larger scavengers, as well as capturing it for themselves. This system of flies and carcasses stands in very striking contrast to the slow rate of decomposition in temperate forests, even in summer heat and humidity, by and large due to the slow rate of action and build-up of the decomposer fly community. Incidentally, it was very striking to observe these same flies only feeding, and not putting eggs/larvae, on the drying python skin in image DHJanzen100505.jpg below. They were capable of discriminating between a drying bit of an animal that would not be good food for the kids, and a newly killed animal rich in food for the kids. |
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