The Calliphora vicina use dead flesh as a source of food for their larvae to develop.  For reproduction to occur the female C. vicina must find a dead host or a piece of dead flesh on said host (a wound of some sort).  Before laying her eggs the C. vicina search for a suitable part of the body for her eggs to feed. (In J.H. Fabre’s study the female nuzzled her eggs between the eye and the beak)  The female sets her ovipositor at right angle and deposits her eggs onto the carcass. The eggs are dispelled form her ovaries in continuous flow for about 30 minutes. She will take several breaks in this process in which she cleans the probe that she uses for placing her eggs and rests aside the carcass.  After a few hours of this and the eggs have all been dispelled (about 300) the mothers work is done and she will die within the day.  The eggs were in a layer going down the birds gullet (esophagus) forming a white layer of them.  In a few days the eggs will hatch and the larvae will make their way into the body to feed on the internal organs. The ovipositor can be extended to get the eggs inside the body in the case that the fly notices a cut or tear in the skin.  In the absence of any way to get into the body eggs will be laid in any area of the body with more delicate skin such as the axillary or the groin (Fabre J.H. 1919).
Once the larvae have hatched and invaded the body they may begin their digestive process.  The C. vicina egg needs a high humidity level in order to hatch. At first the larvae feed on a fluid serum between the muscles fibers while excreting digestive enzymes and ammonia, allowing for the dissolve of the muscle tissues.  Once digested enough the larvae lacerate the product with their mouth hooks (Oldroyd H. 1964). The larvae are generally found in cooler environments in the western European region of the world.  They tend to grow faster in warmer environments (30 degrees C) (Greenberg, 1991) and do not survive well in colder environments (-8 Celsius).  While larger larvae have a good chance to reproduce, they have about a 50% chance to become crippled adults.  The smaller flies only have about a 28% chance to reproduce and a 98% chance of dying before reaching their mature stage. (Saunders D.S.) The amount of centralized C. vicina can affect their development as well. Overcrowding may lead to a reduction in both the size of the blow fly and the size of the population vs. those in less populated areas. (Saunders D.S. & Bee A. 1995)


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