Bulbophyllum biflorum flower and two flies fighting over it

These flies are usually quite wary as in the garden there are a plethora of predators that think of flies as convenience food. However it seems the smell of this Bulbophyllum biflorum had them entranced to such a degree that they would not move from the flower even when I approached very closely. When I shooed one away the other one would quickly jump on the flower. When both landed on the flower a scuffle ensued and one was thrown from the flower. I could not help but think of two gunslingers that were waiting to see who would make the first move. I have tried to detect a smell but it I can't smell anything. Perhaps other people who have this plant can describe the smell. I assume it is a fecal smell due to the type of fly that is attracted to the flower. Even though ordinarily I would shoo the flies away as to prevent them removing the pollen and causing premature folding of the flowers, in this case I am going to allow the poor blighters some leeway. The truth is that the life of these flies must be one big and smelly pile of s**t, so if they are trying to get their jollies in much pleasanter surroundings I will not be the one to deprive them of the opportunity.