METHODS FOR THE STUDY OF BLOWFLY POPULATIONS

1. A simple method of radioactive labelling of L. sericata larvae is described.
2. More uniform count levels are obtained in individuals which have fed entirely on radioactive foods than in those which first feed on non-active food.
3. The radioactive count rates of the larvae are correlated with larval live weight and the counting rates of resulting imagines correlated both with corresponding larval counting rates and with imaginal live weight.
4. The loss of ³²P in the larvae due to causes other than decay of the isotope is traced from the prepupal stage to 3 weeks after emergence. The first and major loss occurs at emergence, when about 10% of the original ³¹P is shed as empty puparium and meconium. Adults lose about 1.5% per day.
5. The distribution of ³²P in the adult body of L. sericata labelled in the larval stage has been determined. The abdominal tissues have a lower activity than the rest of the body.