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Dietary Analysis in Granivores through the Use of Neutron Activation

Smigel, Barbara W., Rosenzweig, Michael L.
Ecology 1974 v.55 no.2 pp. 340-349
feces, foods, gamma radiation, granivores, neutron activation analysis, radionuclides, rodents, seeds, stable isotopes, wavelengths
A technique is used which permits simultaneous tracing of several foods in the field without the use of radioactive isotopes. Seeds are tagged with different stable (nonradioactive) isotopes of rare elements and then distributed in the environment. Free—living rodents that have been exposed to these seeds are then trapped and their feces are collected. The relative amounts of the several tagged foods consumed by the rodents are determined by subjecting the feces to neutron activation analysis in the laboratory. In activation analysis stable isotopes are rendered radioactive by permitting them to capture neutrons in a nuclear reactor. The elements emit characteristic wave lengths of gamma radiation, allowing not only detection but precise quantification. The technique presents many technical problems, enough of which have been solved to allow its application to the investigation of some interesting ecological questions.