SURVIVAL AND REPRODUCTION OF STORED-PRODUCT BEETLES ON SEEDS CACHED BY A DESERT RODENT AND BY NATIVE-AMERICANS

We examined the survival and reproduction of the red flour beetle, Tri bolium castaneum (Herbst), and the sawtoothed grain beetle, Oryzaephil us surinamensis (L.), on seed diets of 16 plants from desert habitats in Arizona. Some of these desert seeds are harvested, stored, and even tually eaten by the banner-tailed kangaroo rat, Dipodomys spectabilis, or by native American Indians. Seed diets were also prepared from cul tivated cereals (e.g., Avena sativa, Hordeum vulgare, Triticum aestivu m and Zea mays) that become infested with stored-product beetles in gr ain stores. Few or no adult beetles remained alive after 30 d on diets of intact seeds of a majority of the native plants we tested. Beetle survival was high, with numerous larvae and pupae, on intact seeds of cultivated barley, wheat, or maize. When flour diets were prepared fro m desert seeds, several also failed to support beetle populations, inc luding species stored by kangaroo rats and native Americans (e.g., Pro sopis juliflora and Monolepis nuttaliana). These results help to expla in the absence of stored-product beetles in seed stores recovered from kangaroo rat burrows in Arizona. With T. castaneum, the nutritive val ue of flour prepared from Panicum sonorum, a seed eaten by native Amer icans, greatly exceeded that of any cultivated cereal we tested. Deser t seeds stored by kangaroo rats or native Americans may be sources of safe antiinsectan natural compounds and other novel gene products to b e used in protecting cultivated cereals from insect pests while having no or low toxic effects on vertebrates.