The genus Astragalus (Leguminosae) is noted for a wide diversity of compounds toxic to animals and for varied fruit morphology. Seed predation by insects was measured in mixed populations of Astragalus cibarius (browse milkvetch or locoweed), a toxic species with glabrous fruits, and Astragalus utahensis (Utah milkvetch), a nontoxic species with pubescent fruits. The study was conducted for 3 yr in areas where both species were sympatric, allowing direct comparison of insect faunas. The major seed predator on both species was a seed beetle (Acanthoscelides fraterculus, Coleoptera: Bruchidae) which destroyed 74% of the A. cibarius seeds and 60% of the A. utahensis seeds examined. Additional A. cibarius seed destruction, principally the result of predation by a seed chalcid wasp (Bruchophagus mexicanus, Hymenoptera: Eurytomidae), averaged 25%. Differential predation on the two plant species may be due to differences in phenology, seed and pod energy content, internal pod temperature, chemicals in the pods, and pod morphology. As A. cibarius and A. utahensis individuals apparently compete for a number of resources when they occur sympatrically, the differential predation rate probably influences the population dynamics of both species. Selection pressure by seed—eating insects may account for much of the chemical an morphological diversity exhibited by the genus Astragalus at the present time.

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Astragalus cibarius and A. utahensis are common perennial species of a widespread legume genus. The pollination of Astragalus has been briefly discussed in the literature, but little work has been done on species in the intermountain West. This study was conducted from 1970–1973 in Utah with mixed and single species populations. The flowers of both species were homogamous and papilionaceous, but the species were different as to color, size, and ultraviolet reflectance. Astragalus cibarius usually flowered 10 days ahead of A. utahensis, but both species flowered earlier than most other plants in the community. Bagging experiments indicated both species were strongly allogamous. Exclosure studies indicated both species relied on insects as pollen vectors. Of the 44 insect species which were observed visiting flowers, only 14 carried Astragalus pollen, and the pollinator fauna varied between study sites. Pollen quantities and distributions on Diptera and Coleoptera indicated a poor potential for pollination. Floral structure, pollen distribution and quantity, and behavior implied that large bees of the families Apidae and Anthophoridae were the primary pollinators. These bees visited only one species of Astragalus when the plants occurred in mixed populations; this constancy may have been related to relative flower abundance. Non‐pollinating floral foragers affect other phases of Astragalus life history.

Starch represents the major component of virtually all plant‐derived foods consumed by man and animal. Hence, a thorough understanding of the starch biosynthetic pathway is critically important not only in understanding the biosynthesis of a major plant storage product, but also in allowing the genetic manipulation of both starch quality and quantity for human benefit. A major goal in these studies has been the identification of key steps in controlling starch levels. Evidence from a number of independent approaches clearly points to the enzyme adenosine diphosphate glucose pyrophosphorylase (AGPase) as a key regulatory step in starch synthesis. Here we highlight and summarize our understanding of this important enzyme.