The primary function of ripe, fleshy fruit is to facilitate seed dispersal by attracting consumers, yet many fruits contain unpleasant-tasting chemicals that deter consumption by vertebrates. Here we investigate this paradox in the chili (Capsicum) and find that capsaicin, the chemical responsible for the fruit's peppery heat, selectively discourages vertebrate predators without deterring more effective seed dispersers.

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A major goal of population biologists involved in restoration work is to restore populations to a level that will allow them to persist over the long term within a dynamic landscape and include the ability to undergo adaptive evolutionary change. We discuss five research areas of particular importance to restoration biology that offer potentially unique opportunities to couple basic research with the practical needs of restorationists. The five research areas are: (1) the influence of numbers of individuals and genetic variation in the initial population on population colonization, establishment, growth, and evolutionary potential; (2) the role of local adaptation and life history traits in the success of restored populations; (3) the influence of the spatial arrangement of landscape elements on metapopulation dynamics and population processes such as migration; (4) the effects of genetic drift, gene flow, and selection on population persistence within an often accelerated, successional time frame; and (5) the influence of interspecific interactions on population dynamics and community development. We also provide a sample of practical problems faced by practitioners, each of which encompasses one or more of the research areas discussed, and that may be solved by addressing fundamental research questions.

The study of crop origins has traditionally involved identifying geographic areas of high morphological diversity, sampling populations of wild progenitor species, and the archaeological retrieval of macroremains. Recent investigations have added identification of plant microremains (phytoliths, pollen, and starch grains), biochemical and molecular genetic approaches, and dating through 14 C accelerator mass spectrometry. We investigate the origin of domesticated chili pepper, Capsicum annuum, by combining two approaches, species distribution modeling and paleobiolinguistics, with microsatellite genetic data and archaeobotanical data. The combination of these four lines of evidence yields consensus models indicating that domestication of C. annuum could have occurred in one or both of two areas of Mexico: northeastern Mexico and central-east Mexico. Genetic evidence shows more support for the more northern location, but jointly all four lines of evidence support central-east Mexico, where preceramic macroremains of chili pepper have been recovered in the Valley of Tehuacán. Located just to the east of this valley is the center of phylogenetic diversity of Proto-Otomanguean, a language spoken in mid-Holocene times and the oldest protolanguage for which a word for chili pepper reconstructs based on historical linguistics. For many crops, especially those that do not have a strong archaeobotanical record or phylogeographic pattern, it is difficult to precisely identify the time and place of their origin. Our results for chili pepper show that expressing all data in similar distance terms allows for combining contrasting lines of evidence and locating the region(s) where cultivation and domestication of a crop began.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to International Journal of Plant Sciences.The floral biology of night-blooming Peniocereus cacti and Datura plants was studied in North America's Sonoran Desert. In populations of two rare cactus species (Peniocereus greggii and Peniocereus striatus), individual plants bloom synchronously on less than five nights per year and are self-incompatible. In contrast, the abundant Datura discolor and Datura wrightii bloom nearly continuously from spring to autumn and are self-compatible. Flowers of all species studied are visited by hawk moths at dusk and by honeybees and native bees the following morning. Hawk moths have the appropriate behavior and body dimensions to pollinate Peniocereus effectively, but visits are rare. Nonnative honeybees also visit P. greggii and may contribute incrementally to fruit set. Peniocereus and Datura flowers are highly reflective at all wavelengths above 400 nm but lack UV reflectance or contrast. All species studied secrete 10-80 mL of sucrose-rich nectar within flared corollas so deep that moths must land within them, ensuring pollen carriage. These flowers provide rich energetic resources for hawk moths because the caloric content of a single flower would support from 3 to 20 min of hovering flight. Floral scents were more species specific than visual cues because D. discolor and D. wrightii emit complex blends of terpenoid, benzenoid, aliphatic, and nitrogenous scent compounds, whereas flowers of P. greggii produce only eight benzenoid compounds (all of which are present in Datura species) and Peniocereus striatus is scentless. Peniocereus cacti may benefit from sequential mutualism with the more abundant Datura species by way of pollinators nurtured as larvae by Datura foliage and as adults by Datura floral nectar.

84 I. Introduction: evolving concerns over loss of crop diversity 85 II. Defining and measuring crop genetic erosion 89 III. Evidence for, and drivers of, changes in crop diversity over time 92 IV. Steps needed to advance knowledge about crop genetic erosion 99 V. Conclusion: mitigating, stemming and reversing losses of crop diversity 102 Acknowledgements 103 References 104 Appendix A1 111

Wild congeners of domesticated crops increasingly serve as sources of genes for improving crop cultivars. Although wild congeners have been included in seed collections for ex situ storage, there has been little work to protect populations of these wild species in their natural habitats for in situ conservation. We assessed the distribution of chile plants ( Capsicum annuum L. var. aviculare [Dierbach] D'Arcy and Eshbaugh) relative to the dominant woody vegetation of one subpopulation in a single drainage in southern Arizona, U.S.A. Wild chiles were not found in direct sun, and the distribution of chiles under different nurse plants could be a function of random chance, microenvironmental differences under different nurse-plant species, or nonrandom dispersal by chile consumers. To examine chile distribution, we measured the association of wild chiles with nurse-plant species and compared these associations with the available cover provided by each nurse plant. We also measured the buffering capacity of each nurse-plant species, conducted mammalian and avian food-preference experiments to determine the taxa dispersing chiles, and conducted time-budget studies of potential chile dispersal agents. Wild chiles were not randomly distributed: over 75% were under the canopies of fleshy-fruited shrubs that collectively made up less than 25% of the cover. We found limited evidence that differences in buffering capacity affected chile distribution. Food-preference experiments suggested that birds are the only effective dispersal agents, and the time budgets of three common bird species were strongly correlated with chile plant distribution. These results lend support for directed dispersal by avian consumers. The distribution of chiles appears to be a function of interactions between consumers, nurse plants, and the secondary chemicals in the chiles themselves. Only through studies of in situ populations can we understand the interactions that sustain both wild-crop relatives and the genetic variability essential to future crop management. Conservación In Situ de Chiles Silvestres y Sus Asociados BióticosResumen: Los parientes silvestres de cultivos domesticados sirven más y más como fuente de genes para el fitomejoramiento de cultivos. A pesar de que los parientes silvestres han sido incluidos en la recolección de semillas para almacenamiento ex situ, es poco el trabajo que se ha hecho en la protección de estas especies silvestres en su hábitat natural para su conservación in situ. Ilustramos lo importante que es el mantenimiento de las interacciones de la comunidad para la conservación efectiva de chiles silvestres o chiltepines ( Capsicum annuum L. var. aviculare [Dierbach] D'Arcy and Eshbaugh) in situ en el sur de Arizona, E.U.A. No se encuentran chiltepines bajo sol directo, pero la distribución de chiltepines bajo diferentes plantas nodrizas podría ser una función de suerte, diferencias microambientales debajo de distintas especies nodrizas, o dispersión no casual por consumidores de chiles. Para tratar con estas ...

Abstract. The function of Olneya tesota (ironwood) as a nurse plant and habitat modifier species in the Sonoran Desert was evaluated at five study sites (using 75 250‐m2 sample plots) from Bahia Kino, Sonora to Organ Pipe Cactus National Monument, Arizona. Beneath the canopy of O. tesota trees 75 perennial plant species were found. A principal component ordination of the plots created three groups: southern, perturbed and protected sites. A strong triple association of columnar cacti, big shrubs with berry type fruits and O. tesota was detected. The relationships of Lophocereus schottii and Peniocereus striatus with O. tesota were studied in more detail. Significant differences in soil surface temperatures and stem temperatures of P. striatus were detected beneath the shade of O. tesota trees compared with soils and plants in open spaces. Olneya tesota must be considered as a habitat modifier species with ecological and conservational importance to the plant communities in the Sonoran Desert.