Temporal variation in pollination services to Cucurbita moschata is determined by bee gender and diversity

It has been proposed that species-rich insect communities and species turnover across landscapes enhance the pollination efficiency of crops through complementarity, where both the dominant and less abundant species contribute to reaching a yield threshold from pollination. Alternatively, fluctuations in the most abundant pollinator species, rather than changes in species richness, may drive temporal variation in pollination services. In this study, we used Cucurbita moschata as a model to investigate temporal variation in pollinator communities in a Mexican tropical dry forest region. We sampled floral visitors in the coastal region of Jalisco during the wet and dry seasons and determined the pollination efficiency of all floral visitors. Our results showed that there was temporal variation in the pollinator community and in the pollination efficiency of the main pollinators of Cucurbita moschata crops. In the wet season, native bees of the genus Peponapis were the most frequent and effective pollinators of C. moschata, whereas in the dry season, Peponapis bees were scarce and Apis mellifera became the most frequent floral visitor. Apis mellifera transfers smaller pollen loads than Peponapis, but it provides an effective pollination service in conjunction with other native bees during the dry season. There was also an interaction between flower gender and pollinator species, where A. mellifera had higher visitation rate to female C. moschata flowers, and Peponapis bees to staminate flowers. Mean visitation rate by Peponapis female bees was 17 times higher than visitation rate by male bees. This is the first report of a vis-à-vis relationship of pollinator gender with respect to plant gender in which plants of the genus Cucurbita that produce unisexual staminate and pistillate flowers are differentially visited by Peponapis male and female bees, where females are the main pollinators. Understanding the temporal variation in pollinator communities and the contribution of the different species of pollinators to the reproductive success of different crop species and varieties can be crucial to maintaining pollination services under the current global pollination crisis.Fil: Delgado-Carrillo, Oliverio. Laboratorio Nacional de Análisis y Síntesis Ecológica; México. Universidad Nacional Autónoma de México; MéxicoFil: Martén-Rodríguez, Silvana. Laboratorio Nacional de Análisis y Síntesis Ecológica; MéxicoFil: Ashworth, Lorena. Laboratorio Nacional de Análisis y Síntesis Ecológica; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Aguilar, Ramiro. Laboratorio Nacional de Análisis y Síntesis Ecológica; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Lopezaraiza-Mikel, Martha. Universidad Autonoma de Guerrero; MéxicoFil: Quesada, Mauricio. Laboratorio Nacional de Análisis y Síntesis Ecológica; Méxic

Chayote, Sechium edule (Jacq.) Sw.

The variable fruits and roots of chayote is an important element in the diet in many parts of Latin America, and it is a valuable export crop. This monograph provides an overview of existing knowledge of the genus with emphasis on genetic resources. Chapters cover the following topics: taxonomy and nomenclature, botany, floral biology, evolution, wild relatives, uses, diversity, breeding, production, ecology, agronomy, pests and diseases, and limitations of the crop, research needs and prospects. An appendix details research contacts and centres of research. (Abstract © CAB ABSTRACTS, CAB International

Wild Plant Genetic Resources in North America: An Overview

North America, including Canada, Mexico, and the United States, is rich in plant species used by humans in both ancient and modern times. A select number of these have become globally important domesticated crops, including maize, beans, cotton, and sunflower. Many other native and also naturalized species have potential for use, either directly or as genetic resources for breeding agricultural crops. However, despite increasing recognition of their potential value, deficiencies in information, conservation, and access to the diversity in these plants hinder their further use. This chapter provides an overview of the agriculturally relevant wild plant resources of North America, with focus on wild relatives of globally important major crops, as well as the wild cousins of regionally and locally important domesticates. The chapter concludes by providing an overview of strategies for conserving wild plant genetic resources, including the international regulatory frameworks affecting policies to various degrees in Canada, Mexico, and the United States

Extinction risk of Mesoamerican crop wild relatives

Ensuring food security is one of the world's most critical issues as agricultural systems are already being impacted by global change. Crop wild relatives (CWR)—wild plants related to crops—possess genetic variability that can help adapt agriculture to a changing environment and sustainably increase crop yields to meet the food security challenge. Here we report the results of an extinction risk assessment of 224 wild relatives of some of the world's most important crops (i.e. chilli pepper, maize, common bean, avocado, cotton, potato, squash, vanilla and husk tomato) in Mesoamerica—an area of global significance as a centre of crop origin, domestication and of high CWR diversity. We show that 35% of the selected CWR taxa are threatened with extinction according to The International Union for Conservation of Nature (IUCN) Red List demonstrates that these valuable genetic resources are under high anthropogenic threat. The dominant threat processes are land use change for agriculture and farming, invasive and other problematic species (e.g. pests, genetically modified organisms) and use of biological resources, including overcollection and logging. The most significant drivers of extinction relate to smallholder agriculture—given its high incidence and ongoing shifts from traditional agriculture to modern practices (e.g. use of herbicides)—smallholder ranching and housing and urban development and introduced genetic material. There is an urgent need to increase knowledge and research around different aspects of CWR. Policies that support in situ and ex situ conservation of CWR and promote sustainable agriculture are pivotal to secure these resources for the benefit of current and future generations

Estudios taxonomics y ecogeograficos de las cucurbitaceae latinoamericanas de importancia economica

Published in collaboration with Instituto de Biologia, UNAM, Mexico. As a preamble for future conservation actions for the cucurbitaceae in Latin America, IPGRI commissioned a taxonomic and ecogeographic study of the different genepools of cucurbits, squashes, gourds, chayotes and achokchas, involving the revision of 2300 herbarium specimens, the collation of 3400 bibliographic references, and field work in Mexico, Guatemala and Costa Rica

Conocimiento tradicional y composición de los huertos familiares totonacas de Caxhuacan, Puebla, México

Abstract: This research focused on the composition of homegardens in a Totonac community of the Sierra Norte de Puebla, as well as traditional ecological knowledge to analyze the current use and management of useful species and their biodiversity. The use and management of useful species and their biodiversity were established through interviews with homegarden owners and subsequently with key informants. We use methodologies of ethnoecology, ethnobotany, and ecology. Flora and fauna present in the orchards of the sample were identified and recorded spatially and mapped using GIS. The average size of the homegarden was 447 m2. The floristic composition of Totonac homegardens is very diverse, 361 plant species were registered, of which 357 species belonging to 263 botanical genera and 102 botanical families were identified. Cultural practices of homegarden management in the Totonac community analyzed showed that small-sized orchards have a complex and diverse physiognomy. These are agroecosystems with relative self-sufficiency, in which ecological interactions are associated with the use and cultural management of species. They constitute an essential ethnobiological reservoir, allow the continuity of traditional ecological knowledge about the management and use of species, and are a constant source of primary products for subsistence.Resumen: Esta investigación se enfocó en la composición de los huertos familiares en una comunidad totonaca de la Sierra Norte de Puebla, así como en el conocimiento ecológico tradicional para conocer el uso actual y manejo de especies útiles y su biodiversidad. Por medio de entrevistas a dueños de los huertos y posteriormente a informantes clave se estableció el uso y manejo de especies útiles y su biodiversidad. Se utilizaron metodologías de etnoecología, etnobotánica y ecología. Se identificaron y registraron espacialmente la flora y fauna presentes en los huertos de la muestra y se mapearon utilizando SIG. El tamaño promedio del huerto fue de 447 m2. La composición florística de los huertos familiares totonacas es muy diversa, se registraron 361 especies vegetales, de las cuales se identificaron 357 especies pertenecientes a 263 géneros botánicos y 102 familias botánicas. Las prácticas culturales de manejo de los huertos en la comunidad totonaca estudiada, mostraron que huertos de tamaño reducido presentan una fisonomía compleja y diversa. Se trata de agroecosistemas con relativa autosuficiencia, en los que las interacciones ecológicas están asociadas al uso y manejo cultural de especies. Constituyen a su vez un importante reservorio etnobiológico, permiten la continuidad del conocimiento ecológico tradicional sobre el manejo y uso las especies y son una fuente constante de productos básicos para la subsistencia

Ecological niche similarities of Peponapis bees and non-domesticated Cucurbita species

Peponapis bees are considered specialized pollinators of Cucurbita flowers, a genus that presents several species of economic value (squashes and pumpkins). Both genera originated in the Americas, and their diversity dispersion center is in Mexico. Ten species of Peponapis and ten species of Cucurbita (only non-domesticated species) were analyzed considering the similarity of their ecological niche characteristics with respect to climatic conditions of their occurrence areas (abiotic variables) and interactions between species (biotic variables). The similarity of climatic conditions (temperature and precipitation) was estimated through cluster analyses. The areas of potential occurrence of the most similar species were obtained through ecological niche modeling and summed with geographic information system tools. Three main clusters were obtained: one with species that shared potential occurrence areas mainly in deserts (P. pruinosa, P. timberlakei, C. digitata, C. palmata, C. foetidissima), another in moist forests (P. limitaris, P. atrata, C. lundelliana, C. o. martinezii) and a third mainly in dry forests (C. a. sororia, C. radicans, C. pedatifolia, P. azteca, P. smithi, P. crassidentata, P. utahensis). Some species with similar ecological niche presented potential shared areas that are also similar to their geographical distribution, like those occurring predominantly on deserts. However, some clustered species presented larger geographical areas, such as P. pruinosa and C. foetidissima suggesting other drivers than climatic conditions to shape their distributions. The domestication of Cucurbita and also the natural history of both genera were considered also as important factors. (C) 2011 Elsevier B.V. All rights reserved.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[04/15801-0]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES