نتایج جستجو برای: visitation
تعداد نتایج: 2007 فیلتر نتایج به سال:
In many nectarless flowering plants, pollen serves as both the carrier of male gametes and as food for pollinators. This can generate an evolutionary conflict if the use of pollen as food by pollinators reduces the number of gametes available for cross-fertilization. Heteranthery, the production of two or more stamen types by individual flowers reduces this conflict by allowing different stamen...
Camelina and pennycress are two annual oil-producing plant species that have recently gained attention as biofuel feedstock crops. Prior to commercial production, information on their breeding and pollination system is essential to ensure sustainable management. We conducted pollination experiments and observed flower visitors in an experimental double-cropping system in southern Germany. We fo...
It has been historically difficult to manipulate secondary compounds in living plants to assess how these compounds influence plant-herbivore and plant-pollinator interactions. Using a hemiparasitic plant that takes up secondary compounds from host plants, I experimentally manipulated secondary compounds in planta and assessed their effects on herbivores and pollinators in the field. Here, I sh...
One of the values of biodiversity is that it may provide 'biological insurance' for services currently rendered by domesticated species or technology. We used crop pollination as a model system, and investigated whether the loss of a domesticated pollinator (the honey bee) could be compensated for by native, wild bee species. We measured pollination provided to watermelon crops at 23 farms in N...
A hypothesized underlying principle of the diversity-functioning relationship is that functional groups respond differently to environmental change. Over 3 years, we investigated how pollinator diversity contributes to the magnitude of pollination service through spatial complementarity and differential response to high winds in California almond orchards. We found honey bees preferentially vis...
It is common in tourism and leisure literature to define and approach tourism subgroups in terms of the presence of the tourists in certain spaces. This approach is challenged in the present paper. It is argued that the understanding of heritage tourism should be based on the link between the individual and the space, namely tourist perceptions of a site relative to their own heritage. Based on...
A common challenge in processing large domain-specific models and in-memory object structures (e.g., complex XML documents) is writing traversals and queries on them. Object-oriented (OO) designs, particularly those based on the Visitor pattern, are commonly used for developing traversals. However, such OO designs limit the reusability and independent evolution of visitation actions (i.e., the ...
Parental investment (involving time or money invested in 3-year-olds) and child health were assessed as an outcome of (a) children's risk status (preterm vs. full-term birth) and (b) maternal resources (defined here in terms of their problem-solving skills in resolving caregiving challenges). Resources were varied systematically as a function of maternal participation in a traditional home visi...
Florivory, or damage to flowers by herbivores, can make flowers less attractive to pollinators, potentially resulting in reduced plant fitness. However, not many studies have combined observations with experiments to assess the causal link between florivory and pollination. We conducted field observations at eight sites in northern California, combined with field experiments that involved artif...
Abstract Context To date, managing honey bees and wild within crop fields remains challenging. Landscape structure is often overlooked when studying the pollination contribution of bees. Increasing our understanding on how to predict bee visitation in crops crucial for sustainable management agroecosystems. Objectives With this study we investigated which landscape field-level variables determi...
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