In this paper we consider the problem of determining an optimal path for an unmanned aerial vehicle which needs to visit multiple targets. The objective is to minimize the travel distance while maximizing the utility of the visitation order. This is known as the TARGET VISITATION PROBLEM and has several applications including combat search and rescue, environmental assessment, and disaster reli...

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...