The diversity and abundance of wild insect pollinators have declined in many agricultural landscapes. Whether such declines reduce crop yields, or are mitigated by managed pollinators such as honey bees, is unclear. We found universally positive associations of fruit set with flower visitation by wild insects in 41 crop systems worldwide. In contrast, fruit set increased significantly with flower visitation by honey bees in only 14% of the systems surveyed. Overall, wild insects pollinated crops more effectively; an increase in wild insect visitation enhanced fruit set by twice as much as an equivalent increase in honey bee visitation. Visitation by wild insects and honey bees promoted fruit set independently, so pollination by managed honey bees supplemented, rather than substituted for, pollination by wild insects. Our results suggest that new practices for integrated management of both honey bees and diverse wild insect assemblages will enhance global crop yields.

Honey bees are important avocado pollinators. However, due to the low attractiveness of flowers, pollination is often inadequate. Previous work has revealed that avocado honey is relatively unattractive to honey bees when compared with honey from competing flowers. We characterized avocado honey and nectar with respect to their odor, color, and composition of sugars, phenolic compounds, and minerals. Furthermore, we tested how honey bees perceive these parameters, using the proboscis extension response bioassay and preference experiments with free-flying bees. Naïve bees were indifferent to odors of avocado and citrus flowers and honey. Experienced bees, which were collected in the field during the blooming season, responded preferentially to odor of citrus flowers. The unique sugar composition of avocado nectar, which contains almost exclusively sucrose and a low concentration of the rare carbohydrate perseitol, and the dark brown color of avocado honey, had no negative effects on its attractiveness to the bees. Phenolic compounds extracted from avocado honey were attractive to bees and adding them to a solution of sucrose increased its attractiveness. Compared with citrus nectar and nonavocado honey, avocado nectar and honey were rich in a wide range of minerals, including potassium, phosphorus, magnesium, sulfur, iron, and copper. Potassium and phosphorus, the two major minerals, both had a repellent effect on the bees. Possible explanations for the presence of repellent components in avocado nectar are discussed.

BackgroundZoonotic cutaneous leishmaniasis has long been endemic in Israel. In recent years reported incidence of cutaneous leishmaniasis increased and endemic transmission is being observed in a growing number of communities in regions previously considered free of the disease. Here we report the results of an intensive sand fly study carried out in a new endemic focus of Leishmania major. The main objective was to establish a method and to generate a data set to determine the exposure risk, sand fly populations' dynamics and evaluate the efficacy of an attempt to create "cordon sanitaire" devoid of active jird burrows around the residential area.Methodology/Principal FindingsSand flies were trapped in three fixed reference sites and an additional 52 varying sites. To mark sand flies in the field, sugar solutions containing different food dyes were sprayed on vegetation in five sites. The catch was counted, identified, Leishmania DNA was detected in pooled female samples and the presence of marked specimens was noted. Phlebotomus papatasi, the vector of L. major in the region was the sole Phlebotomus species in the catch. Leishmania major DNA was detected in ~10% of the pooled samples and the highest risk of transmission was in September. Only a few specimens were collected in the residential area while sand fly numbers often exceeded 1,000 per catch in the agricultural fields. The maximal travel distance recorded was 1.91km for females and 1.51km for males. The calculated mean distance traveled (MDT) was 0.75km.ConclusionsThe overall results indicate the presence of dense and mobile sand fly populations in the study area. There seem to be numerous scattered sand fly microsites suitable for development and resting in the agricultural fields. Sand flies apparently moved in all directions, and reached the residential area from the surrounding agricultural fields. The travel distance noted in the current work, supported previous findings that P. papatasi like P. ariasi, can have a relatively long flight range and does not always stay near breeding sites. Following the results, the width of the "cordon sanitaire" in which actions against the reservoir rodents were planned, was extended into the depth of the agricultural fields.

Summary The concept of pollinator niche complementarity maintains that species‐rich pollinator communities can provide higher and more stable pollination services than species‐poor communities, due to contrasting spatial and/or temporal pollination activity among groups of pollinators. Complementarity has usually been examined in pollinators’ patterns of flower visitation or abundance, while largely neglecting the possibility of complementarity in patterns of single‐visit contribution to fruit/seed set (pollination efficiency). However, variability in pollination efficiency can greatly affect pollinators’ overall pollination services and may therefore contribute an additional, important aspect of complementarity. In this study, we investigated the existence of pollinator complementarity in both visitation rates and pollination efficiencies. The study was conducted in 43 watermelon fields cultivated for seed consumption in a Mediterranean agro‐natural landscape in central Israel. We studied spatiotemporal variation in pollinators’ visitation activity, measured by repeated observations and netting, and single‐visit pollination efficiency, measured by the fruit and seed set rates of hermaphrodite flowers exposed to a single bee visit. Visitation and pollination efficiency were measured throughout the day and season, within and between fields with contrasting availability of nearby wild plants, and among flowers of different sizes. Pollinator species’ visitation rates as well as single‐visit fruit set efficiencies, but not seed set efficiencies, exhibited significant spatiotemporal variation that contributed to their complementarity. Pollinators’ visit frequencies were affected by surrounding land use, location within field, time throughout the season, and time of day. Pollinators’ fruit set efficiencies were affected by ovary size and time of day. Synthesis and applications. Crop pollinators may exhibit complementarity in both their visitation rates and pollination efficiencies, which can promote the overall level and stability of their pollination services. Complementarity in pollination efficiencies suggests further diversity effects on crop yield, and calls for taking into account the variability in pollination efficiency along spatiotemporal scales rather than considering it a constant, species‐specific trait. However, some modes of niche complementarity may not necessarily translate into increased pollination services and crop yield; the relevance and limitations of such mechanisms should be considered in the light of the specific crop and management system studied.

Various nectar components have a repellent effect on flower visitors, and their adaptive advantages for the plant are not well understood. Persea americana (avocado) is an example of a plant that secretes nectar with repellent components. It was demonstrated that the mineral constituents of this nectar, mainly potassium and phosphate, are concentrated enough to repel honey bees, Apis mellifera, a pollinator often used for commercial avocado pollination. Honey bees, however, are not the natural pollinator of P. americana, a plant native to Central America. In order to understand the role of nectar minerals in plant-pollinator relationships, it is important to focus on the plant's interactions with its natural pollinators. Two species of stingless bees and one species of social wasp, all native to the Yucatan Peninsula, Mexico, part of the natural range of P. americana, were tested for their sensitivity to sugar solutions enriched with potassium and phosphate, and compared with the sensitivity of honey bees. In choice tests between control and mineral-enriched solutions, all three native species were indifferent for mineral concentrations lower than those naturally occurring in P. americana nectar. Repellence was expressed at concentrations near or exceeding natural concentrations. The threshold point at which native pollinators showed repellence to increasing levels of minerals was higher than that detected for honey bees. The results do not support the hypothesis that high mineral content is attractive for native Hymenopteran pollinators; nevertheless, nectar mineral composition may still have a role in regulating flower visitors through different levels of repellency.