Honey Bee Visitation Research Articles

Strategic honey bee hive placement improves honey bee visitation but not pollination in northern highbush blueberry

Abstract Commercial blueberry Vaccinium spp. (Ericales: Ericaceae) production relies on insect-mediated pollination. Pollination is mostly provided by rented honey bees, Apis mellifera L. (Hymenoptera: Apidae), but blueberry crop yields can be limited due to pollination deficits. Various hive placement strategies have been recommended to mitigate pollination shortfalls, but the effect of hive placement has received limited formal investigation. This study explores the effects of clumped and dispersed hive placement strategies on honey bee visitation and pollination outcomes in “Bluecrop” and “Duke” fields over 2 years (2021 and 2022) within 2 economically important regions of production in the United States—the Midwest (Michigan) and Pacific Northwest (Oregon and Washington). Clumping hives consistently increased honey bee visitation rate but did not result in higher fruit set, fruit weight, or seed count. Increases in honey bee visitation through clumping could perhaps improve pollination outcomes in more pollination-limited blueberry cultivars and other pollination-dependent crops. Clumping hives is substantially more efficient and cost-effective for beekeepers due to fewer drop locations and could lead to cost savings for both beekeepers and blueberry growers without growers sacrificing pollination levels and crop yields.

Conventional Versus Biorational Insecticides for Controlling Mustard Aphid and Their Effects on Beneficial Insects

Mustard is one of the most important oilseed crops in Bangladesh. However, its production is severely constrained by aphid infestation. Farmers usually spray conventional insecticides to control aphids that negatively affect beneficial insects and environment. Thus, alternatives to conventional insecticides are required. We tested three biorational insecticides (Nimbicidine @ 1ml/L, Spinosad: Libsen 45SC @ 0.5 ml/L and Lufenuron: Hayron 5EC @ 0.5ml/L of water) against aphid infestation and assessed their effect on ladybird beetle and honey bee and compared these effects with two conventional insecticides (Diazinon: Sabion 60EC @ 2ml/L and Cypermethrin: Cypraplus 10EC @ 1ml/L of water) and with an untreated control. The study was conducted in a randomized complete block design with each treatment replicated thrice in the field of Department of Entomology, Bangladesh Agricultural University. Number of infested plants per plot, aphid per plant and per pod, number of ladybird beetle and honey bee per plot was counted and yield per plot was calculated. All tested insecticides reduced aphid infestation compared to untreated control indicating all of them were effective against aphid. However, Lufenuron and Nimbicidine was most effective to reduce plant infestation and number of aphids per plant and pod. Spinosad and Sabion were found fairly effective whereas Cypraplus was found to be least effective. Lufenuron and Nimbicidine did not reduce the number of ladybird beetle and honey bee visit per plot, however, Spinosad and conventional insecticides reduced their number. Lufenuron treated plots provided highest yield (1.35 t/ha) followed by Nimbicidine (1.15 t/ha), Spinosad (1.10 t/ha) and Sabion (1.00 t/ha) whereas Cypraplus treated plots provided lowest yield (0.9 t/ha). In terms of reducing aphid population thus plant infestation and increasing yield, all biorational insecticides performed better than conventional insecticides, however, concerning effect on ladybirds and honey bees, only Lufenuron and Nimbicidine can be recommended to farmers. J Bangladesh Agril Univ 22(3): 335-341, 2024

Impact of the annular solar eclipse on December 26, 2019 on the foraging visits of bees

Solar eclipse has remarkable effect on behavior of animals. South India experienced a 97% magnitude annular eclipse on December 26, 2019 during 08:04–11:04 h with the totality phase appeared during 09:25–09:30 h. We investigated whether the foraging activity of the bees was limited by the eclipse, what bees are affected most, and which part of the eclipse was critical for bee activities to understand how a group of insects that rely the Sun, the sunlight, and the sun rays for their navigation and vision behaves to the eclipse. We opted to watch the bees in their foraging ground, and selected the natural flower populations of Cleome rutidosperma, Hygrophila schulli, Mimosa pudica, and Urena sinuata—some of the bee-friendly plants—to record the visitor richness and visitation rate on the flowers on eclipse and non-eclipse days and during the hour of totality phase and partial phase of the eclipse. Fewer flower-visiting species were recorded on the eclipse day than on the non-eclipse days, but in the period of totality, very few bee species were active, and limited their activity to only one population of C. rutidosperma. Visits of honey bees and stingless bees were affected most, but not that badly of solitary bees and carpenter bees. Bees, particularly the social bees use Sun for navigation and deciphering information on forage sources to fellow workers. The eclipse, like for many other animals, might hamper bees’ orientation, vision, and flight.

Modeling honeybee flower visitation rates in the fragmented agricultural landscapes based on Lévy-flight behavior

AbstractTypically, honeybees (Apis mellifera L.), rely on waggle dances performed by scout bees to communicate information about fruitful nectar and pollen sources across the landscape. However, when this communication is absent, inaccurate, or when resources become depleted, bees resort to alternative search strategies. Field experiments utilizing harmonic radar have revealed that honeybees follow flight patterns that demonstrate a scale-free (Lévy-flight) behavior, representing an optimal search strategy for relocating the original feeder location. If honeybees adhere to a Lévy flight pattern to discover resources, where would honeybees demonstrate the highest flower visitation rates in agricultural landscapes? We generated simulated landscapes with varying proportions of forest cover scenarios, ranging from 5 to 50% of the total landscape area, along with different levels of fragmentation per se. Subsequently, we constrained the richness of flower farm cells in each landscape. To predict honeybee visitation rates, three different methodologies based on random movement were utilized: (1) moving window, (2) random walk, and (3) Lévy flight. We found that honeybee visitation rates were influenced by the degree of forest fragmentation in each scenario. Across all visitation scenarios, the highest average number of visited flowers per cell was observed in landscapes with maximum fragmentation per se. In landscapes with lower forest cover and higher fragmentation, honeybees were more likely to visit a greater number of flowers due to the increased probability of traversing the landscape and encountering more flower cells. honeybee visitation rates in agricultural landscapes are significantly influenced by the degree of forest fragmentation. The study highlights the importance of considering landscape structure, specifically forest fragmentation, when predicting honeybee visitation rates and underscores the need for further research to better understand the intricate relationship between landscape characteristics and pollinator behavior.

An Ecological Study of Alstonia Venenata R.Br. (Apocynaceae: Rauvolfioideae) and Cryptolepis Buchanani R.Br. ex Roem. & Schult. (Apocynaceae: Periplocoideae)

_Alstonia venenata_ and _Cryptolepis buchanani_ with shrubby habit occupy different locations but both bloom during summer season. _A. venanata_ flowers facilitate autonomous autogamy. Butterflies and honey bees visit the flowers during forenoon period and effect self- and cross-pollination. _C. buchanani_ flowers are unattractive to the flower visitors any fruit set is exclusively a function of autonomous autogamy. In both species, fruit is a paired follicle which sheds seeds when dry and the seeds thus liberated are dispersed by wind.

An Ecological Study of Alstonia Venenata R.Br. (Apocynaceae: Rauvolfioideae) and Cryptolepis Buchanani R.Br. Ex Roem. & Schult. (Apocynaceae: Periplocoideae)

_Alstonia venenata_ and _Cryptolepis buchanani_ belong to Apocynaceae family. The two species with shrubby habit occupy different locations but both bloom during summer season. _A. venanata_ flowers are milky white and very prominent during forenoon period. The relative positions of floral sex organs facilitate the occurrence of autonomous autogamy. Butterflies and honey bees visit the flowers during forenoon period only when the former collect nectar while the latter collect pollen but both act as pollinators. The fruit production rate in this species is a result of autognomous autogamy and vector-mediated self- and cross-pollination. _C. buchanani_ flowers are greenish-yellow, nectariferous and unattractive to the flower visitors present in that area. The low fruit production rate in this species is exclusively a result of autonomous autogamy. Fruit is a paired follicle in both plant species and each follicle produces several to numerous seeds according to the production rate of ovules in flowers. Follicles shed seeds when dry and the seeds thus liberated are dispersed by wind and hence both _A. venenata_ and _C. buchanani_ are anemochorous.

Plant virus diversity in bee and pollen samples from apple (Malus domestica) and sweet cherry (Prunus avium) agroecosystems.

Honey bee (Apis mellifera) pollination is widely used in tree fruit production systems to improve fruit set and yield. Many plant viruses can be associated with pollen or transmitted through pollination, and can be detected through bee pollination activities. Honey bees visit multiple plants and flowers in one foraging trip, essentially sampling small amounts of pollen from a wide area. Here we report metagenomics-based area-wide monitoring of plant viruses in cherry (Prunus avium) and apple (Malus domestica) orchards in Creston Valley, British Columbia, Canada, through bee-mediated pollen sampling. Plant viruses were identified in total RNA extracted from bee and pollen samples, and compared with profiles from double stranded RNA extracted from leaf and flower tissues. CVA, PDV, PNRSV, and PVF coat protein nucleotide sequences were aligned and compared for phylogenetic analysis. A wide array of plant viruses were identified in both systems, with cherry virus A (CVA), prune dwarf virus (PDV), prunus necrotic ringspot virus (PNRSV), and prunus virus F (PVF) most commonly detected. Citrus concave gum associated virus and apple stem grooving virus were only identified in samples collected during apple bloom, demonstrating changing viral profiles from the same site over time. Different profiles of viruses were identified in bee and pollen samples compared to leaf and flower samples reflective of pollen transmission affinity of individual viruses. Phylogenetic and pairwise analysis of the coat protein regions of the four most commonly detected viruses showed unique patterns of nucleotide sequence diversity, which could have implications in their evolution and management approaches. Coat protein sequences of CVA and PVF were broadly diverse with multiple distinct phylogroups identified, while PNRSV and PDV were more conserved. The pollen virome in fruit production systems is incredibly diverse, with CVA, PDV, PNRSV, and PVF widely prevalent in this region. Bee-mediated monitoring in agricultural systems is a powerful approach to study viral diversity and can be used to guide more targeted management approaches.

Drivers of flower visit and resource sharing between the honeybee and native bees in Neotropical coastal sand dunes.

The honeybee (Apis mellifera) is one of the most important pollinator species because it can gather resources from a vast variety of plant species, including both natives and introduced, across its geographical distribution. Although A. mellifera interacts with a large diversity of plants and shares resources with other pollinators, there are some plant species with which it interacts more frequently than others. Here, we evaluated the plant traits (i.e., plant length, abundance of bloomed individuals, number of open flowers, and stamen length) that would affect the honeybee visit frequencies to the flowers in a coastal environment in the Gulf of Mexico. Moreover, we evaluated which native bee species (and their body size) overlap floral resource with A. mellifera. We registered 998 plant-bee interactions between 35 plant species and 47 bee species. We observed that plant species with low height and with high abundances of bloomed individuals are positively related to a high frequency of visits by A. mellifera. Moreover, we found that A. mellifera tends to share a higher number of plant species with other bee species with a similar or smaller body size than with bigger species, which makes them a competitor for the resource with honeybees. Our results highlight that the impacts of A. mellifera on plants and native bees could be anticipated based on its individual's characteristics (i.e., plant height and abundance of bloomed individuals) and body size, respectively.

Erythritol sprays reduce D. suzukii infestation without impacting honey bee visitation nor fruit quality.

Spotted-wing drosophila, Drosophila suzukii, is an economic pest of small fruits and cherries. Insecticides primarily control this pest while alternative controls are in development. Laboratory studies show that erythritol is insecticidal to D. suzukii and other pests while safe for human consumption. Moreover, erythritol combined with sucrose or non-caloric sucralose can stimulate feeding and quicken mortality. Before growers can use erythritol, the impact on crop protection, non-target insects, and fruit quality need evaluation. In three blueberry and cherry field cage trials, oviposition on fruit sprayed with erythritol:sucrose or erythritol:sucralose formulations was lowered by 59-81% compared to unsprayed controls. Fly infestation (larval or adult counts from fruit) was 90% lower in a greenhouse blueberry trial, and 49% lower in an open field blueberry trial with 2M erythritol: 0.5M sucrose. Infestation was also 57% lower in an open field cherry trial with 1.5M erythritol: 0.5M sucrose. Other field trials with very low pest pressure or frequent rains revealed no differences from controls. Field trials consistently revealed that honey bees did not preferentially visit plants sprayed with either erythritol formulation, although yellow jackets visited erythritol:sucrose-sprayed plants more frequently. Erythritol formulations consistently led to more leaf spotting, but there was no reduction in quality of treated blueberries or cherries in terms of mold development, firmness, diameter, epidermal penetration force, and Brix° (total soluble solids; TSS) at harvest. Eleven trials conducted over four years show that erythritol formulations can reduce D. suzukii pressure without attracting foraging honey bees nor negatively impacting fruit quality. This article is protected by copyright. All rights reserved.

Honeybee visitation to shared flowers increases Vairimorpha ceranae prevalence in bumblebees.

Vairimorpha (=Nosema) ceranae is a widespread pollinator parasite that commonly infects honeybees and wild pollinators, including bumblebees. Honeybees are highly competent V. ceranae hosts and previous work in experimental flight cages suggests V. ceranae can be transmitted during visitation to shared flowers. However, the relationship between floral visitation in the natural environment and the prevalence of V. ceranae among multiple bee species has not been explored. Here, we analyzed the number and duration of pollinator visits to particular components of squash flowers-including the petals, stamen, and nectary-at six farms in southeastern Michigan, USA. We also determined the prevalence of V. ceranae in honeybees and bumblebees at each site. Our results showed that more honeybee flower contacts and longer duration of contacts with pollen and nectar were linked with greater V. ceranae prevalence in bumblebees. Honeybee visitation patterns appear to have a disproportionately large impact on V. ceranae prevalence in bumblebees even though honeybees are not the most frequent flower visitors. Floral visitation by squash bees or other pollinators was not linked with V. ceranae prevalence in bumblebees. Further, V. ceranae prevalence in honeybees was unaffected by floral visitation behaviors by any pollinator species. These results suggest that honeybee visitation behaviors on shared floral resources may be an important contributor to increased V. ceranae spillover to bumblebees in the field. Understanding how V. ceranae prevalence is influenced by pollinator behavior in the shared floral landscape is critical for reducing parasite spillover into declining wild bee populations.

Effectiveness of honeybee (Apis mellifera) visit on the pollination of different sunflower cultivars

BackgroundUtilizing pollinators is one of the most dependable, economical, and environmentally friendly ways to improve cross-pollination, boost crop output, and improve crop quality. Bees are regarded as the best pollinators among all other pollinators. MethodsThe current study was conducted to elucidate the impact of honeybee (Apis mellifera) visits on the pollination of various sunflower cultivars including Hysum-33, Hysun-38, and FH-106. ResultsOur finding revealed that the highest average number of honeybee visits was observed in the morning followed by noon and afternoon on different sunflower cultivars. The maximum number of honeybee visits was recorded on Hysun-38, while the minimum was recorded on the FH-106 cultivar, which was 87.85 and 73.6, respectively. In (Hysun-33) and (FH-106), the maximum average time spent by the honeybee noticed in the morning on the flower was 34.24 and 32.67 min, whereas the maximum average time spent in the evening on the flower of (Hysun-38), which was 36.41 min. Regression analysis demonstrated that a significant effect between the head diameter of sunflower cultivars and the number of honey bee visits (p < 0.05). In addition, a significant effect was observed between the number of honeybees visited and the number of seed settings on all cultivars of sunflower (p < 0.05). There was a highly strong positive correlation between the number of seed sets and the head diameter of all cultivars. ConclusionIt is concluded that farmers should maintain honeybee colonies close to the desired crop to increase pollination and increase output.

Comparing levels of geitonogamous visitation by honey bees and other pollinators

Geitonogamy, the transfer of pollen from one flower to another on the same plant, is often the primary means of self-pollination in flowering plants. For self-compatible plants, self-fertilization may lead to greatly reduced offspring fitness via inbreeding depression. For self-incompatible plants, geitonogamous pollen transfer can result in low seed set, even when stigmatic pollen loads are substantial. For multiple self-compatible, native California plants, we found that honey bees visited more flowers per plant than native insects, and that offspring resulting from pollination by honey bees had reduced fitness relative to those resulting from native insect pollination. Here we investigate whether honey bees generally make more geitonogamous visits than other pollinators using data from a global survey of 41 manuscripts that reported floral visitation data. Compared to the average of all non-honey bee visitors in a plants pollinator assemblage, honey bees visit significantly more flowers per plant, though they do not differ from the non-honey bee visitor with the highest rate of geitonogamous visitation. However, the disparity between rates of geitonogamous visitation by honey bees and non-honey bee visitors is a function of the frequency of honey bees relative to non-honey bee visitors. As honey bees become increasingly numerically dominant, there is a trend for their rates of geitonogamous visitation to increase, accompanied by a significant decline in flowers visited per plant by non-honey bee visitors. While we found that honey bees visited more flowers per plant compared to the average of other visitors, large or eusocial pollinators were as likely as honey bees to be the most geitonogamous visitor.

The major role of spring trees in Ohio honey production for bees located in high and low agricultural intensity

Nectar is the resource that sustains honey bee colonies through periods of dearth and provides the surplus honey beekeepers harvest for human consumption. While extensive information is available for plants that honey bees visit for pollen and nectar, we lack knowledge on which nectars are stored long-term as honey for harvest and support of colonies through winter. Here, we used citizen science methods and pollen metabarcoding analysis to identify the plants contributing most to honey samples harvested by beekeepers from apiaries with variable intensities of surrounding agriculture. A total of 36 samples were collected from 36 apiaries in Ohio in 2019, with an average of 3 plant genera detected per sample. We found similarity in honey samples collected from all apiaries, regardless of the proportion of agricultural land within a 2-km foraging range, with substantial amounts of honey stored from spring trees, including Salix (willow) and Prunus (cherry). This result suggests the importance of early-season resources regardless of agricultural intensity in the surrounding landscape. This study contributes to a body of work aiming to identify the nectars making it to long-term honey storage and those that are being consumed within the hive shortly after collection.

Electromagnetic fields disrupt the pollination service by honeybees.

We assessed the effect that electromagnetic field (EMF) exerts on honeybees' pollination efficiency using field and laboratory experiments. First, we measured levels of gene and protein expression in metabolic pathways involved in stress and behavioral responses elicited by EMF. Second, we assessed the effect of EMF on honeybee behavior and seed production by the honeybee-pollinated California poppy and, lastly, by measuring the consequences of pollination failure on plants' community richness and abundance. EMF exposure exerted strong physiological stress on honeybees as shown by the enhanced expression of heat-shock proteins and genes involved in antioxidant activity and affected the expression levels of behavior-related genes. Moreover, California poppy individuals growing near EMF received fewer honeybee visits and produced fewer seeds than plants growing far from EMF. Last, we found a hump-shaped relationship between EMF and plant species richness and plant abundance. Our study provides conclusive evidence of detrimental impacts of EMF on honeybee's pollination behavior, leading to negative effects on plant community.

Bee visitation, pollination service, and crop yield in commodity and hybrid seed canola

Insect-mediated pollination of crops is an important service to agriculture, as increased insect visitation can increase fruit production by increasing pollen deposition. Unfortunately, pollination is often treated as a “black box”, and pollination management suffers from key knowledge gaps that hinder its greater utility, particularly the specific mechanisms underlying the processes of visitation, pollination, and fruit production. We present a causal model that links insect visitation to pollination to three separate components of yield, using field data from two types of canola (Brassica napus) production systems. Our results demonstrate that yield in commodity canola fields is primarily determined by plant size, and we found no relationship between honey bee (Apis mellifera) visitation and pollen deposition, or pollen deposition and seed yield. In contrast, yield in hybrid seed canola fields was similarly controlled by plant size, but there was also a strong relationship between alfalfa leafcutting bee (Megachile rotundata) visitation and pollen deposition, as well as pollen deposition and seed yield, meaning that leafcutting bee visitation in increased pollen deposition in seed canola fields, while honey bee visitation did not. This model serves as a step towards a dynamic model of pollination services, and highlights the relative importance of bee pollination in canola production.

Brassica plants promote Apis mellifera visitation to Japanese apricot in cold conditions

Floral resource enhancements are widely used to boost insect pollination in various crops. The Japanese apricot, a winter-flowering fruit crop, requires mid-winter pollination. However, cold weather can restrict pollinator activity. In this study, we explored the use of Brassica plants, which bloom fully during the Japanese apricot blossom period, as additional flower resources to promote honey bee visitation. We sowed Brassica rapa and used existing feral Brassica plants as additional floral resources to compare the honey bee visitation frequency, visitation behavior, and the number of pollen grains on the stigmas of Japanese apricot flowers with those of the control group. The visitation of the managed honey bee (Apis mellifera) to the Japanese apricot flowers was studied at temperatures below 15 ºC. Under such cold conditions, Brassica flowers increased A. mellifera visitation in both the experimental and commercial orchards. Brassica-rich orchards exhibited clear positive effects of flower resources. Observations of flower-visiting behavior and pollen grains on the stigmas suggest that the increased honey bee visitation to Japanese apricot flowers was not caused by spillover from the Brassica flowers. The flower resources did not increase the number of pollen grains on the Japanese apricot stigmas irrespective of the increase in the number of honey bee visits. Fruit production instability caused by cold weather is a major issue in the agricultural management of commercially cultivated Japanese apricot. The findings suggest that Brassica plants can solve pollination-related problems in Japanese apricot orchards. In addition, Brassica plants are easy to grow, do not have common pests with Japanese apricot, and are beneficial for both apiarists and farmers. Therefore, Brassica plants are a promising floral resource for use in Japanese apricot orchards.

Synthetic Nasonov gland pheromone enhances abundance and visitation of honeybee, Apis mellifera, in Korla fragrant pear, Pyrus sinkiangensis

Abstract Korla fragrant pear (Pyrus sinkiangensis Yü) depends on cross‐pollination by honeybees (Apis mellifera) but may suffer from low honeybee visitation. We assessed whether honeybee abundance and visitation frequency are enhanced by using synthetic Nasonov gland pheromone (NGP), which is naturally produced by worker bees to stimulate the aggregation of bees to food resources or nesting sites. The response of honeybees to synthetic NGP was firstly assessed using Y‐tube olfactometer tests in the laboratory, and subsequently in the field, by placing NGP lures on Korla fragrant pear trees in orchards with and without beehives. Honeybee abundance was assessed using coloured pan traps while honeybee visits were assessed by visual observations on pear flowers. Y‐tube olfactometer tests showed a significant preference of honeybees for NGP. In pear orchards with beehives, honeybee abundance was 2.5‐fold higher on trees with NGP lures than on trees without NGP, and 2.2‐fold higher in orchards in which all trees contained NGP lures than in orchards without NGP lures. Such positive effects were not observed in orchards without beehives. Flower visitation by honeybees was significantly higher in trees with NGP lures than without NGP lures, irrespective of the presence (5.7‐fold higher) or absence of beehives (27.6‐fold higher). In mixed pear‐apricot orchards, honeybee abundance was higher in pear trees with NGP lures than without lures. Our results show that NGP lures attract honeybees to flowering pear trees in monoculture pear and mixed pear‐apricot orchards, and that this effect is greatest in orchards with beehives.

Weather conditions affect pollinator activity, fruit set rate, and yield in Japanese apricot

Japanese apricot blooms in mid-winter, and thus severe weather conditions, including low temperatures, sometimes limit pollinator activity and consequently decrease fruit set rate and yield. Plant physiology is also affected by weather conditions. In this study, we aimed to evaluate the effect of pollinator activity on fruit set rate and yield, in comparison with the effects of meteorological factors. First, we conducted field experiments in 2021 and 2022 at Wakayama prefecture. The results showed that honey bee visitation increased as ambient temperature increased. Fruit set rate also increased under warm conditions when Japanese apricot was naturally pollinated by honey bees. In contrast, hand-pollinated flowers were not affected by ambient temperature. These results revealed that low temperature during the flowering period decreased pollinator visitation but did not affect plant fertilization ability. To compare pollinator activity with meteorological factors over a long period, including the pre- and post-flowering periods, we used a state-space model describing the time series of fruit set rate. The model using fruit set rate data and meteorological records over 15 years (2007–2021) at the Japanese Apricot Laboratory showed that the pre-blossom temperature and number of days suitable for pollination significantly affected the fruit set rate. Another model for the time series of fruit yield using the fruit yield records over 46 years (1976–2021) in Wakayama prefecture showed that fruit yield was affected by number of suitable pollination days, pre-blossom temperature, and sunshine duration before harvest. Moreover, the introduction of Western honey bees into orchards had considerable effects on fruit yield. These results indicate that pollinator activity (which is responsive to weather conditions) and pre-blossom temperature have a significant influence on fruit set rate and yield in Japanese apricot.

Landscape-level honey bee hive density, instead of field-level hive density, enhances honey bee visitation in blueberry

ContextTo date, managing honey bees and wild bees within crop fields remains challenging. Landscape structure is often overlooked when studying the pollination contribution of honey bees. Increasing our understanding on how to predict honey bee visitation in crops is crucial for sustainable management of agroecosystems.ObjectivesWith this study we investigated which landscape and field-level variables determine honey bee and wild bee visitation, and whether honey bee or wild bee visitation influence crop pollination.MethodsSixteen highbush blueberry fields were surveyed for honey bees, wild bees, and crop pollination in Washington, USA. Additionally, within a radius of 1000 m around each field all honey bee hives were located and the surrounding landscape was characterized.ResultsHoney bee hive numbers in the landscape positively correlate with the proportion of blueberry in the landscape. Honey bee visitation was best predicted by landscape-level hive density within a radius of 1000 m, whereas semi-natural habitat and field-level hive density did not impact honey bee visitation. The amount of semi-natural habitat and blueberry within a radius of 1000 m had a positive and negative impact, respectively, on wild bee visitation. Honey bee visitation had a positive effect on blueberry seed set.ConclusionWe conclude that honey bee visitation is determined by the number of honey bee hives in the surrounding landscape. Hence, field-level hive density recommendations miss contributions from other hives in the landscape. Furthermore, semi-natural habitat did not impact honey bee visitation and contributes to diversifying pollinator diets and provides wild bee habitat.

Prioritizing pollinators over pests: wild bees are more important than beetle damage for watermelon yield.

Insect pests and pollinators can interact directly and indirectly to affect crop production; however, impacts of these interactions on marketable yield are little known. Thus, the evaluation of interactions between pests and pollinators are needed to best prioritize management efforts. Over 2 years, we evaluated the impact of pollinator visitation and/or beetle (<i>Acalymma vittatum</i>) infestation on fruit set and yield in seedless watermelon production. In 2020, we tested the main effect of pollinator visitation: two or eight honeybee visits, two wild bee visits, hand pollinated and open pollinated. In 2021, we crossed wild and managed pollinator visitation (two or four honeybee visits, two or four wild bee visits, hand pollinated and open pollinated) with varying beetle infestation levels (0, 3, 6 and 9 beetles/plant). In both years, wild bees contributed significantly to high fruit yields, and exclusive visitation from wild bees increased yield by a factor of 1.5-3 compared to honeybees. In 2021, pollination was the only significant factor for fruit set and marketable yield even when compared to the varying beetle infestation levels. These data advocate for a reprioritization of management, to conserve and protect wild bee pollination, which could be more critical than avoiding pest damage for ensuring high yields.