Fig 2 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Fruit-set ratio (a) and number of seeds (b) for each pollination treatment. Pollination treatments were as follows: (1) bagging of flower buds with unwoven cloth bag (NP); (2) bagging with 2-mmmesh bag (2-M); (3) bagging with 3.5-mm-mesh bag (3.5-M); (4) open pollination (OP); (5) hand-pollination followed by enveloping of the flower in paper bag (HPB); and (6) hand-pollination followed by open pollination (HPO). The significance of the coefficients was
Source publication
Oriental persimmon, Diospyros kaki Thunb. (Ericales: Ebenaceae), is a generally diclinous tree. Because the representative cultivar, ‘Fuyu’, sets nearly exclusively female flowers and has low parthenocarpic ability, it requires pollen from other cultivars for pollination. Here, we identified the most important pollinator of D. kaki in hilly orchard...
Contexts in source publication
Context 1
... bags were placed on 22 May and removed on 6 June 2018. Before harvest, seed development was pre-checked on 20 July 2018 in fruit that was not used in the pollination experiments (Fig. S2). Fruit set in each pollination treatment was counted on 1 August 2018, when physiological fruit drop in the early development stage had ceased. Two tags in the HPB treatment group had been lost by harvest of the immature fruit on 1 August 2018 (so n = 23 for the HPB treatment and n = 25 for the other treatments). Diospyros kaki forms, ...
Context 2
... differences in fruit set among the six pollination treatments (GLMM, type 2; df = 5, χ 2 = 58.315, p < 0.001). Tukey's post hoc test detected significant differences (p < 0.05) in the fruitset ratio between treatments in one group (NP, 2-M, and 3.5-M treatments) and those in another group (OP, HPB, and HPO treatments) (nine pairs in total; Fig. 2a). In contrast, no significant difference was detected (p > 0.05) between any of the pairs within each group (six pairs in total). The GLMM revealed significant differences in seed number among four pollination treatments (GLMM, type 2; df = 3, χ 2 = 32.359, p < 0.001). Tukey's post hoc test detected significant differences in seed ...
Context 3
... significant differences in seed number among four pollination treatments (GLMM, type 2; df = 3, χ 2 = 32.359, p < 0.001). Tukey's post hoc test detected significant differences in seed number between the 3.5-M and OP treatments (p = 0.00593), between the 3.5-M and HPB treatments (p < 0.001), and between the 3.5-M and HPO treatments (p < 0.001) (Fig. 2b). ...
Context 4
... not significant (p = 0.62550). With sufficient pollen grains on their body surfaces, small bees can be considered the second-most-important pollinators. Because their head and thorax widths were approximately 2.5 mm (see Table S2), the 3.5-mm mesh would not have prevented their entry. We do not know why the fruit in the NP treatment set seed (see Fig. 2b), because this treatment was designed to prevent insect access. The most likely explanation is that it was a result of the inadvertent bagging of a flower bud at an inappropriate time-that is, slightly later than ...
Similar publications
Flowers on the ground of orchards can provide substantial resources for wild pollinators of orchard trees. Few studies, however, have examined the relative importance of groundcover flowers to orchard pollination by analyzing pollen on the body surface of pollinators. Oriental persimmon trees bloom within the longer blooming period of white clover,...
Citations
... On the one hand, apple trees are often planted in rows in apple orchards. As honeybees prefer to move along the same rows when foraging (Brittain et al., 2013;Greenleaf & Kremen, 2006), whereas wild bees tend to move between rows rather than within rows, wild bees are more likely than honeybees to achieve cross-pollination, ity to carry pollen and facilitate pollen deposition than honeybees, also in case of apples (Eeraerts et al., 2020;Funayama et al., 2022;Nikkeshi et al., 2019). In addition, wild bees are more adaptive to bad weather conditions than honeybees, particularly in earlier spring with low temperature, when apple flowering and honeybee visit efficiency is low (Boyle-Makowski, 1987;Park et al., 2016). ...
Honeybees (Apis mellifera) are increasingly used in commercial crop production, while wild bees are also important pollinators. Few studies have investigated the relative importance of honeybees and wild bees for apple pollination and whether the contribution of wild bees is affected by increasing numbers of honeybees.
Here, we conducted experiments in 52 commercially important Fuji apple orchards across three apple production areas in China, to investigate how wild bees, honeybees and their interaction influences apple quantity (fruit set, weight) and quality (seed number). Both honeybees and wild bees contributed to apples production, resulting in an overall 996%, 26% and 64% increase of apple fruit set, fruit weight and seed number, respectively.
We found a hump‐shaped relationship between bee density and fruit set and fruit weight with the maximum fruit set at intermediate bee density, but honeybees reached the maximum only with one and a half times higher numbers than wild bees. Furthermore, when honeybee activity density was low, an increase in wild bee activity density and species richness led to enhanced pollination contribution. Conversely, when honeybee activity density was high, increased wild bee activity density and species richness were associated with reduced pollination contribution. Additionally, the highest fruit set was observed at high densities of wild bees and intermediate densities of honeybees. These results indicate that high honeybee activity density may interfere with the pollination services provided by wild bees in apple orchards.
Synthesis and applications. Both honeybees and wild bees contribute to apple pollination and production, but wild bees evidenced much higher pollination efficiency than honeybees. Importantly, introducing high density of honeybee colonies appeared to enhance competition with wild bees, decreasing their contribution to pollination. As highest fruit set was found with high wild bee densities, but only intermediate levels of honeybee densities, it is important to carefully assess the number of honeybee colonies before possible introduction of hives for apple production, in particular when wild bee diversity and density are high. Conserving wild bee diversity is of priority to harness pollination services in apple production, given their high diversity and pollination efficiency.
... To clarify relative pollinator importance of the flower visitors, con- The amount of pollen load of each insect was estimated, following the method described in detail in Nikkeshi et al. (2019). Briefly, we cut and eliminated hind legs with corbicular pollen loads using scissors and poured 0.4 M of sucrose solution (1.0-6.0 mL, depending on the body size) into each vial with an insect sample. ...
Despite growing awareness of the importance of monitoring wild crop pollinators worldwide, there are still few reports, especially in East Asia. Considering ongoing global warming may change the distribution range and diurnal activity of pollinators, it is necessary to describe current geographic and diurnal patterns. We clarified pollinators of Cucurbita maxima Duchesne (Cucurbitales: Cucurbitaceae) in three geographically distinct (>350 km, minimum) areas in Japan, focusing on diurnal variation. Apis mellifera L. (Hymenoptera: Apidae) and Halictidae (Hymenoptera) were observed in all of the experimental gardens. Apis cerana japonica Radoszkowski (Hymenoptera: Apidae) were mainly observed in Mie and Kagoshima, while Bombus diversus diversus Smith (Hymenoptera: Apidae) were observed only in Ibaraki. The peak time of flower visits depended both on bee taxa and area, and interestingly, did not necessarily synchronize with the timing of the highest pollen loads and the probability of stigma contact. In particular, visits and probability of contacting stigmas of Halictidae tended to increase as time passed, whereas pollen grains on their bodies sharply decreased with time; only a few individuals of Halictidae that visit early can become effective pollinators. There were no differences in yields between supplementary hand and natural pollination in all areas, and flower‐enclosure experiments using different mesh sizes clarified that small insects that can go across an approximately 4‐mm mesh may not transport sufficient pollen for fruit set. Our study demonstrated that pollination effectiveness, which is usually regarded as a static value, within a taxon can fluctuate in the space of just several hours. Considering such diurnal patterns can be altered by climate change, we need to carefully monitor the diurnal temporal patterns of pollinators worldwide.
... Social pollinating bees, including bumblebees and honeybees, are essential pollinators of wildflowers and crops [1]. While honeybees are often imported to the field for pollination, bumblebees and honeybees are not always interchangeable for plant species, such as tomatoes [2]. ...
... Evaluation of the pollination services provided by small wild pollinators was performed following the method of Nikkeshi et al. (2019), who used 3.5-mm-mesh polyethylene net bags that allow access to flowers by small pollinators, such as those belonging to the Hymenoptera and the Diptera, but exclude A. mellifera and O. cornifrons. From 2019 to 2021, two pollination conditions were set: treatment, in which flower clusters were enclosed in 3.5-mm-mesh polyethylene net bags (20 × 13 cm); and control, open pollination, in which all pollinators had unimpeded access. ...
... Because the amount of pollen that can be carried by small wild pollinators would be less than that of large pollinators owing to the difference in their body size (Yamada et al. 1971), the quality of an apple fruit that develops after pollination by small wild pollinators might be somewhat inferior to that by large pollinators. However, for successful pollination of an apple flower, as few as only 40 pollen grains need to attach to the stigma of the pistil (Marcucci and Visser 1987), and small bees belonging to the Andrenidae or the Halictidae collected in Oriental persimmon orchards have been observed to each carry approximately 10,000 grains of pollen (Nikkeshi et al. 2019). Moreover, even if the quality of fruit resulting from pollination by small wild pollinators is slightly inferior to that by large pollinators, it might present no problem, because in any case apple growers ultimately remove around three-quarters of all young fruits by thinning, leaving only carefully selected high-quality fruits (Moriya-Tanaka et al. 2016). ...
The pollination services provided by small wild pollinators in apple orchards were investigated in Akita Prefecture, northern Japan. In the apple orchard in 2017 and 2018, wild species constituted about 43% of all pollinators collected; these wild pollinators belonged to the order Hymenoptera (with most in the families Andrenidae [Andrena spp.] and Halictidae [Lasioglossum spp.]) and the order Diptera (mainly Melanostoma spp.). To exclude the introduced bees Apis mellifera and Osmia cornifrons, we protected flower bud clusters with 3.5-mm-mesh net bags that allowed access only to small wild pollinators from 2019 to 2021. There was no significant difference between protected and unprotected king flowers in terms of fruit set or the number of ventricles with seeds in the king fruits. Moreover, significantly fewer lateral fruits, which need to be removed by thinning, set in the protected clusters. These observations indicated that apple fruits might set normally without the need for introduced pollinators, and in some cases introduced bees might promote fruiting beyond the capacity of labor to manage.
... Populations of honey bees [62][63][64][65] and other wild bees 66,67 have declined globally in recent years. The importance of maintaining an abundance of wild insect fauna that can serve as crop pollinators is increasingly recognized 5,68,69 , but few studies have examined the effectiveness of wild pollinators at pollinating and fruiting crops 70,71 . Clarification of multiple individual pollination systems could support the worldwide conservation of ecosystem services. ...
Understanding of pollination systems is an important topic for evolutionary ecology, food production, and biodiversity conservation. However, it is difficult to grasp the whole picture of an individual system, because the activity of pollinators fluctuates depending on the flowering period and time of day. In order to reveal effective pollinator taxa and timing of visitation to the reproductive success of plants under the complex biological interactions and fluctuating abiotic factors, we developed an automatic system to take photographs at 5-s intervals to get near-complete flower visitation by pollinators during the entire flowering period of selected flowers of Nelumbo nucifera and track the reproductive success of the same flowers until fruiting. Bee visits during the early morning hours of 05:00–07:59 on the second day of flowering under optimal temperatures with no rainfall or strong winds contributed strongly to seed set, with possible indirect negative effects by predators of the pollinators. Our results indicate the availability of periodic and consecutive photography system in clarifying the plant-pollinator interaction and its consequence to reproductive success of the plant. Further development is required to build a monitoring system to collect higher-resolution time-lapse images and automatically identify visiting insect species in the natural environment.
... Our previous studies suggested that a bumblebee, Bombus ardens ardens Smith (Hymenoptera: Apidae), was a common wild pollinator of Oriental persimmon at some study sites in western Japan, whereas the dominance of A. mellifera as a pollinator fluctuated among years (Nakamura et al. 2020;Nikkeshi et al. 2019). Miyamoto (1961) also reported that B. ardens ardens was a persimmon flower visitor. ...
... The sequences were deposited in the DNA Data Bank of Japan (DDBJ accession numbers LC682290-LC682345; see Table S2). For details of the procedure, see Nikkeshi et al. (2019). ...
... Our data suggest that B. ardens ardens is a predominant wild pollinator of Oriental persimmon over a wide area in Japan. It was previously recorded as a flower visitor to D. kaki in western Honshu: in Hyogo (Miyamoto 1961), Shimane (Miura 1982;Nakamura et al. 2020), and Hiroshima (Nikkeshi et al. 2019). Here, it was also recorded in Kyushu, Shikoku, and the Kanto and southern Tohoku districts, implying that it functions as an effective pollinator of D. kaki almost everywhere in Japan, provided that nesting habitats are available nearby. ...
Japanese farmers who grow Oriental persimmon, Diospyros kaki Thunb. (Ericales: Ebenaceae), occasionally introduce Apis mellifera L. (Hymenoptera: Apidae) hives into their orchards during the flowering season, mainly because cultivars such as ‘Fuyu’ require pollination for stable fruit set. However, wild pollinators might serve this function. Thus, we aimed at identifying the most important pollinators of D. kaki in Japan by surveying visitation frequency across ten prefectures and pollination efficiency. The predominant flower visitors were Bombus ardens ardens Smith (Hymenoptera: Apidae) and A. mellifera , with similar pollination efficiencies. The estimated threshold number of pollen grains for fruit set of D. kaki ‘Fuyu’ was 27, which was comparable to the number deposited by a single visit of either species, meaning one visit of these dominant visitors probably induces fruit set. However, more pollen grains deposited by multiple visits further ensured fruit set. To achieve > 80% fruit set, more than about 70 pollen grains were needed. These results indicate that several visits by the bees would be sufficient for fruit set of D. kaki ‘Fuyu’.
... After vigorously shaking the vials containing the insect's body, 10 µL of solution from the vial was taken by micropipette on a clear glass slide and the number of pollen grains suspended in the solution were counted with the help of a light microscope. We repeated this procedure five times for each sample and estimated the average number of pollen grains in 10 µL and then the total number of pollen grains (on the body surface) in accordance with the initial volume of the solution (Nikkeshi et al., 2019). The number of pollen grains per paired corbicular loads was estimated using a hemocytometer. ...
The yield of many crops benefits from pollinating insects; thus, recently reported declines in pollinator abundance and diversity are concerning for global food production. The pollinator dependency and amount of yield enhancement may vary according to crop species and geographical location. Fennel (Foeniculum vulgare) is an important spice crop cultivated in Indian states. However, comprehensive knowledge about pollination demand and yield enhancement potential of managed bees is still unknown. Here, we conducted a replicated study in two successive years (2020 and 2021) in West Bengal by combining pollinator surveys, pollinator-exclusion experiments, and field manipulation on fennel, which quantifies the impacts of supplemental stingless bees (Tetragonula iridipennis) pollination on native pollinators and crop yield. The crop species attracted many insect species belonging to diverse groups. Among those, important native pollinators (based on "approximate pollination value") were Apis cerana, Apis dorsata, Apis florea, and Oxybelus furculatus in open condition (i.e., without field manipulation and in the absence of managed bees). We derived the coefficient of pollination deficit (D) from the fruit set percentages in open and manual cross-pollination treatments. The obtained value (D = 0.18) implies that the crop species have pollen transfer limitations, resulting in retardation of crop yield. From field manipulation with managed stingless bee colonies, the abundance of visitors (especially stingless bee foragers) on fennel increased (without altering the foraging activity of other native pollinators), thereby fruit set and crop yield increased by about 14.89 and 19.31%, respectively. Native managed stingless bees had no negative impacts on other native unmanaged species and can be promoted as complementary and short-term means of boosting yields and improving agricultural sustainability.
... We counted the numbers of C. maxima pollen grains on the body surfaces (excluding pollen loads) of flower visitors captured on male and female flowers, following the experimental protocol of Nikkeshi et al. (2019). We captured 23 and 14 honeybees, and 9 and 4 B. diversus diversus from female and male flowers, respectively, at Farm A on 20 September 2020. ...
Kabocha squash, Cucurbita maxima Duchesne, in delayed-start culture is one of the major cultivation systems in southwestern Japan. Honeybee introduction or hand-pollination has been practiced in this crop system, but the species composition, abundance , and pollination efficiency of major pollinators remain unclear. In the current study, we investigated which insect(s) accomplish pollination of kabocha squash. Among the total visitations to female flowers, honeybees, mostly Apis mellifera L. (Hymenoptera: Apidae), dominated at 94.4% and 85.3% at the experimental field in 2019 and 2020, respectively, followed by the bumblebee Bombus diversus diversus Smith (Hymenoptera: Apidae) and the hummingbird hawkmoth Macroglossum pyrrhosticta Butler (Lepidoptera: Sphingidae). The number of pollen grains on the body surface of B. diversus diversus individuals was significantly greater than that on honeybees, such that a single visit by B. diversus diversus deposited 5-6 times more pollen grains on a stigma than a honeybee visit, meaning that the bumblebee is a more efficient pollinator at the individual level. However, visitations by numerous honeybees compensated for their lower individual efficiency and resulted in fruit set. In addition, we report for the first time that a lepidopteran can pollinate squash: our data indicate that pollen grains deposited by several visits of M. pyrrhosticta were likely to exceed the estimated minimum number of pollen grains required for fruit set. Our survey at the experimental field and at three private farms revealed that far more pollen than is required for fruit set was deposited on the stigmas by wild pollinators and wintering honeybees. These findings indicate that kabocha squash production in delayed-start culture in this region is practicable without pollination enhancement effort, such as honeybee introduction or hand-pollination.
... Megachilidae) have been used globally as pollinators in some fruit tree crops: for example, Osmia cornifrons Radoszkowski (Maeta & Kitamura, 1965;Sekita, 1998) for apple in Japan, O. lignaria (Say) for almond, apple, sweet cherry and apricot in North America (Bosch & Kemp, 1999;Torchio, 1985) and O. cornuta (Latreille) for almond, apple and pear in Europe (Bosch, 1994;Maccagnani et al., 2007;Vicens & Bosch, 2000). Reportedly, in open pollination of oriental persimmon, Bombus ardens Smith, 1879, distributed throughout almost all regions in Japan, functions as the most important pollinator species (key species) (Nikkeshi et al., 2019). ...
... The fruit-set ratio and the number of seeds were compared among pollination treatments using a generalized linear mixed model (GLMM), as described by Nikkeshi et al. (2019). Briefly, the fruit set and the numbers of seeds, pollination treatment and tree ID were set, respectively, as response variables, an explanatory variable and a random effect. ...
Cultivated Japanese pear varieties, mostly showing self-incompatibility, require pollen transfer from other varieties. To elucidate the underlying mechanisms of open Japanese pear insect pollination, we first collected flower-visiting insects using plastic vials and sticky traps in orchards located at different regions in Japan. Results showed that insects assigned to the families Andrenidae (Hymenoptera), Apidae (Hymenoptera), Halictidae (Hymenoptera), Syrphidae (Diptera) and Empididae (Diptera) are abundant in the orchards. Second, we restricted the flower-visiting insects to access Japanese pear flowers using bags with mesh sizes of 0, 2 and 3.5 mm. Results indicated that insects which allowed to pass through bags with 3.5-mm mesh size but not through bags with 2-mm mesh size contribute primarily to pollination, represented as the fruit-set ratio and seed number. Third, we measured head and thorax widths of the flower-visiting insects and counted pollen grains on their body surfaces to estimate their pollination potential. Results indicated that insects assigned to the families Andrenidae, Halictidae, Syrphidae, Bibionidae (Diptera) and Muscidae (Diptera), including species with both widths smaller than 3.5 mm, harbour large quantities of Pyrus pollen grains, in addition to Apis mellifera (Apidae) with both widths greater than 3.5 mm. Consequently, the families Andrenidae, Apidae, Halictidae and Syrphidae might be the most important insect families for Japanese pear pollination. However, species identification of the flower-visiting insects showed no common key species that contribute remarkably to pollination services other than A. mellifera. Consecutive insect collection using plastic vials and sticky traps demonstrated that compositions of the flower-visiting insects are fluctuating continuously in the orchards. Nevertheless, year-to-year fluctuation of the fruit-set ratio was less pronounced in open-pollinated orchards than in hand-pollinated orchards. These results suggest that mutual complementation among diverse pollinator species might be the mechanism underlying open Japanese pear insect pollination.
... However, it is important to note that these factors are not necessarily restricted to forests but are likely most often found within forests. For instance, orchards and gardens can also offer similarly early resources as natural or seminatural forest habitats (Watson et al. 2011, Nakamura and Kudo 2019, Nikkeshi et al. 2019). As we show in the case study with B. affinis (box 1), developed lands can offer substantial foraging opportunities for bumble bees and other studies demonstrate urban habitats can be suitable landscapes (McFrederick and LeBuhn 2006, Glaum et al. 2017, Reeher et al. 2020). ...
Declines of many bumble bee species have raised concerns because of their importance as pollinators and potential harbingers of declines among other insect taxa. At present, bumble bee conservation is predominantly focused on midsummer flower restoration in open habitats. However, a growing body of evidence suggests that forests may play an important role in bumble bee life history. Compared with open habitats, forests and woody edges provide food resources during phenologically distinct periods, are often preferred nesting and overwintering habitats, and can offer favorable abiotic conditions in a changing climate. Future research efforts are needed in order to anticipate how ongoing changes in forests, such as overbrowsing by deer, plant invasions, and shifting canopy demographics, affect the suitability of these habitats for bumble bees. Forested habitats are increasingly appreciated in the life cycles of many bumble bees, and they deserve greater attention from those who wish to understand bumble bee populations and aid in their conservation.
