Animal Pollinators Research Articles

Análise de dados virtuais de herbário sobre Melocactus (Cactaceae) na Caatinga: uma síntese reprodutiva e de distribuição geográfica

ABSTRACT The objective of this study was to analyze data of the genus Melocactus (Cactaceae) in the Caatinga biome using a virtual herbarium, determine its reproductive aspects, and establish its geographical distribution. Data were collected from the SpeciesLink platform. Notes on exsiccata labels were analyzed to assess reproductive characteristics. Coordinate information was used to develop a distribution map for the genus in the Caatinga biome. A total of 469 records were found in 35 herbaria in Brazil. Melocactus zehntneri stood out with 208 records, followed by M. ernestii, and M. bahiensis. The data were concentrated in a few herbaria, mainly in the Herbarium of the State University of Feira de Santana, which had 28% of the records. Collections were carried out in June (63 records) and in July (59 records). Regarding the reproductive period, Melocactus was active throughout the year, but more concentrated from June to October. The genus is composed of species that depend on animal pollination and dispersal, according to coloration and visitation data. Melocactus is widely distributed throughout the Caatinga, with a tendency to concentrated in drier areas of the biome, in the states of Bahia, Pernambuco, and Paraiba. Herbaria are valuable tools for ecological investigations; therefore, promoting the digitalization of collections and improving the quality and quantity of annotations on specimens are necessary. The genus Melocactus has several characteristics that make it an essential group for maintaining biodiversity in the Caatinga biome.

Bee pollination effects on yield and chemical composition of West Indian gherkin fruits (Cucumis anguria L., Cucurbitaceae) in the Brazilian semi-arid region.

Animal pollination plays a key role in global agricultural production and especially of monoecious crops, which are essentially dependent on pollinators. The West Indian gherkin fruit (Cucumis anguria L., Cucurbitaceae) is a monoecious vegetable adaptable to adverse abiotic conditions, resistant to diseases, and rich in minerals and vitamins, thus being a relevant alternative for improving nutritional security of socioeconomically vulnerable populations. The knowledge on the influence of pollination and of specific pollinators on chemical characteristics of fruits would help pollinators' management, but it is still poorly understood. In this study we investigated the influence of pollination on quantitative and qualitative aspects of fruits fruits of West Indian gherkin fruits (Cucumis anguria L., Cucurbitaceae) in the Brazilian semi-arid region. Data on pollination biology and on fruits resulted from controlled crosses (open-OP, cross-CP and Apis mellifera Linnaeus, 1758 pollinations) were compared among crosses: number, length, weight, number of seeds, firmness and chemical traits related to flavor and shelf life. Flowers were pollinated by four bee species, and Apis mellifera was the most frequent. followed by two native bee species. OP and A. mellifera resulted in more fruits than CP. Fruits resulting from OP were heavier than CP and had similar weight when compared to A. mellifera. The other variables did not differ between treatments. The better performance of OP and A. mellifera when compared to CP is probably related to the xenia, i.e., the influence of tissues bearing paternal genes (pollen and pollen tube) in maternal tissues. OP and A. mellifera experiments apparently resulted in the deposition of a greater genotypic diversity of the pollen loads when compared to CP. This result is also explained by the higher functional diversity of pollinators related to OP when compared to CP. This study not only elucidates immediate impacts on yield but also emphasizes the deeper connections between floral biology, pollinator diversity, and sustainable crop production, once West Indian gherkin profit was enhanced by bee pollination.

Contribution of pollinators to production and reproduction of neglected and underutilized food species in family farming systems in Patagonia

ABSTRACT Many of the species used in family farming systems (FFS) in Patagonia belong to the group known as neglected and underutilized species (NUS), which promote biocultural diversity and contribute to food sovereignty. Due to the scarce attention paid to NUS by agronomic sciences, little is known about their biotic pollination, although it is a well-studied aspect for commercially important plants. We evaluate the contribution of animal pollination to NUS managed by Patagonian FFS. We present a literature review of the NUS used and aspects related to their pollination and floral visitors, for which 725 papers were reviewed. FFS use 426 NUS (414 angiosperms, 10 gymnosperms and 2 ferns). Most NUS (86.7%) depend to some extent on animal pollination, either for the production of fruits or seeds that are harvested for consumption (direct dependence, 35%) or for obtaining seeds (indirect dependence, 65%), which in many cases are necessary for reseeding. Gathering and cultivation are the most common management practices for these species. Hymenoptera and Diptera are the animals that contribute most to NUS biotic pollination. Our results show that animal pollination is a key contribution of nature to sustain cultural aspects and food sovereignty of FFS in Patagonia.

PolLimCrop, a global dataset of pollen limitation in crops

Pollination is a crucial ecosystem service for maintaining plant communities and food production. 75% of the main crops depend on or benefit from pollination services provided by animal pollinators. However, when these services are insufficient and/or inefficient, crops experience pollen limitation with, often, lower associated yield, which may translate into economic losses. We constructed a global dataset that gathers studies with pollination experiments, aiming to provide pollen limitation values of animal-pollinated crops worldwide. Pollination experiments included hand pollen supplementation treatments, where plants were subjected to pollen supplementation of outcross pollen, and natural pollination treatments. The PolLimCrop dataset comprises 294 studies and 1169 unique pollen supplementation experiments with values of pollen limitation for 108 crops, spanning 50 years and 62 countries.

Economic benefits of animal pollination to Punjab agriculture

Indian Punjab is gradually becoming the promised land of diversified farming with beekeeping as an important component, as farmers are looking for ways to get out of the paddy-wheat cycle. With this consideration, the present study estimated that the contribution of animal pollinators toward state agriculture. The economic value due to pollination service (EVP) was Rs 1391.2 crores forming about a 2 per cent share in the EV of output from state agriculture. Among the entomophilous crops, the insect pollination was essential for 2; great for 3; modest for 4 and of little importance to another 4 crops. About 42 per cent of the non-animal pollination-dependent crops accounted for a major share in the EV i.e. 97.87 per cent of the total agriculture output of the state. The share of cereals was the highest in the EV i.e. 86.79 per cent followed by vegetables (5.50%), fruits (5.32%), cotton (1.69%), sugarcane (0.35%), oilseeds (0.32%) and gram (0.01%) while based on dependence rate, the EVP was the highest in fruits (49.78%) followed by vegetables (21.49%), cotton (19.85%) and oilseeds (8.88%) and there existed no EVP for cereals and sugarcane and gram. The crops having great dependence on pollination contributed the maximum (Rs 741.13 crore) i.e. about 53 per cent to the EVP and about 1 per cent to the EV in the state agriculture. There is a strong need to realize the potential of this segment and formulate crop and commodity-specific strategies for optimum utilization of animal pollination inputs followed by crop diversification to high-value commodities. Punjab agriculture faces challenges on the production front and increased production cost needs such as “micro concepts” with “macro-economic” impacts.

Assessing the biodiversity and the impact of pollinators on carob production.

As the current climate crisis intensifies, drought resistant crops are becoming more important due to their ability to withstand the increasingly hotter and drier summers. Such crops are valuable for pollinators as they provide food resources for wild and managed species. The carob tree (Ceratonia siliqua L.) represents an example of a heat- and drought- resistant crop, able to grow in dry areas with practically no inputs. The current study assessed over two growing seasons the diversity of wild bees and other pollinators relying on carob flowers, as well as the contribution of animal pollination to carob production. Carob flowers were subjected to two treatments: Open pollination, where inflorescences were left untreated, and wind pollination, where inflorescences were bagged in a mesh during blooming. Weekly observations during blooming showed that Apis mellifera was the most frequent floral visitor followed by wild bees and wasps. Carob flowers were visited by at least 10 different wild bee species. Open-pollinated flowers produced significantly more pods, with the benefit ranging from 4 to 16 times higher production, depending on the region. Open pollination led to pods with greater weight, length and number of seeds compared to pods derived from wind pollination. The results of the current study highlight the importance of animal pollination to carob production, as well as the significance of carob trees to wild bee conservation.

Is there silicon in flowers and what does it tell us?

The emergence of flowers marked an important development in plant evolution. Flowers in many species evolved to attract animal pollinators to increase fertilisation chances. In leaves, silicon (Si) discourages herbivores, for example by wearing down mouthparts. Flowers are essentially modified leaves and hence may also have the capacity to accumulate Si. If Si in flowers discourages animal visitors as it does in leaves, Si accumulation may be disadvantageous for pollination. Whether flowers accumulate Si, and what the implications may be, was not known for many species. We analysed leaves and flowers of different taxa, separated into their different anatomical parts. Flowers mostly have low Si concentrations in all parts (mean ± SE of BSi in mg g-1 was 0.22 ± 0.04 in petals, 0.59 ± 0.24 in sepals, 0.14 ± 0.03 in stamens, 0.15 ± 0.04 in styles and stigmas and 0.37 ± 0.19 in ovaries for a subset of 56 species). In most cases, less Si was accumulated in flowers than in leaves (mean ± SE of BSi in mg g-1 was 1.51 ± 0.55 in whole flowers vs. 2.97 ± 0.57 in leaves in 104 species) though intriguing exceptions are found, with some species accumulating more Si in flowers than leaves. The large variation in concentration among flowers across the taxa examined, with a particularly high concentration in grass inflorescences, tantalisingly suggests differences in the use of Si for flowers across plant groups. We conclude that the study of the functions of Si for flowers warrants more attention, with pollination strategy a potential contributing factor.

New calculations indicate that 90% of flowering plant species are animal-pollinated.

Abstract The number of angiosperms that may depend on animals for pollination has been difficult to estimate because the pollination modes of tens of thousands of species of tall trees, canopy climbers, and epiphytes, especially from the tropics, remain unknown. Ecological research over the past 50 years, however, has established a strong correlation between pollination by wind or water and particular flower traits. Based on a literature search for pollination-ecological data for the families, genera, and species compiled by the Global Biological Information Facility (GBIF) and the World Flora Online (WFO) databases, we estimated the number of species with abiotic pollination and then subtracted it from the total number of taxa. The results show that based on GBIF, 68% of 465 families, 88% of 14,437 genera, and 90% of 332,341 species rely on animal pollination. Based on WFO, 64% of 414 families, 88% of 13772 genera, and 90% of 339,876 species rely on animal pollination. Species exhibiting both pollination modes were identified in about 48 families and 0.1% of species. Finding that 90% of all angiosperm species depend on animals for cross pollination reinforces the importance of prioritizing the conservation of plant-pollinator interactions in both natural and agricultural ecosystems. These results match a previous estimate (87.5% or, after a mathematical correction, 89.5%) obtained by extrapolation from local community studies and also the finding that insects have pollinated flowering plants for most of angiosperm evolutionary history, a consilience of results that supports the validity of these estimates.

Apple flower-visiting insects’ diversity and abundance in selected central Kenya orchards

Flower-visiting insects are essential in maintaining a healthy and productive agricultural landscape through ecosystem services such as pollination. Fruits are important sources of vitamins and micronutrients, and several fruit crops depend on animal pollination, which enhances their nutritional content. Besides honey bees, apple orchards can sustain a large number of arthropod species that also aid in pollination. In this present study, we assessed the diversity and abundance of insect flower visitors in six apple orchards in Nyeri and Laikipia East. Six plots, each with more than 20 apple trees, were purposefully selected. Data were collected through timed visual searches and sweep netting. Sampling was done from 0900 hours to 1700 hours, six days a week, for five months consecutively in 2019. Diversity indices were computed using the Shannon-Wiener diversity index, while abundance patterns were displayed using species abundance curves. Differences in species diversity and abundance between sites were compared using a one-way analysis of variance. A total of 1,221 insects belonging to 23 families, 82 species, and 4 orders (Hymenoptera, Lepidoptera, Coleoptera, and Diptera) were recorded. The order Hymenoptera (bees, wasps, and ants) was the most abundant, with 1,176 individuals, and had the most species-rich taxa, with 56 species in 9 families. The order Coleoptera (beetles) was second, with 26 individuals and 12 species in 6 families. Lepidoptera were the least abundant with 10 individuals and the least species-rich taxa with 7 species in 5 families, followed closely by Diptera with 7 individuals and 7 species in 3 families. There were significant differences in flower visitors’ composition among the six sites. The study provides important information on the status of key apple flower visitors, which can guide orchard management practises to increase apple yield through pollinator conservation. Conserving apple pollinators will enhance fruit production, promote the livelihoods of farmers, and contribute to the national economy.

Global meta-analysis shows reduced quality of food crops under inadequate animal pollination

Animal pollination supports the production of a wide range of food crops fundamental to maintaining diverse and nutritionally balanced diets. Here, we present a global meta-analysis quantifying the contribution of pollination to multiple facets of crop quality, including both organoleptic and nutritional traits. In fruits and vegetables, pollinators strongly improve several commercially important attributes related to appearance and shelf life, whereas they have smaller effects on nutritional value. Pollination does not increase quality in stimulant crops, nuts, and spices. We report weak signals of a pollination deficit for organoleptic traits, which might indicate a potential service decline across agricultural landscapes. However, the deficit is small and non-significant at the α = 0.05 level, suggesting that pollen deposition from wild and/or managed pollinators is sufficient to maximise quality in most cases. As producing commercially suboptimal fruits can have multiple negative economic and environmental consequences, safeguarding pollination services is important to maintain food security.

Honeybees (Apis mellifera) decrease the fitness of plants they pollinate.

Most flowering plants require animal pollination and are visited by multiple pollinator species. Historically, the effects of pollinators on plant fitness have been compared using the number of pollen grains they deposit, and the number of seeds or fruits produced following a visit to a virgin flower. While useful, these methods fail to consider differences in pollen quality and the fitness of zygotes resulting from pollination by different floral visitors. Here we show that, for three common native self-compatible plants in Southern California, super-abundant, non-native honeybees (Apis mellifera L.) visit more flowers on an individual before moving to the next plant compared with the suite of native insect visitors. This probably increases the transfer of self-pollen. Offspring produced after honeybee pollination have similar fitness to those resulting from hand self-pollination and both are far less fit than those produced after pollination by native insects or by cross-pollination. Because honeybees often forage methodically, visiting many flowers on each plant, low offspring fitness may commonly result from honeybee pollination of self-compatible plants. To our knowledge, this is the first study to directly compare the fitness of offspring resulting from honeybee pollination to that of other floral visitors.

Towards a better understanding of the relationships between pollinators, human well‐being, and medicine plants in the Great Lakes Region of Eastern North America

Societal Impact StatementA diversity of values is needed to maximize the effectiveness of conservation planning, including policies and programs. The results of the United Nations Biodiversity Conference (COP 15) in Montreal, Canada, highlight the importance of a shift towards recognizing multiple ways of knowing in ecology and conservation. This review aims to provide a baseline of what is known about culturally significant plants in the Great Lakes Region of Eastern North America. The results of this research provide insight into the ways in which ecology has been conducted in the past and the importance of changing the way ecology is conducted in the future.SummaryBiocultural conservation theory allows for an examination of complex problems using systems thinking and conserving biological and cultural diversity together. In the Great Lakes Region of Eastern North America, wild medicine plants are an important part of what Anishinaabe people understand as Mini bimaadizi, or the good life, and of aki miijim, or traditional food systems. Given the various threats facing wild plant populations and continued global change, this review aims to investigate what is known about the pollination and breeding systems of culturally significant plants in the Great Lakes Region. The overall goal is to determine what proportion of these plants have had basic ecological studies done and the degree to which culturally significant plants in this region rely on insect pollination. A systematic review of the literature was conducted on breeding systems and pollination of culturally significant plants. Half of all the culturally significant plants included lacked specific information related to reproduction. Most plants that have been studied relied on outcrossing, and the most commonly reported pollinators were in the Apidae family. With the complex interactions between plants and pollinators and many insect pollinators experiencing population declines, it is important to determine the dependence of culturally significant plants on animal pollination. These findings will be relevant to conservation planning and policy in the future.

The fertilization process in Lithocarpus dealbatus (Fagaceae) and its implication on the sexual reproduction evolution of Fagales.

The pistillate flowers of Lithocarpus dealbatus show two pollen tube (PT) arresting sites (the style-joining and micropyle) within the pistil during the postpollination-prezygotic stage. The PT, arrested at the pre-ovule stage, enhanced PT competition allowing the most compatible PTs to enter the ovary to ensure the highest fertilization success. During the shift from animal pollination to wind pollination, plants require a series of changes in reproductive traits. The mode of pollination is striking labile in Fagaceae. Lithocarpus is insect pollinated and is closely related to wind-pollinated Quercus. Little is known about the sexual reproduction of Lithocarpus. This study aimed to reveal the sexual reproduction of Lithocarpus dealbatus and to explore the evolutionary pattern of the key sexual reproduction traits to better understand their possible role in labile pollination. We found that after pollination, L. dealbatus PTs grew slowly in the style reaching style-joining in mid-January of the second year; then PT growth was arrested at style-joining for four months. Only two to three PTs resumed growth in mid-May to reach the micropyle, where PT growth ceased for one month before one PT resumed growth and passed through the micropyle to the embryo sac. Fagaceae showed a generalized mating system. Vast pollen production, small-sized pollen grains, long stigmatic receptive time, and reduced perianth were compatible with beetle pollination syndrome, representing the plesiomorphic status in Fagaceae. A large stigmatic surface and dry pollen grains linked to wind pollination might be independently derived several times in fagaceous lineages. Beetle pollination syndrome can cope with the uncertainty of pollinators to ensure conspecific pollen capture, which represents pre-adaptation status and has a selective advantage when conditions change, favouring wind pollination. The arrest of the PT at style-joining is a unique mechanism in later derived fagaceous lineages to enhance PT competition and promote outcrossing.

Insect pollination for most of angiosperm evolutionary history.

Most contemporary angiosperms (flowering plants) are insect pollinated, but pollination by wind, water or vertebrates occurs in many lineages. Though evidence suggests insect pollination may be ancestral in angiosperms, this is yet to be assessed across the full phylogeny. Here, we reconstruct the ancestral pollination mode of angiosperms and quantify the timing and environmental associations of pollination shifts. We use a robust, dated phylogeny and species-level sampling across all angiosperm families to model the evolution of pollination modes. Data on the pollination system or syndrome of 1160 species were collated from the primary literature. Angiosperms were ancestrally insect pollinated, and insects have pollinated angiosperms for c. 86% of angiosperm evolutionary history. Wind pollination evolved at least 42 times, with few reversals to animal pollination. Transitions between insect and vertebrate pollination were more frequent: vertebrate pollination evolved at least 39 times from an insect-pollinated ancestor with at least 26 reversals. The probability of wind pollination increases with habitat openness (measured by Leaf Area Index) and distance from the equator. Our reconstruction gives a clear overview of pollination macroevolution across angiosperms, highlighting the long history of interactions between insect pollinators and angiosperms still vital to biodiversity today.

Pollination by sexual deception

The flower is arguably the centrepiece of angiosperm evolution. Its primary function is to secure pollination - the transfer of pollen from the anther (male) to the stigma (female). As plants are sessile organisms, the extraordinary diversity of flowers in large part reflects countless alternative evolutionary solutions to achieve this critical step in the flowering plant life cycle. The majority of flowering plants, some 87% by one estimate, depend on animals for pollination, with most of these paying for the service of pollination via food rewards of nectar or pollen. As in human economic systems, however, some cheating and deception occurs, with the pollination strategy of sexual deception being one such example.

A tale of two mistletoes: phenology and fauna associated with two sympatric species

Mistletoes are parasitic plants that largely rely on animals for pollination and seed dispersal but establish complex interactions with their host plants. Mistletoes are considered keystone species in forest ecosystems as they facilitate several interactions. We studied the fauna associated with two sympatric mistletoe species ( Tristerix corymbosus (L.) Kuijt and Desmaria mutabilis (Poepp. & Endl.) Tiegh.) from the temperate rainforests of southern Chile. We set 40 camera traps from November 2021 to May 2022 to monitor the main pollinator (the hummingbird Sephanoides sephaniodes (R. Lesson & Garnot, 1827)), the main seed disperser (the arboreal marsupial Dromiciops bozinovici D’Elía, Hurtado & D’Anatro, 2016), and other animals (birds, mammals, reptiles, and insects). We compared fauna associated with Tristerix corymbosus between spring and summer–fall periods and between Tristerix corymbosus and Desmaria mutabilis during summer–fall. Species composition associated with Tristerix corymbosus showed a significant temporal variation, mainly explained by Sephanoides sephaniodes and Dromiciops bozinovici, which are more abundant in the summer–fall period. We found that animal species composition differences between mistletoe species were mainly explained by S. sephaniodes, Dromiciops bozinovici, and insects. While Tristerix corymbosus was mainly pollinated by hummingbirds, insects frequently visited Desmaria mutabilis flowers. Although both mistletoes have many similarities, they also have some phenology differences that affect their associations with animals, potentially influencing ecological processes.

Partitioning pollination services to faba bean (Vicia faba L.) between managed honeybees and wild bees

Animal pollination of crops is an important ecosystem service provided especially by managed honeybees and wild bees, but the relative importance of these taxa for crop pollination remains debated. Faba bean (Vicia faba L.) is a grain legume crop grown worldwide for food and feed which is partially dependent on insects for pollination. I determined the relative contribution of honeybees and wild bees to faba bean pollination. Visitation rates and foraging behaviours of pollinators were measured in a total of 20 faba bean fields over two years (10 fields per year) in Sweden, and the bean mass per flower visit for different pollinator taxa was quantified in a field experiment which was repeated over two years in a single site. By combining information on visitation rates, foraging behaviours and gains in bean mass from single visits to flowers, I estimate that 47% of insect pollination services to faba bean is delivered by honeybees, 40% by short-tongued bumblebees, 6% by long-tongued bumblebees and 8% by solitary bees. I conclude that both managed honeybees and wild bees, especially short-tongued bumblebees, contribute substantially to faba bean pollination in Sweden, and I recommend faba bean farmers to manage for both these pollinator taxa.

Neutral influence of animal pollination in the common bean (Phaseolus vulgaris L., Fabaceae) production and seed germination

The influence of animal pollination on the common bean (Phaseolus vulgaris L., Fabaceae) production is quite variable, but there is a tendency towards the predominance of strong self-fertility. Few studies tested for the influence of pollination on quality aspects of production and seed germination. In view of the global economic importance of the common bean, and the pollinator crisis that the planet is experiencing, the objective of this study was to investigate the influence of animal pollination in the amount and quality of fruits, seeds, and seed germination of the common bean, using four plantations of the ‘mulatinho’ variety in a region under semiarid climate of NE Brazil as a model. Our hypotheses are: 1) Flowers are visited mainly by bees; 2) The production of fruits, seeds and seed germination are favored by pollinators. Data were collected during the 2017 and 2018 plantings, when data on floral visitors were collected. Controlled crosses (spontaneous self-, cross- and natural pollinations) were performed and the number and morphometry of fruits, number, morphometry, and germination of seeds were compared between the experiments. Reproductive efficiency (RE) and pollen limitation index (PLI) were calculated. Number of formed fruits, measurements, weight, and germination resulting from spontaneous self-pollination showed higher values than those formed by natural and cross-pollination. In 2017, the RE was high (1.44) and the ILP was 0.14, indicating no pollen limitation. In 2018, RE was also high (1.8), but the ILP was 0.3, indicating pollen limitation. Overall, the frequency of visits on focal individuals was low. Conversely to what was expected, butterflies and moths were the most frequent floral visitors, although the flowers were also visited by bees, ants, flies beetles and spiders. None were considered pollinators because they did not touch the reproductive structures of the flower. The bee Xylocopa sp. was the only species capable of pollinating the flowers, as its size allows it to expose the reproductive parts present inside the keel when it lands on the flower to collect the floral resource. However, its frequency was very low, and it did not visit the focal plants. Apparently, low temperatures and high rainfall negatively interfered with pollination and, consequently, with the production. The common bean can be considered a relevant crop in the face of the current global pollinator crisis, as it does not depend on pollinators to produce food, the flowers are used by several pollinator groups and, additionally, it contributes to soil nitrogenating, reducing input costs for farmers.

Hawkmoth and bee pollinators impact pollen dispersal at the landscape but not local scales in two species of Oenothera.

Animal pollinators play an important role in pollen dispersal. Here, we assessed differences in pollen and seed dispersal and the role of pollinator functional groups with different foraging behaviors in generating patterns of genetic diversity over similar geographic ranges for two closely related taxa. We focused on two members of Oenothera section Calylophus (Onagraceae) that co-occur on gypsum outcrops throughout the northern Chihuahuan Desert but differ in floral phenotype and primary pollinator: Oenothera gayleana (bee) and O. hartwegii subsp. filifolia (hawkmoth). We measured breeding system and floral traits and studied gene flow and population differentiation at the local (<13 km; four populations) and landscape (60-440 km; five populations) scales using 10-11 nuclear (pollen dispersal) and three plastid (seed dispersal) microsatellite markers. Both taxa were self-incompatible and floral traits were consistent with expectations for different pollinators. Seed and pollen dispersal patterns were distinctly different for both species. We found no evidence of genetic structure at the local scale but did at the landscape scale; O. gayleana showed greater differentiation and significant isolation by distance than in O. hartwegii subsp. filifolia. The plastid data were consistent with gravity dispersal of seeds and suggest that pollen dispersal is the principal driver of genetic structure in both species. We demonstrated that pollinator functional groups can impact genetic differentiation in different and predictable ways. Hawkmoths, with larger foraging distances, can maintain gene flow across greater spatial scales than bees.

Inoculum source dependent effects of ericoid, mycorrhizal fungi on flowering and reproductive success in highbush blueberry (Vaccinium corymbosum).

Most terrestrial angiosperms form mutualisms with both mycorrhizal fungi and animal pollinators. Yet, the effects of mycorrhizae on pollinator behavior and plant reproduction are unknown for most species, and whether the source or type of mycorrhizal fungi affects reproductive success has rarely been examined. We examined whether inoculating highbush blueberry (Vaccinium corymbosum; Ericaceae) with ericoid mycorrhizal fungi enhanced investment in flowering and attractiveness to pollinators, and thus reduced their levels of pollen limitation over that of non-inoculated plants. We also examined the degree to which pollen limitation was dependent on inoculation source and the surrounding pollinator community context. Three-year-old saplings of Vaccinium corymbosum 'Bluecrop' or highbush blueberry (Ericaceae) were inoculated with a) ericoid mycorrhizal fungi within soil of the rhizosphere of plants growing at a local blueberry farm, b) a commercially available ericoid inoculant, c) both the local soils and commercial inoculum, or d) were not inoculated and served as controls. They were grown for one year in pots in a common garden and, in the following year, were moved to six farms in central Vermont that were known from prior studies to differ in pollinator abundance and diversity. We conducted a hand pollination experiment at each farm to examine if inoculation or pollinator abundance (i.e., farm context) affected reproductive success. Plants treated with all types of inoculums were more likely to flower, and produced more inflorescence buds than non-inoculated plants in 2018. However, in 2019, plants in the combination inoculum treatment, alone, produced more inflorescence buds than those in the other treatments. Neither the source of inoculum nor hand pollination affected fruit set (the proportion of flowers setting fruit), or fruit sugar content. Hand pollination, but not inoculation, increased berry mass and the average number of seeds produced/berry. Our results add to the growing body of evidence that mycorrhizal fungi can affect reproductive traits of their hosts but that the effects of mycorrhizal fungi depend on the mycorrhizal symbionts.