Pollinator Loss Research Articles

Adapt research to the Anthropocene

Scientists measure how humans’ footprints deteriorate the global environment and our life, but neither monitoring nor technical solutions bend the curves. Homo sapiens is the dominating species of the Anthropocene. Should we re-focus research and explore potential transformation of the command centers of overexploitation: people's minds? The most important challenge for research in the Anthropocene is transformation of humans and their political and economic entities to respect the planet’s boundaries. Non-adapted research can mislead policies. On the example of two crucial risks, pollinator loss and climate change, the manuscript compares state-of-the-art research and what is needed. The examples show the necessary scope and depth of transformation. How to give more room for divergent intelligence, creativity and criticality in scientific and educational environments? The research sector must decide to either transform humans’ minds towards planetary responsible political performance or accept that AIscene might follow the Anthropocene and adapt humans to earth.

Influence of Pesticide Application Method, Timing, and Rate on Contamination of Nectar with Systemic and Nonsystemic Pesticides.

Exposure to pesticides is one potential factor contributing to the recent loss of pollinators and pollinator diversity. Few studies have specifically focused on the relationship between pesticide management during ornamental plant production and contamination of nectar. We evaluated contamination of nectar in Salvia 'Indigo Spires' (Salvia longispicata M. Martens & Galeotti × S. farinacea Benth.) associated with applications of the systemic insecticide thiamethoxam, and the nonsystemic fungicides boscalid and pyraclostrobin. Applications were made at the labeled rates for the commercially available products, and we compared the influence of application method (drench vs. spray), timing (relative to flowering), and rate (low vs. high) for each pesticide. Nectar was sampled using 50-µL microcapillary tubes and analyzed by liquid chromatography-tandem mass spectrometry. The results indicate that concentrations from the spray application resulted in the least contamination of nectar with the systemic thiamethoxam, with lower concentrations occurring when thiamethoxam was applied before blooming at the lowest rate. Concentrations of thiamethoxam and its metabolite clothianidin were detected in nectar in all treatments (regardless of the method, timing, or rate of application), and ranged from 3.6 ± 0.5 ng/mL (spray-applied before blooming, low rate) to 1720.0 ± 80.9 ng/mL (drench-applied after blooming, high rate). Residues of clothianidin in nectar ranged from below quantification limits (spray-applied before blooming, low rate) to 81.2 ± 4.6 ng/mL (drench-applied after blooming, high rate). Drench applications resulted in the highest levels of nectar contamination with thiamethoxam, and exceeded published median lethal concentrations (LC50s/median lethal doses for native bees and/or honeybees in all cases). Spray treatments resulted in nectar concentrations exceeding published LC50s for some bee species. In comparison, all nonsystemic treatments resulted in concentrations much lower than the published no-observable-effect doses and sublethal toxicity values, indicating low risks of toxicity. Environ Toxicol Chem 2024;001:1-12. © 2024 SETAC.

Consequences of intraspecific competition for floral resources in heterogeneous landscapes for eusocial bees

Agricultural intensification is widely recognised as a primary driver of pollinator loss, but the success of land-management actions designed to remediate its impact is often mixed. Payments to farmers to increase habitat connectivity or the availability of floral and nesting resources may only result in short-term gains or even unintended consequences. The reasons may lie in changes to interaction networks or competition intensity that remain poorly understood. Models of pollination service typically implicitly assume pollinator population dynamics are regulated by nest-site availability, even though empirical evidence suggests nest-site occupancy is likely at least in part dependent on floral resource availability. To investigate the consequences of competition for floral resources in coarse-grained agricultural landscapes we extended an established model for bees combining optimal foraging and population dynamics, to include new functions for floral resource depletion and realistic colony dynamics. We find that intra-specific competition occurs late in the season forcing bees to forage underutilised sites situated further towards their foraging range limits. A lower rate of energy acquisition ultimately limits the size of the colony peak and delays its timing. Consequently, competition for floral resources can limit population size and distribution while at the same time contributing to a more stable and efficacious pollination service. Although competition was not found to be important in nest-site establishment success, the effect of a hunger gap early in the season on nest-site occupancy indirectly influences competition later in the season leading to complex outcomes.

Experimental evolution suggests rapid assembly of the 'selfing syndrome' from standing variation in Mimulus guttatus.

Ecological and evolutionary changes are likely to occur rapidly when outcrossing populations experience pollinator loss. However, the number and identify of plant traits that will respond to this form of selection, as well as the overall predictability of evolutionary responses, remain unclear. We experimentally evolved 20 large replicate populations of Mimulus guttatus for 10 generations under three treatments: pure outcrossing, mixed mating (10% outcrossing) and pure selfing. These populations were founded from the same genetically diverse and outcrossing natural population. After 10 generations, all measured traits evolved with flower size, phenology, and reproductive traits diverging consistently among mating system treatments. Autogamy increased dramatically in the selfing treatment, but the magnitude of adaptation only becomes clear once inbreeding depression is factored out. Selfing treatment plants evolved reduced stigma-anther separation, and also exhibited declines in flower size and per-flower reproductive capacity. Flower size also declined in selfing populations but this was driven mainly by inbreeding depression and cannot be attributed to adaptation towards the selfing syndrome. Generally, the mixed mating populations evolved trait values intermediate to the fully selfing and outcrossing populations. Overall, our experimental treatments reiterated differences that have been documented in interspecific comparisons between selfing and outcrossing species pairs. Given that such contrasts involve species separated by thousands or even millions of generations, it is noteworthy that large evolutionary responses were obtained from genetic variation segregating within a single natural population.

Pollinator visitation decline due to pesticide application beyond threshold frequency brings down crop yield

Abstract The deleterious effects of pesticides on pollinating insect abundance are well established but the relationship among pesticide application, pollinator decline and the corresponding change in marketable yield is not fully understood. In this study, we assessed what level of pesticide exposure causes maximum pollinator loss and at that level of pollinator loss if there is any crop yield loss. We primarily assessed pollinator crop flower visitation in 27 aubergine farms with different degrees of pesticide application. Subsequently, we also observed pollinator activity and aubergine yield (fruit set) in a semi‐controlled field experiment with four different pesticide treatments. Pesticide application frequency was the most important driver of pollinator visitation compared with quantity. Pesticide spray above once a week caused a drastic drop in pollinator visitation in a non‐linear fashion showing a threshold of pesticide application. In high pesticide frequency experimental plots, pollinator visitation was significantly lower than in control, low and medium frequency plots. This resulted in lowering of aubergine fruit set by 27.4% in high pesticide frequency plots. Use of synthetic pesticides to safeguard yield seems to be doing just the opposite by bringing down yield from pesticide‐induced pollinator limitation.

Erratum for the Research Article: "Key tropical crops at risk from pollinator loss due to climate change and land use" by Millard et al.

Erratum for the Research Article: "Key tropical crops at risk from pollinator loss due to climate change and land use" by Millard et al.

Influence of agricultural intensification on pollinator pesticide exposure, food acquisition and diversity

Abstract Pollinators are essential for maintaining sustainable crop production, while the decline of pollinators is a widespread concern. Agricultural intensification is one of the primary drivers of the decline of insect pollinators. Agricultural intensification usually involves a decreasing of non‐crop semi‐natural habitat and an increasing of pesticide exposure for pollinators. However, causal links between agricultural intensification, increased pesticide exposure, and reduced pollinator's food sources and pollinator diversity remain underexplored. We assessed pollinator diversity across a landscape gradient where the proportion of rice ranged from 11% to 85% in South China. We placed honeybee (Apis mellifera) and mason bee (Osmia excavata) in these landscapes and investigated pesticide exposure in honeybee foragers and pollen, and in mason bee pollen and nesting materials. We also assessed the acquisition of food by mason bees. We found a higher frequency of pesticide detection in honeybee foragers and honeybee pollen samples in areas with a higher proportion of rice fields. There was a strong positive relationship between mason bee food acquisition and the proportion of semi‐natural habitats, while no significant effects of pesticide exposure on pollinator diversity were found in addition to the effect of semi‐natural habitat. Synthesis and applications: Our results suggest that pollinator communities could be at an increased risk of pesticide exposure due to intensified agriculture, while the negative impact on pollinator diversity mainly results from the loss of habitat and/or reduced food sources. This study highlights the importance of conserving semi‐natural habitat to mitigate the causes of decline in pollinator diversity. We also recommend long‐term, multi‐year studies to further understand the mechanisms behind the loss of pollinators in farming landscapes.

Bee and butterfly records indicate diversity losses in western and southern North America, but extensive knowledge gaps remain.

Pollinator losses threaten ecosystems and food security, diminishing gene flow and reproductive output for ecological communities and impacting ecosystem services broadly. For four focal families of bees and butterflies, we constructed over 1400 ensemble species distribution models over two time periods for North America. Models indicated disproportionally increased richness in eastern North America over time, with decreases in richness over time in the western US and southern Mexico. To further pinpoint geographic areas of vulnerability, we mapped records of potential pollinator species of conservation concern and found high concentrations of detections in the Great Lakes region, US East Coast, and southern Canada. Finally, we estimated asymptotic diversity indices for genera known to include species that visit flowers and may carry pollen for ecoregions across two time periods. Patterns of generic diversity through time mirrored those of species-level analyses, again indicating a decline in pollinators in the western U.S. Increases in generic diversity were observed in cooler and wetter ecoregions. Overall, changes in pollinator diversity appear to reflect changes in climate, though other factors such as land use change may also explain regional shifts. While statistical methods were employed to account for unequal sampling effort across regions and time, improved monitoring efforts with rigorous sampling designs would provide a deeper understanding of pollinator communities and their responses to ongoing environmental change.

The distribution of self-incompatibility systems in angiosperms: the relationship between mating system diversity, life span, growth habit and latitude in a changing global environment.

There is ample theoretical and experimental evidence that angiosperms harbouring self-incompatibility (SI) systems are likely to respond to global changes in unique ways relative to taxa with other mating systems. In this paper, we present an updated database on the prevalence of SI systems across angiosperms and examine the relationship between the presence of SI and latitude, biomes, life-history traits and management conditions to evaluate the potential vulnerability of SI taxa to climate change and habitat disturbance. We performed literature searches to identify studies that employed controlled crosses, microscopic analyses and/or genetic data to classify taxa as having SI, self-compatibility (SC), partial self-compatibility (PSC) or self-sterility (SS). Where described, the site of the SI reaction and the presence of dimorphic versus monomorphic flowers were also recorded. We then combined this database on the distribution of mating systems with information about the life span, growth habit, management conditions and geographic distribution of taxa. Information about the geographic distribution of taxa was obtained from a manually curated version of the Global Biodiversity Information Facility database, and from vegetation surveys encompassing 9 biomes. We employed multinomial logit regression to assess the relationship between mating system and life-history traits, management condition, latitude and latitude-squared using self-compatible taxa as the baseline. Additionally, we employed LOESS regression to examine the relationship between the probability of SI and latitude. Finally, by summarizing information at the family level, we plotted the distribution of SI systems across angiosperms including information about the presence of SI or dioecy, the inferred reaction site of the SI system when known, as well as the proportion of taxa in a family for which information is available. We obtained information about the SI status of 5686 hermaphroditic taxa, of which 55% exhibited SC, and the remaining 45% harbour SI, self-sterility (SS), or PSC. Highlights of the multinomial logit regression include that taxa with PSC have a greater odds of being short- (OR=1.3) or long- (OR=1.57) lived perennials relative to SC ones, and that SS/SI taxa (pooled) are less likely to be annuals (OR=0.64) and more likely to be long-lived perennials (OR=1.32). SS/SI taxa had a greater odds of being succulent (OR=2.4) or a tree (OR=2.05), and were less likely to be weeds (OR=0.34). Further, we find a quadratic relationship between the probability of being SI with latitude: SI taxa were more common in the tropics, a finding that was further supported by the vegetation surveys which showed fewer species with SS/SI in temperate and northern latitudes compared to mediterranean and tropical biomes. We conclude that in the short-term habitat fragmentation, pollinator loss and temperature increases may negatively impact plants with SI systems, particularly long-lived perennial and woody species dominant in tropical forests. In the longer term, these and other global changes are likely to select for self-compatible or partially self-compatible taxa which, due to the apparent importance of SI as a driver of plant diversification across the angiosperm tree of life, may globally influence plant species richness.

Ecological perspectives on female and male reproductive success with competition in two Serapias species.

The deceptive strategies by which orchids are pollinated and how these are capable of attracting pollinators remain understudied with regard to their implications for plant fitness. Despite their ecological importance, limited investigations have been conducted on sexual deception and shelter mimicry in orchid species, making this a compelling avenue in orchid biology research. To expand the knowledge of these reproductive mechanisms, we studied the pollination of Serapias lingua and S. parviflora in co-occurring and isolated sites in the Balearic Islands (Spain), further accentuated by the presence of a hybrid, indicating shared pollinators. We employed bagging and hand pollination experiments to examine the reproductive biology of the two species. Furthermore, we evaluated the influence of phenotypical and ecological factors on reproductive success, including biometric measurements, reproductive performance and neighbourhood diversity (co-flowering and pollinator communities). Reproductive mechanisms between these two orchid species exhibit substantial disparities. Serapias lingua relies primarily on insect-mediated pollination, while S. parviflora demonstrates self-reproduction capacity. Although events of open pollination are rare, hybridization occurs predominantly when S. lingua is the pollen donor. Fruit set in S. parviflora was positively correlated with plant height, while in S. lingua it was negatively associated with flower size. The coexistence of the two species positively affected pollinium removal in S. parviflora, but did not exert an influence on reproductive traits in S. lingua. Overall, biometric parameters were diminished in isolated compared with co-occurring sites. At the community level, the increased diversity of co-flowering species in the vicinity exhibited an inhibitory effect on pollinium removal in S. parviflora. Under a context of pollinator loss or phenological mismatch between pollinator presence and flowering, the selfing capacity of S. parviflora would guarantee reproduction whereas S. lingua survival would be compromised. Furthers studies are needed to assess the effects of phenotypical and ecological factors on reproductive success of S. lingua in pollinator-decline scenarios.

Quantifying farm sustainability through the lens of ecological theory.

The achievements of the Green Revolution in meeting the nutritional needs of a growing global population have been won at the expense of unintended consequences for the environment. Some of these negative impacts are now threatening the sustainability of food production through the loss of pollinators and natural enemies of crop pests, the evolution of pesticide resistance, declining soil health and vulnerability to climate change. In the search for farming systems that are sustainable both agronomically and environmentally, alternative approaches have been proposed variously called 'agroecological', 'conservation agriculture', 'regenerative' and 'sustainable intensification'. While the widespread recognition of the need for more sustainable farming is to be welcomed, this has created etymological confusion that has the potential to become a barrier to transformation. There is a need, therefore, for objective criteria to evaluate alternative farming systems and to quantify farm sustainability against multiple outcomes. To help meet this challenge, we reviewed the ecological theories that explain variance in regulating and supporting ecosystem services delivered by biological communities in farmland to identify guiding principles for management change. For each theory, we identified associated system metrics that could be used as proxies for agroecosystem function. We identified five principles derived from ecological theory: (i) provide key habitats for ecosystem service providers; (ii) increase crop and non-crop habitat diversity; (iii) increase edge density: (iv) increase nutrient-use efficiency; and (v) avoid extremes of disturbance. By making published knowledge the foundation of the choice of associated metrics, our aim was to establish a broad consensus for their use in sustainability assessment frameworks. Further analysis of their association with farm-scale data on biological communities and/or ecosystem service delivery would provide additional validation for their selection and support for the underpinning theories.

Floral biology, pollination biology, and breeding mechanisms reveal challenges to the restoration of Buchanania lanzan, a vulnerable plant species

Understanding a species' reproductive biology, which encompasses floral biology, pollination biology, and breeding system, is necessary for the restoration of endangered plant species. Buchanania lanzan is a vulnerable evergreen tree in IUCN Red Data Book due to excessive deforestation and over-exploitation. Light and scanning electron microscopy and histochemical analysis were used to study floral and pollination biology. Experiments were conducted to study floral and pollination biology, including pollen viability, stigma receptivity, and pollen-pistil interactions. Bisexual, pentamerous, complete yellowish-white flowers have an annual growth of 11 months and are arranged in terminal and axillary panicles. Anthers dehisce between 10.30 and noon, 9–10 h after anthesis. Stigmas were receptive at the time of anther dehiscence and remained receptive for two days. The flowers contain sucrose-rich nectar and emit a mild scent to attract visitors, including Musca domestica, Apis cerena indica, and black ants. None of these visitors appeared to be an effective pollinator. The results of pollination trials showed that the species outcrosses with low levels of selfing. Cross-pollinated flowers had a higher percentage of fruit sets (74.4 %) compared to self-pollinated (43.4 %) and open (3 %). The index of self-incompatibility (ISI) indicates partial self-incompatibility. Due to the probable loss of pollinators or the lack of efficient pollinators, the natural population of B. lanzan has not yet been restored. To achieve the required fruit or seed set cross-pollination facilitated by humans would be a feasible technique. Therefore, to prevent the extinction of this species, human management is required in terms of cross-pollination. As a result, the scientific knowledge produced by the current study may prove helpful in various breeding initiatives and the preservation of this medicinal plant species. Further, this knowledge forms the basis for taking measures for the conservation and management of forests.

Better soon than never: climate change induces strong phenological reassembly in the flowering of a Mediterranean shrub community

Abstract Background and Aims Flowering is a key process in the life cycle of a plant. Climate change is shifting flowering phenologies in the Northern Hemisphere, but studies with long data series at the community level are scarce, especially those considering the consequences of phenological changes for emerging ecological interactions. In the Mediterranean region, the effects of climate change are stronger than the global average and there is an urgent need to understand how biodiversity will be affected in this area. Methods In this study, we investigated how the entire flowering phenology of a community comprising 51 perennial species from the south of the Iberian Peninsula changed from the decade of the 1980s to the 2020s. Furthermore, we have analysed the consequences of these changes for flowering order and co-flowering patterns. Key Results We have found that the flowering phenology of the community has advanced by ~20 days, which is coherent with the increasing temperatures related to climate change. Individual species have generally advanced their entire flowering phenology (start and end) and increased their flowering duration. The early flowering has resulted in a re-organization of the flowering order of the community and generated new co-flowering assemblages of species, with a slight trend towards an increase of shared flowering time among species. Conclusions The advanced flowering phenology and changes in flowering duration reported here were of unprecedented magnitude, showcasing the extreme effects of climate change on Mediterranean ecosystems. Furthermore, the effects were not similar among species, which could be attributed to differences in sensitivities of environmental cues for flowering. One consequence of these changes in flowering times is ecological mismatches, indicated by changes in the flowering order and co-flowering between decades. This new scenario might lead to new competitive or facilitative interactions and to the loss or gain of pollinators.

Protecting Farmland Pollinators: Whole Farm Scorecard - Experiences and Recommendations

Protecting Farmland Pollinators is about identifying small actions that farmers can take that will allow biodiversity to coexist within a productive farming system. Farmers in Ireland recognise the importance of pollinators, but farmland has experienced wide-scale loss of wild pollinators over the last fifty years. By working closely with 40 farmers, management practices that benefit bees and hoverflies on Irish farmland were identified, and a whole farm pollinator scoring system was developed. Using a whole farm pollinator scorecard, farmers receive ‘pollinator points’ each year based on the amount and quality of pollinator friendly habitat maintained and/or created and, each year, farmers receive a results-based payment that relates to the points. Irish farms have great potential to improve both the quantity and quality of biodiversity friendly habitats without negatively impacting on farm productivity. Thirty-one farmers increased their score between year one and year three of the results-based payment and four farms more than tripled their score. The median whole farm pollinator score for the 40 farms increased from 25,696 in year one to 33,572 in year two (31% increase), to, 40,211 pollinator points in year three (56% increase). Each farm type (beef, dairy, mixed and arable) increased their median score over the three years and dairy and arable farms showed the largest increase. This project has helped farmers better understand and engage with nature on their land and has created a measurable system for improving habitats for biodiversity on farms that is accessible to all and has the potential to be rolled out on a wider scale.

Key tropical crops at risk from pollinator loss due to climate change and land use.

Insect pollinator biodiversity is changing rapidly, with potential consequences for the provision of crop pollination. However, the role of land use-climate interactions in pollinator biodiversity changes, as well as consequent economic effects via changes in crop pollination, remains poorly understood. We present a global assessment of the interactive effects of climate change and land use on pollinator abundance and richness and predictions of the risk to crop pollination from the inferred changes. Using a dataset containing 2673 sites and 3080 insect pollinator species, we show that the interactive combination of agriculture and climate change is associated with large reductions in insect pollinators. As a result, it is expected that the tropics will experience the greatest risk to crop production from pollinator losses. Localized risk is highest and predicted to increase most rapidly, in regions of sub-Saharan Africa, northern South America, and Southeast Asia. Via pollinator loss alone, climate change and agricultural land use could be a risk to human well-being.

The evolution of flower-pollinator trait matching, and why do some alpine gingers appear to be mismatched?

Morphological matching between flower and pollinator traits has been documented in diverse plant lineages. Indeed, the matching of corolla tube length and pollinator tongue length has been cited repeatedly as a classic case of coevolution. However, there are many possible evolutionary routes to trait matching. Our aim here is both to review the evolutionary mechanisms of plant-pollinator trait matching and to investigate a specific case of trait matching/mismatching in a genus of alpine gingers. Roscoea gingers with long corolla tubes in the western Himalayas have pollinators with correspondingly long tongues, but the match between corolla tube and pollinator tongue lengths is not seen in the eastern Himalayas. Six floral traits were measured, including corolla tube depth, an internal trait controlling pollinator access to nectar. We calculated coefficients of variation and phylogenetically controlled correlation patterns of these traits in six Roscoea species in order to gain possible insights into stabilizing selection and modularization of these traits. The distal (nectar-containing) portion of the corolla tube exhibited lower coefficients of variations than did the basal portion. This is consistent with the hypothesis that pollinators mediate stabilizing selection on the distal, but not basal, portion of the corolla tube. This result, combined with phylogenetic data, suggests that the elevated liquid level of nectar in the distal tube evolved subsequent to dispersal into the eastern Himalayan region and loss of long-tongue pollinators. After accounting for phylogeny, corolla tube length, anther length, style length and labellum width were all intercorrelated. Corolla-tube depth was not part of this covariational module, however, suggesting separate adaptation to short-tongued pollinators. The reduction in functional corolla tube depth in the Roscoea appears to be related to the loss of long-tongued pollinators associated with dispersal to the eastern Himalayas and pollination by short-tongued pollinators. The apparent mismatch between floral tubes and pollinator tongues is a case of cryptic trait matching between flowers and pollinators, underscoring the importance of combining floral anatomy with pollination ecology in assessing plant-pollinator trait matching.

Dependency of Crops on Pollinators and Pollination Deficits: An Approach to Measurement Considering the Influence of Various Reproductive Traits

Pollinators provide crucial ecosystem services, i.e., pollination, which determines crops’ reproductive fitness and yield. As pollinators decline, flowering crops might face pollination-deficit stress depending on their dependence on pollinators and pollinator availability. Here, we assessed the dependency of some crops (belonging to diverse plant families) on biotic pollinators based on their maximum reproductive potential in a supplementary pollination treatment and minimum reproductive success in a pollinator exclusion treatment. Additionally, we determined the pollen transfer limitation of the crops in open field conditions. We also determined the influence of the different reproductive traits with the index of dependency of crops on pollinators (IDP) and the coefficient of pollination deficit (D). Based on the values of IDP, members of Cucurbitaceae are obligatorily dependent on pollinators for their fruit set. Members of Brassicaceae and Rutaceae are highly reliant on pollinators. A few crops, like Lablab purpureus and Nigella sativa, are less dependent on pollinators. In open field conditions, most crops have a low pollination deficit, some without pollen transfer limitations, and only a few crops (Citrus × limon and Citrus maxima) show a higher pollination deficit. The IDP is negatively influenced by the pollen–ovule ratio, which also negatively affects the pollination deficit of the crops. This study will be useful in understanding and mitigating the effects of pollinator losses, as well as in choosing crops (those under pollination deficit stress and largely dependent on pollinators for fruit set) for supplemental pollination services to increase agricultural production.

Valuing Pollination as an Ecosystem Services: The Case of Hand Pollination for Cocoa Production in Ghana

The promotion of cocoa farm productivity has necessitated the intensification of input use with ensuing loss of natural pollinators. Ghana Cocoa Board’s (COCOBOD) remedy to declining pollinator population is addressed in the rolling out of hand pollination in the 2016/17 crop year. Applying contingent valuation on field data covering 608 farmers in five cocoa growing regions, we estimate the value of pollinator services to the cocoa industry in Ghana and farmers willingness to pay for the service. We find that cocoa farmers in Ghana are willing to pay for hand pollination to improve on their farm yields. Farmers averagely value pollinator services at $1.3 per acre of land. Extrapolated to cover all cultivated cocoa lands for 2017/18 crop year, the value of pollinator services to Ghana’s cocoa industry is averagely $6.1 million per annum. Hand pollination can improve cocoa farms yields given the statistically significant mean difference in yields between hand-pollinated and non-hand-pollinated farms. Having established the loss to the cocoa industry from pollinator decline and the need for effective pollination to support crop productivity, it is imperative for COCOBOD to ramp up strategies at preserving cocoa farm ecology to safe guard the industry.

Forest conservation maximises açaí palm pollination services and yield in the Brazilian Amazon

Abstract Agricultural expansion is one of the main drivers of global pollinator loss. Paradoxically, this occurs while agriculture is becoming increasingly dependent on biotic pollination, raising concerns about food production. Integrated Crop Pollination (ICP), the use of both wild and managed pollinators in crop fields, can help conserve pollinator diversity while ensuring effective pollination services for growers. However, given the context‐dependent nature of this approach, there is an urgent need to evaluate its application across different landscapes and crops. We apply the ICP approach to açaí palm (Euterpe oleracea Mart.) production in the eastern Brazilian Amazon to explore effects of a native stingless bee, Scaptotrigona aff. postica (Apidae: Meliponini), and landscape‐level forest conservation on yield and socioeconomic outcomes for açaí fruit growers. We assessed flower visitor assemblages and fruit production on 18 plantations across a landscape forest cover gradient, with bee colonies introduced on nine plantations. Field data were combined with information from semistructured interviews of growers to estimate yield and profit per hectare under different pollinator management scenarios. Bee colonies and forest cover enhanced flower visitor abundance on palm inflorescences, but abundance increases attributed to managed bees were associated with shifts in flower visitor evenness and diversity (species richness), due to reduced visitation of wild bees near managed colonies. Fruit production on inflorescences was positively related to bee abundance and bee diversity. Consequently, overall pollination performance was lower in plantations with bee colonies. This was repeated at the hectare scale, where yield and profit were associated with surrounding forest cover and not bee colonies. Synthesis and applications. Managed bees can increase pollinator densities and fruit production, but the increased environmental and socioeconomic risks associated with this activity means açaí growers should prioritise forest conservation to safeguard pollination services and improve overall sustainability of açaí production in the eastern Brazilian Amazon.

Community context mediates effects of pollinator loss on seed production

AbstractA critical goal for ecologists is understanding how ongoing local and global species losses will affect ecosystem functions and services. Diversity–functioning relationships, which are well‐characterized in primary producer communities, are much less consistently predictable for ecosystem functions involving two or more trophic levels, particularly in situations where multiple species in one trophic level impact functional outcomes at another trophic level. This is particularly relevant to pollination functioning, given ongoing pollinator declines and the value of understanding pollination functioning for single plant species like crops or threatened plants. We used spatially replicated, controlled single‐pollinator‐species removal experiments to assess how changes in bumble bee species richness impacted the production of fertilized seeds in a perennial herb—Delphinium barbeyi—in the Rocky Mountains of Colorado, USA. To improve predictability, we also assessed how traits and abundances in the plant and bumble bee communities were related to D. barbeyi reproductive success. We hypothesized that trait‐matching between pollinator proboscis length and D. barbeyi's nectar spurs would produce a greater number of fertilized seeds, while morphological similarity within the floral community would dilute pollination services. We found that the effects of pollinator removal differed depending on the behavioral patterns of pollinators and compositional features of the plant and pollinator communities. While pollinator floral fidelity generally increased D. barbeyi seed production, that positive effect was primarily evident when more than half of the Bombus community was experimentally removed. Similarly, communities comprising primarily long‐tongued bees were most beneficial to D. barbeyi seed production in tandem with a strong removal. Finally, we observed contrasting effects of morphological similarity in the plant community, with evidence of both competition and facilitation among plants. These results offer an example of the complex dynamics underlying ecosystem function in multitrophic systems and demonstrate that community context can impact diversity–functioning relationships between trophic levels.