Insect Pollinator Populations Research Articles

The degree of urbanisation reduces wild bee and butterfly diversity and alters the patterns of flower-visitation in urban dry grasslands

Insect-provided pollination services are increasingly threatened due to alarming declines in insect pollinator populations. One of the main threats to insect pollinators and consequently pollination is urbanisation. Here, we investigate the effects of local habitat quality (patch size, flowering plant richness, bare soil cover, vegetation structure), degree of urbanisation (impervious surfaces) and 3D connectivity on bee, hoverfly and butterfly flower visitors and plant-flower visitor networks in flower-rich urban dry grasslands. Overall, the degree of urbanisation and the quality of the local habitat influenced the flowering plant and pollinator communities. Although flowering plant abundance increased with urbanisation, bee species richness and butterfly species richness decreased with increasing impervious surfaces. Flowering plant richness and ground nesting resource availability were positively related to bee richness and local vegetation structure boosted hoverfly and butterfly visitation rates. In terms of plant–pollinator interactions, insect pollinators visited a lower proportion of the available flowering plants in more urbanised areas and network modularity and specialisation increased with patch size. Our findings show that urban dry grasslands are valuable habitats for species-rich pollinator communities and further highlight the importance of minimizing the intensity of urbanisation and the potential of local management practices to support insect biodiversity in cities.

Flower Visitation Time and Number of Visitor Species Are Reduced by the Use of Agrochemicals in Coffee Home Gardens

Pollination services, from both wild and managed populations of insect pollinators, have degraded as a result of agricultural intensification. Whilst 75% of economically important crops depend on insect pollinators for cultivation, 40% of insect pollinator species are threatened with extinction. Pollination services must be preserved if there is to be enough food for a global population whose demand is expected to double, if not triple, by 2050. Pollinator diversity and pollinator efficiency have been found to increase as a result of wildlife-friendly farming practices (i.e., natural chemicals and fertilizers and agroforestry). We evaluated the presence of insect pollinators in 42 coffee home gardens in West Java, Indonesia. Via generalized linear mixed models, we found that number of visitor species (β = 0.418 ± SE 0.194, p = 0.031) and visitation time (β = 0.845 ± SE 0.308, p = 0.006) decreased as farms were more intensely managed, (i.e., used chemical pesticides), compared to fields using organic practices. As knowledge of pollination services is widespread amongst smallholder farmers in Indonesia and beyond due to the long-held tradition of beekeeping, these results will add to their existing knowledge and empower farmers to enhance resources for pollinator species through agroforestry and natural pest management. Although we found significant differences in pollination services provided in intensely managed and wildlife-friendly farms, chemical use can affect farms far beyond a particular area of production. Therefore, pollinator conservation must be applied at a landscape level and involve all stakeholders, including farmers, when making effective policies.

Wildness and Wild Spaces in Residential Yards: Changing Neighborhood Norms to Support Pollinator Populations

Insect pollinator populations, critical to the global food supply, are declining. Research has found robust bee communities in cities, which are supported by diverse urban habitat and foraging resources. Accounting for 35–50% of urban green space, U.S. private residential yards can serve as important forage and nesting sources for pollinators. Incorporating wild attributes and wildness, such as native vegetation and less intensive yard-management practices, is key. However, urban vegetation, and its effects on local native bee populations, is shaped by social and cultural preferences, norms, aesthetics, values, and identities. The perfect lawn ideal of a highly manicured turfgrass yard dominates neighborhood landscapes and is often at odds with the habitat needs of pollinators. As part of a three-year study investigating the sociocultural drivers of residential vegetation choices in St. Louis, MO, USA, we interviewed 85 decisionmakers in order to understand choices about private residential yard maintenance. This paper presents an emergent finding concerning how residents conceptualize and talk about the urban-yard aesthetic, using the terms “wild” and “wildness”, which reflect a range of levels in the demand for urban wild spaces in their neighborhoods. The discourse of wildness offers a nontechnical route for understanding the connections between the ecological consequences of urbanization, with human attitudes towards nature that shape the biological functioning of human-generated habitats.

Veterinarians and beekeeping: What roles, expectations and future perspectives? - a review paper

Apiculture is an important economy sector, facing a real health crisis. Honeybees, as well as other insect pollinator populations have been in decline over recent decades, and diseases are one of the principal challenges. To face this situation, public and private veterinary services are needed to manage surveillance, control, eradication and prevention measures of honeybee diseases within their territories, in close collaboration with beekeepers and farmers. It is necessary urgently to clarify the current problems and threats to apiculture in the public health sector. Due to possible interactions between bee health and production, the negative effects of environmental xenobiotics and climate change, this field must be considered as an interdisciplinary research issue. Moreover, honeybee veterinary medicine is increasingly engaged in the One Health approach, due to the possibility that the poor health of honeybee colonies affects human life. This review identified the key veterinarian roles, gaps in their higher education curriculum, as well as the necessity for research linkage between expectations and professional perspectives.

Native flower strips increase visitation by non-bee insects to avocado flowers and promote yield

Pollination is an essential ecosystem service for pollinator-dependent crops and plant communities. Apis mellifera L. is by far the most commonly used species to obtain this service in agriculture. However, there is growing evidence of the importance for crop yields of the service provided by wild bees and non-bee insect pollinators. Establishing flower resources in agricultural landscapes is a management practice that can increase insect pollinator populations and improve crop yields. We established perennial native flower strips (NFS) in four avocado orchards in central Chile during autumn 2017. We monitored flower visitors and counted newly formed fruits in avocados near and far from NFS in spring 2019, to assess flower visitor groups, flower visitation rates and fruit numbers. Only A. mellifera visited avocado flowers within bees, whereas both the managed A. mellifera and wild bees were the main visitors to the NFS. NFS increased visitation rates to adjacent avocado of flies, and with a trend for the sum of all non-managed flower visitors (i.e. excluding A. mellifera). However, there were no differences in the rates of A. mellifera visitation to avocados near and far from NFS. Avocado fruit numbers were higher among avocados near NFS than among those farther away. This difference could be due to better pollination by the increased visits to avocado flowers by flies or other wild insects. Therefore, NFS could contribute to crop fruit number, as well as conservation of native flora, wild bees and non-bee pollinators on fruit farms in the “Central Chile” biodiversity hotspot.

Microhabitats created by log landings support abundant flowers and insect pollinators within regenerating mixed-oak stands in the Central Appalachian Mountains

Despite their role as keystone organisms, insect pollinator populations have declined across many regions. Although pollinator populations face a multitude of threats, among the most important is habitat loss and degradation. In eastern North America, forested landscapes are thought to serve as strongholds for robust pollinator populations, however, even these high-quality landscapes are increasingly unsuitable for pollinators due to suppression of natural disturbances, which results in mature forests with few floral resources. To enhance landscapes for forest-dependent wildlife, land managers increasingly recognize the value of silviculture for promoting forest regeneration to support early-successional species. Although timber harvest has proven to be an invaluable tool for enhancing forest pollinator habitat, the role of microhabitat components like log landings remains unassessed. Log landings (open areas where harvested logs are loaded for transport) may serve as an important microhabitat component of early seral stands because they are expected to support open conditions and high floral abundance. We sampled 20 log landing/timber harvest interior pairs for bees, butterflies, floral resources, and structural vegetation in the Pocono Mountains of Pennsylvania from June-September 2019. Hierarchical distance models revealed that log landings supported twice as many bees (897 vs 351 bees/ha) and five times as many butterflies (433 vs 88 butterflies/ha) as timber harvest interiors. Likewise, log landings supported about 14 times as many floral resources than timber harvest interiors (109,572 vs 8,431/transect). Among log landings, those with the most floral resources also supported the most bees and butterflies. Collectively, our results support the hypothesis that log landings serve as concentrated resource hubs for bees and butterflies. Future work exploring the role of different plant species (e.g., native vs exotic) in habitat quality for early-successional pollinators would prove useful.

Potential Risk to Pollinators from Nanotechnology-Based Pesticides.

The decline in populations of insect pollinators is a global concern. While multiple factors are implicated, there is uncertainty surrounding the contribution of certain groups of pesticides to losses in wild and managed bees. Nanotechnology-based pesticides (NBPs) are formulations based on multiple particle sizes and types. By packaging active ingredients in engineered particles, NBPs offer many benefits and novel functions, but may also exhibit different properties in the environment when compared with older pesticide formulations. These new properties raise questions about the environmental disposition and fate of NBPs and their exposure to pollinators. Pollinators such as honey bees have evolved structural adaptations to collect pollen, but also inadvertently gather other types of environmental particles which may accumulate in hive materials. Knowledge of the interaction between pollinators, NBPs, and other types of particles is needed to better understand their exposure to pesticides, and essential for characterizing risk from diverse environmental contaminants. The present review discusses the properties, benefits and types of nanotechnology-based pesticides, the propensity of bees to collect such particles and potential impacts on bee pollinators.

A validated workflow for rapid taxonomic assignment and monitoring of a national fauna of bees (Apiformes) using high throughput DNA barcoding

Improved taxonomic methods are needed to quantify declining populations of insect pollinators. This study devises a high-throughput DNA barcoding protocol for a regional fauna (United Kingdom) of bees (Apiformes), consisting of reference library construction, a proof-of-concept monitoring scheme, and the deep barcoding of individuals to assess potential artefacts and organismal associations. A reference database of cytochrome oxidase c subunit 1 (cox1) sequences including 92.4% of 278 bee species known from the UK showed high congruence with morphological taxon concepts, but molecular species delimitations resulted in numerous split and (fewer) lumped entities within the Linnaean species. Double tagging permitted deep Illumina sequencing of 762 separate individuals of bees from a UK-wide survey. Extracting the target barcode from the amplicon mix required a new protocol employing read abundance and phylogenetic position, which revealed 180 molecular entities of Apiformes identifiable to species. An additional 72 entities were ascribed to nuclear pseudogenes based on patterns of read abundance and phylogenetic relatedness to the reference set. Clustering of reads revealed a range of secondary operational taxonomic units (OTUs) in almost all samples, resulting from traces of insect species caught in the same traps, organisms associated with the insects including a known mite parasite of bees, and the common detection of human DNA, besides evidence for low-level cross-contamination in pan traps and laboratory procedures. Custom scripts were generated to conduct critical steps of the bioinformatics protocol. The resources built here will greatly aid DNA-based monitoring to inform management and conservation policies for the protection of pollinators.

Bee Communities across Gap, Edge, and Closed-Canopy Microsites in Forest Stands with Group Selection Openings

Abstract As insect pollinator populations continue to decline, it is essential to understand the impacts of anthropogenic activities, including forest management, on pollinator communities. Although multiple studies have shown that clearcutting is beneficial for bees, other less intense, selective silvicultural methods that result in disproportionate increases in edge habitat within stands are less well understood. We investigated bee community characteristics across microsites (center of cut, edge of cut, and closed-canopy forest) in three mixed-mesophytic forest stands subjected to group selection cuttings. Results revealed bee communities in the center of cuts and their edges to differ from those in forest microsites, and their diversity measures were higher than in forest microsites. Within-stand edge microsites did not differ from their cut centers in terms of their communities or their diversity. Finally, center of cut and edge microsites combined, and forest microsites, were characterized by different indicator species, thereby exemplifying differences between these two microsite groupings. These results suggest that group selection harvests support differing communities of bees across microsites and sustain a wide range of bee species, and that edges within these forest stands behaved more like extensions of canopy gap openings despite differences in forest physiognomy.

Keanekaragaman serangga pengunjung bunga pada tanaman tumpang sari kedelai dengan tanaman orok-orok (Crotalaria juncea)

Tumbuhan berbunga dapat meningkatkan populasi serangga polinator, yang sekaligus berperan penting dalam meningkatkan hasil tanaman. Tujuan penelitian ini untuk mengetahui pengaruh tumpang sari Crotalaria juncea dengan kedelai terhadap keanekaragaman serangga pengunjung bunga dan polinator alami terhadap hasil kedelai. Penelitian dirancang pada petak tunggal, dengan perlakuan: tanpa C. juncea (kontrol), penanaman C. juncea mengelilingi lahan kedelai, penanaman C. juncea setiap 5 baris kedelai, dan penanaman C. juncea setiap 10 baris kedelai. Pengaruh polinator alami terhadap hasil kedelai diamati melalui penyungkupan tanaman dengan jaring serangga. Hasil penelitian menunjukan, bahwa penanaman C. juncea dapat meningkatkan keanekaragaman serangga pengunjung bunga. Indeks keanekaragaman tertinggi 2,37 tercatat pada petak penanaman C. juncea setiap 10 baris kedelai. Keanekaragaman serangga pengunjung bunga terbanyak, yaitu 18 spesies ditemukan pada perlakuan penanaman C. juncea setiap 5 baris kedelai. Serangga pengunjung bunga yang dominan adalah Coccinella transversalis, Apis mellifera, Xylocopa virginica, Megachile parientina, Megachile relativa, Ropalidia fasciata, dan Vespa sp. Polinator alami (tanpa sungkup) dapat meningkatkan jumlah polong 30,11%, jumlah biji 44,63%, dan berat biji per tanaman 15,44% sehingga berperanan penting pada hasil kedelai.

Synergistic effects of pathogen and pesticide exposure on honey bee (Apis mellifera) survival and immunity.

Declines in native insect pollinator populations and substantial losses in managed honey bees have been reported on a global scale and become a widespread concern because of the importance of these insects for human food production and ecosystem stability. Several potential factors have been studied as possible causes of declining pollinator health, such as parasites and pathogens, exposure to agricultural pesticides, habitat loss and/or climate change. More recently, a combination of these factors rather than a single cause have been blamed for observed pollinator losses, but field studies of such interactions are challenging, especially in the presence of confounding environmental stressors. We therefore examined the impact of single and combined stressors on the honey bee (Apis mellifera) in a generally healthy Australian population. We exposed workers during their larval development and drones until they reached sexual maturity to the neonicotinoid pesticide Thiamethoxam, at concentrations more than 20 times lower than we initially measured in the field, the microsporidian gut pathogen Nosema apis or both stressors at the same time. We found that simultaneous exposure significantly reduced bee health. We observed a substantial increase in mortality and a reduction of immunocompetence in workers exposed to both the pathogen and the pesticide. We conclude that the exposure of generally healthy bees to multiple environmental stressors results in synergistic effects where the effects are expected to negatively impact performance and could be sufficient to trigger colony collapse. We found that the vast majority of males did not survive to sexual maturity after exposure to very low levels of Thiamethoxam. This would not only reduce the reproductive success of individual colonies, but can also impact gene flow and genetic diversity at the population level, which are both known as key components of honey bee health.

The perfect lawn: exploring neighborhood socio-cultural drivers for insect pollinator habitat

In the United States, residential yards are typically overlooked for biodiversity conservation, yet they account for a significant portion of urban green space. Yard vegetation can serve as valuable habitat patches for insect pollinator populations in cities, providing important foraging and nesting resources. Based on long-term native bee sampling data, we investigate the social and cultural drivers shaping front yard vegetation composition and configuration at two study sites with consistently low native bee species diversity and abundance. We employ quantitative remote sensing approaches with analysis of qualitative interview data to examine residential vegetation patterns and analyze the socio-cultural relationships between people and vegetation. Data analyses reveal both study sites have lower levels of vegetation composition and complexity, resulting in reduced habitat resources. We find neighborhood public-facing landscaping is shaped by various socio-cultural influences: aesthetics, norms, reference-group behavior, institutions, socioeconomics, and identity. Front yard land-use and decision-making practices are particularly meaning laden, as these spaces are often perceived as visible representations of longstanding neighborhood identity and contiguous common areas to be managed to a “perfect lawn” ideal. The quantitative and qualitative data are used to characterize the two study sites and inform future urban conservation and development efforts salient to citizen stakeholders.

PENGGUNAAN BERBAGAI PLASMA NUTFAH KELAPA SAWIT KOLEKSI PPKS RIAU TERHADAP POPULASI SERANGGA PENYERBUK KELAPA SAWIT

This research was to study the use of various oil palm germplasm collection of Indonesian Oil PalmResearch Institute (IOPRI) Riau on a population of insect pollinators (Elaeidobius kamerunicus Faust.)in Riau Province Kalianta Gardens. The research was conducted from May until July 2016 bya purposive sampling method. The results showed that E. kamerunicus total population of 9,123head/0.5ha with E. kamerunicus male sex ratio of 3,160 head/0.5ha and females amounted to 5,963heads/0.5ha in male flowers and a total population of 433 head/0.5ha with a ratio E. kamerunicusmale genitals of 182 head/0.5ha and females of 251 head/0.5ha in the female flowers. The populationof E. kamerunicus on more male flowers than the female flowers. Germplasm highest in V3 (AccessionWild Angola) on the male flowers and V1 (Elaeis guineensis) in the female flowers, while the lowestgermplasm on male and female flowers are V7 (Elaeis oleifera).

Preliminary Test of Agri-Environmental Scheme Implementation in Farmland in Northern Slope of Mount Slamet

An Agri-Environmental Scheme (AES) was designed to enhance flower availability in crops using local wild plants. The goals of this research were to determine the impact of four wild plants on three cash corps, focusing on the diversity and abundance of insect pollinators, and to test the efficacy of this scheme using farmland on the northern slope of Mount Slamet. This research was done using a split block design, with the three cash crops as blocks (strawberry [ Fragaria x ananassa Duchesne], chili pepper [ Capsicum spp.], and tomatoes [ Solanum lycopersicum L.]) and four wild plant species as treatments ( Cleome rutidosperma , Borreria laevicaulis , Euphorbia heterophylla , and Tridax procumbens ) at different precentages (0, 5, 10, and 15 %) of cash crop plant density. The results show that growing wild plants with cash crops enhanced the abundance and diversity of insect pollinators. Moreover, the addition of wild plant species to the crops at four densities had significantly different effects on insect pollinators in terms of abundance and diversity. The combination of 15 % C. rutidospermae and tomatoes had the largest population of insect pollinators. From the experiments it concluded that an AES could be implemented in farmland on the northern slope of Mount Slamet.

Improving Mitochondrial Function Protects Bumblebees from Neonicotinoid Pesticides.

Global pollination is threatened by declining insect pollinator populations that may be linked to neonicotinoid pesticide use. Neonicotinoids over stimulate neurons and depolarize their mitochondria, producing immobility and death. However, mitochondrial function can be improved by near infrared light absorbed by cytochrome c oxidase in mitochondrial respiration. In flies, daily exposure to 670nm light throughout life increases average lifespan and aged mobility, and reduces systemic inflammation. Here we treat bumble bees with Imidacloprid a common neonicotinoid. This undermined ATP and rapidly induced immobility and reduced visual function and survival. Bees exposed to insecticide and daily to 670nm light showed corrected ATP levels and significantly improved mobility allowing them to feed. Physiological recordings from eyes revealed that light exposure corrected deficits induced by the pesticide. Overall, death rates in bees exposed to insecticide but also given 670nm light were indistinguishable from controls. When Imidacloprid and light exposure were withdrawn, survival was maintained. Bees and insects generally cannot see deep red light so it does not disturb their behaviour. Hence, we show that deep red light exposure that improves mitochondrial function, reverses the sensory and motor deficits induced by Imidacloprid. These results may have important implications as light delivery is economic and can be placed in hives/colonies.

Measuring the economic value of pollination services: Principles, evidence and knowledge gaps

An increasing degree of attention is being given to the ecosystem services which insect pollinators supply, and the economic value of these services. Recent research suggests that a range of factors are contributing to a global decline in pollination services, which are often used as a “headline” ecosystem service in terms of communicating the concept of ecosystem services, and how this ties peoples׳ well-being to the condition of ecosystems and the biodiversity found therein. Our paper offers a conceptual framework for measuring the economic value of changes in insect pollinator populations, and then reviews what evidence exists on the empirical magnitude of these values (both market and non-market). This allows us to highlight where the largest gaps in knowledge are, where the greatest conceptual and empirical challenges remain, and where research is most needed.

Exposure to neonicotinoids influences the motor function of adult worker honeybees.

Systemic pesticides such as neonicotinoids are commonly used on flowering crops visited by pollinators, and their use has been implicated in the decline of insect pollinator populations in Europe and North America. Several studies show that neonicotinoids affect navigation and learning in bees but few studies have examined whether these substances influence their basic motor function. Here, we investigated how prolonged exposure to sublethal doses of four neonicotinoid pesticides (imidacloprid, thiamethoxam, clothianidin, dinotefuran) and the plant toxin, nicotine, affect basic motor function and postural control in foraging-age worker honeybees. We used doses of 10 nM for each neonicotinoid: field-relevant doses that we determined to be sublethal and willingly consumed by bees. The neonicotinoids were placed in food solutions given to bees for 24 h. After the exposure period, bees were more likely to lose postural control during the motor function assay and fail to right themselves if exposed to imidacloprid, thiamethoxam, clothianidin. Bees exposed to thiamethoxam and nicotine also spent more time grooming. Other behaviours (walking, sitting and flying) were not significantly affected. Expression of changes in motor function after exposure to imidacloprid was dose-dependent and affected all measured behaviours. Our data illustrate that 24 h exposure to sublethal doses of neonicotinoid pesticides has a subtle influence on bee behaviour that is likely to affect normal function in a field setting.

The Economic Value of Bees as Pollinators of Crops in Iran

Assessment of the economic value of crop pollination by bees necessitates the need for conserving the insect pollinator diversity. A decline in the population of insect pollinators in ecosystems can result in a decrease in crop production, vegetation cover, an extinction of a number of plant species, and as a result the degradation of ecosystem services and health. The economic value of bee pollinators was determined based on the portion of the value of crops attributed to pollination by bees. This value was calculated based on the yield and the value of each crop, the dependency of each crop on bee pollinators and the proportion of wild native bee and honey bee pollinators. The economic value of crop pollination by bees was 6.59 billion dollars, of which, 5.72 billion dollars is attributable to the pollinators that are honey bees and 0.87 billion dollars is attributable to native bees. The value of the crops pollinated by bees was estimated to be 25% of the total value of crops. The value of crops pollinated by honey bees was 54 times the value of honey production by bees. Based on the economic value of bee pollinators, the use of organic farming techniques, the use of less toxic and highly selective pesticides and herbicides, construction of nest boxes for pollinators and introduction of a variety of native plant species can help to conserve high level of diversity of bee pollinator species and the pollination services.

Threats to an ecosystem service: pressures on pollinators

Insect pollinators of crops and wild plants are under threat globally and their decline or loss could have profound economic and environmental consequences. Here, we argue that multiple anthropogenic pressures – including land‐use intensification, climate change, and the spread of alien species and diseases – are primarily responsible for insect‐pollinator declines. We show that a complex interplay between pressures (eg lack of food sources, diseases, and pesticides) and biological processes (eg species dispersal and interactions) at a range of scales (from genes to ecosystems) underpins the general decline in insect‐pollinator populations. Interdisciplinary research on the nature and impacts of these interactions will be needed if human food security and ecosystem function are to be preserved. We highlight key areas that require research focus and outline some practical steps to alleviate the pressures on pollinators and the pollination services they deliver to wild and crop plants.

English

Pollinator-dependent production of food nutrients in China has not been evaluated previously. Using Food and Agriculture Organization (FAO) crop production data and United States Department of Agriculture (USDA) food composition data, we examined the nutritional values of 41 common fruits and vegetables to assess the contribution of animal pollination to human nutrition. Most of these crops rely on insect pollinators to set fruit or seed to some degree. Pollinator-dependent plants yielded more than 80% of the protein, fat, zinc, selenium, calcium, phosphorus, potassium, copper, vitamin B1 and vitamin B5, over 90% of the dietary fiber, vitamin B6 and vitamin C, almost the entire quantity of alpha-carotene and beta-tocopherol, and the full amount of beta-cryptoxanthin and lycopene. On average, pollinator-dependent crops accounted for approximately 80% of the food nutrients produced by the plants surveyed in this study, and 20% of all nutrient output was directly derived from insect pollination. Careful management of insect pollinator populations is therefore of vital importance to providing a nutritionally adequate diet for the people of China.   Key words: China, Food and Agriculture Organization (FAO), food nutrients, fruits, insect pollinators, vegetables.