Pollinator Type Research Articles

Pollination phenotypes in Phalaenopsis crosses: Guiding selection for optimal breeding

Phalaenopsis orchid is one of the most popular flowers that have a large share of global flower and plant market due to its attractiveness, color varieties, and medicinal properties. In this study, the morphological (capsule length, full weight of capsule, empty weight of capsule, the weight of seeds in capsule and capsule volume) and phenological (time of pollination symptom, time of capsule swelling, and time of capsule ripening) traits of pollination were evaluated in 5 varieties of Phalaenopsis by the first plant pollination syringe of orchids in 5 types of self-pollination and 20 combinations of cross-pollination during 2019-2023. The results showed that 92% of the total variations were explained by the first 4 components in the analysis of the main components. The first and second components accounted for about 57.5% and 19.6% of the total data. Using cluster analysis results, pollination types were classified into three groups based on pollination factors. Discriminant analysis showed that clustering based on the Euclidean distance criterion was better than other distance criteria and was obtained favorably clustering based on it. Low heritability and genetic improvement were observed for time to petal wilting after pollination (TPS) characteristic. Nottingham × Nottingham pollination has the highest amount of capsule length, weight of seeds per capsule, capsule volume, and fresh weight of capsule. Capsule length had the most phenotypic and genotypic variation coefficient among all of the examined characteristics in 25 pollination types. The results of this study are used to select parents and favorable crosses to produce new varieties and capsules containing seeds.

Analysis of Chemical Traits of Pollen from Nine Ericaceous Species in Southwestern China

Chemical traits (primary and secondary metabolites) are important features of plants. An increasing number of studies have focused on the ecological significance of secondary metabolites in plant parts, especially in pollen. Ericaceae species exhibit significant morphological variations and diverse colors, are widely distributed throughout China and are popular ornamental garden plants. The chemical trait of pollen in Ericaceae species and their potential ecological significance remain unclear. We selected a total of nine Ericaceae species from three nature reserves in southwestern China, which were the predominant flowering Ericaceae plants for each site, and measured their floral characteristics, nectar volume and sugar concentration. We determined the types of pollinators of these species based on a literature review and used UPLC-QTOF-MS to analyze the types and relative contents of primary metabolites (amino acids and fatty acids) and secondary metabolites (terpenoids, phenolics and nitrogenous compounds) in the pollen and other tissues, including the stems, leaves, petals and nectar. The results showed that each species exhibited unique floral characteristics. Enkianthus ruber, Pieris formosa, Rhododendron agastum, R. irroratum, R. virgatum and R. rubiginosum were pollinated by bees, and R. delavayi, R. decorum and R. excellens were pollinated by diverse animals (bees, birds and Lepidoptera). The pollen of these Ericaceae species was rich in phenolics and terpenoids, especially flavonoids. Grayanotoxin, andromedotoxin and asebotin (toxic diterpene compounds) were also detected in the pollen of some of the Ericaceae species in our study, and their response value was low. The relative contents and diversity of secondary metabolites in the pollen were higher than those in the nectar but lower than those in the leaves, petals and stems. The five chemical compounds with the highest content (four flavonoids, one triterpene) in the pollen were also detected in the stems, leaves and petals, and the response value of most of these chemicals in pollen was not significantly correlated with that in other tissues. Rhododendron species has a closer relationship with chemical traits in pollen compared with Enkianthus and Pieris species. The response value of total secondary metabolites in the pollen of species pollinated only by bees was higher than that of species pollinated by diverse animals. Our research indicates that the pollen of ericaceous species contains a wide array of metabolites, establishing a foundation for advancing the nutritional potential of the pollen of horticultural ericaceous species and deepening our understanding of its chemical and ecological significance.

Pollen dispersal distance of Brazilian native tree species: a systematic review

Knowledge of the pollen dispersal distance (PDD) is crucial for delimitating the collection radius of subpopulations in seed collection areas used as germplasm sources for genetic breeding, conservation, and restoration projects. Some studies have reported the PDD of trees, but these are scattered throughout the literature. Therefore, the objective of this study was to systematically review and report as many PDDs as possible found in the literature on native Brazilian tree species. In the present study, we identified the most and least studied species, temporal trends in publications, geographic distribution of studies, mating systems, and pollinator types for each species. A systematic review protocol was established, and the search criteria were improved, resulting in 543 articles. Forty-four articles contained information on native species, and 319 PDD from 41 tree species were extracted. The most investigated species for pollen dispersal were Cariniana estrellensis (Raddi) Kuntze (Jequitibá-branco) and Araucaria angustifolia (Bertol.) Kuntze (Araucária). The PDD values ranged from 9 m to 5229 m, averaging 543.9273 m. The five species with the highest average PDDs were Centrolobium tomentosum Guill. ex Benth. (Araribá), Swietenia macrophylla King (Mogno-brasileiro), Hymenaea courbaril L. (Jatobá), Dipteryx alata Vogel (Baru) and Hymenaea stigonocarpa Mart. Ex-Hayne (Jatobá do Cerrado) at 3191 m, 1472 m, 1450 m, 1215.12 m, and 1086.81 m, respectively. Theobroma cacao L. and Ilex paraguariensis A.St.-Hil. had the shortest PDDs averages at 28 m and 15.9 m, respectively. This work provides a valuable PDD database that will expand the possibilities for new research and guide projects related to seed collection, forest restoration, germplasm conservation, and genetic breeding of native Brazilian trees.

Saliciylic Acid is also Effective Along with Abscisic Acid and Gibberellic Acid in the Orchid Post-Pollination Process

The aim of this study is to determine the endogenous hormone activities of abscisic acid (ABA), Jasmonic acid (JA) and Salicylic acid (SA) in compatible (Intraspecific = ISP) and incompatible pollination (Intergeneric = IGP) in stigmatic ovaries during orchid post-pollination process. It was designed to be Himantoglossum robertianum in ISP experiments and Himantoglossum robertianum and Orchis italica in IGP experiments. Polynariums taken from O. italica have been applied with needles to the flower stigmas of H. robertianum. Ovaries with stigma from both pollination types were taken separately for each day for a total of 10 days and quantitative endogenous hormone analyzes have been performed by LC-MS/MS. After all, SA hormone has been detected for the first time in both ISP and IGP, but only ISP values were significant. The statistical analysis revealed that while SA is significant in only ISP, ABA values were found to be highly significant in both ISP and IGP. ISP9 also showed high significance. Additionally, ABA values were generally higher than SA values, especially in IGP experiments. The results also emphasized the importance of ovarian endogenous hormone activities for the first time. JA was not detected in the analysis.

Butterflies, bumblebees and hoverflies are equally effective pollinators of Knautia arvensis (Caprifoliaceae), a generalist plant species with compound inflorescences

AbstractPlant‐pollinator interactions exist along a continuum from complete specialisation to highly generalised, that may vary in time and space. A long‐held assumption is that large bees are usually the most effective pollinators of generalist plants. We tested this by studying the relative importance of different groups of pollinators of Knautia arvensis (L.) Coult. (Caprifoliaceae: Dipsacoideae). This plant is suitable for such a study because it attracts a diversity of flower visitors, belonging to different functional groups. We asked whether all functional groups of pollinators are equally effective, or if one group is most effective, which has been documented in other species with apparently generalised pollination systems. We studied two subpopulations of K. arvensis, one at low and one at high density in Northampton, UK. To assess pollinator importance we exposed unvisited inflorescences to single visits by different groups of pollinators (butterflies, bumblebees, hoverflies and others) and assessed the proportion of pollinated stigmas. We then multiplied the effectiveness of each pollinator group with their proportional visitation frequency in five different years. For each group we also compared time spent on flowers and flight distance between visits. The relative importance of each pollinator group varied between years, as did their flight distances between flower visits. Butterflies were the best pollinators on a per visit basis (in terms of the proportion of stigmas pollinated) and flew further after visiting an inflorescence. Different measures and proxies of pollinator effectiveness varied between taxa, subpopulations, and years, and no one group of pollinators was consistently more effective than the others. Our results demonstrate the adaptive value of generalised pollination strategies when variation in relative abundance of different types of pollinators is considered. Such strategies may have buffered the ability of plants to reproduce during past periods of environmental change and may do so in the future.

Pollen viability, stigma receptivity and reproduction mode of spineless cactus (Nopalea cochenillifera Salm-Dyck) accessions

Forage cactus (Opuntia spp. and Nopalea spp.) have great potential for animal feed and human consumption due to their adaptability to semi-arid conditions. This study evaluated six accessions of N. cochenillifera, analyzing pollen viability, stigma receptivity and reproduction mode. Four types of pollination were tested: spontaneous self-pollination, manual self-pollination, natural pollination and cross-pollination. The results indicated high pollen viability and stigma receptivity in some accessions during flower bud development, allowing for self-pollination and controlled hybridization. After 24 hours of anthesis, pollen viability decreased, but stigma receptivity reached 100%. Fruiting occurred via natural pollination in all accessions, and by self-pollination and cross-pollination in accessions ac-02 and ac-03, which showed a mixed reproductive system. These results are essential for breeding programs, contributing to sustainable agriculture in semi-arid regions.

Exploring Biodiversity through the Lens of Knautia arvensis Pollinators: Knautia Pollinator Walks as a Monitoring Method.

Declining populations of native pollinators, especially wild bees, underline the urgent need for effective monitoring within agricultural ecosystems. This study aims to (i) establish the 'Knautia Pollinator Walk' as an innovative pollinator monitoring method, (ii) examine the link between pollinator richness/density and land cover, and (iii) assess if specialist solitary bees indicate pollinator abundance and morphogroup richness. The approach involves surveying 500 Knautia arvensis inflorescences per site thrice per season. Observations of 11,567 pollinators across 203 taxa showed significant correlations between pollinator diversity and land use. Pollinator populations fluctuated with land cover type, increasing in open areas but decreasing or stabilising in forested and shrubby regions. Noteworthy differences in pollinator types were seen between Russia (solitary bees, small Diptera, Lepidoptera) and Sweden (bumblebees, beetles, furry Diptera). The "Knautia Pollinator Walk" shows promising signs of being an effective tool for monitoring spatiotemporal biodiversity trends. The method offers a scalable approach to pollinator monitoring, which is essential for developing conservation strategies and supporting pollinator populations.

Pollen transfer efficiency in Erica depends on type of pollinator.

Pollen transfer efficiency (PTE; the proportion of pollen removed from flowers that reaches conspecific stigmas) is expected to vary with the type of pollinator and flower morphology, and to influence male siring success. Many species in the genus Erica are pollinated by bees (which consume pollen and should thus lower PTE) but during its radiation in the Cape, several independent shifts to both sunbird and long-proboscid fly (LP fly) pollinators, which do not consume pollen have taken place. Improvements in PTE could be one of the factors driving these pollinator shifts. PTE data for 15 Erica species (five for each of the three pollinator types) were collected and compared in relation to type of pollinator and anther exsertion. LP fly- and bird-pollinated species had higher PTE in comparison with bee-pollinated species. Species with inserted anthers had higher PTE than those with exserted anthers. This suggests that sunbirds and LP flies are more efficient pollinators than bees. Additionally, the study suggests that insertion of anthers within the corolla tube can reduce pollen losses.

Effects of ecological factors on the pollination biology and seed production of Salvia daiguii: A critically endangered ornamental species from China

Salvia constitutes one of the largest genera in the Lamiaceae, with approximately 1,000 species found worldwide, and is recognized for its high ornamental and medicinal value. Salvia daiguii is a multipurpose perennial herb that grows on cliffs in the Zhangjiajie City, Hunan Province, China. Nevertheless, the pollination biology of vulnerable plants on cliffs, specifically the effects of abiotic factors on flower visitation and seed set, remains poorly understood. In this study, we observed the effects of biotic factors: flowering phenology and flower characteristics, flower longevity, nectar volume and concentration, pollen viability and stigma receptivity, pollinator visitation frequency, pollen remaining and deposition, and breeding systems, as well as abiotic factors: habitat fountain, temperature, and humidity, on the pollination and seed production of S. daiguii in two populations in Zhangjiajie City. The pollination biology results reveal that S. daiguii has a mixed mating system that depends on pollinators. The flower visitation and seed set of S. daiguii in the absence of natural fountain areas in Tianmenshan National Forest Park was scarcely affected by biotic factors. However, we observed a significant reduction in pollinator types, visitation frequency, and natural seed set of this population owing to abiotic factors, including the presence of a fountain habitat and increased humidity. Further, seed set in the Zhangjiaxi Ecological Forest Reserve was affected by both biotic (serious pollen limitation) and abiotic (higher population temperature) factors. We considered that pollinators types, flower visitation frequency, and natural seed set are vulnerable to the influence of ecological factors in fragmented habitats. Our results reveal the mechanisms contributing to the endangerment of species exemplified by S. daiguii and underscore the significance of conservation efforts for the sustainable use of other endangered species.

Impact of a heterogeneous environment on the population expansion of the harmful plant Iris ruthenica Ker-Gawl. in the high mountain grasslands.

Iris ruthenica Ker-Gawl. (Russian iris) is a perennial, clonal, herbaceous plant that is spread across the degraded mountain grasslands in northern Xinjiang. In this study, to explore the breeding system and the impact of slope orientation on the flowering phenology, pollination characteristics, and other aspects of I. ruthenica, we used a combination of field observations and controlled experiments to compare the population density, flowering phenology, floral characteristics, breeding system, and pollinator type and behavior of plants on different slope orientations. Vegetation coverage on the north (N), southwest (SW), and southeast (SE) slopes was 90%, 67%, and 53%, respectively. Differences in plant height and diameter were observed between the SE slope and the N and SW slopes, whereas the N and SW slopes were similar in these respects. The SE slope exhibited the earliest initial flowering time, followed by the SW and N slopes. The diameter of the corolla, distance between the stigma and anther, length of the anther and ovary, number of pollen grains, and number of ovules on the N slope were smaller than those on the SE and SW slopes, whereas those of the SE and SW slopes were similar. Artificial pollination experiments showed that neither bagging nor unbagging resulted in seed formation after emasculation for all slope orientations. The pollinating insects of I. ruthenica included Bombus sp., Amegilla leptocoma, Andrena sp., and Halictus sp.; the types and numbers of pollinating insects differed among slopes. In summary, on SE and SW slopes with high temperatures and sufficient sunlight, this species attracted pollinators and provided them with more opportunities to visit and pollinate by flowering early, with large numbers of blooms, and a longer flowering period and lifespan, ensuring successful reproduction. Under unfavorable conditions, such as insufficient pollinators and limited activity caused by the more stressful environmental conditions of the N slope (including low temperature and insufficient light), this species ensures a certain seed yield by increasing its self-compatibility.

Phenotypic selection patterns in a hybrid zone between two Calceolaria species with contrasting pollinators: insights from field surveys and fitness assessments.

Hybrid zones provide natural experimental settings to test hypotheses about species divergence. We concentrated on a hybrid swarm in which oil-collecting bees and flower-pecking birds act as pollinators of two Calceolaria species. We asked whether both pollinators contributed to flower divergence by differentially promoting prezygotic fitness at the phenotypic extremes that represent parentals. We studied pollinator-mediated selection on phenotypic traits critical in plant-pollinator mechanical interaction, namely plant height, reward-to-stigma distance, and flower shape. We utilised the quantity and quality of pollen deposited as fitness measures and distinguished between the contribution of the two pollinator types. Results showed uni- and bivariate disruptive selection for most traits through pollen grains deposited by both pollinators. Bird-mediated fitness favoured low plants with a long reward-to-stigma distance and a straight corolla, while bee-mediated fitness favoured tall plants with a short reward-to-stigma distance and curved corolla. In addition, stabilising selection at one end of the phenotypic range showed a bird-mediated reproductive asymmetry within the swarm. The disruptive pattern was countered, albeit weakly, by hybrids receiving higher-quality pollen on the stigmas. Results suggest that pollinator-mediated selection promotes divergence of integrated flower phenotypes mechanically adjusted either to bees or birds underscoring the importance of pollinator specialisation in diversification.

The influence of the pollination compatibility type on the pistil S-RNase expression in European pear (Pyrus communis).

The S-RNase gene plays an essential role in the gametophytic self-incompatibility (GSI) system of Pyrus. It codes for the stylar-expressed S-RNase protein which inhibits the growth of incompatible pollen tubes through cytotoxicity and the induction of programmed cell death in the pollen tube. While research on the Pyrus GSI system has primarily focused on the S-RNase gene, there is still a lack of insight into its spatiotemporal expression profile and the factors that regulate it. Previous studies have suggested that S-RNase expression in the style is influenced by pollination and is dependent on the compatibility type. We here continue on this basic hypothesis by analyzing the spatiotemporal expression of the S-RNase alleles in Pyrus communis "Conference" styles in response to different types of pollination; namely, upon full- and semi-compatible pollination and upon incompatible selfing. The results revealed that temporal dynamics of S-RNase expression are influenced by the pollen's compatibility type, indicating the presence of a signaling mechanism between pollen and style to control S-RNase production during pollen tube growth. In our experiment, S-RNase expression continuously decreased after cross-pollination and in the unpollinated control. However, after a fully incompatible pollination, S-RNase expression remained constant. Finally, semi-compatible pollination showed a initially constant S-RNase expression for both alleles followed by a strong decrease in expression. Based on these results and previous findings, we propose a regulatory mechanism to explain the effect of pollination and the associated compatibility type on S-RNase expression in the style. This proposed mechanism could be used as a starting point for future research.

Corolla micromorphology in 12 plant species with different pollination systems

Background: Floral microstructure, with multiple functions, is very important in pollination biology.
 Questions: Are the expected general characteristics of corolla micromorphology fulfilled in the selected species with different pollination systems?
 Studied species: Agave americana, Arbutus unedo, Aristolochia paucinervis, Cestrum nocturnum, Cytinus hypocistis subsp. macranthus, C. ruber, Dianthus lusitanus, Grevillea robusta, Musa x paradisiaca, Nicotiana glauca, Stellaria media and Teucrium fruticans.
 Study site and dates: Southern Spain, 2017-2019.
 Methods: Floral micromorphological characters were studied by light and scanning electron microscopy and analyzed using different statistical tests.
 Results: The adaxial side of the corolla lobes in melittophilous, myrmecophilous, psychophilous and sapromyophilous species showed papillose cells, and the same was true of the sphingophilous species Cestrum nocturnum and hummingbird-pollinated Nicotiana glauca. In contrast, tabular cells were observed in the perching-pollinator ornithophilous species Grevillea robusta, the two studied chiropterophilous species, and autogamous Stellaria media. In addition, corolla mesophyll was thicker in chiropterophilous species. Furthermore, differences were detected in cell turgidity (in protogynous Aristolochia paucinervis) and in mesophyll thickness between male and female flowers (Cytinus).
 Conclusions: Papillose cells were present in corollas in physical contact with pollinators, as expected, but also appeared in corollas of some other species without such contact. We recommend that studies of dichogamous and unisexual species include comparisons of corolla micromorphology between sexual states, as differences may exist in cell turgidity or mesophyll thickness. We also caution against the widespread view that certain types of pollinators do not mechanically interact with the epidermal surface of the corolla.

Reproductive biology of Sphaeralcea species with ornamental interest

The genus Sphaeralcea belongs to the Malvaceae family and has native species from South America. Their attractive morphological characteristics with ornamental value have not yet been explored. The objective of this work was to know the viability of pollen, stigma receptivity, type of pollination and combining ability of four Sphaeralcea species (S. australis, S. bonariensis, S. crispa and S. mendocina), with the aim to develop new ornamental varieties. Fructification, fertility, seed germination and survival seedlings on intraspecific and reciprocal interspecific offspring were assessed. The highest values ​​of stigma receptivity and pollen viability were obtained at 2:00 pm for the four species. S. mendocina also showed high values ​​of pollen viability at 4:00 pm. The species proved to be self-incompatible and allogamous, with different degrees of reproductive compatibility. The interspecific crosses of S. mendocina and the intraspecific of S. crispa did not produce descendants. The crosses between S. australis and S. bonariensis as maternal parent presented the best combining ability with good fruit production, seed germination and survival. This research provides useful information for the formulation and implementation of breeding strategies, to improve pollination efficiency, and to breed new Sphaeralcea varieties with ornamental potential.

The state of populations of honey bees, Apis mellifera L., with an increase in the pesticide load in agroce- noses

It is generally recognised that pesticides play a significant role in the decline in the number of insects observed worldwide. The analysis of the causes of unprecedented losses of Apis mellifera L. bee colonies has been carried out. When using plant protection products in agrocenoses. The current state of knowledge on assessing the impact of pesticides on non–target objects is summarised as honey bees and other types of bee pollinators of plants. The mechanisms and features of selective exposure of insecticides from the group of neonicotinoids, butenolides and based on fipronil are described. In addition to direct lethal effects, there is a decrease in the viability and subsequent death of bee colonies as a result of changes in the cognitive abilities of worker bees, the reproductive potential of queens and drones, changes in the immune status of bee colonies and the etiological characteristics of insects. Examples of the negative impact on honeybee populations of various regions of the Russian Federation when using pesticides in agrocenoses are given. The role of organic agriculture in the conservation of honey bees and other pollinators, providing a yield comparable to the integrated plant protection system of entomophilic crops, is noted. Measures to prevent the reduction of honey bee populations due to pesticide toxicosis are outlined: 1. Compliance with the requirements of regulatory documents; 2. Providing apiaries with an optimal feed base; 3. Exclusion of highly toxic insecticides from entomophilic crop protection programs; 4. Realisation of the adaptive potential of honey bees in changing environmental conditions; 5. Transition to organic farming in the cultivation of entomophilic crops.

Nectar availability and Interactions with Bird Pollinators in Grevillea banksii R. Br. (Proteaceae) in a Restinga Ecosystem in Southeastern Brazil

The mutualistic relationship between plants and their pollinators may influence species’ spatial distribution, richness, and abundance. We assessed the nectar availability and interaction with pollinators in Grevillea banksii (Proteaceae), an alien plant in Brazil. Our objectives were to study the floral biology and the pollination system and identify the pollinators in a G. banksii population in a Restinga ecosystem (sand-coastal-plain) in southeastern Brazil. We described the behavioral parameters of the pollinator-plant interaction and determined how the pollinators contribute to reproduction. Floral biology was analyzed by taking morphometric measurements of the flowers and determining the distribution of their structures. The reproductive system was assessed via different pollination treatments (open pollination, self-pollination, manual selfpollination, manual cross-pollination). The pollinators were identified and their behaviors were assessed by focal observation. Flower morphometrics showed compatibility between the mean calyx length and the beak length of the flower-visiting hummingbirds. All the pollination types tested were efficient, and we identified eight bird species (Chionomesa fimbriata, Eupetomena macroura, Chlorestes notata, Polytmus guainumbi, Florisuga fusca, Coereba flaveola, Cyanerpes cyaneus and Dacnis cayana) that visit G. banksii in the study area. The results show a positive interaction between pollinators and plants, with offers of resources, pollination, and pollen dispersal.

Origin and Function of Amino Acids in Nectar and Nectaries of Pitcairnia Species with Particular Emphasis on Alanine and Glutamine.

Floral nectar contains sugars and numerous other compounds, including amino acids, but little is known about their function and origin in nectar. Therefore, the amino acid, sugar, and inorganic ion concentrations, as well as the activity of alanine aminotransferase (AlaAT) and glutamine synthetase (GS) in nectar, nectaries, and leaves were analyzed in 30 Pitcairnia species. These data were compared with various floral traits, the pollinator type, and the phylogenetic relationships of the species to find possible causes for the high amino acid concentrations in the nectar of some species. The highest concentrations of amino acids (especially alanine) in nectar were found in species with reddish flowers. Furthermore, the concentration of amino acids in nectar and nectaries is determined through analyzing flower color/pollination type rather than phylogenetic relations. This study provides new insights into the origin of amino acids in nectar. The presence of almost all amino acids in nectar is mainly due to their transport in the phloem to the nectaries, with the exception of alanine, which is partially produced in nectaries. In addition, active regulatory mechanisms are required in nectaries that retain most of the amino acids and allow the selective secretion of specific amino acids, such as alanine.

Effect of climate, anther morphology and pollination syndrome on pollen availability in Penstemon

Traditionally, pollen presentation is thought to be a function of pollinator type and visitation frequency. However, despite the repeated observation that pollen presentation is influenced by flower morphology and abiotic factors, these aspects have been little studied in the wild. Here, we evaluated the effect of climate, anther morphology, and pollination syndrome on anther dehiscence time (the length of time an anther takes to fully dehisce after a flower opens). We recorded anther dehiscence time in twelve species of Penstemon including the four major anther types and the two most common pollination syndromes. We also conducted an experiment to measure the effect of humidity and temperature on anther dehiscence. We found that anther morphology was correlated with anther dehiscence time. Anthers with wide openings take the longest time to dehiscence. These results provide some support for the hypothesis that anther dehiscence time has evolved to decrease pollen wastage. Contrary to the assumption that bird-pollinated species have simultaneous pollen presentation, hummingbird-pollinated species had longer anther dehiscence time than most bee-pollinated species. The experiment revealed that high humidity and low temperature increase anther dehiscence time. Our results suggest that pollen presentation is influenced by anther morphology, pollination syndrome, and the physical environment. Optimal pollen presentation presumably maximizes conspecific pollen transfer and reduces pollen thieving.

Temporal and spatial variation of floral resources of woody species in a vereda ecosystem: Uniformity and habitat complementarity

Floral resource distribution, pollinator community structure, and flowering season are essential for maintaining and preserving pollination services in ecosystems. In humid Cerrado areas, veredas are considered hygrophilous communities, marked by the presence of the Mauritia flexuosa palm tree emerging in the wetter zones. Waterlogged portions present dense hygrophilous forests, whereas open areas predominant present herbaceous and shrubby components. We identified the pollination syndromes of woody species in a vereda ecosystem and characterized the pollination resource availability between habitats (hygrophilous forest and open area). The study was conducted on a vereda located in the north of Minas Gerais, Brazil. We characterized pollination syndromes using information on floral attributes, pollinator observations, and a literature survey. We performed phenological monitoring for 24 months and examined the occurrence of flowering using circular statistics. The differences in pollination syndrome occurrence among months and habitats were determined using modularity analysis. We found eight pollination syndromes, with melittophily being the most frequent pollination type among the woody species in the studied vereda. Flowering occurs throughout the year in the community and peaks from September to November during the transition from the dry to the wet season. In hygrophilous forest the species flowered preferentially in November, whereas in open area, preferentially between September and October. The syndromes distribution differed between the habitats, as well as resource availability. This difference between habitats can influence pollinator diversity. Modularity showed complementarity among the habitats, with continuous resource availability throughout the entire ecosystem. Species present in the hygrophilous forest provide their resources mainly during the rainy season, whereas species from the open area, during the dry season. Information on these interactions is necessary to understand the functionality of a vereda ecosystem, through the characterization of the resource's availability, and maintenance of pollination services in the ecosystem. In addition, our results demonstrate the importance of the vereda ecosystem as an important area in the availability of resources for the Cerrado formation. This information can strengthen protection laws and contribute to sustainable practices that boost the conservation of pollinators in the biome.

Non-Parametric Machine Learning for Pollinator Image Classification: A Comparative Study

Pollinators play a crucial role in maintaining the health of our planet's ecosystems by aiding in plant reproduction. However, identifying and differentiating between different types of pollinators can be a difficult task, especially when they have similar appearances. This difficulty in identification can cause significant problems for conservation efforts, as effective conservation requires knowledge of the specific pollinator species present in an ecosystem. Thus, the aim of this study is to identify the most effective methods, features, and classifiers for developing a reliable pollinator classifier. Specifically, this initial study uses two primary features to differentiate between the pollinator types: shape and colour. To develop the pollinator classifiers, a dataset of 186 images of black ants, ladybirds, and yellow jacket wasps was collected. The dataset was then divided into training and testing sets, and four different non-parametric classifiers were used to train the extracted features. The classifiers used were the k-Nearest Neighbour, Decision Tree, Random Forest, and Support Vector Machine classifiers. The results showed that the Random Forest classifier was the most accurate, with a maximum accuracy of 92.11% when the dataset was partitioned into 80% training and 20% testing sets. By developing a reliable pollinator classifier, researchers and conservationists can better understand the roles of different pollinator species in maintaining ecosystem health. This understanding can lead to better conservation strategies to protect these important creatures, ultimately helping to preserve our planet's biodiversity.