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Journal of Evolutionary Biology Jun 2024Pollinators are thought to be the main drivers of floral evolution. Flowers are also colonized by abundant communities of microbes that can affect the interaction...
Pollinators are thought to be the main drivers of floral evolution. Flowers are also colonized by abundant communities of microbes that can affect the interaction between plants and their pollinators. Very little is known, however, about how flower-colonizing microbes influence floral evolution. Here we performed a six-generation experimental evolution study using fast-cycling Brassica rapa, in which we factorially manipulated the presence of pollinators and flower microbes to determine how pollinators and microbes interact in driving floral evolution. We measured the evolution of six morphological traits, as well as plant mating system and flower attractiveness. Only one of the six traits (flower number) evolved in response to pollinators, while microbes did not drive the evolution of any trait, nor did they interact with pollinators in driving evolution of morphological traits. Moreover, we did not find evidence that pollinators or microbes affected the evolution of flower attractiveness to pollinators. However, we found an interactive effect of pollinators and microbes on the evolution of autonomous selfing, a trait that is expected to evolve in response to pollinator limitation. Overall, we found only weak evidence that microbes mediate floral evolution. However, our ability to detect an interactive effect of pollinators and microbes might have been limited by weak pollinator-mediated selection in our experimental setting. Our results contrast with previous (similar) experimental evolution studies, highlighting the susceptibility of such experiments to drift and to experimental artefacts.
PubMed: 38902913
DOI: 10.1093/jeb/voae078 -
PloS One 2024Pollination biology in the widespread species Impatiens capensis Meerb. has only been studied in America, specifically in zones of the U.S.A. and Canada. In this study,...
Pollination biology in the widespread species Impatiens capensis Meerb. has only been studied in America, specifically in zones of the U.S.A. and Canada. In this study, we investigated the pollination biology of I. capensis using an integrative identification approach using morphological and molecular tools in four populations of Northwest Poland. We also determined and compared the functional characteristics of the pollinators of the introduced species from the study sites and the native ones reported, for the latter collecting information from bibliographic sources. Visitors were identified using standard morphological keys, including identifying and classifying insect mouthparts. Molecular identification was carried out using mitochondrial DNA's cytochrome oxidase subunit I (COI). We morphologically identified 20 species of visitors constituted by 17 pollinators and three nectar robbers. DNA barcoding of 59 individuals proved the identification of 18 species (also 18 BINs). The frequency of pollinator species was primarily made up of representatives of both Hymenoptera (75%) and Diptera (21%). The morphological traits, such as the chewing and sucking mouthparts, small and big body height, and robber and pollinator behavior explained mainly the native and introduced visitors' arrangements that allow pollination success. However, to understand the process comprehensively, further investigation of other causalities in pollination success and understanding the diversity of pollinators in outer native ranges are necessary.
Topics: Pollination; Animals; Impatiens; Introduced Species; Diptera; Poland; DNA Barcoding, Taxonomic; Hymenoptera
PubMed: 38900825
DOI: 10.1371/journal.pone.0302283 -
Molecular Phylogenetics and Evolution Jun 2024Small carpenter bees in the genus Ceratina are behaviourally diverse, species-rich, and cosmopolitan, with over 370 species and a range including all continents except...
Small carpenter bees in the genus Ceratina are behaviourally diverse, species-rich, and cosmopolitan, with over 370 species and a range including all continents except Antarctica. Here, we present the first comprehensive phylogeny of the genus based on ultraconserved element (UCE) phylogenomic data, covering a total of 185 ingroup specimens representing 22 of the 25 current subgenera. Our results support most recognized subgenera as natural groups, but we also highlight several groups in need of taxonomic revision - particularly the nominate subgenus Ceratina sensu stricto - and several clades that likely need to be described as new subgenera. In addition to phylogeny, we explore the evolutionary history of Ceratina through divergence time estimation and biogeographic reconstruction. Our findings suggest that Ceratinini split from its sister tribe Allodapini about 72 million years ago. The common ancestor of Ceratina emerged in the Afrotropical realm approximately 42 million years ago, near the Middle Eocene Climatic Optimum. Multiple subsequent dispersal events led to the present cosmopolitan distribution of Ceratina, with the majority of transitions occurring between the Afrotropics, Indomalaya, and the Palearctic. Additional movements also led to the arrival of Ceratina in Madagascar, Australasia, and a single colonization of the Americas. Dispersal events were asymmetrical overall, with temperate regions primarily acting as destinations for migrations from tropical source regions.
PubMed: 38897426
DOI: 10.1016/j.ympev.2024.108133 -
Brazilian Journal of Biology = Revista... 2024Terminalia argentea tree, native to Brazil, is widely used in landscaping, recovering degraded areas, its wood, coal production, and the bark or leaf extracts has...
Terminalia argentea tree, native to Brazil, is widely used in landscaping, recovering degraded areas, its wood, coal production, and the bark or leaf extracts has medicinal use. Despite of its importance, the arthropod fauna associated to this plant and its interspecific relationships still needs further studies. The objectives of this study were to evaluate the arthropods, their ecological indices and the distribution in the leaf faces on T. argentea saplings. The numbers of phytophagous insects (e.g., Cephalocoema sp.), pollinators (e.g., Tetragonisca angustula), and natural enemies (e.g., Oxyopidae), and their ecological indices (e.g., species richness), were higher on the adaxial leaf faces on T. argentea saplings. Aggregated distribution of phytophagous insects (e.g., Aphis spiraecola), pollinators (e.g., Trigona spinipes), and natural enemies (e.g., Camponotus sp.) on T. argentea saplings was observed. Abundance, diversity, and species richness of natural enemies correlated, positively, with those of phytophagous and pollinators insects. Predators and tending ants followed their prey and sucking insects, respectively. Tending ants protected sucking insects against predators, and reduced chewing insects. The high number of Cephalocoema sp. on T. argentea saplings is a problem, because this insect can feed on leaves of this plant, but its preference for the adaxial leaf face favors its control. The aggregation behavior of arthropods on T. argentea saplings favors the control of potential pests of this plant. There seems to be competition between tending ants for space and food resources on T. argentea saplings.
Topics: Animals; Plant Leaves; Arthropods; Terminalia; Population Density; Biodiversity; Brazil; Insecta
PubMed: 38896730
DOI: 10.1590/1519-6984.281588 -
Ecology and Evolution Jun 2024The decline of honey bee populations significantly impacts the human food supply due to poor pollination and yield decreases of essential crop species. Given the...
The decline of honey bee populations significantly impacts the human food supply due to poor pollination and yield decreases of essential crop species. Given the reduction of pollinators, research into critical landscape components, such as floral resource availability and land use change, might provide valuable information about the nutritional status and health of honey bee colonies. To address this issue, we examine the effects of landscape factors like agricultural area, urban area, and climatic factors, including maximum temperature, minimum temperature, relative humidity, and precipitation, on honey bee hive populations and nutritional health of 326 honey bee colonies across varying landscapes in Mexico. DNA metabarcoding facilitated the precise identification of pollen from 267 plant species, encompassing 243 genera and 80 families, revealing a primary herb-based diet. Areas characterized by high landscape diversity exhibited greater pollen diversity within the colony. Conversely, colonies situated in regions with higher proportions of agricultural and urban landscapes demonstrated lower bee density. The maximum ambient temperature outside hives positively correlated with pollen diversity, aligning with a simultaneous decrease in bee density. Conversely, higher relative humidity positively influenced both the bee density of the colony and the diversity of foraged pollen. Our national-level study investigated pollen dietary availability and colony size in different habitat types, latitudes, climatic conditions, and varied levels and types of disturbances. This effort was taken to gain a better insight into the mechanisms driving declines in honey bee populations. This study illustrates the need for more biodiverse agricultural landscapes, the preservation of diverse habitats, and the conservation of natural and semi-natural spaces. These measures can help to improve the habitat quality of other bee species, as well as restore essential ecosystem processes, such as pollination and pest control.
PubMed: 38895569
DOI: 10.1002/ece3.11456 -
Ecology and Evolution Jun 2024Concerns about competition between pollinators are predicated on the assumption of floral resource limitation. Floral resource limitation, however, is a complex...
Concerns about competition between pollinators are predicated on the assumption of floral resource limitation. Floral resource limitation, however, is a complex phenomenon involving the interplay of resource production by plants, resource demand by pollinators, and exogenous factors-like weather conditions-that constrain both plants and pollinators. In this study, we examined nectar limitation during the mass flowering of rosaceous fruit trees in early spring. Our study was set in the same region as a previous study that found severe nectar limitation in summer grasslands. We used this seasonal contrast to evaluate two alternative hypotheses concerning the seasonal dynamics of floral resource limitation: either (H1) rates of resource production and consumption are matched through seasonal time to maintain a consistent degree of resource limitation, or (H2) a mismatch of high floral resource production and low pollinator activity in early spring creates a period of relaxed resource limitation that intensifies later in the year. We found generally much lower depletion in our spring study compared to the near 100% depletion found in the summer study, but depletion rates varied markedly through diel time and across sampling days, with afternoon depletion rates sometimes exceeding 80%. In some cases, there were also pronounced differences in depletion rates across simultaneously sampled floral species, indicating different degrees of nectar exploitation. These findings generally support the seasonal mismatch hypothesis (H2) but underscore the complex contingency of nectar depletion. The challenge of future work is to discern how the fluctuation of resource limitation across diel, inter-diel, and seasonal time scales translates into population-level outcomes for pollinators.
PubMed: 38895567
DOI: 10.1002/ece3.11531 -
Ecology and Evolution Jun 2024Plant-pollinator interactions are constrained by floral traits and available pollinators, both of which can vary across environmental gradients, with consequences for...
Plant-pollinator interactions are constrained by floral traits and available pollinators, both of which can vary across environmental gradients, with consequences for the stability of the interaction. Here, we quantified how the pollination ecology of a high-mountain hummingbird-pollinated plant changes across a progressively more stressful environmental gradient of the Venezuelan Andes. We compared pollination ecology between two populations of this plant: Piedras Blancas (PB) and Gavidia (GV), 4450 and 3600 m asl, respectively. We hypothesised that self-compatibility might be higher at the higher altitude site, however we found that flowers showed similar capacities for self-compatibility in both localities. Seed production by flowers exposed to natural pollinators was significantly higher in the lower locality, where we also found higher nectar quality, larger flowers and increased frequencies of pollinator visitations. Interestingly, the population energy offered in the nectar was the same for both localities due to the higher density and floral aggregation found in the higher altitude population. Our study demonstrates how two plant populations in different environmental conditions have different pollination ecology strategies. Pollinator visitations or their absence result in trait associations in one population that are independent in the other. These population differences are not explained by differences in pollinator assembly, but by environmental heterogeneity.
PubMed: 38895562
DOI: 10.1002/ece3.11553 -
International Journal of Molecular... Jun 2024Spinach ( L.) is a dioecious, diploid, wind-pollinated crop cultivated worldwide. Sex determination plays an important role in spinach breeding. Hence, this study aimed...
Spinach ( L.) is a dioecious, diploid, wind-pollinated crop cultivated worldwide. Sex determination plays an important role in spinach breeding. Hence, this study aimed to understand the differences in sexual differentiation and floral organ development of dioecious flowers, as well as the differences in the regulatory mechanisms of floral organ development of dioecious and monoecious flowers. We compared transcriptional-level differences between different genders and identified differentially expressed genes (DEGs) related to spinach floral development, as well as sex-biased genes to investigate the flower development mechanisms in spinach. In this study, 9189 DEGs were identified among the different genders. DEG analysis showed the participation of four main transcription factor families, MIKC_MADS, MYB, NAC, and bHLH, in spinach flower development. In our key findings, abscisic acid (ABA) and gibberellic acid (GA) signal transduction pathways play major roles in male flower development, while auxin regulates both male and female flower development. By constructing a gene regulatory network (GRN) for floral organ development, core transcription factors (TFs) controlling organ initiation and growth were discovered. This analysis of the development of female, male, and monoecious flowers in spinach provides new insights into the molecular mechanisms of floral organ development and sexual differentiation in dioecious and monoecious plants in spinach.
Topics: Spinacia oleracea; Flowers; Gene Regulatory Networks; Gene Expression Regulation, Plant; Transcription Factors; Plant Proteins; Gene Expression Profiling; Abscisic Acid; Gibberellins
PubMed: 38892313
DOI: 10.3390/ijms25116127 -
Plants (Basel, Switzerland) Jun 2024This study investigated the thermal properties of potato and hop pollen for cryopreservation and subsequent cross-breeding. Phase transitions and frozen water content in...
This study investigated the thermal properties of potato and hop pollen for cryopreservation and subsequent cross-breeding. Phase transitions and frozen water content in selected pollen samples were measured using a differential scanning calorimeter (DSC). Unlike hop pollen, potato pollen showed high variability in thermal properties and water content. Three specific types of pollen samples based on their thermal characteristics and water content were distinguished by DSC in potato: (1) 'glassy', with a water content lower than 0.21 g water per g dry matter; (2) 'transient', with a water content between 0.27 and 0.34 g of water per g of dry matter; (3) 'frozen', with a water content higher than 0.34 g of water per g of dry matter. Only the 'glassy' pollen samples with a low water content showed suitable properties for its long-term storage using cryopreservation in potato and hops. Cryopreservation of pollen did not significantly reduce its viability, and cryopreserved pollen was successfully used to produce both potato and hop hybrids. The results indicate that cryopreservation is a feasible technique for the preservation and utilization of pollen of these crops in the breeding process.
PubMed: 38891386
DOI: 10.3390/plants13111578 -
Plants (Basel, Switzerland) Jun 2024An initial cross of 'Johnblue' (Darrow's blueberry) × 'Red Sunset' (lingonberry) produced more than 30 true intersectional diploid hybrids as confirmed by molecular...
An initial cross of 'Johnblue' (Darrow's blueberry) × 'Red Sunset' (lingonberry) produced more than 30 true intersectional diploid hybrids as confirmed by molecular markers. The most vigorous of these hybrids was extensively evaluated. This hybrid, US 2535-A, was floriferous and morphologically intermediate to the respective parents. Examination of pollen suggested low male fertility. Numerous crosses using the hybrid as a female reflected similarly low fertility and potential crossing barriers. Stylar examination suggested blockage of pollen tube growth in self-pollinations and significantly retarded growth in backcross pollinations. Nonetheless, two confirmed hybrid offspring were produced using the F hybrid as a female in crosses with and , respectively. In a second set of crosses utilizing additional and genotypes, another 23 verified hybrids in seven parental combinations were produced. Hybrids such as the ones presented offer the potential for generating de novo interspecific fruit types in blueberry and/or broadening the adaptation of lingonberry.
PubMed: 38891380
DOI: 10.3390/plants13111572