Pollen Transport Research Articles

Orchestrated Flowering and Interspecific Facilitation: Key Factors in the Maintenance of the Main Pollinator of Coexisting Threatened Species of Andean Wax Palms (Ceroxylon spp.)

Solitary, dioecious, and mostly endemic to Andean cloud forests, wax palms (Ceroxylon Bonpl. ex DC. spp.) are currently under worrisome conservation status. The establishment of management plans for their dwindling populations rely on detailed biological data, including their reproductive ecology. As in the case of numerous other Neotropical palm taxa, small beetles are assumed to be selective pollinators of wax palms, but their identity and relevance in successful fruit yield were unknown. During three consecutive reproductive seasons we collected data on population phenology and reproductive and floral biology of three syntopic species of wax palms native to the Colombian Andes. We also determined the composition of the associated flower-visiting entomofauna, quantifying the extent of the role of individual species as effective pollinators through standardized value indexes that take into consideration abundance, constancy, and pollen transport efficiency. The studied populations of C. parvifrons (Engel) H. Wendl., C. ventricosum Burret, and C. vogelianum (Engel) H. Wendl. exhibit seasonal reproductive cycles with marked temporal patterns of flower and fruit production. The composition of the associated flower-visiting entomofauna, comprised by ca. 50 morphotypes, was constant across flowering seasons and differed only marginally among species. Nonetheless, a fraction of the insect species associated with pistillate inflorescences actually carried pollen, and calculated pollinator importance indexes demonstrated that one insect species alone, Mystrops rotundula Sharp, accounted for 94%–99% of the effective pollination services for all three species of wax palms. The sequential asynchronous flowering of C. parvifrons, C. ventricosum, and C. vogelianum provides an abundant and constant supply of pollen, pivotal for the maintenance of large populations of their shared pollinators, a cooperative strategy proven effective by high fruit yield rates (up to 79%). Reproductive success might be compromised for all species by the population decline of one of them, as it would tamper with the temporal orchestration of pollen offer.

A 24,000-year ancient DNA and pollen record from the Polar Urals reveals temporal dynamics of arctic and boreal plant communities

A 24,000-year record of plant community dynamics, based on pollen and ancient DNA from the sediments (sedaDNA) of Lake Bolshoye Shchuchye in the Polar Ural Mountains, provides detailed information on the flora of the Last Glacial Maximum (LGM) and also changes in plant community composition and dominance. It greatly improves on incomplete records from short and fragmented stratigraphic sequences found in exposed sedimentary sections in the western Russian Arctic. In total, 162 plant taxa were detected by sedaDNA and 115 by pollen analysis. Several shifts in dominance between and within plant functional groups occurred over the studied period, but most taxa appear to have survived in situ. A diverse arctic-alpine herb flora characterised the interval ca. 24,000–17,000 cal years BP and persisted into the Holocene. Around 17,000 cal years BP, sedges (e.g. Carex) and bryophytes (e.g. Bryum, Aulacomnium) increased. The establishment of shrub-tundra communities of Dryas and Vaccinium sp., with potentially some Betula pubescens trees (influx ∼290 grains cm2 year−1), followed at ca. 15,000 cal years BP. Forest taxa such as Picea and ferns (e.g. Dryopteris fragrans, Gymnocarpium dryopteris) established near the lake from ca. 10,000 cal years BP, followed by the establishment of Larix trees from ca. 9000 cal years BP. Picea began to decline from ca. 7000 cal years BP. A complete withdrawal of forest tree taxa occurred by ca. 4000 cal years BP, presumably due to decreasing growing-season temperatures, allowing the expansion of dwarf-shrub tundra and a diverse herb community similar to the present-day vegetation mosaic. Contrary to some earlier comparative studies, sedaDNA and pollen from Lake Bolshoye Shchuchye showed high similarity in the timing of compositional changes and the occurrence of key plant taxa. The sedaDNA record revealed several features that the pollen stratigraphy and earlier palaeorecords in the region failed to detect; a sustained, long-term increase in floristic richness since the LGM until the early Holocene, turnover in grass and forb genera over the Pleistocene-Holocene transition, persistence of a diverse arctic-alpine flora over the late Quaternary, and a variable bryophyte flora through time. As pollen records are often limited by taxonomic resolution, differential productivity and dispersal, sedaDNA can provide improved estimates of floristic richness and is better able to distinguish between different plant assemblages. However, pollen remains superior at providing quantitative estimates of plant abundance changes and detecting several diverse groups (e.g. Poaceae, Cyperaceae, Asteraceae) which may be underreported in the sedaDNA. Joint use of the two proxies provided unprecedented floristic detail of past plant communities and helped to distinguish between long-distance transport of pollen and local presence, particularly for woody plant taxa.

Pollen Transport to Lycium cooperi (Solanaceae) Flowers by Flies and Moths

Lycium cooperi (Solanaceae) is a woody shrub found along the eastern, northern, and western edges of the Mojave Desert in Arizona, Nevada, and California and along the western edge of the Sonoran Desert in California and Mexico. The plant produces funnel-shaped flowers during spring with stamens and a pistil that extend to near the top of a greenish-white corolla. I investigated the pollination of L. cooperi in southern Nevada during 30 March–21 April 2019 by aspirating insects from flowers, determining where they carried pollen on their bodies, and estimating the proportions of conspecific pollen in their pollen loads. Flowers were mostly visited at night by 8 species of moths (Lepidoptera) in Noctuidae and Geometridae and less frequently during the day by 3 species of flies (Diptera) in Syrphidae. The most frequent visitor to flowers was Euxoa serricornis (Noctuidae), followed by Digrammia colorata (Geometridae) and Peridroma saucia (Noctuidae), a widespread agricultural pest. Most flies at flowers were 2 large species of Copestylum. Flowers were also visited by the migratory butterfly Vanessa cardui (Lepidoptera: Nymphalidae). Pollen was carried mainly on the proboscis of moths and butterflies and on the anterior thorax of flies. Lycium cooperi pollen grains in brightfield microscopy are trilobed in polar view, elliptic in equatorial view, and grainy in appearance. A higher mean proportion of L. cooperi pollen was carried by moths and butterflies (0.50) compared with flies (0.21), and moths in Noctuidae carried a higher proportion of conspecific pollen (0.59) compared with moths in Geometridae (0.25). Insects pollinated only 19.8% of the profuse flowers produced by shrubs. Pollination of L. cooperi primarily by moths corresponds with the shrub's partially white and tubular flowers. Similar flowers on most other Lycium species in the Mojave and Sonoran Deserts indicate a likelihood of similar pollination by moths.

Early Miocene palaeoflora and palaeoecology of the Soma Basin, Western Turkey

In this study comprehensive palaeofloristic data of lower Miocene deposits from the Soma Basin, western Anatolia is presented considering the stratigraphical concept. The sediments of the basin, derived from outcrop sections, were deposited in the terrestrial environment. The basin includes three different successions: lower and middle lignite successions of the Soma Formation and upper lignite succession of the Denis Formation. In this paper, we address the early Miocene palaeoecology via pollen and leaf assemblages from the Soma Basin, dated precisely using radiometric data. High percentages of Cupressaceae in the lower lignite succession of the Soma Formation, and minor quantities of elements such as Carya, Nyssa, Myrica, Ulmus and Salix reflect a local riparian and swamp vegetation. Marls overlying the lower lignite succession represent an environment close to the source area, with a variety of flora. During the deposition of middle lignite succession wet conditions played an essential role in the swamp forest fostering some distance transport of pollen which reflect the mesophytic forest vegetation as well as higher altitudes in the hinterland. The high percentages of lacustrine plankton Botryococcus and presence of Spirogyra in the upper lignite succession of the Denis Formation imply a shallow water environment with less rainfall surrounded by evergreen and deciduous mixed forest.

Facial area and hairiness of pollinators visiting semi‐natural grassland wild plants predict their facial pollen load

1. Consequences of a decline in pollination function in semi‐natural ecosystems are largely unknown due to variability in pollinator effectiveness, that is, their contribution to pollen deposition alone. While pollination effectiveness has been shown to be related to body size and hairiness of pollinators for some crops, studies encompassing a wide diversity of pollinators interacting with wild plant communities are lacking.2. Thus, the relationships between pollen load, which is a measurement of pollen transport ability and a proxy of pollinator effectiveness, and morphological traits of pollinators sampled in 16 grasslands in Moselle, France, were investigated. The area, hairiness, and pollen load of each pollinator's face were measured for 658 individuals from 127 bee and fly species interacting with 36 wild plant species. Pollinator dry mass was also measured on 543 individuals from 109 species.3. Dry body mass and facial area of pollinators were positively linked. This study highlights that bees transported significantly more pollen grains on their face than flies. Furthermore, bees' faces were larger and hairier. We also found that pollinators' facial pollen load increased with facial area and hairiness when we considered all pollinators. However, hairiness is not significant within pollinator group (bees or flies), mirroring a potential phylogenetic signal.4. Hence, this study shows a wide diversity of pollinator and plant species in which larger and hairier pollinators may transport more pollen grains, at least on their face. However, future studies involving other pollinator body parts are needed to generalise these relationships.

Plant flowering mirrored in airborne pollen seasons? Evidence from phenological observations in 14 woody taxa

Abstract Flowering and pollen seasons are sensitive to environmental variability and are considered climate change indicators. However, it has not been concluded to what extent flowering phenology is indeed reflected in airborne pollen season locally. The aim of this study was to investigate, for a wide spectrum of plant species, the responsiveness of flowering to different environmental regimes and also to check for commensurate changes in the respective pollen seasons. Fourteen taxa were selected representing the families of Corylaceae, Cupressaceae, Fagaceae, Oleaceae, Pinaceae and Platanaceae. Each was studied for at least one full flowering year and in at least two sampling stations differing in elevation or direction within the period 2004–2011. Flowering observations were made 2–3 times a week, from flower differentiation to flower desiccation; >1000 daily observations were made in 225 plant individuals, in total. Data were regressed against meteorological parameters in an attempt to identify the driving factors of flowering onset and offset. Flowering dates were compared with dates of the related airborne pollen seasons per taxon; airborne pollen monitoring took place daily using a Hirst-type volumetric sampler. For all taxa, flowering started earlier at lower elevations or southern direction. Cumulative temperature proved to be the factor most significantly affecting flowering onset and end for all species (p 0.70). For the majority of the taxa examined, airborne pollen season did not coincide locally with the respective flowering periods of the selected species: flowering could precede pollen season, even for more than one month (as in C. avellana), or start after the pollen season onset (as in P. brutia). The strong sensitivity of flowering to air temperature is not the case in the respective pollen seasons. This raises questions on the relationship between flowering times and airborne pollen seasons and on the rather underestimated role of long-distance transport of pollen.

Revision of the palm-pollinating weevil genus Elaeidobius Kuschel, 1952 (Curculionidae, Curculioninae, Derelomini) with descriptions of two new species

The genus Elaeidobius Kuschel, 1952 (Curculionidae, Curculioniae, Derelomini) is an Afrotropical genus associated with the male inflorescences of the oil palm Elaeis guineensis Jacq. The activity of species in this genus is critical for pollen transportation and for the fruit set of this economically important palm. In this study, the genus Elaeidobius was revised using an integrative taxonomic approach, combining traditional taxonomic treatment of species and an analysis of sequences of mitochondrial genes (COI and COII). A total of eight species is now recognized: five now formally included within it [E. bilineatus Hustache, 1924) comb. nov., E. kamerunicus (Faust, 1898) comb. nov., E. plagiatus (Fåhraeus, 1844) comb. nov., E. singularis (Faust, 1898) comb. nov., E. subvittatus Faust, 1898)], one transferred here from the genus Prosoestus to the genus Elaeidobius, E. spatulifer (Marshall, 1950) comb. nov., and two newly described species (E. pilimargo Haran & Kuschel sp. nov., E. piliventris Haran & Kuschel sp. nov.). The following new synonymies are proposed: Prosoestus armatus Voss, 1956 = E. bilineatus (Hustache, 1924) comb. nov. and Derelomus uelensis Hustache = E. singularis (Faust, 1898). An illustrated key to the species is provided with photographs of the adult habitus and male genitalia.

Biología reproductiva de la palma amarga (<i>Sabal mauritiiformis</i>: Arecaceae): especie económicamente importante para la Costa Caribe colombiana

Sabal mauritiiformis es uno de los recursos forestales no maderables económicamente más importantes en el Caribe colombiano pues sus hojas se comercializan para techado de viviendas típicas. Entre enero de 2013 y diciembre de 2015 se observó quincenalmente su fenología reproductiva, las fases de la biología floral se siguieron cada cuatro horas durante quince días. Se estudió el sistema reproductivo realizando polinizaciones controladas en 3000 flores. La eficiencia reproductiva se evaluó siguiendo a 21 inflorescencias, registrando el número de botones florales, flores, frutos maduros y frutos abortados. Los visitantes florales se determinaron a partir de capturas de 32 inflorescencias y al igual que su comportamiento se registró a partir de observaciones directas. Las palmas reproductivas de S. mauritiiformis presentaron entre una a nueve inflorescencias. La floración ocurrió desde abril a noviembre. Cada inflorescencia florece entre diez y 20 días, con flores hermafroditas que entran en antesis entre 01h:00–04h:00, pero las anteras liberan polen entre 06h:30–07h:30 y los estigmas estuvieron receptivos entre las 10h:00–13h:00. S. mauritiiformis es auto-incompatible, sin apomixis y predominantemente xenógama. Un total de 65 especies de insectos y diez de arácnidos visitaron las inflorescencias, pero la polinización cruzada fue realizada principalmente por las abejas Nannotrigona mellaria y Scaptotrigona sp.1 (Meliponini). La eficiencia reproductiva fue sólo el 7,6 %, fenómeno que podría estar asociado con el continuo corte de hojas, altas tasas de depredación de flores y baja eficiencia del transporte de polen.

A review of the challenges and opportunities for restoring animal-mediated pollination of native plants.

Ecological restoration is increasingly implemented to reverse habitat loss and concomitant declines in biological diversity. Typically, restoration success is evaluated by measuring the abundance and/or diversity of a single taxon. However, for a restoration to be successful and persistent, critical ecosystem functions such as animal-mediated pollination must be maintained. In this review, we focus on three aspects of pollination within ecological restorations. First, we address the need to measure pollination directly in restored habitats. Proxies such as pollinator abundance and richness do not always accurately assess pollination function. Pollen supplementation experiments, pollen deposition studies, and pollen transport networks are more robust methods for assessing pollination function within restorations. Second, we highlight how local-scale management and landscape-level factors may influence pollination within restorations. Local-scale management actions such as prescribed fire and removal of non-native species can have large impacts on pollinator communities and ultimately on pollination services. In addition, landscape context including proximity and connectivity to natural habitats may be an important factor for land managers and conservation practitioners to consider to maximize restoration success. Third, as climate change is predicted to be a primary driver of future loss in biodiversity, we discuss the potential effects climate change may have on animal-mediated pollination within restorations. An increased mechanistic understanding of how climate change affects pollination and incorporation of climate change predictions will help practitioners design stable, functioning restorations into the future.

Palynomorphs in surface sediments of the North-Western Black Sea as indicators of environmental conditions

Most previous Black Sea palynology studies have used pollen-spore assemblages as proxies for climate and landscape changes, and dinocyst assemblages as proxies for surface water salinity. However, there are few data on within-region variations in these assemblages using large sets of surface samples and a full suite of palynomorphs, including terrigenous pollen + spores, freshwater algal spores, and organic remains of marine microplankton, micro- and meiobenthos. Here we fill this knowledge gap, using results from a palynological study of 43 surface samples from water depths of 71–905 mbsl on the Ukrainian Shelf and adjoining continental slope, NW Black Sea. The palynology samples were collected in conjunction with water and sediment chemistry data, grain-size, micropaleontological and meiobenthos data from the EU-FP6 project HERMES “Hotspot Ecosystems Research on the Margins of European Seas”. This dataset uniquely covers shelf and upper slope areas east and west of the Odessa-Sinop Fault Zone (OSFZ) that delimits areas of lower and higher hydrocarbon gas contents, respectively.The new data show that on the wide shelf with a shallow (ca. 80 m) oxycline, pollen assemblages differ from classical models for marine pollen transport. On the Ukrainian Shelf, pollen concentrations are extraordinarily high far offshore and the grains are often pyrite-infilled. These features apparently reflect high pollen preservation potential in low oxygen sediments, probably enhanced by cross-shelf transport of land-derived particulate organic matter. The new data have important consequences for accurate modelling of carbon burial and storage in epicontinental seas, and they provide a baseline for evaluating marine pollen concentrations expected to reflect the early Neolithic farming on the Ukrainian shelf. Furthermore, although large concentrations of dinocysts comprise more than half of the total Non-Pollen Palynomorphs (NPP), the high pollen concentrations skew the P:D index (pollen:dinocyst ratio) commonly used to evaluate changes in paleo-shoreline (proxy sea-level) positions. Despite the discharge of several large rivers to the Ukrainian Shelf, there are negligible traces of freshwater algae in the HERMES samples except at Sta. 15 where Pediastrum is abundant. Overall, palynomorphs of terrestrial origin make up about half (52%) of the acid-resistant organic-walled particles on the outer NW Black Sea Shelf and adjacent slope.The abundances of the major micro- and meiobenthic palynomorph groups show the same trends east and west of the OSFZ as the micropaleontological data reported for the HERMES samples taken at the same sites. The combined microzooplankton and zoobenthos surface assemblage data provide an important new baseline for evaluating historical and past changes in biodiversity and aquatic foodweb structure in the now polluted NW Black Sea. Comparison can also be made with foodweb reconstructions for Permian black shales.

High Ambrosia pollen concentrations in Poland respecting the long distance transport (LDT)

High Ambrosia pollen concentrations in Poland rather rarely come from the local sources. The aim of this study was to define the temporal and spatial differences of the high Ambrosia pollen concentrations by creating models for the pollen transport from the distant sources. This study was thought to determine the direction of the air masses inflow into Poland, carrying Ambrosia pollen, from areas of the bordering countries with the pollen concentrations higher than iSTOTEN_n Poland. Pollen and meteorological datasets at 8 monitoring sites in Poland, and daily pollen concentrations at 11 sites in the Czech Republic, 5 sites in Slovakia and 3 sites in Ukraine were analysed recently. Days with concentrations ≥10 Pollen/m3 and concurrent meteorological situations were analysed in great deal. The HYSPLIT model was applied to compute backward trajectories up to 4 days backward (96 h) and at three altitudes: 20, 500 and 1000 m above ground level (a.g.l.). High pollen concentrations occur most frequently when the air masses inflow into Poland from southerly (S, SE, SW, 44%) and easterly (E, 6%) directions and in no advection situations (25%). In years with the highest frequency of days over 10 Pollen/m3, the prevailing directions of the pollen influx into Poland were from the South (2004–2006, 2008, 2011) but in one year (2014) from the East. Trajectories for the studied period show that air masses come most frequently from Slovakia and the Czech Republic. Sometimes, the Ambrosia pollen transport happens from Ukraine.

Nocturnal pollinators strongly contribute to pollen transport of wild flowers in an agricultural landscape.

Dramatic declines in diurnal pollinators have created great scientific interest in plant-pollinator relationships and associated pollination services. Existing literature, however, is generally focused on diurnal pollinating insect taxa, especially on Apidae (Hymenoptera) and Syrphidae (Diptera) pollinators, while nocturnal macro-moths that comprise extremely species-rich flower-visiting families have been largely neglected. Here, we report that in agricultural landscapes, macro-moths can provide unique, highly complex pollen transport links, making them vital components of overall wild plant-pollinator networks in agro-ecosystems. Pollen transport occurred more frequently on the moths' ventral thorax rather than on their mouthparts that have been traditionally targeted for pollen swabbing. Pollen transport loads suggest that nocturnal moths contribute key pollination services for several wild plant families in agricultural landscapes, in addition to providing functional resilience to diurnal networks. Severe declines in richness and abundance of settling moth populations highlight the urgent need to include them in future management and conservation strategies within agricultural landscapes.

An examination of rockshelter palynology: Carpenter’s Gap 1, northwestern Australia

Carpenter’s Gap 1 is a large rockshelter located within the Kimberley region of northwestern Australia. The site provides valuable archives of late Quaternary palaeoecological information within an area known for a lack of deposits preserving long-term continuous botanical records. Previous studies of the macrobotanic, phytolith and wood charcoal records from Carpenter’s Gap 1 are in general agreement about changes in broad vegetation patterns over time but differ in the time scales used, in the representation of some species, and in the interpretation of changes – particularly on the degree to which the variations in the record represent cultural activities. An examination of palynology (the transport, deposition and preservation of pollen within the rockshelter environment) provides more detail to the vegetation patterns identified in these previous studies. In addition, because the pollen most likely reflects the vegetation of the site’s surrounds over time rather than plants introduced into the shelter by people, interpretation can be more confidently linked to environmental change, and by inference climatic conditions. The pollen data reveal pre-glacial mixed wooded vegetation. From the beginning of the Holocene, tree loss occurred in a transition from monsoonal forest to thicket and eucalypt forest to woodland. Vegetation transition around the mid Holocene suggests a shift in climate, becoming drier and more variable towards and into the late Holocene. The role of fire in the establishment of vegetation communities remains under investigation.

Surface pollen distribution in alpine zone of the higher Himalaya: a case study from the Kalla glacier valley, India

ABSTRACT In order to understand the relationship between modern pollen spectra and vegetation, we analysed 20 surface sediment samples collected from the alpine zone of Kalla Bank glacier valley, Dhauliganga Basin, India covering an elevational stretch of c. 3600 to 5000 m asl and vegetation zones like the alpine scrub, alpine meadow and alpine barren. This study also provides insights into the vertical pollen transport along the elevational gradient of the glacier valley. Numerical analyses such as cluster analysis (CA), discriminant analysis (DA) and detrended correspondence analysis (DCA) are used to explore and discuss the modern pollen deposition patterns in the alpine settings. Despite the inconsistencies observed between modern vegetation and surface palynoassemblages, a good agreement is noticed between CA and DA classifications and DCA ordination results which reveal signature of upslope wind transport. High percentages of pine, cedar, alder and birch pollen grains in the above tree-line surface pollen assemblages are indicative of their upslope wind transport from a lower elevation. The inconsistencies may be attributed to the differential pollen representation between species, differential flowering and pollination of herbaceous taxa. The present study suggests altitude and monsoonal winds might be the two most influential factors that attributed changes in the surface palynoassemblages of the alpine vegetation in the Kalla Bank glacier (Kunti-Banar) valley. Therefore, while interpreting the fossil pollen spectra from any high altitude mountainous zone, long-distance pollen transport should always be taken into account, especially for anemophilous plant taxa.

High post-season Alnus pollen loads successfully identified as long-range transport of an alpine species

Abstract Alnus pollen is one of the Northern Hemisphere's major aeroallergens. In Central Europe, the genus is represented by three species (Alnus glutinosa, Alnus incana, and Alnus viridis). The most common one, A. glutinosa (L.) Gaertn., is widespread in lowland riparian forests, swamps, and forest edges. However, to date is still unknown if all of them - in terms of pollen exposure - are clinically relevant for sensitized individuals. To investigate the associated pollen exposure, particularly also because of long-range transport of airborne pollen, we used backward air mass trajectories and tested this method for the year 2015, based on daily Alnus pollen concentrations at 26 sites in Bavaria, Germany. A. glutinosa's main pollen season extends from February to March, but a six-day, post-season episode was additionally identified in June. For this episode and all sites, 72-h backward trajectories were calculated at 3-h intervals using high spatial and temporal resolution ERA5 reanalysis data and the HYSPLIT (hybrid single-particle Lagrangian integrated trajectory) model. This backward trajectory method identified air masses from the alpine region in Switzerland and Austria, where relevant areas of A. viridis (Chaix) DC as potential pollen sources exist. These may explain the post-season episode in June, as additionally confirmed by its unique spatial distribution, by a considerably later flowering period, and by repeated long-range transport events as observed in a 23-year pollen time series.

Pollen spectra of Polar Ural glaciers

The subject of this article is the pollen spectra of the samples from the surface of Romantic's Glacier, located in the Polar Urals in the Rai-Iz mountain range, as well as generalization of the results of published studies dedicated to glaciers of the Urals. The author also examines the pollen spectra of massive ice, which can be attributed to ice of atmospheric origin on the basis of similarity with the pollen spectra obtained from the surface of the glacier. The article reviews climatic peculiarities of the Polar Urals due to the existence of glaciers below the snow line, namely the landscapes of the Polar Urals, including vegetation as a source of pollen and spores falling onto the surface of glaciers of the Polar Urals, as well as possibility of distant pollen drift to the surface of Romantic’s Glacier. The main result consists in the conclusion that the composition pollen spectra of the Romantic’s Glacier in the Rai-Iz mountainous area is mainly determined by the long-range transport of pollen and spores from the western and south-western regions in a latitude direction. The pollen spectra obtained from the surface of the Romantic’s Glacier are characterized by significant presence of various pollen from broad-leaved rocks of lip, maple, oak, and hazel. Pine pollen and high forest birch are prevalent. Local vegetation is very poor. However, the pollen spectra indicates pollen of heath and crowfoot family, and grasses.

Structure and development of anthers and connective glands in two species of Stigmaphyllon (Malpighiaceae): are heteromorphic anthers related to division of labour?

Heteranthery has been largely associated with a division of labour between anthers. Most species of Stigmaphyllon (Malpighiaceae) present heteromorphic anthers and glandular connectives of different development; yet, the functional meaning of this condition has never been explored in the genus. The aims of this study were to provide a comparative description of the structure and development of anthers and their connective glands in S. bonariense and S. jatrophifolium and to assess the existence of division of functions. Natural populations were selected to collect flowers at different stages. Anthers were subjected to morpho-anatomical, histochemical and pollen viability studies. For both species, abundance of pollen grains and size of anther and their connective glands were estimated. Three types of stamens are recognized: stamen with small, intermediate and large anthers. Anthers of both species exhibit a similar glandular tissue in the connective, and the histochemical analysis revealed that it produce a mucilagous secretion. The pattern of anther wall development, stainability and release of pollen grains was identical among anther types. For both species, we observed a positive relationship between anther size and abundance of pollen grains, but an inverse relationship between area of anthers and size (area and thickness) of connective glands in small anthers vs. intermediate and large ones. Our results evidence a specialization of anthers related to division of labour between heteromorphic stamens in two species of Stigmaphyllon. Thus, one set of anthers produces large amount of pollen grains for pollination and another sets large quantities of mucilage, which would improve pollen transport (better adherence to pollinator body and dampness maintenance). Nevertheless, heteranthery in both Stigmaphyllon species would represent a transitional state towards the division of labour rather than a stable state.

Modern pollen source and spatial distribution from surface lake sediments in the southwestern Pampa grasslands, Argentina: Implications to interpret Holocene pollen records

In the Pampa grasslands of Argentina nothing is known about the transport, deposition and spatial distribution of pollen in lakes. To analyze and understand how well lake surface sediment pollen assemblages reflect the contemporary vegetation in relation to pollen source area, bathymetry and grain size sediments 36 surface sediment samples from Chasicó Lake and 5 from its only tributary were analyzed. Lake pollen assemblages showed two major patterns above and below the range between 4 and 6 m depth. Below this range the percentage and concentration of main pollen taxa are relatively homogeneous, without overrepresented taxa and with well-preserved pollen. They reflect the extra-local and regional source areas from Pampa grasslands and xerophylous forest and indicate that pollen from cores taken below this range will be suitable for paleocological studies. Isopoll of the main taxa and grain size distribution maps allowed understand how pollen and sediment was transported, deposited and distributed in the lake. The spatial distributions of main pollen taxa differ considerably among them, generating various pollen assemblages at different sampling points. There is no significant correlation between total pollen concentration and both depth and grain size, suggesting that there are not a totally pollen and sediment focusing in the lake. The pollen distribution indicates that wind and surface runoff are the primary transport vectors to the lake. However, tributary also contributes with the waterborne pollen, particularly around the river mouth. Implications of these processes will be of particular interest for reliable interpretation of fossil pollen records in similar environments.

Potential role of lava lizards as pollinators across the Galápagos Islands

Lizards have been reported as important pollinators on several oceanic islands. Here we evaluate the potential role of Galápagos lava lizards (Microlophus spp.) as pollinators across their radiation. Over 3 years, we sampled pollen transport by 9 lava lizard species on the 10 islands where they are present, including 7 single-island endemics. Overall, only 25 of 296 individuals sampled (8.4%) transported pollen of 10 plant species, the most common being Prosopis juliflora, Exodeconus miersii, Sesuvium sp. and Cordia leucophlyctis. At least 8 of these plant species were native, and none were confirmed as introduced to the archipelago. Despite the low overall proportion of individuals carrying pollen, this was observed in 7 of the nine lizard species, and on 8 of the ten main islands (Española, Fernandina, Floreana, Isabela, Marchena, Pinta, Santa Cruz and Santiago), suggesting that this is a widespread interaction. The results reported here support the potential role of lava lizards as pollinators across their radiation, although they may represent a relatively modest contribution when compared with birds and insects. However, we cannot discard that lizards may be ecologically significant for particular plant species and ecosystems given the specific climatic condition and functional diversity of each island.

Emergence of the Leaf Beetle Triarius trivittatus (Coleoptera: Chrysomelidae) from Sacahuista Nolina microcarpa (Asparagaceae)

Nolina microcarpa S. Watson (Asparagaceae) shrubs in northwest Arizona were covered with insect-emergence traps to determine whether Triarius trivittatus Horn (Coleoptera: Chrysomelidae), a beetle species that carries pollen from male to female flowers, undergoes larval development on the plant. The 3 traps covered different clumps of leaf rosettes and caught 39 beetles, 15 males and 24 females, during 27 May–24 June 2019. Larvae of T. trivittatus likely develop on roots, similar to other beetles in the same tribe, or on underground stems that connect leaf rosettes. Development of larvae on the plant, as well as pollen transport to female flowers by the adult beetles, suggests that N. microcarpa and T. trivittatus have a mutualistic relationship.