Application of Atmospheric Solids Analysis Probe Mass Spectrometry for the Taxonomic Analysis of Pollen

Globally, both managed and wild pollination services are unable to meet current rates of crop production and pollination demand. Wild pollination services could be improved through the reforestation of agricultural land margins, however plant–pollinator networks remain poorly understood and the collection of key floral traits a complex process. Herein, we consider the merits of pollen as a floral trait and the application of a rapid pollen comparison method in assessing whether pollen traits are conserved at a taxonomic level. Reporting the previously unstudied, pollen fingerprints of 18 Australian plant species, these are compared against the seed crop Daucus carota L. and two naturalised Brassica hybrids. Applying atmospheric solids analysis probe mass spectrometry (ASAP-MS) for rapid pollen fingerprinting, pollens are compared through non-metric multidimensional scaling (NMDS), Jaccard index correlation and hierarchical clustering. Demonstrating the merits of this analytical method for the grouping of potential revegetation flora, we identify key pollen similarities and differences that could correlate with wild pollinator preferences.

Pollinators: Their Relevance in Conservation and Sustainable Agro-Ecosystem

Survival and reproduction of several wild plants and crops is mostly by insects pollinator, their recognition and importance have been increased in this climatic changing scenario, which affects the various aspects of their life cycle. According to an estimate, approximately 30,000 species of bees are known in entomology, and about 190 species of bees have been reported to be associated with pollination. There can be an established link between seed production and pollinator diversity, for the plants with a generalist pollination system. The increasing of human habitation affects insect pollinators in various ways, i.e. of habitat destruction, results in low availability of food sources, nesting, oviposition, resting, and mating sites. Pollinator availability restraints the geographical distribution of plant species, i.e. to develop an ecological niche of certain plant species. Failure of pollinator- plant interaction mutualism results in lower seed production and sometimes extirpation of plant population has been recorded. The declining pollinators’ population strengthens existing plant-pollinator interaction or allows new pant pollinator interaction to form. Maintaining the commercial and wild pollinator populations and preventing future shortages of pollination services, therefore, is extremely significant.

DNA metabarcoding unveils the effects of habitat fragmentation on pollinator diversity, plant-pollinator interactions, and pollination efficiency in tropical islands

Habitat fragmentation is known to affect biodiversity, but the impact on pollinators and their interactions with plants is still unclear in anthropized landscapes. Islands are open-air laboratories for ecological studies with simplified communities and interactions, suitable to disentangle how land-use alteration impacts pollination ecology and its ecosystem service. Here, we used Maldives islands as model systems to investigate how pollinator richness, their mutualistic interactions with plants, and pollination efficiency are shaped by the degree of green area fragmentation (i.e., gardens, parks and semi-natural green covered patches), by considering both community- and species-level responses. To do this, we surveyed pollinators from 11 islands showing a gradient of green area fragmentation. In order to characterize the interactions between plants and pollinators and obtain a novel and comprehensive view of the key ecological dynamics, a DNA metabarcoding approach was adopted to identify the pollen carried by pollinators. We found that green area fragmentation at intermediate levels played positive effects on pollinator richness. However, fragmentation decreased interaction network complexity. Intriguingly, body size mediated the effect of landscape alteration on plant-pollinator interactions, as only the largest bee species expanded the foraging breath in terms of transported pollen richness at increasing fragmentation. In parallel, the pollination efficiency increased with pollinator species richness in two sentinel plants. This study shows that moderate landscape fragmentation of green areas shapes the ecosystem service of pollination, where in spite of interactions being less complex and mediated by pollinator body size, pollinator biodiversity and potential plant reproduction are supported.

Structure-based identification of sensor species for anticipating critical transitions

Ecological systems can undergo sudden, catastrophic changes known as critical transitions. Anticipating these critical transitions remains challenging in systems with many species because the associated early warning signals can be weakly present or even absent in some species, depending on the system dynamics. Therefore, our limited knowledge of ecological dynamics may suggest that it is hard to identify those species in the system that display early warning signals. Here, we show that, in mutualistic ecological systems, it is possible to identify species that early anticipate critical transitions by knowing only the system structure—that is, the network topology of plant–animal interactions. Specifically, we leverage the mathematical theory of structural observability of dynamical systems to identify a minimum set of “sensor species,” whose measurement guarantees that we can infer changes in the abundance of all other species. Importantly, such a minimum set of sensor species can be identified by using the system structure only. We analyzed the performance of such minimum sets of sensor species for detecting early warnings using a large dataset of empirical plant–pollinator and seed-dispersal networks. We found that species that are more likely to be sensors tend to anticipate earlier critical transitions than other species. Our results underscore how knowing the structure of multispecies systems can improve our ability to anticipate critical transitions.

Trade-offs among plant reproductive traits determine interactions with floral visitors

Plant life-history strategies are constrained by cost-benefit trade-offs that determine plant form and function. However, despite recent advances in the understanding of trade-offs for vegetative and physiological traits, little is known about plant reproductive economics and how they constrain plant life-history strategies and shape interactions with floral visitors. Here, we investigate plant reproductive trade-offs and how these drive interactions with floral visitors using a dataset of 17 reproductive traits for 1,506 plant species from 28 plant-pollinator studies across 18 countries. We tested whether a plant's reproductive strategy predicts its interactions with floral visitors and if the different reproductive traits predict the plant's role within the pollination network. We found that over half of all plant reproductive trait variation was explained by two independent axes that encompassed plant form and function. Specifically, the first axis indicated the presence of a trade-off between flower number and flower size, while the second axis indicated a pollinator dependency trade-off. Plant reproductive trade-offs helped explain partly the presence or absence of interactions with floral visitors, but not differences in visitation rate. However, we did find important differences in the interaction level among floral visitor guilds on the different axes of trait variation. Finally, we found that plant size and floral rewards were the most important traits in the understanding of the plant species network role. Our results highlight the importance of plant reproductive trade-offs in determining plant life-history strategies and plant-pollinator interactions in a global context.

Patterns of flower-visiting insects depend on flowering phenological shifts along an altitudinal gradient in subalpine moorland ecosystems

Alpine and subalpine moorland ecosystems contain unique plant communities, often with many endemic and threatened species, some of which depend on insect pollination. Although alpine and subalpine moorland ecosystems are vulnerable to climatic change, few studies have investigated flower-visiting insects in such ecosystems and examined the factors regulating plant-pollinator interactions along altitudinal gradients. Here, we explored how altitudinal patterns in flower visitors change according to altitudinal shifts in flowering phenology in subalpine moorland ecosystems in northern Japan. We surveyed flower-visiting insects and flowering plants at five sites differing in altitude in early July (soon after snowmelt) and mid-August (peak growing season). In July, we found a higher visiting frequency by more variable insect orders including Dipteran, Hymenopteran, Coleopteran, and Lepidopteran species at the higher altitude sites in association with the mass flowering of Geum pentapetalum and Nephrophyllidium crista-galli. In August, such altitudinal patterns were not observed, and Dipteran species dominated across the sites due to the flowering of Narthecium asiaticum and Drosera rotundifolia. Earlier snowmelt associated with recent climate change is expected to extend the growth period of moorland plants and modify flowering phenology in moorland ecosystems, leading to altered plant-pollinator interactions. Our study provides key baselines for the detection of endangered biotic interactions and extinction risks of moorland plants under ongoing climate change.

Mapping trait versus species turnover reveals spatiotemporal variation in functional redundancy in a plant-pollinator network

Functional overlap between species (redundancy) shapes competitive and mutualistic interactions, determining community responses to perturbations. Most studies view functional redundancy as static, even though individuals within species vary in traits over seasonal or spatial gradients. Consequently, we lack knowledge on trait turnover within species, how functional redundancy spatiotemporally varies, and when and where interaction networks are vulnerable to functional loss. Studying an Arctic bumblebee community, we investigated how body-size turnover with elevation and over a season shapes their host-plant interactions, and test how sensitive networks are to sequentially losing body-size groups. With trait turnover being larger than species, we found: i) late-season networks were less specialised when nodes comprised functionally similar bumblebees; ii) removal of bumblebee-body-size groups over species accelerated coextinction of host plants, with the magnitude varying in space and time. We demonstrate functional redundancy can vary spatiotemporally, and functional loss impacts interaction partners more than expected from species loss alone.