Island plants with newly discovered reproductive traits have higher capacity for uniparental reproduction, supporting Baker's law.

Uniparental reproduction is advantageous when lack of mates limits outcrossing opportunities in plants. Baker's law predicts an enrichment of uniparental reproduction in habitats colonized via long-distance dispersal, such as volcanic islands. To test it, we analyzed reproductive traits at multiple hierarchical levels and compared seed-set after selfing and crossing experiments in both island and mainland populations of Limonium lobatum, a widespread species that Baker assumed to be self-incompatible because it had been described as pollen-stigma dimorphic, i.e., characterized by floral morphs differing in pollen-surface morphology and stigma-papillae shape that are typically self-incompatible. We discovered new types and combinations of pollen and stigma traits hitherto unknown in the literature on pollen-stigma dimorphism and a lack of correspondence between such combinations and pollen compatibility. Contrary to previous reports, we conclude that Limonium lobatum comprises both self-compatible and self-incompatible plants characterized by both known and previously undescribed combinations of reproductive traits. Most importantly, plants with novel combinations are overrepresented on islands, selfed seed-set is higher in islands than the mainland, and insular plants with novel pollen-stigma trait-combinations disproportionally contribute to uniparental reproduction on islands. Our results thus support Baker's law, connecting research on reproductive and island biology.

High floral disparity without pollinator shifts in buzz-bee-pollinated Melastomataceae.

Shifts among functional pollinator groups are commonly regarded as sources of floral morphological diversity (disparity) through the formation of distinct pollination syndromes. While pollination syndromes may be used for predicting pollinators, their predictive accuracy remains debated, and they are rarely used to test whether floral disparity is indeed associated with pollinator shifts. We apply classification models trained and validated on 44 functional floral traits across 252 species with empirical pollinator observations and then use the validated models to predict pollinators for 159 species lacking observations. In addition, we employ multivariate statistics and phylogenetic comparative analyses to test whether pollinator shifts are the main source of floral disparity in Melastomataceae. We find strong support for four well-differentiated pollination syndromes ('buzz-bee', 'nectar-foraging vertebrate', 'food-body-foraging vertebrate', 'generalist'). While pollinator shifts add significantly to floral disparity, we find that the most species-rich 'buzz-bee' pollination syndrome is most disparate, indicating that high floral disparity may evolve without pollinator shifts. Also, relatively species-poor clades and geographic areas contributed substantially to total disparity. Finally, our results show that machine-learning approaches are a powerful tool for evaluating the predictive accuracy of the pollination syndrome concept as well as for predicting pollinators where observations are missing.

Fields of flowers with few strikes: how oligolectic bees manage their foraging behavior on Calibrachoa elegans (Solanaceae).

In specialized plant-pollinator associations, partners may exhibit adaptive traits, which favor the maintenance of the interaction. The association between Calibrachoa elegans (Solanaceae) and its oligolectic bee pollinator, Hexantheda missionica (Colletidae), is mutualistic and forms a narrowly specialized pollination system. Flowers of C. elegans are pollinated exclusively by this bee species, and the bees restrict their pollen resources to this plant species. The pollen presentation schedules of C. elegans were evaluated at the population level to test the hypothesis that H. missionica females adjust their foraging behavior to the resource offering regime of C. elegans plants. For this, the number of new flowers and anthers opened per hour (as a proxy for pollen offering) was determined, and pollen advertisement was correlated with the frequency of flower visits during the day. Preferences of female bees for flowers of different stages were also investigated, and their efficiency as pollinators was evaluated. Pollen offering by C. elegans was found to be partitioned throughout the day through scattered flower openings. Females of H. missionica indeed adjusted their foraging activity to the most profitable periods of pollen availability. The females preferred new, pollen-rich flowers over old ones and gathered pollen and nectar selectively according to flower age. Such behaviors must optimize female bee foraging efficiency on flowers. Female bees set 93% of fruit after a single visit. These findings guarantee their importance as pollinators and the persistence of the specialized plant-pollinator association.

Ecological drivers of flower-leaf sequences: aridity and proxies for pollinator attraction select for flowering-first in the American plums.

Across temperate forests, many tree species produce flowers before their leaves emerge. This flower-leaf phenological sequence, known as hysteranthy, is generally described as an adaptation for wind pollination. However, this explanation does not address why hysteranthy is also common in biotically pollinated taxa. We quantified flower-leaf sequence variation in the American plums (Prunus, subg. Prunus sect. Prunocerasus), a clade of insect-pollinated trees, using herbaria specimens and Bayesian hierarchical modeling. We tested two common, but rarely interrogated hypotheses - that hysteranthy confers aridity tolerance and/or pollinator visibility - by modeling the associations between hysteranthy and related traits. To understand how these phenology-trait associations were sensitive to taxonomic scale and flower-leaf sequence classification, we then extended these analyses to all Prunus species in North America. Our findings across two taxonomic levels support the hypotheses that hysteranthy may help temporally partition hydraulic demand to reduce water stress and increase pollinator visibility - thereby reducing selective pressure on inflorescence size. Our results provide foundational insights into the evolution of flower-leaf sequences in the genus Prunus, with implications for understanding these patterns in biotically pollinated plants in general. Our approach suggests a path to advance these hypotheses to other clades, but teasing out drivers fully will require new experiments.

Heat and desiccation tolerances predict bee abundance under climate change.

Climate change could pose an urgent threat to pollinators, with critical ecological and economic consequences. However, for most insect pollinator species, we lack the long-term data and mechanistic evidence that are necessary to identify climate-driven declines and predict future trends. Here we document 16 years of abundance patterns for a hyper-diverse bee assemblage1 in a warming and drying region2, link bee declines with experimentally determined heat and desiccation tolerances, and use climate sensitivity models to project bee communities into the future. Aridity strongly predicted bee abundance for 71% of 665 bee populations (species × ecosystem combinations). Bee taxa that best tolerated heat and desiccation increased the most over time. Models forecasted declines for 46% of species and predicted more homogeneous communities dominated by drought-tolerant taxa, even while total bee abundance may remain unchanged. Such community reordering could reduce pollination services, because diverse bee assemblages typically maximize pollination for plant communities3. Larger-bodied bees also dominated under intermediate to high aridity, identifying body size as a valuable trait for understanding how climate-driven shifts in bee communities influence pollination4. We provide evidence that climate change directly threatens bee diversity, indicating that bee conservation efforts should account for the stress of aridity on bee physiology.

Flower opening dynamics, pollen-ovule ratio, stigma receptivity and stigmatic pollen germination (in-vivo) in Chaenomeles speciosa (Sweet) Nakai.

Although Chaenomeles is widely used in horticulture, traditional Chinese medicine and landscape greening, insufficient research has hindered its breeding and seed selection. This study investigated the floral phenology, floral organ characteristics, palynology, and breeding systems of Chaenomeles speciosa (Sweet) Nakai. The floral characteristics of C. speciosa were observed both visually and stereoscopically. The microstructures of the flower organs were observed using scanning electron microscopy. Pollen stainability was determined using triphenyl tetrazolium chloride staining. Stigma receptivity was determined using the benzidine-H2O2 method and the post-artificial pollination pollen germination method. The breeding system was assessed based on the outcrossing index and pollen-ovule ratio. The flowers of C. speciosa were bisexual with a flowering period from March to April. The flowering periods of single flowers ranged from 8 to 19 d, and those of single plants lasted 18-20 d. The anthers were cylindrical, with the base attached to the filament, and were split longitudinally to release pollen. The flower had five styles, with a connate base. The ovaries had five carpels and five compartments. The inverted ovules were arranged in two rows on the placental axis. The stigma of C. speciosa was dry and had many papillary protrusions. In the early flowering stage (1-2 d of flowering), the pollen exhibited high stainability (up to 84.24%), but all stainability was lost at 7 d of flowering. Storage at - 20 °C effectively delayed pollen inactivation. The stigma receptivity of C. speciosa lasted for approximately 7 days, and the breeding system was classified as outcrossing with partial self-compatibility.

Floral pigments and their perception by avian pollinators in three Chilean Puya species.

The Chilean Puya species, Puya coerulea var. violacea and P. chilensis bear blue and pale-yellow flowers, respectively, while P. alpestris considered to be their hybrid-derived species has unique turquoise flowers. In this study, the chemical basis underlying the different coloration of the three Puya species was explored. We first isolated and identified three anthocyanins: delphinidin 3,3',5'-tri-O-glucoside, delphinidin 3,3'-di-O-glucoside and delphinidin 3-O-glucoside; seven flavonols: quercetin 3-O-rutinoside-3'-O-glucoside, quercetin 3,3'-di-O-glucoside, quercetin 3-O-rutinoside, isorhamnetin 3-O-rutinoside, myricetin 3,3',5'-tri-O-glucoside, myricetin 3,3'-di-O-glucoside and laricitrin 3,5'-di-O-glucoside; and six flavones: luteolin 4'-O-glucoside, apigenin 4'-O-glucoside, tricetin 4'-O-glucoside, tricetin 3',5'-di-O-glucoside, tricetin 3'-O-glucoside and selagin 5'-O-glucoside, which is a previously undescribed flavone, from their petals. We also compared compositions of floral flavonoid and their aglycone among these species, which suggested that the turquoise species P. alpestris has an essentially intermediate composition between the blue and pale-yellow species. The vacuolar pH was relatively higher in the turquoise (pH 6.2) and pale-yellow (pH 6.2) flower species, while that of blue flower species was usual (pH 5.2). The flower color was reconstructed in vitro using isolated anthocyanin, flavonol and flavone at neutral and acidic pH, and its color was analyzed by reflectance spectra and the visual modeling of their avian pollinators. The modeling demonstrated that the higher pH of the turquoise and pale-yellow species enhances the chromatic contrast and spectral purity. The precise regulation of flower color by flavonoid composition and vacuolar pH may be adapted to the visual perception of their avian pollinator vision.

Defective pollen tube tip growth induces neo-polyploid infertility.

Genome duplication (generating polyploids) is an engine of novelty in eukaryotic evolution and a promising crop improvement tool. Yet newly formed polyploids often have low fertility. Here we report that a severe fertility-compromising defect in pollen tube tip growth arises in new polyploids of Arabidopsis arenosa. Pollen tubes of newly polyploid A. arenosa grow slowly, have aberrant anatomy and disrupted physiology, often burst prematurely, and have altered gene expression. These phenotypes recover in evolved polyploids. We also show that gametophytic (pollen tube) genotypes of two tip-growth genes under selection in natural tetraploid A. arenosa are strongly associated with pollen tube performance in the tetraploid. Our work establishes pollen tube tip growth as an important fertility challenge for neo-polyploid plants and provides insights into a naturally evolved multigenic solution.

Olfaction in the Anthropocene: NO3 negatively affects floral scent and nocturnal pollination.

There is growing concern about sensory pollutants affecting ecological communities. Anthropogenically enhanced oxidants [ozone (O3) and nitrate radicals (NO3)] rapidly degrade floral scents, potentially reducing pollinator attraction to flowers. However, the physiological and behavioral impacts on pollinators and plant fitness are unknown. Using a nocturnal flower-moth system, we found that atmospherically relevant concentrations of NO3 eliminate flower visitation by moths, and the reaction of NO3 with a subset of monoterpenes is what reduces the scent's attractiveness. Global atmospheric models of floral scent oxidation reveal that pollinators in certain urban areas may have a reduced ability to perceive and navigate to flowers. These results illustrate the impact of anthropogenic pollutants on an animal's olfactory ability and indicate that such pollutants may be critical regulators of global pollination.

Pollen, anther, stamen, and androecium mimicry.

Floral colours represent a highly diverse communication signal mainly involved in flower visitors' attraction and guidance, but also flower discrimination, filtering non-pollinators and discouraging floral antagonists. The divergent visual systems and colour preferences of flower visitors, as well as the necessity of cues for flower detection and discrimination, foster the diversity of floral colours and colour patterns. Despite the bewildering diversity of floral colour patterns, a recurrent component is a yellow UV-absorbing floral centre, and it is still not clear why this pattern is so frequent in angiosperms. The pollen, anther, stamen, and androecium mimicry (PASAM) hypothesis suggests that the system composed of the flowers possessing such yellow UV-absorbing floral reproductive structures, the flowers displaying central yellow UV-absorbing structures as floral guides, and the pollen-collecting, as well as pollen-eating, flower visitors responding to such signals constitute the world's most speciose mimicry system. In this review, we call the attention of researchers to some hypothetical PASAM systems around the globe, presenting some fascinating examples that illustrate their huge diversity. We will also present new and published data on pollen-eating and pollen-collecting pollinators' responses to PASAM structures supporting the PASAM hypothesis and will discuss how widespread these systems are around the globe. Ultimately, our goal is to promote the idea that PASAM is a plausible first approach to understanding floral colour patterns in angiosperms.

Ozone alters the chemical signal required for plant - insect pollination: The case of the Mediterranean fig tree and its specific pollinator.

Tropospheric ozone (O3) is likely to affect the chemical signal emitted by flowers to attract their pollinators through its effects on the emission of volatile organic compounds (VOCs) and its high reactivity with these compounds in the atmosphere. We investigated these possible effects using a plant-pollinator interaction where the VOCs responsible for pollinator attraction are known and which is commonly exposed to high O3 concentration episodes: the Mediterranean fig tree (Ficus carica) and its unique pollinator, the fig wasp (Blastophaga psenes). In controlled conditions, we exposed fig trees bearing receptive figs to a high-O3 episode (5 h) of 200 ppb and analyzed VOC emission. In addition, we investigated the chemical reactions occurring in the atmosphere between O3 and pollinator-attractive VOCs using real-time monitoring. Finally, we tested the response of fig wasps to the chemical signal when exposed to increasing O3 mixing ratios (0, 40, 80, 120 and 200 ppb). The exposure of the fig tree to high O3 levels induced a significant decrease in leaf stomatal conductance, a limited change in the emission by receptive figs of VOCs not involved in pollinator attraction, but a major change in the relative abundances of the compounds among pollinator-attractive VOCs in O3-enriched atmosphere. Fig VOCs reacted with O3 in the atmosphere even at the lowest level tested (40 ppb) and the resulting changes in VOC composition significantly disrupted the attraction of the specific pollinator. These results strongly suggest that current O3 episodes are probably already affecting the interaction between the fig tree and its specific pollinator.

Using individual-based trait frequency distributions to forecast plant-pollinator network responses to environmental change.

Determining how and why organisms interact is fundamental to understanding ecosystem responses to future environmental change. To assess the impact on plant-pollinator interactions, recent studies have examined how the effects of environmental change on individual interactions accumulate to generate species-level responses. Here, we review recent developments in using plant-pollinator networks of interacting individuals along with their functional traits, where individuals are nested within species nodes. We highlight how these individual-level, trait-based networks connect intraspecific trait variation (as frequency distributions of multiple traits) with dynamic responses within plant-pollinator communities. This approach can better explain interaction plasticity, and changes to interaction probabilities and network structure over spatiotemporal or other environmental gradients. We argue that only through appreciating such trait-based interaction plasticity can we accurately forecast the potential vulnerability of interactions to future environmental change. We follow this with general guidance on how future studies can collect and analyse high-resolution interaction and trait data, with the hope of improving predictions of future plant-pollinator network responses for targeted and effective conservation.

Adaptive foraging of pollinators fosters gradual tipping under resource competition and rapid environmental change.

Plant and pollinator communities are vital for transnational food chains. Like many natural systems, they are affected by global change: rapidly deteriorating conditions threaten their numbers. Previous theoretical studies identified the potential for community-wide collapse above critical levels of environmental stressors-so-called bifurcation-induced tipping points. Fortunately, even as conditions deteriorate, individuals have some adaptive capacity, potentially increasing the boundary for a safe operating space where changes in ecological processes are reversible. Our study considers this adaptive capacity of pollinators to resource availability and identifies a new threat to disturbed pollinator communities. We model the adaptive foraging of pollinators in changing environments. Pollinator's adaptive foraging alters the dynamical responses of species, to the advantage of some-typically generalists-and the disadvantage of others, with systematic non-linear and non-monotonic effects on the abundance of particular species. We show that, in addition to the extent of environmental stress, the pace of change of environmental stress can also lead to the early collapse of both adaptive and nonadaptive pollinator communities. Specifically, perturbed communities exhibit rate-induced tipping points at stress levels within the safe boundary defined for constant stressors. With adaptive foraging, tipping is a more asynchronous collapse of species compared to nonadaptive pollinator communities, meaning that not all pollinator species reach a tipping event simultaneously. These results suggest that it is essential to consider the adaptive capacity of pollinator communities for monitoring and conservation. Both the extent and the rate of stress change relative to the ability of communities to recover are critical environmental boundaries.

Discussion: Harnessing microbiome-mediated adaptations in insect pollinators to mitigate climate change impact on crop pollination.

Insect pollinators, vital for agriculture and biodiversity, face escalating threats from climate change. We argue and explore the pivotal role of the microbiomes in shaping adaptations of insect pollinator resilience amid climate-induced challenges (climate change and habitat alteration). Examining diverse taxonomic groups, we unravel the interplay between insect physiology, microbiomes, and adaptive mechanisms. Climate-driven alterations in microbiomes impact insect health, behavior, and plant interactions, posing significant effects on agricultural ecosystems. We propose harnessing microbiome-mediated adaptations as a strategic approach to mitigate climate change impacts on crop pollination. Insights into insect-pollinator microbiomes offer transformative avenues for sustainable agriculture, including probiotic interventions (use of EM PROBIOTIC) and microbiome engineering (such as engineering gut bacteria) to induce immune responses and enhanced pollination services. Integrating microbiome insights into conservation practices elucidates strategies for preserving pollinator habitats, optimizing agricultural landscapes, and developing policies to safeguard pollinator health in the face of environmental changes. Finally, we stress interdisciplinary collaboration and the urgency of understanding pollinator microbiome dynamics under climate change in future research.

Arabidopsis leucine-rich repeat malectin receptor-like kinases regulate pollen-stigma interactions.

Flowering plants contain tightly controlled pollen-pistil interactions required for promoting intraspecific fertilization and preventing interspecific hybridizations. In Arabidopsis (Arabidopsis thaliana), several receptor kinases (RKs) are known to regulate the later stages of intraspecific pollen tube growth and ovular reception in the pistil, but less is known about RK regulation of the earlier stages. The Arabidopsis RECEPTOR-LIKE KINASE IN FLOWERS1 (RKF1)/RKF1-LIKE (RKFL) 1-3 cluster of 4 leucine-rich repeat malectin (LRR-MAL) RKs was previously found to function in the stigma to promote intraspecific pollen hydration. In this study, we tested additional combinations of up to 7 Arabidopsis LRR-MAL RK knockout mutants, including RKF1, RKFL1-3, LysM RLK1-INTERACTING KINASE1, REMORIN-INTERACTING RECEPTOR1, and NEMATODE-INDUCED LRR-RLK2. These LRR-MAL RKs were discovered to function in the female stigma to support intraspecific Arabidopsis pollen tube growth and to establish a prezygotic interspecific barrier against Capsella rubella pollen. Thus, this study uncovered additional biological functions for this poorly understood group of RKs in regulating the early stages of Arabidopsis sexual reproduction.

Multifunctionality of angiosperm floral bracts: a review.

Floral bracts (bracteoles, cataphylls) are leaf-like organs that subtend flowers or inflorescences but are of non-floral origin; they occur in a wide diversity of species, representing multiple independent origins, and exhibit great variation in form and function. Although much attention has been paid to bracts over the past 150 years, our understanding of their adaptive significance remains remarkably incomplete. This is because most studies of bract function and evolution focus on only one or a few selective factors. It is widely recognised that bracts experience selection mediated by pollinators, particularly for enhancing pollinator attraction through strong visual, olfactory, or echo-acoustic contrast with the background and through signalling the presence of pollinator rewards, either honestly (providing rewards for pollinators), or deceptively (attraction without reward or even trapping pollinators). However, studies in recent decades have demonstrated that bract evolution is also affected by agents other than pollinators. Bracts can protect flowers, fruits, or seeds from herbivores by displaying warning signals, camouflaging conspicuous reproductive organs, or by providing physical barriers or toxic chemicals. Reviews of published studies show that bracts can also promote seed dispersal and ameliorate the effects of abiotic stressors, such as low temperature, strong ultraviolet radiation, heavy rain, drought, and/or mechanical abrasion, on reproductive organs or for the plants' pollinators. In addition, green bracts and greening of colourful bracts after pollination promote photosynthetic activity, providing substantial carbon (photosynthates) for fruit or seed development, especially late in a plant's life cycle or season, when leaves have started to senesce. A further layer of complexity derives from the fact that the agents of selection driving the evolution of bracts vary between species and even between different developmental stages within a species, and selection by one agent can be reinforced or opposed by other agents. In summary, our survey of the literature reveals that bracts are multifunctional and subject to multiple agents of selection. To understand fully the functional and evolutionary significance of bracts, it is necessary to consider multiple selection agents throughout the life of the plant, using integrative approaches to data collection and analysis.

Pollinator-mediated effects of landscape-scale land use on grassland plant community composition and ecosystem functioning - seven hypotheses.

Environmental change is disrupting mutualisms between organisms worldwide. Reported declines in insect populations and changes in pollinator community compositions in response to land use and other environmental drivers have put the spotlight on the need to conserve pollinators. While this is often motivated by their role in supporting crop yields, the role of pollinators for reproduction and resulting taxonomic and functional assembly in wild plant communities has received less attention. Recent findings suggest that observed and experimental gradients in pollinator availability can affect plant community composition, but we know little about when such shifts are to be expected, or the impact they have on ecosystem functioning. Correlations between plant traits related to pollination and plant traits related to other important ecosystem functions, such as productivity, nitrogen uptake or palatability to herbivores, lead us to expect non-random shifts in ecosystem functioning in response to changes in pollinator communities. At the same time, ecological and evolutionary processes may counteract these effects of pollinator declines, limiting changes in plant community composition, and in ecosystem functioning. Despite calls to investigate community- and ecosystem-level impacts of reduced pollination, the study of pollinator effects on plants has largely been confined to impacts on plant individuals or single-species populations. With this review we aim to break new ground by bringing together aspects of landscape ecology, ecological and evolutionary plant-insect interactions, and biodiversity-ecosystem functioning research, to generate new ideas and hypotheses about the ecosystem-level consequences of pollinator declines in response to land-use change, using grasslands as a focal system. Based on an integrated set of seven hypotheses, we call for more research investigating the putative pollinator-mediated links between landscape-scale land use and ecosystem functioning. In particular, future research should use combinations of experimental and observational approaches to assess the effects of changes in pollinator communities over multiple years and across species on plant communities and on trait distributions both within and among species.

Embryological observations on seed abortion in Hibiscus syriacus L. and physiological studies on nutrients, enzyme activity and endogenous hormones.

Under natural conditions, most Hibiscus syriacus L. individuals form very few mature seeds or the mature seeds that do form are of poor quality. As a result, seed yield is poor and seeds have low natural germinability. These phenomena strongly hinder utilization of the excellent germplasm resources of H. syriacus. The study has shown that pollen activity and stigma receptivity were high on the day of anthesis, and the pistils and stamens were fertile. Pollen release and stigma receptivity were synchronous. But in styles following self and cross-pollination, pollen tube abnormalities (distortion and twisting of the pollen tubes) and callose deposition were observed. Cross-pollinated pollen tubes elongated faster and fewer pollen tube abnormalities were observed compared with self-pollinated pollen tubes. And during embryo development, abnormalities during the heart-shaped embryo stage led to embryo abortion. Imbalance in antioxidant enzyme activities and low contents of auxin and cytokinin during early stages of embryo development may affect embryo development. Therefore, a low frequency of outcrossing and mid-development embryo abortion may be important developmental causes of H. syriacus seed abortion. Nutrient deficiencies, imbalance in antioxidant enzyme activities, and a high content of abscisic acid at advanced stages of seed development may be physiological causes of seed abortion.

Ancient insect vision tuned for flight among rocks and plants underpins natural flower colour diversity.

Understanding the origins of flower colour signalling to pollinators is fundamental to evolutionary biology and ecology. Flower colour evolves under pressure from visual systems of pollinators, like birds and insects, to establish global signatures among flowers with similar pollinators. However, an understanding of the ancient origins of this relationship remains elusive. Here, we employ computer simulations to generate artificial flower backgrounds assembled from real material sample spectra of rocks, leaves and dead plant materials, against which to test flowers' visibility to birds and bees. Our results indicate how flower colours differ from their backgrounds in strength, and the distributions of salient reflectance features when perceived by these key pollinators, to reveal the possible origins of their colours. Since Hymenopteran visual perception evolved before flowers, the terrestrial chromatic context for its evolution to facilitate flight and orientation consisted of rocks, leaves, sticks and bark. Flowers exploited these pre-evolved visual capacities of their visitors, in response evolving chromatic features to signal to bees, and differently to birds, against a backdrop of other natural materials. Consequently, it appears that today's flower colours may be an evolutionary response to the vision of diurnal pollinators navigating their world millennia prior to the first flowers.

Association between land use, land cover, plant genera, and pollinator abundance in mixed-use landscapes.

Pollinators are threatened by land-use and land-cover changes, with the magnitude of the threat depending on the pollinating taxa, land-use type and intensity, the amount of natural habitat remaining, and the ecosystem considered. This study aims to determine the effect of land use (protected areas, plantations, pastures), land cover (percentage of forest and open areas within buffers of different sizes), and plant genera on the relative abundance of nectivorous birds (honeyeaters), bees (native and introduced), and beetles in the mixed-use landscape of the Tasman Peninsula (Tasmania, Australia) using mixed-effect models. We found the predictor selected (through model selection based on R2) and the effect of the predictors varied depending on the pollinating taxa. The land-use predictors were selected for only the honeyeater abundance model with protected areas and plantations having substantive positive effects. Land-cover predictors were selected for the honeyeater and native bee abundance models with open land cover within 1500 m and 250 m buffers having substantive negative and positive effects on honeyeaters and native bees respectively. Bees and beetles were observed on 24 plant genera of which only native plants (and not invasive/naturalised) were positively associated with pollinating insects. Pultenaea and Leucopogon were positively associated with native bees while Leucopogon, Lissanthe, Pimelea, and Pomaderris were positively associated with introduced bees. Leptospermum was the only plant genus positively associated with beetles. Our results highlight that one size does not fit all-that is pollinator responses to different landscape characteristics vary, emphasising the importance of considering multiple habitat factors to manage and support different pollinator taxa.