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Convergence between species and entire clades can occur due to shared environmental conditions and shared resource use. Comparisons of biogeography between convergent clades and taxa may reveal some of these properties unique to each taxon. We sought to characterize and compare the global scale biogeography of hummingbirds (family Trochilidae), which possess unique adaptations for nectar feeding, with sunbirds (family Nectariniidae), which also feed on nectar but are more generalist in their feeding ecology. We collected the latitudinal and elevational range of all species in both clades to create species distributions along those gradients by way of empirical cumulative distribution functions. We compared those distributions to see 1) if they differed, by way of minimum difference estimation and 2) how they differed, by way of non-linear regression. Hummingbirds are shown to extend into higher elevations and latitudes compared to sunbirds, and better maintain their species number in these more extreme environments. We provide possible reasons for these patterns including dispersal limitation, land area, diversity of resources, and climatic conditions. In one particularly interesting hypothesis, we propose that hummingbirds’ unique adaptations for nectar feeding allow them to exploit resources more efficiently, gain higher intrinsic fitness, and therefore speciate and spread into more extreme climates than less efficient nectar feeding sunbirds.

Aim: Among the world's three major nectar-feeding bird taxa, hummingbirds are the most phenotypically specialized for nectarivory, followed by sunbirds, while the honeyeaters are the least phenotypically specialized taxa. We tested whether this phenotypic specialization gradient is also found in the interaction patterns with their floral resources. Location: Americas, Africa, Asia and Oceania/Australia. Methods: We compiled interaction networks between birds and floral resources for 79 hummingbird, nine sunbird and 33 honeyeater communities. Interaction specialization was quantified through connectance (C), complementary specialization (H2′), binary (QB) and weighted modularity (Q), with both observed and null-model corrected values. We compared interaction specialization among the three types of bird–flower communities, both independently and while controlling for potential confounding variables, such as plant species richness, asymmetry, latitude, insularity, topography, sampling methods and intensity. Results: Hummingbird–flower networks were more specialized than honeyeater–flower networks. Specifically, hummingbird–flower networks had a lower proportion of realized interactions (lower C), decreased niche overlap (greater H2′) and greater modularity (greater QB). However, we found no significant differences between hummingbird– and sunbird–flower networks, nor between sunbird– and honeyeater–flower networks. Main conclusions: As expected, hummingbirds and their floral resources have greater interaction specialization than honeyeaters, possibly because of greater phenotypic specialization and greater floral resource richness in the New World. Interaction specialization in sunbird–flower communities was similar to both hummingbird–flower and honeyeater–flower communities. This may either be due to the relatively small number of sunbird–flower networks available, or because sunbird–flower communities share features of both hummingbird–flower communities (specialized floral shapes) and honeyeater–flower communities (fewer floral resources). These results suggest a link between interaction specialization and both phenotypic specialization and floral resource richness within bird–flower communities at a global scale.

Introduced plants become decoupled from their usual pollinators and by relying on resident pollinator species or other reproductive strategies become established in new areas, spread and, eventually, invade. Here, using breeding system experiments, we studied the reproductive biology of the bird-pollinated South American species Nicotiana glauca across native and non-native areas, both inside and outside the range of flower-visiting birds. In the native range, where the species is visited by hummingbirds, open cross-pollinated flowers set as many seeds and almost as many fruits as open pollination controls, suggesting that pollinators make a major contribution to reproductive success. In South Africa, the flowers were pollinated by sunbirds which, although less efficiently, also contributed to N. glauca reproduction, replacing hummingbirds. In contrast, in Mallorca, where nectar feeding birds are absent, fruit production in open cross-pollinated flowers was near zero, and significantly lower than in open pollination controls, suggesting that reproduction is almost entirely by autonomous self-pollination. Hand-pollination experiments showed that the species is self-compatible throughout its range. Pollinator exclusion experiment showed that N. glauca relies on self-pollination only in pollinator poor areas, where plants have a much higher capacity for autonomous self-pollination than elsewhere. A reduction in anther-stigma distance does not seem to account the higher self-pollination capacity in the non-native environment without pollinators. Despite probable evolutionary adaptation, and flexibility in pollinator association and mating system, seed production in the introduced range was somewhat pollen limited, suggesting that the mismatch between N. glauca and its novel pollination environment might retard invasion.

Due to drastic changes in pollinators between native and invaded habitats, we might expect that pollinator-mediated selection on floral traits of alien plants differ from that in their native ranges. Here, through geometric morphometric tools and phenotypic selection analyses, we examined whether adaptation in flower shape and length occurred in Nicotiana glauca as a response to pollinator selection in contrasting pollination environments. We assessed populations of this plant species in the native range (South America), where plants depend on hummingbird pollination, and in two invaded areas, one where sunbirds act as pollinators (South Africa), and another where nectar feeding birds are absent and reproduction is entirely by autonomous self-pollination (Mallorca, Spain). Corolla length and shape varied significantly among pollination environments. Non-native sites were less variable and their range of variation fell within the native range of variation. Flower length in native populations and in a South African population matched the bill length of their respective pollinators. In contrast with the straight floral tubes in the native range, both non-native areas had significantly curved tubes. Curvature may improve the fit with the curved bills of sunbirds in South Africa (versus straight beaks of hummingbirds) and may enhance self-pollination in Mallorca, but this similarity between invaded areas may equally be due to drift and a shared colonization route. We found spatial variation in selection acting on corolla length but not on corolla shape. Overall, selection patterns were not consistent with floral trait variation. Although some results are consistent with both drift and selection, our study suggests that population divergence in flower shape and length is more likely the result of long-term diversifying pollinator-driven selection, which is difficult to detect by studying a single selection event.

Vertebrate pollination is widespread in Musaceae, with birds and bats serving as the main pollen vectors across the family. While these systems are typically well defined, the Golden Lotus (Musella lasiocarpa) has long been regarded as an exception, presumed to rely on insect, particularly bee, pollination. In this study, we challenge that assumption by providing the first comprehensive evidence of bird visitation and putative pollination in M. lasiocarpa. Through field surveys complemented by citizen science observations, we documented an unexpectedly rich assemblage of avian visitors: twelve bird species from five families regularly foraged at flowers and likely acted as pollinators. This represents a striking expansion of the known potential pollinator spectrum for the species and highlights a previously overlooked dimension of its reproductive ecology. The floral traits of M. lasiocarpa, including vivid bracts, accessible nectar, and extended flowering, align closely with adaptations to bird pollination. Beyond clarifying the natural history of the Golden Lotus, our findings reveal broader insights into the ecological and cultural significance of bird pollination in the Chinese flora, with implications for both biodiversity conservation and horticultural practices.

QUESTION: Pollinators are often implicated in the origin of plant species, but their role during the assembly of diverse plant communities has only rarely been investigated. Intra‐specific competition for pollinators can theoretically facilitate plant species co‐occurrence by limiting the density of any one species, while inter‐specific competition can potentially structure communities through the exclusion of inferior competitors. We analyse plant community composition and use field experiments to test whether intra‐ and inter‐specific competition for pollinators structures communities of co‐occurring Erica species. LOCATION: Cape Floral Region, southwestern South Africa (ca. 34° S, 18° E). METHODS AND RESULTS: In the study area, the genus Erica has diversified into ca. 680 species that differ primarily in their floral morphologies, reflecting insect, bird and wind pollination syndromes. Vegetation plot data from nine regions throughout the Fynbos Biome were used to test whether the frequency of co‐occurrence of species with the same pollination syndrome differs from a null model of random community assembly. We found that Erica communities were assembled randomly with respect to pollination in six regions, but that pollination syndrome co‐occurrence was significantly lower than expected in three regions. This over‐dispersion of syndromes across communities is consistent with communities being structured by inter‐specific competition for pollinators. To better understand the processes generating these patterns, we conducted competition experiments with six Erica species that share the Orange‐breasted sunbird (Anthobaphes violacea) as pollinator. We transplanted inflorescences of a focal Erica species into communities containing another resident Orange‐breasted sunbird bird‐pollinated Erica species and recorded pollination and nectar robbing rates in both the resident and the transplanted species in relation to the floral density of the resident species. Consistent with the observed community structure, pollination rate in both the resident and the introduced species declined with increasing density of the resident species, but the effect was not consistent among all populations. Nectar robbing rates of the resident species were negatively related to its own density. CONCLUSION: Our analyses concur that both intra‐ and inter‐specific competition for pollination can contribute to structuring plant communities, but it is not the dominant factor structuring Erica communities.

Despite a growing number of studies, the role of pollinators as a selection agent for nectar traits remains unclear. Moreover, the lack of data from some biogeographic regions prohibits us from determining their general importance and global patterns. We analyzed nectar carbohydrate traits and determined the main pollinators of 66 plant species in the tropical forests of Mount Cameroon (tropical West Africa). The measured nectar traits included total sugar amounts and proportions of sucrose and hexoses (i.e., glucose and fructose). We report the nectar properties for plants visited by five pollinator groups (bees, butterflies, moths, hoverflies, and specialized birds). Our results indicate that, rather than specific evolution in each of the five plant groups, there was a unique nectar-trait evolution in plants pollinated by specialized birds. The ornithophilous plants had a higher proportion of sucrose and produced larger sugar amounts than the plants pollinated by insects. We also demonstrated a significant phylogenetic signal in the nectar properties in some lineages of the studied plants.

Adaptation to pollinators can include the spatial arrangement of flowers on inflorescences. A brush-like arrangement of flowers has evolved in multiple plant families. The accessible rewards in these “brush flowers” are often utilized by both birds and insects, making it challenging to assess which are the main contributors to pollination. We investigated two such species,  Scadoxus puniceus  and  S.   membranaceus , by means of camera trapping, direct observations, and selective exclusion and controlled pollination experiments in order to determine the extent to which sunbirds contribute to their pollination. We found that flowers of  S. puniceus  are frequently visited by sunbirds, butterflies and honeybees, whereas those of  S. membranaceus  are rarely visited. Birds typically perch directly on the densely packed flowers of  S. puniceus  and pick up large, visible pollen loads on their beaks, heads and feet as they feed on nectar. The flowers of this species match the bills of the sunbirds in length, and the floral nectar properties are also consistent with specialisation for pollination by sunbirds. Butterflies feed on the nectar of  S. puniceus , but seldom contact the reproductive structures, likely limiting their effectiveness for pollen transfer. Selective exclusion of larger visitors, including birds and butterflies, negatively affected fruit and seed set for both species. Controlled pollination experiments revealed that  S. puniceus  is self-incompatible, whereas  S. membranaceus  is self-compatible and can set fruit autonomously. This study reveals that these two paintbrush lilies which are considered to be closely related have divergent pollination and breeding systems despite sharing similar inflorescence architecture.

The coevolutionary relationships between avian malaria parasites and their hosts influence the host specificity, geographical distribution and pathogenicity of these parasites. However, to understand fine scale coevolutionary host–parasite relationships, robust and widespread sampling from closely related hosts is needed. We thus sought to explore the coevolutionary history of avian Plasmodium and the widespread African sunbirds, family Nectariniidae. These birds are distributed throughout Africa and occupy a variety of habitats. Considering the role that habitat plays in influencing host-specificity and the role that host-specificity plays in coevolutionary relationships, African sunbirds provide an exceptional model system to study the processes that govern the distribution and diversity of avian malaria. Here we evaluated the coevolutionary histories using a multi-gene phylogeny for Nectariniidae and avian Plasmodium found in Nectariniidae. We then assessed the host–parasite biogeography and the structuring of parasite assemblages. We recovered Plasmodium lineages concurrently in East, West, South and Island regions of Africa. However, several Plasmodium lineages were recovered exclusively within one respective region, despite being found in widely distributed hosts. In addition, we inferred the biogeographic history of these parasites and provide evidence supporting a model of biotic diversification in avian Plasmodium of African sunbirds.