Sepals Research Articles

Aristolochia sanheensis (Aristolochiaceae), a new species from Yunnan, Southwest China

Aristolochia sanheensis, a new species from Yunnan, Southwest China, is described and illustrated for the first time. It is similar to A. luudamcui from northern Vietnam in the morphology of the calyx shape and the color of the inner calyx tube and limb, but is clearly distinguished by the limb triangular in lateral view, the prickly outgrowths of the inner limb, and the upper part of limb separated to ca. 1/2–2/3. It is evaluated as Critically Endangered (CR) according to the IUCN categories and criteria.

Evidence for moth pollination in a rhinomyiophilous Erica species from the Cape Floristic Region of South Africa.

Contrasting pollination syndromes in closely related species suggest that floral trait divergence is associated with differences in pollination system, but empirical observations are required to confirm syndrome-based predictions. We present a comparative study of two closely related Erica species with contrasting pollination syndromes from the Cape Floristic Region of South Africa. Ericacylindrica has narrowly tubular pale and strongly scented flowers and is known to be hawkmoth-pollinated. The closely related Ericainfundibuliformis has bright flower colours and appears to lack scent, traits that are suggestive of pollination by long-tongued nemestrinid flies (rhinomyiophily). Floral trait measurements revealed that both species exhibit predominantly upright flower orientation and elongated floral tubes, although tube length of E.infundibuliformis is consistently greater than that of E.cylindrica. For both species, petals are brighter than floral tube surfaces, but flowers of E.cylindrica lack the strong UV reflectance found in E.infundibuliformis. Nectar of E.infundibuliformis is more concentrated and produced in larger volumes. Scent composition, but not evening scent emission rates, differed between the species: scent of E.cylindrica is dominated by aromatic compounds, whereas scent of E.infundibuliformis is dominated by (E)-ocimene and other terpenoid compounds and is emitted at higher rates during the day than the evening. Pollinator observations contradicted trait-based predictions: although a single nemestrinid fly captured in the vicinity of E.infundibuliformis did carry Erica pollen, almost all other diurnal flower visitors were nectar-robbing Hymenoptera which did not carry Erica pollen. Contrary to predictions, at two sites and over two flowering seasons, flowers were consistently visited in the evenings by several species of settling moths and hawkmoths which carried pollen, almost exclusively of Erica, on their proboscides. Our findings thus suggest that, despite objective differences in key floral traits between the closely related hawkmoth-pollinated E.cylindrica and E.infundibuliformis, moths are also important pollinators of E.infundibuliformis. A bimodal pollination system involving predominant pollination by moths and occasional visits by long-proboscid flies could partially reconcile findings with predictions. Our study further suggests that hawkmoth pollination may be more widespread in both Erica and the broader Cape flora than has hitherto been assumed and emphasises the importance of nocturnal pollinator observations.

New distributional record of Henckelia monantha (Gesneriaceae) from India

Henckelia monantha only known from China so far is newly recorded for the Flora of India from Arunachal Pradesh. The species is close to Henckelia briggsioides but can be differentiated by its size of the calyx tube as well as the presence and absence of ovary indumentum. Detailed description of H. monantha, live plant photographs and ecology are presented here.

Boesenbergia kalakadensis sp. nov. (Zingiberaceae) from southern Western Ghats, India

Boesenbergia kalakadensis (Zingiberaceae), a new species from Kalakad‐Mundanthurai Tiger Reserve (KMTR), Tirunelveli District of Tamil Nadu, India is described and illustrated. Boesenbergia kalakadensis is closely allied to B. rotunda Mansf., and B. tiliifolia (Baker) Kuntze, but differs from them in its rhizome, leaves, inflorescence, length of flowers, glabrous nature of bract and bracteoles, length of calyx and corolla tube, size and shape of the corolla lobes, size, colour and margins of lateral staminodes, broader, orbicular, flat labellum, sessile, glandular hairy, crested anther, and length of style. A key to species of Boesenbergia in Peninsular India is provided.

Fruiting Characteristics and Molecular-Assisted Identification of Korla Fragrant Pear Bud Mutation Materials

Korla fragrant pear is a high-quality local pear variety native to Xinjiang, China. Currently, the low fruit-setting rate and low calyx shedding rate problems in Korla fragrant pears have been highlighted, which seriously affect the fruit yield and quality. It is of great significance to research the fruiting characteristics and molecular-assisted identification of Korla fragrant pear bud mutation materials for enriching the germplasm resources of Korla fragrant pear. In this research, a natural pollination group (YB) of Korla fragrant pear bud mutation materials and a natural pollination group (CK) of Korla fragrant pears were established. On the fruiting characteristics, the fruit-setting rate and calyx-removal rate of the two groups were investigated. In terms of fruit quality, the fruit shape index, fruit specific gravity, soluble solids content, sugar:acid ratio, soluble sugar content, and other indicators were measured. For the anatomical structure of the calyx tube, the detachment cells were observed. The formation time of the two groups of detached cells was compared. In the GBS simplified genome sequencing, a phylogenetic tree was constructed based on the obtained SNP sites. A principal component analysis, population genetic structure analysis, and genetic diversity index analysis were carried out. In the aspect of SSR molecular marker identification, the SSR types were counted. Polyacrylamide gel electrophoresis was performed. The results demonstrate the following: (1) the fruit-setting rate (30.87%) and calyx-removal rate (68.11%) in the YB group were significantly higher than those in the CK group (19.37%) and the calyx-removal rate (55.18%). (2) There was no significant difference in fruit quality indexes, such as average fruit weight (127.10–130.00 g) and soluble sugar content (9.47–9.56%) between the two groups. (3) Abscission-layer cells were observed at 2, 4, 6, 8, and 10 h after calyx tube discoloration in the YB group and at 48, 72, and 96 h after calyx tube discoloration in the CK group. (4) The genetic background of the YB group and the CK group was similar at the GBS level, but there were differences at the DNA level. This research finally shows that Korla fragrant pear bud mutation material is a good germplasm resource. This germplasm resource can promote the structural optimization of Korla fragrant pear varieties and the healthy development of the industry.

Clinopodium eplingianum (Lamiaceae), a new species from Oaxaca, Mexico

Recent botanical exploration in grasslands in northwestern Oaxaca have revealed a Clinopodium (Lamiaceae) taxon that cannot be referred to any of the current described species. This plant is most similar to C. hintoniorum from northeastern Mexico, in Nuevo Léon, in general habit and architecture; however, it can be easily distinguished by leaf blade shape and width, calyx teeth shape and length, lack of tufts of hairs between them and a distinction in the relative proportion between calyx and corolla tube. This new species represents an addition to the flora of Oaxaca and to the biogeographic province of Sierra Madre del Sur, being endemic to these two areas. The taxon is here presented as C. eplingianum in honor to Carl Epling, the most prominent scholar in the study of American Lamiaceae. Morphological description, distribution map and illustration of the species are provided.

Self-Incompatibility in Devil's Potato (Echites umbellatus Jacq., Apocynaceae) May Explain Why Few Flowers Set Fruit.

Pollinators are needed for the reproduction of Echites umbellatus, and only sphingid moths have mouthparts long enough to reach the nectar at the bottom of the species' long, twisted floral tube. Though plants produce many flowers over a period of several months, one observes very few fruits in nature. We asked: (1) Are plants self-compatible, or do they need pollen from another individual to set fruit and seed? (2) Are cross-pollinations between unrelated individuals more successful than crosses with relatives? (3) How does the relatedness of pollen and ovule parent plants affect fruit set, seed number, and seed quality? We investigated the breeding system of E. umbellatus by collecting fruits from seven sites, growing plants and performing hand pollinations over a period of several years, collecting and measuring fruits and counting seeds. Echites umbellatus is self-incompatible, though some individuals produce fruit by self-pollination. Cross-pollinations between unrelated individuals set the most fruit (59%), and those that were self-pollinated set the least (9%). Fruit set from cross-pollinations between related individuals was intermediate (32%). Although the number of seeds per fruit did not differ significantly among pollination treatments, fruits from self-pollinations had substantially fewer viable seeds than outcrossed fruits, with fruits from sibling crosses being intermediate. There were higher levels of self-compatibility in the fragment populations compared with plants from intact habitats. Self-incompatibility may explain why fruit set is low in this plant species; future investigation into the breakdown of self-incompatibility in smaller populations is warranted.

Floral thermal biology in relation to pollen thermal performance in an early spring flowering plant.

The floral microenvironment impacts gametophyte viability and plant-pollinator interactions. Plants employ mechanisms to modify floral temperature, including thermogenesis, absorption of solar radiation, and evaporative cooling. Whether floral thermoregulation impacts reproductive fitness, and how floral morphological variation mediates thermoregulatory capacity are poorly understood. We measured temperature of the floral microenvironment in the field and tested for thermogenesis in the lab in early spring flowering Hexastylis arifolia (Aristolochiaceae). We evaluated whether thermoregulatory capacity was associated with floral morphological variation. Finally, we experimentally determined the thermal optimum and tolerance of pollen to assess whether thermoregulation may ameliorate thermal stress to pollen. Pollen germination was optimal near 21 °C, with a 50% tolerance breadth of ~18 °C. In laboratory conditions, flowers exhibited thermogenesis of 1.5-4.8 °C for short intervals within a conserved timeframe (08:00-09:00 h). In the field, temperature inside the floral tube often deviated from ambient - floral interiors were up to 4 °C above ambient when it was cold, but some fell nearly 10 °C below ambient during peak heat. Flowers with smaller openings were cooler and more thermally stable than those with larger openings during peak heat. Thermoregulation maintained a floral microenvironment within the thermal tolerance breadth of pollen. Results suggest that H. arifolia flowers have a stronger capacity to cool than to warm, and that narrower floral openings create a distinct floral microenvironment, enhancing floral cooling effects. While deviation of floral temperature from ambient conditions maintains a suitable environment for pollen and suggests an adaptive role of thermoregulation, we discuss adaptive and nonadaptive mechanisms underlying floral warming and cooling.

A new species of Phlogacanthus (Acanthaceae) from India

Phlogacanthus sudhansusekharii, a new species is described here from the state of Arunachal Pradesh, India. This newly described species is closely allied to Phlogacanthus guttatus (Wall.) Nees, but can be differentiated by its strikingly different yellowish-cream colored corolla with yellow patches and brown maculation, ratio of calyx lobes and tube length being ~1:1 and deltoid staminodes (vs. greenish-cream to white corolla with red-maroon maculation, ratio of calyx lobes and tube length ~2:1 and subulate-ensiform staminodes in the latter).

Adaptive generalization in pollination systems: Hawkmoths increase fitness to long-tubed flowers, but secondary pollinators remain important.

Selection on floral traits by animal pollinators is important in the evolution of flowering plants, yet whether floral divergence requires specialized pollination remains uncertain. Longer floral tubes, a trait associated with long-tongued pollinators, can also exclude other pollinators from accessing rewards, a potential mechanism for specialization. Across most of its range, Castilleja sessiliflora displays much longer corollas than most Castilleja species, though tube length varies geographically and correlates partially with hawkmoth visitation. To assess whether long corolla tubes reflect adaptation to hawkmoth pollinators, we performed a day/night pollinator exclusion experiment in nine natural populations that varied in corolla length across the range of C. sessiliflora and short-tubed members of the parapatric C. purpurea complex. We compared the fitness contributions of nocturnal and diurnal visitors, revealing that long-tubed populations visited predominantly by hawkmoths experienced greater fruit set at night, in contrast with short-tubed populations or those visited mainly by diurnal pollinators. Next, leveraging a range-wide multiyear dataset of pollinator visitation to these species, we identify that hawkmoth visitation is associated with increased fitness in long-tubed populations overall, and that long tubes are associated with less diverse visitor assemblages. Thus, long corollas represent an adaptation to hawkmoth pollination at the exclusion of diverse pollinators. Nonetheless, while hawkmoths were scarce in the northern range, secondary diurnal pollinators contributed to fruit set across the range, providing reproductive assurance despite possible trait mismatch. This study illustrates adaptive generalization in pollination systems and that floral divergence may proceed along a continuum of generalized and specialized pollinator interactions.

Diverse material properties and morphology of moth proboscises relates to the feeding habits of some macromoth and other lepidopteran lineages.

Insects have evolved unique structures that host a diversity of material and mechanical properties, and the mouthparts (proboscis) of butterflies and moths (Lepidoptera) are no exception. Here, we examined proboscis morphology and material properties from several previously unstudied moth lineages to determine if they relate to flower visiting and non-flower visiting feeding habits. Scanning electron microscopy and three-dimensional imaging were used to study proboscis morphology and assess surface roughness patterns on the galeal surface, respectively. Confocal laser scanning microscopy was used to study patterns of cuticular autofluorescence, which was quantified with colour analysis software. We found that moth proboscises display similar autofluorescent signals and morphological patterns in relation to feeding habits to those previously described for flower and non-flower visiting butterflies. The distal region of proboscises of non-flower visitors is brush-like for augmented capillarity and exhibited blue autofluorescence, indicating the possible presence of resilin and increased flexibility. Flower visitors have smoother proboscises and show red autofluorescence, an indicator of high sclerotization, which is adaptive for floral tube entry. We propose the lepidopteran proboscis as a model structure for understanding how insects have evolved a suite of morphological and material adaptations to overcome the challenges of acquiring fluids from diverse sources.

Natural history of pollination of an Asian bignoniaceous tree: The long-tubed flower and the not-so-long bird bill

Bird pollination is well-established in New World Bignoniaceae, but studies of species with floral traits suggestive of bird pollination in the Old World are lacking. Here we studied the pollination ecology of Mayodendron igneum to test the prediction of pollination by specialist flower-visiting birds. Observations from multiple sites showed that both the Streaked Spiderhunter (Arachnothera magna) and pollen-collecting bees were floral visitors. However, almost no fruit was produced if birds were excluded, suggesting that bees do not play a role in pollination, and that pollination is performed almost exclusively by birds in this self-incompatible tree. Measurements of floral traits revealed a typical bird pollination syndrome, and the nectar concentration and volume were both within the proposed ranges based on other flowers pollinated by specialist birds. However, the rather low level of sucrose (less than 2 %) in nectar sugar contradicts the expectation for nectar of flowers pollinated by specialist nectar-feeding birds. Although the Streaked Spiderhunter is among the longest-billed flower-visiting birds in Asia, its bill is only 2/3 of the corolla tube in length, suggesting that the bird can extend the tongue to access nectar. This study is the first to experimentally confirm bird pollination in the Old World Bignoniaceae. It also indicates aspects that are possibly characteristic of spiderhunter pollination systems, i.e. high degrees of specialization, unusual nectar sugar composition, and floral tubes much longer than bird bills.

Genetic Analyses of Flower Main Traits from Two Pitayas and Their Progenies: A Cactus Plant.

Elucidation of the genetic foundation governing crucial traits in pitaya flowers is imperative for enhancing both the ornamental and economic values. In this study, the dynamic variation in flower genetics, segregation variation patterns, and a mixed inheritance model of the major and multigene flower traits of 'Dahong' and 'Honghuaqinglong' pitayas and their progenies were explored. The results showed that the main traits of flowers exhibited varying degrees of variation among the reciprocal F1 hybrids, with the data exhibiting the characteristics of quantitative traits. The betalain content, petal number, and stigma number exhibited values below the median values of the parents, suggesting a genetic inclination towards lower values. Perianth width, calyx tube width, petal number, and stigma number had the same genetic effects and significant correlation. Stigma-related traits had a clear maternal inheritance tendency. The heritability of flower length, stigma relative to anther distance, and petal betalain content was governed by two pairs of additive-dominant major genes. Perianth width, calyx tube width, petal number, and stigma number all conformed to the model of two pairs of equal-additive-dominant major genes. This study provides valuable information for parental selection, cross-breeding, and the enhancement of pitaya varieties to meet market preferences and environmental conditions.

Relictithismia kimotsukiensis, a new genus and species of Thismiaceae from southern Japan with discussions on its phylogenetic relationship.

The family Thismiaceae, known as "fairy lanterns" for their urn- or bell-shaped flowers with basally fused tepals, consists of non-photosynthetic flowering monocots mainly in tropical regions, extending into subtropical and temperate areas. Here, we propose a new mycoheterotrophic genus, Relictithismia Suetsugu & Tagane (Thismiaceae), with its monotypic species Relictithismia kimotsukiensis Suetsugu, Yas.Nakam. & Tagane from Kimotsuki Mountains in the Osumi Peninsula, Kagoshima Prefecture, Kyushu Island, southern Japan. Relictithismia resembles Haplothismia Airy Shaw in having a cluster of tuberous roots, a feature previously observed only in this genus within the family Thismiaceae. However, it differs in having solitary flowers (vs. 2-6-flowered pseudo-raceme in Haplothismia), anther thecae largely separated (vs. connate), and the presence of an annulus (vs. absent). Additionally, Relictithismia differs from the geographically overlapping genus Thismia Griff. in its stamen structure and the position of the annulus. In Relictithismia, the stamens lack connectives, and its free filaments arise from the annulus located inside the perianth mouth, while in Thismia, the stamens typically have connate connectives, forming a staminal tube pendulous from the annulus located at the mouth of the floral tube. Our morphological and phylogenetic data indicated that R. kimotsukiensis holds an early-diverging position within the family, situated outside the Old World Thismia clade. This paper offers an extensive description and color photographs of R. kimotsukiensis, complemented by notes on its phylogenetic relationship and evolutionary history.

Hydrangeaxinfeniae (Hydrangeaceae), a new species from Sichuan, China.

Hydrangeaxinfeniae W.B.Ju & J.Ru, a new species of Hydrangeaceae from Sichuan Province, China, is described and illustrated. The new species belongs to Hydrangeasect.Dichroa (Lour.) Y.De Smet & Samain, with its distinctive characteristic being the nearly superior ovary. It shares morphological similarities with H.yaoshanensis (Y.C.Wu) Y.De Smet & C.Granados, but can be distinguished by its hirsute trichomes densely covered on the branchlets, leaves, peduncles and pedicels, broadly elliptic to rectangular-elliptic leaf blade with nearly rounded base, coarse teeth leaf margins, 3-4 pairs of lateral veins, corymbose cyme with few and loose branches, lanceolate bract, the calyx tube and lobes margin with sparsely hirsute trichomes, adaxially glabrous and abaxially sparsely hirsute petal, outer whorl filaments are linear, inner ones are awl-shaped, glabrous styles, and the nearly superior ovary. H.xinfeniaesp. nov. currently known from only three relatively small populations of the type locality, and its conservation status is assessed as Data Deficient (DD).

Cuphea vazquezii (Lythraceae), a yellow-flowered new species from the Cerro Grande, Sierra de Manantlán, Colima, Mexico

Cuphea vazquezii (subgen. Cuphea, sect. Archocuphea, Lythraceae), a minute new species from Cerro Grande, Comala, Colima, Mexico, is described and illustrated. It is morphologically similar to C. mimuloides, from which it differs in having a none-rhizomatous habit; mostly alternate leaves and flowers; larger leaf blades; shorter pedicels; spurred floral tubes; two yellow petals; deflexed nectariferous disc; and larger seeds. According to IUCN criteria, the species was assessed as critically endangered (CR).

Pollination of Chamaepentas nobilis (Rubiaceae) by long‐proboscid hawkmoths in south‐central Africa: Trait mismatching and floral scent chemistry

AbstractThe evolution of extremely long (>10 cm) floral tubes in angiosperms is closely linked with adaptation for pollination by long‐proboscid hawkmoths. In most cases, pollen is placed on the head or body of these moths, selecting for floral tubes that match or slightly exceed their proboscis length as this ensures contact with reproductive parts of the flower. However, in the case of Chamaepentas nobilis (Rubiaceae), anthers are inserted inside the c. 12‐cm floral tubes and coat the proboscis of visiting hawkmoths with sticky pollen, meaning that insects with proboscides longer than the floral tube can be effective pollinators, despite trait mismatching. Direct observations and camera trapping on granite outcrops in central Zambia showed that C. nobilis was visited both by Agrius convolvuli (proboscis length c. 13 cm) and Xanthopan morganii (proboscis length c. 17 cm), which are the only moth species in Africa that can access the small amounts of dilute nectar at the base of the floral tube. Pollen on the proboscides of captured hawkmoths was confirmed to originate from C. nobilis. Key floral advertising traits of C. nobilis include early evening anthesis, the highly reflective white limbus, and the evening production of scent dominated by oxygenated aromatic and terpenoid compounds known to elicit antennal responses of A. convolvuli. This study shows that that A. convolvuli and X. morganii share floral resources and jointly pollinate C. nobilis, despite their proboscides differing in length and being mismatched with the corolla tube length.

Chamaeamygdalus, a new genus segregated from Amygdalus sensu lato (Prunus sensu latissimo, Rosaceae), based on available morphological and phylogenetic evidence

A rational generic concept in the group of Prunus sensu latissimo (Rosaceae) remains debatable, with two main approaches or traditions: one favouring a broad circumscription of Prunus, and another preferring its splitting into numerous segregate genera such as Armeniaca, Cerasus, Emplectocladus, Laurocerasus, Maddenia, Padus, Persica, Prunus s. str., Pygeum, etc. Members of these groups often hybridise with each other to form intermediates. This situation is parallel to the taxonomic options in another group of Rosaceae, the tribe Maleae, in which some authors recognise numerous genera (Aria, Aronia, Chaenomeles, Cotoneaster, Cydonia, Eriobotrya, Malus, Photinia, Sorbus, etc.). In contrast, others prefer a mega-genus Pyrus sensu latissimo. The genus Amygdalus (as well as other segregated genera mentioned above) is not recognised by many researchers and is considered a part of the genus Prunus s. l. However, species usually placed in Amygdalus are quite peculiar and habitually differ from other “prunoid” genera. The main feature distinguishing Amygdalus from closely related genera is the dry pericarp that opens when ripe. The group described as the section Chamaeamygdalus is the most isolated in Amygdalus. It includes low thornless shrubs with narrow leaves and small, densely tomentose-shaggy fruits. The shape of the calyx tube is a morphological feature that distinguishes the species of the section Chamaeamygdalus from the typical section of the genus. Phylogenetic analyses based on molecular data confirm the morphological differences between species of the section Chamaeamygdalus, which is the basis for assigning the generic rank to this group. The new genus Chamaeamygdalus is erected here, and three new species-rank nomenclatural combinations are validated for species of this genus.

Molecular and morphological evidence of hybridization between two dimorphic sympatric species of Fuchsia (Onagraceae).

Hybridization is commonly reported in angiosperms, generally based on morphology, and in few cases confirmed by molecular markers. Fuchsia has a long tradition of ornamental cultivars with different hybrids produced by artificial crosses, so natural hybridization between sympatric Fuchsia species could be common. Natural hybridization between F. microphylla and F. thymifolia was tested using six newly developed microsatellites for F. microphylla in addition to other molecular markers with codominant and maternal inheritance. Geometric morphometrics of leaves and floral structures were also used to identify putative hybrids. Hybrids showed a different degree of genetic admixture between both parental species. Chloroplast DNA (cpDNA) sequences indicated that hybridization occurs in both directions, in fact, some of the hybrids showed new haplotypes for cpDNA and ITS (internal transcriber spacer of nuclear ribosomal RNA genes) sequences. The morphology of hybrid individuals varied between the two parental species, but they could be better identified by their leaves and floral tubes. Our study is the first to confirm the hybridization in natural populations of Fuchsia species and suggests that hybridization has probably occurred repeatedly throughout the entire distribution of the species. Phylogeographic analysis of both species will be essential to understanding the impact of hybridization throughout their complete distribution.

Drivers of sunbird‐plant interactions on Mount Cameroon: Between neutrality and niche‐based processes

AbstractThe drivers behind plant‐pollinator interactions still need to be fully understood. Previous research has suggested that observed interactions result from either neutral interaction between species based on their abundance or from niche‐based processes, which are reflected in the adaptations of both plants and pollinators. Furthermore, the importance of both scenarios can differ depending on seasonal dynamics translated into differences in resource availability. Extensive research has been conducted on New‐World hummingbirds (Trochilidae), whereas much less is known about Old World nectar‐feeding sunbirds (Nectariniidae). Our study aimed to explore whether sunbird‐plant interactions are explained by neutral and/or niche‐based processes. Thus, we tested the effects of abundance, morphology, and nectar sugar content on the observed interactions and the link between sunbirds and plant traits. Moreover, we explored the effects of robbing on these mechanisms. Finally, we investigated the partitioning of bird pollination niches, based on floral traits. We used a dataset of sunbird‐plant interactions collected at Mount Cameroon during two seasons (dry and wet seasons). Our study shows that sunbird‐plant interactions are influenced by both neutral and niche‐based processes. Neutral processes and nectar reward were the main mechanisms underlaying the observed interactions in the dry season. However, as more ornithophilous plants bloom during the rainy season, morphological trait‐matching becomes more important. We found a correlation between bill length and floral tube dimensions and observed niche overlap among the sunbird species. Considering this and other research, we suggest that plant‐pollinator interactions are influenced by a combination of both neutral and niche‐based processes.