Specialized Pollination Systems Research Articles

Cospeciation is not the dominant driver of plant-pollinator codiversification in specialized pollination systems.

This study systematically rejects the long-standing notion of cospeciation as the dominant driver of codiversification between flowering plants and their specialist pollinators. Through cophylogenetic analysis of six classical specialized pollination systems, the research finds that cospeciation events are consistently outnumbered by non-cospeciation events, such as host-switch, duplication, and association losses. The findings support a more dynamic and diffuse codiversification paradigm, highlighting the importance of considering a broader range of evolutionary events in understanding plant-pollinator codiversification. This new understanding is robust across diverse pollination systems and has significant implications for conservation strategies in the face of environmental change.

Sex, flies and flower trap: Trapping trichomes and their function in pollination

Abstract Trapping trichomes, a common trait found in protogynous trap flowers, are thought to enable interaction with pollinators, promoting both pollen removal and fruit set. However, this hypothesis has yet to be empirically confirmed. In this study, we experimentally tested whether trapping trichomes favour male and female functions in trap flowers. Using protogynous South American Aristolochia esperanzae trap flowers, we observed the temporal variation in both sexual functions and associated them with the wilting of the flower and trapping trichomes. Next, we described the trapping trichomes features associated with the capture, entrapment and release of pollinators. Finally, we used manipulative experiments involving trapping trichome removal to quantify their influence on pollinator entrapment, pollen removal and fruit set. While flowers wilted after the end of the female phase, the trapping trichomes only wilted some hours after pollen presentation, promoting a delay in the exit of pollinators, so they carried pollen. Trapping trichomes features, such as a density gradient towards the interior of the tube, unidirectional orientation and epicuticular waxes, may be important in the capture and entrapment of pollinators. Trapping trichome removal decreased drastically the probability of pollinator entrapment and pollen removal, leading to no fruit set. These results indicate that the evolution and maintenance of trapping trichomes in trap flowers probably occurred through selective pressures from both sexual functions and highlight their role in the functioning of this highly phenotypically specialized pollination system. Read the free Plain Language Summary for this article on the Journal blog.

Long‐proboscid horseflies (Philoliche: Tabanidae) as pollinators of co‐adapted plants in Africa and Asia

AbstractElongated nectar‐feeding mouthparts have evolved in several fly families, most notably Nemestrinidae, Bombylidae and Tabanidae. Plants pollinated by these “long‐proboscid flies” tend to have relatively specialized pollination systems. In this review, I focus on the blood‐ and nectar‐feeding horsefly genus Philoliche (Tabanidae: Pangoniinae) which includes species that are important pollinators of plants in Africa and, to a lesser extent, in Asia. The nectar‐feeding mouthparts of flower‐visiting Philoliche species range from 5 to 65 mm in length, with considerable intraspecific variation evident in some taxa. Plants pollinated by Philoliche species tend to have corolla tubes (or highly exerted reproductive structures) that match the proboscis dimensions of their pollinators. Some Philoliche species and their nectar host plants show population‐level covariation in proboscis lengths and flower depths that is indicative of co‐adaptation. I summarize existing information on the distribution and morphology of Philoliche species known to pollinate flowers as well as the identity, morphology and nectar properties of plants pollinated by these insects. This survey identifies some Philoliche species as keystone pollinators. Distinct guilds of plants are adapted to different horsefly species in different geographical regions and are generally ecologically reliant on these insects, although some plant species share tabanid and nemestrinid pollinators that are functionally similar on account of convergent evolution of their proboscis dimensions. Lack of information about the larval biology, nectar host plants, fire ecology and dispersal distances of Philoliche species is the biggest challenge for the conservation of these specialized pollinators and the plants that depend on them.

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.

Selfing in epiphytic bromeliads compensates for the limited pollination services provided by nectarivorous bats in a neotropical montane forest.

Abstract. Plants with specialized pollination systems frequently exhibit adaptations for self-pollination, and this contradictory situation has been explained in terms of the reproductive assurance function of selfing. In the neotropics, several plant lineages rely on specialized vertebrate pollinators for sexual reproduction, including the highly diverse Bromeliaceae family, which also displays a propensity for selfing. Thus far, the scarce evidence on the role of selfing in bromeliads and in other neotropical plant groups is inconclusive. To provide insights into the evolution and persistence of self-fertilization in the breeding systems of Bromeliaceae, we studied four sympatric epiphytic species from the genus Werauhia (Tillandsioideae) in Costa Rica. We documented their floral biology, pollination ecology and breeding systems. We estimated the contribution of selfing by comparing the reproductive success between emasculated flowers requiring pollinator visits and un-manipulated flowers capable of selfing and exposed to open pollination across two flowering seasons. The studied species displayed specialized pollination by nectar-feeding bats as well as a high selfing ability (auto-fertility index values > 0.53), which was attained by a delayed selfing mechanism. Fruit set from natural cross-pollination was low (<26% in both years) and suggested limited pollinator visitation. In line with this, we found a very low bat visitation to flowers using video-camera recording, from 0 to 0.24 visits per plant per night. On the contrary, the contribution of selfing was comparatively significant since 54-80% of the fruit set from un-manipulated flowers can be attributed to autonomous self-pollination. We concluded that inadequate cross-pollination services diminished the reproductive success of the studied Werauhia, which was compensated for by a delayed selfing mechanism. The low negative effects of inbreeding on seed set and germination likely reinforce the persistence of selfing in this bromeliad group. These results suggest that selfing in bat-pollinated bromeliads may have evolved as a response to pollinator limitation.

Recovery of the reproductive functional diversity of edible fruit plant assemblages along the regeneration of a Caatinga dry forest

The ability of dry forests to deliver ecosystem services of both local and global relevance depends on the capacity of those forests to recover from constant disturbances in human-modified landscapes. Here we examine the effects posed by biomass, chronic human disturbances and aridity on the recovery of reproductive functional diversity by edible fruit plant assemblages following slash-and-burn agriculture in a Caatinga dry forest, in northeastern Brazil. The edible fruit plant assemblages were described across 24 forest stands, including regenerating stands of varying age (4 to 50 yr old) and old-growth stands, adopting a large set of reproductive traits as floral sizes, reproductive systems, and pollination systems. Such a chronosequence covered a gradient relative to aboveground biomass, aridity, and chronic anthropogenic disturbances (CAD). We observed that edible fruit plant assemblages across both regenerating and old-growth forest stands exhibited similar taxonomic diversity scores. This pattern is also figured in the recovery of reproductive traits, which is relatively fast as regenerating forest scores are generally similar or higher to those in old-growth forests. Generally, regenerating forest stands support more specialized reproductive traits and strategies than old-growth forest stands [e.g., edible fruit plants with very large flowers (>30 mm), specialized pollination systems, large fruits (>1.5 ≤3.0 mm), and medium-sized seeds (>0.6 ≤1.5 cm). However, the functional diversity of specialist reproductive traits decreased with increases in the levels of biomass and aridity, isolated, but was also impacted by the interactive effect. Considering the effects of biomass, CAD or aridity individually, we observed that biomass itself was responsible for most of the effects (42.8%), while 52.3% of the reproductive traits were negatively affected by CAD or aridity, which seems to be a major force against the recovery.

Specialized pollination system with generalized visitors in &lt;i&gt;Alocasia odora&lt;/i&gt;

Specialized pollination system with generalized visitors in &lt;i&gt;Alocasia odora&lt;/i&gt;

Reproductive ecology of Dianthus inoxianus: A rare wild carnation with a specialized pollination system

Plants with specialized pollination systems may be susceptible to reproductive failure when pollinator service is unpredictable. This can influence the selection of floral traits that promote outcrossing in the presence of pollinators and selfing in their absence. Limited evidence exists regarding the association between specialized pollination and reproductive assurance, necessitating further investigation. We studied the reproductive biology of Dianthus inoxianus, a rare Mediterranean carnation endemic to a semi-arid region in SW Spain. D. inoxianus exhibited protandrus flowers and additional phenotypic signs of specialization for nocturnal pollination. Nectar sugar concentration remains relatively constant throughout the day (average 33.4%), while the standing crop varies considerably (average 1.5 μL/flower), peaking in the late afternoon and early evening. Controlled hand pollinations revealed that D. inoxianus is fully self-compatible, with similar reproductive success in autogamous, geitonogamous, and allogamous crosses. However, a small proportion of bagged flowers exhibited autonomous selfing. To assess the impact of presumed nocturnal pollination, we studied reproductive fitness and flower visitors over five years in three populations. Over 210 h of pollinator censuses, the hawkmoth species Hyles livornica and Macroglossum stellatarum, which were mainly dusk-active, accounted for > 95% of flower visits. Fruit and seed set positively correlated with hawkmoth visitation rate across years and populations. Additionally, pollinator exclusion experiments demonstrated that reproduction relies predominantly on nocturnal pollinators. However, under natural conditions, D. inoxianus also showed a non-negligible degree of autonomous self-pollination, with fruit- and seed-set being equivalent in absence of pollinators or under diurnal pollinators. We found evidence of an ecologically specialized pollination system and capacity for autonomous selfing, a combination that may enable the persistence of this taxon in a markedly unpredictable pollination environment.

Calceolariaceae809: A bait set for targeted sequencing of nuclear loci.

The genus Calceolaria (Calceolariaceae) is emblematic of the Andes, is hypothesized to have originated as a recent, rapid radiation, and has important taxonomic needs. Additionally, the genus is a model for the study of specialized pollination systems, as its flowers are nectarless and many offer floral oils as a pollination reward collected by specialist bees. Despite their evolutionary and ecological significance, obtaining a resolved phylogeny for the group has proved difficult. To address this challenge, we present a new bait set for targeted sequencing of nuclear loci in Calceolariaceae and close relatives. We developed a bioinformatic workflow to use incomplete, low-coverage genomes of 10 Calceolaria species to identify single-copy loci suitable for phylogenetic studies and design baits for targeted sequencing. Our approach resulted in the identification of 809 single-copy loci (733 noncoding and 76 coding regions) and the development of 39,937 baits, which we validated in silico (10 specimens) and in vitro (29 Calceolariaceae and six outgroups). In both cases, the data allowed us to recover robust phylogenetic estimates. Our results demonstrate the appropriateness of the bait set for sequencing recent and historic specimens of Calceolariaceae and close relatives, and open new doors for further investigation of the evolutionary history of this hyperdiverse genus.

Janusia anisandra (A. Juss.) Griseb (Malpighiaceae): The first case of enantiostyly in oil‐flower species

AbstractEnantiostyly is a floral polymorphism characterized by style deflection to the right and left, which results in flowers with mirror images. To date, enantiostyly occurs only in species that offer pollen or nectar as floral resource. Here we describe the first case of enantiostyly in an oil‐flower species. Janusia anisandra (A. Juss.) Griseb (Malpighiaceae) shows right and left‐styled flowers in individuals occurring in an area of tropical dry forest in Northeastern Brazil. We described the floral morphology, investigate the reproductive system, and made focal observations of flower visitors behaviour. J. anisandra has morphological traits that are part of the floral conservatism found in the neotropical species of Malpighiaceae, which preserves features that are decisive for the interaction with oil‐collecting bees of the Centridini tribe, performing a highly specialized pollination system. The six stamens (two major and four smaller), located in the center of the flower, characterizes heteranthery, an intrafloral polymorphism, in which the stamens differ in shape, size, and function and is commonly associated with enantiostyly. We identified the two floral morphs in the same individual, characterizing a monomorphic enantiostyly; each of the morphs differs by lateral displacement of the style to the right or to the left, always accompanied by one larger stamen. The species is moderately self‐compatible. Four species of solitary bees of the genus Centris were registered visiting the two morphs of J. anisandra flowers. Centris aenea and C. fuscata were the main pollinators, performing 65% of the visits. This new discovery of a classical monomorphic enantiostyly in J. anisandra opens the way for investigations in the evolution of this system in oil‐secreting flowers.

Pollinator Proboscis Length Plays a Key Role in Floral Integration of Honeysuckle Flowers (Lonicera spp.).

Pollinator-mediated selection is supposed to influence floral integration. However, the potential pathway through which pollinators drive floral integration needs further investigations. We propose that pollinator proboscis length may play a key role in the evolution of floral integration. We first assessed the divergence of floral traits in 11 Lonicera species. Further, we detected the influence of pollinator proboscis length and eight floral traits on floral integration. We then used phylogenetic structural equation models (PSEMs) to illustrate the pathway through which pollinators drive the divergence of floral integration. Results of PCA indicated that species significantly differed in floral traits. Floral integration increased along with corolla tube length, stigma height, lip length, and the main pollinators' proboscis length. PSEMs revealed a potential pathway by which pollinator proboscis length directly selected on corolla tube length and stigma height, while lip length co-varied with stigma height. Compared to species with short corolla tubes, long-tube flowers may experience more intense pollinator-mediated selection due to more specialized pollination systems and thus reduce variation in the floral traits. Along elongation of corolla tube and stigma height, the covariation of other relevant traits might help to maintain pollination success. The direct and indirect pollinator-mediation selection collectively enhances floral integration.

Cone humidity is a strong attractant in an obligate cycad pollination system

Studies of pollination biology often focus on visual and olfactory aspects of attraction, with few studies addressing behavioral responses and morphological adaptation to primary metabolic attributes. As part of an in-depth study of obligate nursery pollination of cycads, we find that Rhopalotria furfuracea weevils show a strong physiological response and behavioral orientation to the cone humidity of the host plant Zamia furfuracea in an equally sensitive manner to their responses to Z.furfuracea-produced cone volatiles. Our results demonstrate that weevils can perceive fine-scale differences in relative humidity (RH) and that individuals exhibit a strong behavioral preference for higher RH in binary choice assays. Host plant Z.furfuracea produces a localized cloud of higher than ambient humidity around both pollen and ovulate cones, and R.furfuracea weevils preferentially land at the zone of maximum humidity on ovulate cones, i.e., the cracks between rows of megasporophylls that provide access to the ovules. Moreover, R.furfuracea weevils exhibit striking antennal morphological traits associated with RH perception, suggesting the importance of humidity sensing in the evolution of this insect lineage. Results from this study suggest that humidity functions in a signal-like fashion in this highly specialized pollination system and help to characterize a key pollination-mediating trait in an ancient plant lineage.

Environmental gradualism explains variation in pollination systems of columnar cacti: Phylogenetic and trait evolution analyses

AbstractAimThe geographical dichotomy hypothesis (GDH) states several flowering plant groups have specialized pollination systems in tropical areas where resources are more reliable and pollinator communities tend to be more stable, than in extratropical areas. Our main goal was to understand the scope of the GDH and/or gradual environmental variation considering the evolutionary history of the pollination traits.LocationNeotropical tropics and adjacent extratropics.Major taxa studiedColumnar cacti.MethodsUsing a database composed of ~54 columnar cacti species (31.7% of the global columnar cactus species), four complex traits were analysed: pollination syndromes, reproductive systems, type of anthesis, and duration of anthesis. We conducted generalized linear models (GLMs), phylogenetic regressions, evolutionary trait optimization, and multivariate models with 19 bioclimatic variables and potential evapotranspiration.ResultsWeak phylogenetic signal was detected for all traits, giving consistent results between GLMs and phylogenetic regression analysis. The pollination syndrome and duration of anthesis varied with latitude, in contrast to the reproductive system and the type of anthesis. In the Southern Hemisphere, the pollinators were more diverse and the duration of anthesis was longer. Different evolutionary paths between hemispheres were detected and optimization showed a complex pattern in the evolution of traits, suggesting high homoplasy with multiple transformations by convergence and/or parallelism. The environmental models showed thermic seasonality may be at the core of the latitudinal variation of the pollination system.Main conclusionsWe did not detect a geographical dichotomy in pollination systems of the cacti, but rather a gradual change in different pollination attributes. Therefore, instead of a GDH, we propose an environmental gradient hypothesis (EGH). Environmental variables may be explaining the variation detected in pollination system traits by conditioning floral properties (morphology, phenology), diversity and distribution of pollinators, and/or coevolution occurrence. The complexity implied in these traits is consistent with high homoplasy levels and a differential evolutionary history between the hemispheres.

Are floral traits and their phenotypic variability related to plants with generalized or specialized pollination systems? A community perspective

Flower traits under selection by specialized pollinators may experience a decrease in their phenotypic variation. Another viewpoint suggests that flower traits of plants under selection by generalized pollinators could display comparable variability to that of plant species with a specialized pollination system. We evaluated the following alternatives: (a) species with specialized pollination system (zygomorphic flowers, long corolla tube and higher amount of nectar, and visited by only one group of pollinators) will present higher natural fruit set and less floral phenotypic variation in comparison with species with generalized pollination system (actinomorphic flowers with short corolla tube and comparatively lower amount of nectar, and visited by a wide spectrum of taxonomically diverse pollinator species); (b) alternatively, if species with generalized pollination system show similar reproductive success to that of with specialized pollination system, comparable phenotypic variation in flower traits will be expected between them. Natural fruit set, corolla tube length, amount of nectar per flower, nectar sugar composition, and variability of these floral traits were measured in 43 biotically-pollinated species growing in a Chaco Serrano community from central Argentina. Plants were classified as specialists or generalists based on focal observations made to record their pollinators. Correlations and General Linear Models were used to compare fruit set and flower traits between plant species with generalized and specialized pollination system. Plants with specialized pollination system display flowers with higher amounts of nectar than plants with generalized pollination system. Nevertheless, species with generalized and specialized pollination system showed similar fruit set and floral phenotypic variation (except for the percentage of sucrose). The trends observed in species with generalized or specialized pollination systems from the Chaco forests suggest that pollinators could be an effective evolutionary force in selecting primary and secondary floral traits for both types of plant species.

Understanding floral variation in Leiothrix (Poales: Eriocaulaceae): anatomy, development and insights into pollination

Abstract Leiothrix differs from other genera of Eriocaulaceae by having pistillate flowers with nectariferous and stigmatic branches that diverge at different heights on the style and staminate flowers with free or fused petals. To understand the ontogenetic processes that result in these morphological variations, we studied the development and floral vasculature in six species of the genus. In pistillate flowers, the nectariferous branches, which are in a carinal position, correspond to the apex of the carpels, whereas the stigmatic branches, in a commissural position, are formed by the marginal tissues of the carpels and initiate later than the nectariferous branches. The upper margins of the carpels elongate, forming a tubular structure that raises the stigmatic branches; the greater its development, the greater the distance between the stigmatic and nectariferous branches. In staminate flowers, the fusion of the petals appears to be post-genital in the median and apical portions and congenital in the more basal portion. Despite the differences in floral development, Leiothrix shares the same pattern of floral vasculature with other genera of Eriocaulaceae, exhibiting a central vascular plexus in the receptacle from which a single trace diverges for each sepal, petal and stamen. The staminodes are not vascularized. The dorsal carpellary bundles supply the nectariferous branches, but the ventral carpel bundles are reduced and are not involved in the supply of the ovules and stigmas. The differences in the height of insertion of the nectariferous branches are probably the result of selective pressure exerted by different groups of pollinating insects. Our hypothesis is that species in which the nectariferous branches are inserted below the stigmatic branches, and are therefore less accessible, exhibit a more specialized pollination system. The absence of nectariferous branches in L. angustifolia indicates secondary loss probably associated with spontaneous geitonogamy.

Hawkmoth pollination of the scented South African fynbos endemic Erica cylindrica Thunb. (Ericaceae)

The predictive power of pollination syndromes has been demonstrated for many South African plant species with specialized pollination systems, but has rarely been tested in the florally diverse genus Erica. Here we evaluate the hypothesis that Erica cylindrica is moth-pollinated, based on its tubular, pale, and strongly scented flowers. Pollinator observations revealed exclusive nocturnal flower visitation by several hawkmoth species, and assessment of pollen loads confirmed that two hawkmoth species carried Erica pollen grains on their proboscises. Floral scent showed no clear periodicity in emission, but was dominated by benzenoid scent compounds including benzaldehyde, benzyl alcohol, benzyl acetate, and eugenol that are known to elicit antennal responses in hawkmoths. The pale cream flower colour was characterized by uniform reflectance across the human-visible light spectrum and a small secondary peak in the UV region. The volume of nectar produced was small, but the intermediate sugar concentration and sucrose:hexose ratio of 0.7 are consistent with hawkmoth pollination. More than three-quarters of flowers in an inflorescence are oriented upwards, which is highly unusual among South African ericas but has been shown to be adaptive in other hawkmoth-pollinated flowers. Anther-ring disruption indicated that at least 62% of flowers received visits and was associated with pollen deposition in 68% of visited flowers, suggesting that visitors are effective pollinators. Our study provides evidence for hawkmoth pollination of an Erica species, a system hitherto rarely recorded in Ericaceae. Several floral traits are consistent with the hawkmoth pollination syndrome, but further work is required to confirm the functional significance of these traits and the level of specialization in this hawkmoth pollination system.

Heterostyly, incompatibility system and pollinators in Varronia spinescens Borhidi (L.) (Cordiaceae)

Heterostyly, the reciprocal position of sexual organs between different morphs within a population, is assumed to promote cross-pollination in hermaphroditic plants. Heterostyly is usually linked to an incompatibility system where only the crosses between the different morphs produce fruit. Although heterostyly has been frequently studied in plant species with specialized pollination systems, few studies have investigated this in species with a broad spectrum of floral visitors. Here, we describe the heterostyly of Varronia spinescens and conducted hand-pollination experiments in the field to determine the incompatibility system. We also analysed perianth morphology, morph-ratio, adaptive inaccuracy in reciprocity and pollinator visitation rate in relation to floral morph and number of open flowers. Our results indicate that V. spinescens is a distylous species with a high degree of reciprocity between the sexual organs, presenting a non isoplethic morph ratio with a bias towards the long style (L-) morph. The incompatibility system is heteromorphic and the studied population received visits by a very high number of visitor and pollinator species. Varronia spinescens is thus the heterostylous species of the genus with the second-highest number of registered pollinators. Our results suggest that in a generalist pollination system with little floral morphological restriction to pollinators, the maintenance of sexual polymorphism is likely associated with a high reciprocity between morphs.

Temporal Consistency in Foraging Time and Bouts of a Carpenter Bee in a Specialized Pollination System

Temporal Consistency in Foraging Time and Bouts of a Carpenter Bee in a Specialized Pollination System

Two dioecious Simarouba species with a specialized pollination system and low reproductive efficacy in Central Brazil

Abstract Several possible correlations between dioecy and eco-morphological features have been suggested to infer the conditions that would favor this sexual system. Dioecy has been associated either with specialized or generalized pollination systems. The genus Simarouba has six dioecious species that seem to have generalized pollinators. In this study, we examined the reproductive biology aspects of two Simarouba species to evaluate which of their eco-morphological attributes may favor dioecy. Our data suggest that S. amara and S. versicolor have small, inconspicuous, and abundant flowers of nocturnal anthesis and are only pollinated by nocturnal moths. They have a stable sexual system with flower, inflorescence, and flowering phenology dimorphism that is part of their pollination system strategies. Male plants of both species produce more flowers per individual than do female plants. A larger floral display may have an essential role in increasing male reproductive success. However, both species showed low reproductive efficacy, especially S. versicolor. The low reproductive efficacy may be due to the lack of pollinators or to the inefficacy of the pollinators available locally.

Evidence for hawkmoth pollination in the chiropterophilous African baobab (Adansonia digitata)

AbstractChiropterophily, or bat pollination, is typically considered a highly specialized pollination system that has evolved independently numerous times across the angiosperm phylogeny, with distinct lineages often converging on a similar suite of floral traits. The African baobab, Adansonia digitata, occurs widespread across continental Africa and introduced throughout much of the tropics, possesses floral traits classically associated with bat pollination, namely nocturnal anthesis, pendulous white flowers, and a “musky” fragrance. Despite this, our observations and pollination exclusion experiments in South African baobab populations suggested little if any role for bats, but instead showed that hawkmoths are the main pollinators. Hand pollination indicated strong self‐incompatibility and crossing experiments suggest minimal diurnal receptivity. Furthermore, our analyses of floral volatiles revealed not only sulfur‐containing compounds, commonly associated with bat pollination, but also a high concentration of the sesquiterpene β‐caryophyllene, a compound generally more typical of hawkmoth pollination. Comparing previous pollination studies and published floral scent profiles from West Africa suggests that the classic bat pollination system in baobabs may be more labile than previously thought. This study provides an empirical example of a species that most likely evolved due to bat pollination yet has some degree of generality and possible geographic variation in floral traits and pollinator visitation patterns across its range.