Bat pollinators: a decade of monitoring reveals declining visitation rates for some species in Thailand.

Bats are important pollinators, but they are difficult to study since they are volant and nocturnal. Thus, long-term studies of nectarivorous bats are scarce, despite their potential to help assess trends in bat populations and their pollination services. We used capture rates of nectarivorous bats at chiropterophilous flowers in order to examine temporal trends in bat visitation in an area that is undergoing extensive land use change. We mist-netted at five bat-pollinated plant taxa (Durio zibethinus, Musa acuminata, Oroxylum indicum, Parkia speciosa, and Sonneratia spp.) in southern Thailand over six years between 2011 and 2021. We found that the most common bat species, Eonycteris spelaea, was the main visitor at all five plant taxa and had consistent visitation rates across all study years. In contrast, two other important pollinators, Macroglossus minimus and M. sobrinus, showed 80% declines in the number of individuals netted at mangrove apple (Sonneratia spp.) and banana (Musa acuminata) flowers, respectively. These findings suggest that E. spelaea (a large, cave-roosting species with a broad diet) is more tolerant of anthropogenic change than are Macroglossus bats (small, foliage-roosting species with specialized diets), which may in turn affect the reproductive success of plants pollinated by these species. Our study demonstrates how decade-long monitoring can reveal species-specific temporal patterns in pollinator visitation, emphasizing the need for tailored conservation plans. While the conservation status of most nectarivorous bats in the area is Least Concern, our results indicate that population studies in Southeast Asia are urgently needed for updated bat species conservation assessments.

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.

To be or not to be fragrant: floral scent of some bat-pollinated cacti.

Floral scent is a key olfactory cue in both diurnal and nocturnal pollination systems. In the case of nocturnal systems, such as bat-pollinated flowers, odour seems to play a more important role than visual cues. Cactaceae include many bat-pollinated species; however, few studies have investigated the olfactory cues in this family. We analysed and compared the chemical composition of the floral bouquet of three chiropterophilous cactus species, among which are a pair of congeners that differ considerably in scent intensity. Our research presents novel findings regarding the floral scent chemistry of chiropterophilous cactus species. We documented the first case of a bat-pollinated cactus whose flowers lack perceptible floral scent and in which no volatile compounds were detected in our chemical analyses. Additionally, we provide a comprehensive analysis of the chemical composition of the floral bouquet of the other two bat-pollinated species, revealing a resemblance among closely related species within the same genus. We highlight the need for further studies using biotests to investigate the mechanisms through which bats find flowers lacking scent.

Reproductive isolation between two sympatric bat-pollinated Bauhinia (Leguminosae).

Several barriers contribute to reproductive isolation between plant species, which can be classified as pre- or post-pollination. Understanding the strength of these barriers could clarify the factors that maintain reproductive isolation and thus species integrity. In this study, we quantified reproductive isolation between two bat-pollinated co-occurring Bauhinia species (B. acuruana and B. pentandra) with similar flower morphology. Over the course of 18 months, we assessed reproductive isolation between these two Bauhinia species by quantifying the individual strengths and absolute contributions of five pre- and post- pollination barriers. Our data showed that both species are completely isolated in their reproduction by a combination of several barriers. Although they co-occur in a few populations, we found a high degree of geographic isolation between them. And although their flowering periods overlap, there is a significant difference in flowering peaks. Both species have the same pollinating bats, but the interspecific transfer of pollen between the plant species may be reduced due to the different length of the flower stamens, resulting in different pollen deposition on the bats' bodies. We have documented complete incompatibility between taxa and conclude that pre- and post-pollination barriers are important factors in preventing gene flow, even in contact zones between these two species of Bauhinia. We highlight that our work is the first study to use methods to estimate the strength of reproductive isolation barriers between bat-pollinated species.

Spatiotemporal trends in floral visitation and interaction networks reveal shifting niches for bats in a Neotropical savanna.

Flower-vising bats are important components of tropical pollinator communities, yet little is known about the structure of their pollination networks and how resource availability through time (seasons) and space (habitat heterogeneity) affects the extent to which bats interact with plants within a community-wide context. This information is key for the conservation of threatened nectarivore species, such as the Cerrado-endemic Lonchophylla dekeyseri, for which data on its specialization on floral-resources is scarce. Within a seasonal and heterogeneous savanna in the central Brazilian Cerrado, we performed a year-round assessment of an inclusive assemblage of flower-visiting bats (both nectarivores and other guilds that can also feed on nectar) within a savanna-edge-forest gradient, the phenological trends and spatial distribution of bat and their resource plants, and the resultant temporal and spatial interaction networks between bats and plants in order to associate network structure to resource availability. Clear spatiotemporal trends emerged in the community. Nectarivores dominated the flower-visiting niche outside forests and were prolific floral visitors, resulting in networks with lower specialization and modularity. These bats diverged into savanna foragers active during the wet season and the wet-dry transition, and edge foragers active mostly during the dry season. The latter group encompassed L. dekeyseri, which visited mostly Bauhinia species. Frugivores took over as main floral visitors within forests, as well as during peak dry season, when fewer fruits were available, resulting in more specialized and modular networks. Our work shows that the turnover of floral resources across seasons and vegetation types has a defining role in bat-plant interactions and relates to network structure, as bat trophic guilds interact with plants in distinct habitats and times of the year. Frugivores dominate the flower-visiting niche in certain temporal and spatial subsets of the network, which calls for the inclusion of this guild in future studies. Moreover, the high visitation to Bauhinia species by L. dekeyseri during the dry season might reduce competition with other nectarivores and is relevant to the management of the species, although more data is needed on its resource consumption on a larger time frame and across its geographic range.

Morcegos visitantes florais são importantes componentes de comunidades tropicais de polinizadores, apesar de pouco ser conhecido sobre a estrutura de suas redes de polinização com plantas e como a disponibilidade de recursos através do tempo (estações) e espaço (heterogeneidade espacial) afeta a intensidade com a qual morcegos interagem com plantas na escala de comunidades. Estas são informações chave para a conservação de espécies ameaçadas de nectarívoros, como o morcego endêmico do Cerrado Lonchophylla dekeyseri, para o qual dados sobre especialização em recursos florais são escassos. Na savana sazonal e heterogênea do Cerrado central brasileiro, nós realizamos uma avaliação de uma assembleia de morcegos visitantes florais (incluindo nectarívoros e outras guildas que também podem alimentar-se de néctar) ao longo de um ano em um gradiente savana-borda-floresta, explorando as tendências fenológicas e distribuição espacial de morcegos e de suas plantas recurso, assim como a redes espaciais e temporais resultantes entre morcegos e plantas com o objetivo de associar a disponibilidade de recurso à sua estrutura. Claros padrões espaciotemporais emergiram na comunidade. Nectarívoros dominaram o nicho de visitação floral fora das florestas e foram visitantes prolíficos, resultando em redes marcadas por baixa especialização e modularidade. Estes morcegos divergiram entre aqueles que forrageiam em savanas e durante a estação chuvosa ou na transição chuva-seca, e aqueles forrageando nas bordas de mata e ativos principalmente na estação seca. Estes últimos incluíram L. dekeyseri, a qual visitou primariamente espécies de Bauhinia. Frugívoros dominaram o papel de visitantes florais dentro de florestas, assim como durante o pico da estação seca quando há menor disponibilidade de frutos, o que resultou em redes mais especializadas e modulares. Mostramos que a substituição de recursos florais ao longo das estações e de tipos de vegetação tem um papel preponderante nas interações morcego-planta e está relacionada à estrutura de rede, pois guildas tróficas interagem com plantas em habitas e em períodos do ano distintos. Frugívoros dominam o nicho de visitante floral em determinados subconjuntos temporais e espaciais da rede, o que destaca a importância de inclusão desta guilda em estudos futuros. Além disso, a forte visitação a espécies de Bauhinia por L. dekeiseri durante a estação seca pode resultar em uma competição reduzida com outros nectarívoros e é uma informação relevante para seu manejo da espécie, apesar de dados do consumo de recursos pela espécie em janelas temporais maiores e em toda sua extensão de ocorrência são necessários.

An ultrasound-absorbing inflorescence zone enhances echo-acoustic contrast of bat-pollinated cactus flowers.

Flowering plants have evolved an extraordinary variety of signalling traits to attract their pollinators. Most flowers rely on visual and chemical signals, but some bat-pollinated plants have evolved passive acoustic floral signals. All known acoustic flower signals rely on the same principle of increased sonar reflectivity. Here, we describe a novel mechanism that relies on increased absorption of the area surrounding the flower. In a bat-pollinated cactus (Espostoa frutescens) we found a hairy inflorescence zone, a so-called cephalium. Flowers solely emerge out of this zone. We measured the echoes of cephalia, flowers and unspecialized column surfaces and recorded echolocation calls of approaching bats. We found that the cephalium acts as a strong ultrasound absorber, attenuating the sound by -14 dB. The absorption was highest around the echolocation call frequencies of approaching bats. Our results indicate that, instead of making flowers more reflective, plants can also evolve structures to attenuate the background echo, thereby enhancing the acoustic contrast with the target.

A negative association between nectar standing crop and pollen transfer suggests nectar functions as a manipulator of pollinating bats.

BACKGROUND AND AIMS: Nectar standing crop has a fundamental role in controlling pollinator movements between flowers and individuals within a population. In bat pollination systems, plants take advantage of the cognitive abilities of nectarivorous bats, which integrate complex perceptions of the quality and spatial distribution of resources. Here, we propose that associations between standing crop and pollen transfer help to reveal the role of nectar as a manipulator of pollinator behaviour. METHODS: We used Harpochilus neesianus Ness (Acanthaceae), a bat-pollinated shrub from the Brazilian Caatinga, as a model system to assess nectar removal effects and standing crop, respectively, over the night and to test associations between the amount of nectar available to pollinators, and pollen import and export. KEY RESULTS: Harpochilus neesianus showed continuous nectar secretion throughout the flower lifespan. Flowers subjected to successive nectar removals produced less nectar than flowers sampled just once, and showed, despite a higher sugar concentration, a lower absolute amount of sugar. Under these conditions, bats may realize that nectar production is decreasing after repeated visits to the same flower and could be manipulated to avoid such already pollinated flowers with little nectar, thus increasing the probability of visits to flowers with a high amount of nectar, and a still high pollen availability on anthers and low pollen deposition on stigmas. We found that during most of the period of anthesis, nectar standing crop volume was positively correlated with the number of pollen grains remaining in the anthers, and negatively with the number of pollen grains deposited on the stigma. CONCLUSIONS: Nectar secretion patterns can function as a manipulator of pollinating bats in H. neesianus. We propose that the assessment of variability in nectar secretion in response to removal, and the correlation between nectar standing crop and relative pollen transfer throughout anthesis should be considered in order to understand the role of nectar in the manipulation of pollinators.

NeoBat Interactions: A data set of bat-plant interactions in the Neotropics.

Data papers and open databases have revolutionized contemporary science, as they provide the long-needed incentive to collaborate in large international teams and make natural history information widely available. Nevertheless, most data papers have focused on species occurrence or abundance, whereas interactions have received much less attention. To help fill this gap, we have compiled a georeferenced data set of interactions between 93 bat species of the family Phyllostomidae (Chiroptera) and 501 plant species of 68 families. Data came from 169 studies published between 1957 and 2007 covering the entire Neotropical Region, with most records from Brazil (34.5% of all study sites), Costa Rica (16%), and Mexico (14%). Our data set includes 2571 records of frugivory (75.1% of all records) and nectarivory (24.9%). The best represented bat genera are Artibeus (28% of all records), Carollia (24%), Sturnira (10.1%), and Glossophaga (8.8%). Carollia perspicillata (187), Artibeus lituratus (125), Artibeus jamaicensis (94), Glossophaga soricina (86), and Artibeus planirostris (74) were the bat species with the broadest diets recorded based on the number of plant species. Among the plants, the best represented families were Moraceae (17%), Piperaceae (15.4%), Urticaceae (9.2%), and Solanaceae (9%). Plants of the genera Cecropia (46), Ficus (42), Piper (40), Solanum (31), and Vismia (27) exhibited the largest number of interactions. These data are stored as arrays (records, sites, and studies) organized by logical keys and rich metadata, which helped to compile the information on different ecological and geographic scales, according to how they should be used. Our data set on bat-plant interactions is by far the most extensive, both in geographic and taxonomic terms, and includes abiotic information of study sites, as well as ecological information of plants and bats. It has already facilitated several studies and we hope it will stimulate novel analyses and syntheses, in addition to pointing out important gaps in knowledge. Data are provided under the Creative Commons Attribution 4.0 International License. Please cite this paper when the data are used in any kind of publication related to research, outreach, and teaching activities.

Pollinators drive floral evolution in an Atlantic Forest genus.

Pollinators are important drivers of angiosperm diversification at both micro- and macroevolutionary scales. Both hummingbirds and bats pollinate the species-rich and morphologically diverse genus Vriesea across its distribution in the Brazilian Atlantic Forest. Here, we (i) determine if floral traits predict functional groups of pollinators as documented, confirming the pollination syndromes in Vriesea and (ii) test if genetic structure in Vriesea is driven by geography (latitudinal and altitudinal heterogeneity) or ecology (pollination syndromes). We analysed 11 floral traits of 58 Vriesea species and performed a literature survey of Vriesea pollination biology. The genealogy of haplotypes was inferred and phylogenetic analyses were performed using chloroplast (rps16-trnk and matK) and nuclear (PHYC) molecular markers. Floral traits accurately predict functional groups of pollinators in Vriesea. Genetic groupings match the different pollination syndromes. Species with intermediate position were found between the groups, which share haplotypes and differ morphologically from the typical hummingbird- and bat-pollinated flowers of Vriesea. The phylogeny revealed moderately to well-supported clades which may be interpreted as species complexes. Our results suggest a role of pollinators driving ecological isolation in Vriesea clades. Incipient speciation and incomplete lineage sorting may explain the overall low genetic divergence within and among morphologically defined species, precluding the identification of clear species boundaries. The intermediate species with mixed floral types likely represent a window into shifts between pollinator syndromes. This study reports the morphological-genetic continuum that may be typical of ongoing pollinator-driven speciation in biodiversity hotspots.

Bromeliads going batty: pollinator partitioning among sympatric chiropterophilous Bromeliaceae.

Pollinators can be a limited resource and natural selection should favour differences in phenotypic characteristics to reduce competition among plants. Bats are important pollinators of many Neotropical plants, including the Bromeliaceae; however, the pre-pollination mechanisms for isolation among sympatric bat-pollinated bromeliads are unknown. Here, we studied the mechanisms for reproductive segregation between Pitcairnia recurvata, Pseudalcantarea viridiflora, Werauhia noctiflorens and W. nutans. The study was conducted at Los Tuxtlas Biosphere Reserve, in Veracruz, Mexico We carried out ex situ and in situ manual pollination treatments to determine the breeding system by assessing fruiting and seedling success and sampled bat visitors using mist-nets and infrared cameras. We determined the nocturnal nectar production pattern, estimating the energetic content of this reward. All four bromeliads are self-compatible, but only P. recurvata appears to require pollinators, because the physical separation between anthers and stigma prevents self-pollination, it is xenogamous and presents a strictly nocturnal anthesis. The bats Anoura geoffroyi, Glossophaga soricina and Hylonycteris underwoodi are probable pollinators of three of the studied bromeliads. We did not record any animal visiting the fourth species. The flowering season of each species is staggered throughout the year, with minimal overlap, and the floral morphology segregates the locations on the body of the bat where the pollen is deposited. The most abundant nectar per flower is provided by P. viridiflora, but P. recurvata offers the best reward per hectare, considering the density of flowering plants. Staggered flowering, different pollen deposition sites on the body of the pollinator and differences in the reward offered may have evolved to reduce the competitive costs of sharing pollinators while providing a constant supply of food to maintain a stable nectarivorous bat community.

Pollination by the locally endangered island flying fox (Pteropus hypomelanus) enhances fruit production of the economically important durian (Durio zibethinus).

Fruit bats provide valuable pollination services to humans through a unique coevolutionary relationship with chiropterophilous plants. However, chiropterophily in the Old World and the pollination roles of large bats, such as flying foxes (Pteropus spp., Acerodon spp., Desmalopex spp.), are still poorly understood and require further elucidation. Efforts to protect these bats have been hampered by a lack of basic quantitative information on their role as ecosystem service providers. Here, we investigate the role of the locally endangered island flying fox Pteropus hypomelanus in the pollination ecology of durian (Durio zibethinus), an economically important crop in Southeast Asia. On Tioman Island, Peninsular Malaysia, we deployed 19 stations of paired infrared camera and video traps across varying heights at four individual flowering trees in a durian orchard. We detected at least nine species of animal visitors, but only bats had mutualistic interactions with durian flowers. There was a clear vertical stratification in the feeding niches of flying foxes and nectar bats, with flying foxes feeding at greater heights in the trees. Flying foxes had a positive effect on mature fruit set and therefore serve as important pollinators for durian trees. As such, semi-wild durian trees-particularly tall ones-may be dependent on flying foxes for enhancing reproductive success. Our study is the first to quantify the role of flying foxes in durian pollination, demonstrating that these giant fruit bats may have far more important ecological, evolutionary, and economic roles than previously thought. This has important implications and can aid efforts to promote flying fox conservation, especially in Southeast Asian countries.

Finding flowers in the dark: nectar-feeding bats integrate olfaction and echolocation while foraging for nectar.

Nectar-feeding bats depend mainly on floral nectar to fulfil their energetic requirements. Chiropterophilous flowers generally present strong floral scents and provide conspicuous acoustic echoes to attract bats. While floral scents are assumed to attract bats over long distances, acoustic properties of flower structures may provide detailed information, thus supporting the localization of a flower at close ranges. So far, to our knowledge, there is no study trying to understand the relative importance as well as the combination of these generally coupled cues for detection (presence) and localization (exact position) of open flowers in nature. For a better comprehension of the significance of olfaction and echolocation in the foraging behaviour of nectar-feeding bats, we conducted two-choice experiments with Leptonycteris yerbabuenae. We tested the bats' behaviour in three experimental scenarios with different cues: (i) olfaction versus echolocation, (ii) echolocation versus echolocation and olfaction, and (iii) olfaction versus echolocation and olfaction. We used the floral scent of the bat-pollinated cactus Pachycereus pringlei as olfactory cue and an acrylic paraboloid as acoustic cue. Additionally, we recorded the echolocation behaviour of the bats and analysed the floral scent of P. pringlei. When decoupled cues were offered, bats displayed no preference in choice for any of the two cues. However, bats reacted first to and chose more often the coupled cues. All bats echolocated continuously and broadcast a long terminal group before a successful visit. The floral scent bouquet of P. pringlei is composed of 20 compounds, some of which (e.g. methyl benzoate) were already reported from chiropterophilous plants. Our investigation demonstrates for the first time to our knowledge, that nectar-feeding bats integrate over different sensory modes for detection and precise localization of open flowers. The combined information from olfactory and acoustic cues allows bats to forage more efficiently.

From dusk till dawn: nocturnal and diurnal pollination in the epiphyte Tillandsia heterophylla (Bromeliaceae).

In order to compare the effectiveness of diurnal and nocturnal pollinators, we studied the reproductive biology and pollinators of Tillandsia heterophylla E. Morren, an epiphytic tank bromeliad endemic to southeastern Mexico. Since anthesis in T. heterophylla is predominantly nocturnal but lasts until the following day, we hypothesised that this bromeliad would receive visits from both diurnal and nocturnal visitors, but that nocturnal visitors would be the most effective pollinators, since they arrive first to the receptive flower, and that bats would be the most frequent nocturnal visitors, given the characteristics of the nectar. Flowering of T. heterophylla began in May and lasted until July. The species is fully self-compatible, with an anthesis that lasts for ca. 15-16 h. Mean volume of nectar produced per flower was 82.21 µl, with a mean sugar concentration of 6.33%. The highest volume and concentration of nectar were found at 20:00 h, with a subsequent decline in both to almost zero over the following 12-h period. T. heterophylla has a generalist pollination system, since at least four different morphospecies of visitors pollinate its flowers: bats, moths, hummingbirds and bees. Most of the pollinating visits corresponded to bats and took place in the early evening, when stigma receptivity had already begun; making bats the probable pollinator on most occasions. However, diurnal pollinators may be important as a 'fail-safe' system by which to guarantee the pollination of T. heterophylla.

Differential pollen placement on an Old World nectar bat increases pollination efficiency.

BACKGROUND AND AIMS: Plant species that share pollinators are potentially subject to non-adaptive interspecific pollen transfer, resulting in reduced reproductive success. Mechanisms that increase pollination efficiency between conspecific individuals are therefore highly beneficial. Many nocturnally flowering plant species in Thailand are pollinated by the nectar bat Eonycteris spelaea (Pteropodidae). This study tested the hypothesis that plant species within a community reduce interspecific pollen movement by placing pollen on different areas of the bat's body. METHODS: Using flight cage trials, pollen transfer by E. spelaea was compared between conspecific versus heterospecific flowers across four bat-pollinated plant genera. Pollen from four locations on the bat's body was also quantified to determine if pollen placement varies by plant species. KEY RESULTS: It was found that E. spelaea transfers significantly more pollen between conspecific than heterospecific flowers, and that diverse floral designs produce significantly different patterns of pollen deposition on E. spelaea. CONCLUSIONS: In the Old World tropics, differential pollen placement is a mechanism that reduces competition among bat-pollinated plant species sharing a common pollinator.

Floral traits driving reproductive isolation of two co-flowering taxa that share vertebrate pollinators.

Floral attributes evolve in response to frequent and efficient pollinators, which are potentially important drivers of floral diversification and reproductive isolation. In this context, we asked, how do flowers evolve in a bat-hummingbird pollination system? Hence, we investigated the pollination ecology of two co-flowering Ipomoea taxa (I. marcellia and I. aff. marcellia) pollinated by bats and hummingbirds, and factors favouring reproductive isolation and pollinator sharing in these plants. To identify the most important drivers of reproductive isolation, we compared the flowers of the two Ipomoea taxa in terms of morphometry, anthesis and nectar production. Pollinator services were assessed using frequency of visits, fruit set and the number of seeds per fruit after visits. The studied Ipomoea taxa differed in corolla size and width, beginning and duration of anthesis, and nectar attributes. However, they shared the same diurnal and nocturnal visitors. The hummingbird Heliomaster squamosus was more frequent in I. marcellia (1.90 visits h(-1)) than in I. aff. marcellia (0.57 visits h(-1)), whereas glossophagine bats showed similar visit rates in both taxa (I. marcellia: 0.57 visits h(-1) and I. aff. marcellia: 0.64 visits h(-1)). Bat pollination was more efficient in I. aff. marcellia, whereas pollination by hummingbirds was more efficient in I. marcellia. Differences in floral attributes between Ipomoea taxa, especially related to the anthesis period, length of floral parts and floral arrangement in the inflorescence, favour reproductive isolation from congeners through differential pollen placement on pollinators. This bat-hummingbird pollination system seems to be advantageous in the study area, where the availability of pollinators and floral resources changes considerably throughout the year, mainly as a result of rainfall seasonality. This interaction is beneficial for both sides, as it maximizes the number of potential pollen vectors for plants and resource availability for pollinators.

First record of bat-pollination in the species-rich genus Tillandsia (Bromeliaceae).

BACKGROUND AND AIMS: Bromeliaceae is a species-rich neotropical plant family that uses a variety of pollinators, principally vertebrates. Tillandsia is the most diverse genus, and includes more than one-third of all bromeliad species. Within this genus, the majority of species rely on diurnal pollination by hummingbirds; however, the flowers of some Tillandsia species show some characteristics typical for pollination by nocturnal animals, particularly bats and moths. In this study an examination is made of the floral and reproductive biology of the epiphytic bromeliad Tillandsia macropetala in a fragment of humid montane forest in central Veracruz, Mexico. METHODS: The reproductive system of the species, duration of anthesis, production of nectar and floral scent, as well as diurnal and nocturnal floral visitors and their effectiveness in pollination were determined. KEY RESULTS: Tillandsia macropetala is a self-compatible species that achieves a higher fruit production through outcrossing. Nectar production is restricted to the night, and only nocturnal visits result in the development of fruits. The most frequent visitor (75 % of visits) and the only pollinator of this bromeliad (in 96 % of visits) was the nectarivorous bat Anoura geoffroyi (Phyllostomidae: Glossophaginae). CONCLUSIONS: This is the first report of chiropterophily within the genus Tillandsia. The results on the pollination biology of this bromeliad suggest an ongoing evolutionary switch from pollination by birds or moths to bats.