Evolutionary disruption in the pollination system of Vanilla (Orchidaceae).

Pollination of the pantropical Vanilla has been linked to melittophily and food deception. Here we investigated the role of flower traits on the reproduction of Neotropical Vanilla. We also studied the evolution of pollination systems in order to understand the origin of production of flower resources and the diversification of pollinators in this orchid genus. Our study was founded on data of adaptations in flower morphology, production of resources, scent release, pollinators and breeding systems of Vanilla and presenting new data on reproductive biology of V. palmarum. Data on reproductive biology of Vanilla were mapped onto a phylogeny to address our queries on the evolution of pollination systems in this genus. Vanilla palmarum shows a mixed mating system, with its facultative autogamous flowers being pollinated by hummingbirds. Its yellow flowers are scentless and produces nectar. Mapping of the pollination system onto trees resulted in one origin for bird pollination and at least two origins for autogamy in Vanilla. Nectar secretion has a single origin in the Neotropical thick-leafed lineage. Bird pollination of Vanilla is shown for the first time. The origin of ornithophily within a bee-pollinated clade is supported by flower morphology. Floral transitions to ornithophily have been favoured by the occupation of a distinct niche from that of the other thick-leafed Vanilla species. Despite its specialized pollination, V. palmarum is autogamous. A mixed mating system can promote reproductive assurance in the case of a decline in pollinator populations, or in areas where pollinator services are irregular or absent.

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.

Hummingbird pollination and the diversification of angiosperms: an old and successful association in Gesneriaceae.

The effects of specific functional groups of pollinators in the diversification of angiosperms are still to be elucidated. We investigated whether the pollination shifts or the specific association with hummingbirds affected the diversification of a highly diverse angiosperm lineage in the Neotropics. We reconstructed a phylogeny of 583 species from the Gesneriaceae family and detected diversification shifts through time, inferred the timing and amount of transitions among pollinator functional groups, and tested the association between hummingbird pollination and speciation and extinction rates. We identified a high frequency of pollinator transitions, including reversals to insect pollination. Diversification rates of the group increased through time since 25 Ma, coinciding with the evolution of hummingbird-adapted flowers and the arrival of hummingbirds in South America. We showed that plants pollinated by hummingbirds have a twofold higher speciation rate compared with plants pollinated by insects, and that transitions among functional groups of pollinators had little impact on the diversification process. We demonstrated that floral specialization on hummingbirds for pollination has triggered rapid diversification in the Gesneriaceae family since the Early Miocene, and that it represents one of the oldest identified plant-hummingbird associations. Biotic drivers of plant diversification in the Neotropics could be more related to this specific type of pollinator (hummingbirds) than to shifts among different functional groups of pollinators.

Reproductive biology of a hummingbird-pollinated Billbergia: light influence on pollinator behaviour and specificity in a Brazilian semi-deciduous forest.

Ornithophily has evolved in parallel several times during evolution of angiosperms. Bird pollination is reported for 65 families, including Bromeliaceae. One of the most diverse bromeliad is Billbergia, which comprises species pollinated mainly by hummingbirds. Based on investigations on flowering phenology, morpho-anatomy, volume and concentration of nectar, pollinators and breeding system, this paper explores the reproductive biology and pollinator specificity of B. distachia in a mesophytic semi-deciduous forest of southeastern Brazil. The results have show that B. distachia is pollinated by a single species of hermit hummingbird, Phaethornis eurynome, which search for nectar produced by a septal nectary, where the secretory tissue is located above the placenta. The species is self-incompatible. The combination of pollinator specificity, due to long corolla tubes that exclude visitation of short-billed hummingbirds, complete self-incompatibility and non-territorial behaviour of pollinators, it is very important to reduce pollen loss and increase gene flow within population. Our results indicate that studies on pollination biology and reproduction are essential to understand the evolutionary history of pollination systems of plants since, at least in Billbergia, variation in the pollinator spectrum has been recorded for different habitats among Brazilian forests. Furthermore, according to our data, foraging of Phaethornis on flowers is independent of air temperature and humidity, while the main factor influencing hummingbird visitation is daylight. Considering current knowledge on climatic parameters influencing hummingbird foraging, pollination and reproductive biology of Neotropical flora and environment of the hermit hummingbird in tropical forests, new insights on plant-pollinator interaction are provided.

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.

Convergence beyond flower morphology? Reproductive biology of hummingbird-pollinated plants in the Brazilian Cerrado.

Convergent reproductive traits in non-related plants may be the result of similar environmental conditions and/or specialised interactions with pollinators. Here, we documented the pollination and reproductive biology of Bionia coriacea (Fabaceae), Esterhazya splendida (Orobanchaceae) and Ananas ananassoides (Bromeliaceae) as case studies in the context of hummingbird pollination in Cerrado, the Neotropical savanna of Central South America. We combined our results with a survey of hummingbird pollination studies in the region to investigate the recently suggested association of hummingbird pollination and self-compatibility. Plant species studied here differed in their specialisation for ornithophily, from more generalist A. ananassoides to somewhat specialist B. coriacea and E. splendida. This continuum of specialisation in floral traits also translated into floral visitor composition. Amazilia fimbriata was the most frequent pollinator for all species, and the differences in floral display and nectar energy availability among plant species affect hummingbirds' behaviour. Most of the hummingbird-pollinated Cerrado plants (60.0%, n = 20), including those studied here, were self-incompatible, in contrast to other biomes in the Neotropics. Association to more generalist, often territorial, hummingbirds, and resulting reduced pollen flow in open savanna areas may explain predominance of self-incompatibility. But it is possible that mating system is more associated with the predominance of woody hummingbird plants in the Cerrado plant assemblage than to the pollination system itself.

Pollination ecology of two species of Elleanthus (Orchidaceae): novel mechanisms and underlying adaptations to hummingbird pollination.

Relationships among floral biology, floral micromorphology and pollinator behaviour in bird-pollinated orchids are important issues to understand the evolution of the huge flower diversity within Orchidaceae. We aimed to investigate floral mechanisms underlying the interaction with pollinators in two hummingbird-pollinated orchids occurring in the Atlantic forest. We assessed floral biology, nectar traits, nectary and column micromorphologies, breeding systems and pollinators. In both species, nectar is secreted by lip calli through spaces between the medial lamellar surfaces of epidermal cells. Such a form of floral nectar secretion has not been previously described. Both species present functional protandry and are self-compatible yet pollinator-dependent. Fruit set in hand-pollination experiments was more than twice that under natural conditions, evidencing pollen limitation. The absence of fruit set in interspecific crosses suggests the existence of post-pollination barriers between these sympatric co-flowering species. In Elleanthus brasiliensis, fruits resulting from cross-pollination and natural conditions were heavier than those resulting from self-pollination, suggesting advantages to cross-pollination. Hummingbirds pollinated both species, which share at least one pollinator species. Species differences in floral morphologies led to distinct pollination mechanisms. In E. brasiliensis, attachment of pollinarium to the hummingbird bill occurs through a lever apparatus formed by an appendage in the column, another novelty to our knowledge of orchid pollination. In E. crinipes, pollinarium attachment occurs by simple contact with the bill during insertion into the flower tube, which fits tightly around it. The novelties described here illustrate the overlooked richness in ecology and morphophysiology in Orchidaceae.

A comunidade de beija-flores e as plantas que visitam em uma área de cerrado ralo da Chapada Diamantina, Bahia, Brasil / The hummingbird community and the plants which they visit at a savannah in the Chapada Diamantina, Bahia, Brazil

Na Chapada Diamantina, porção norte da Cadeia do Espinhaço, ainda é escasso o conhecimento sobre as comunidades de beija-flores e das plantas que visitam, sendo que os registros disponíveis são de áreas de campo rupestre e caatinga. Este estudo objetivou identificar a troquilofauna de uma área de cerrado ralo da Chapada Diamantina, Bahia, reportando sua sazonalidade e interações agonísticas, além das espécies de plantas que exploram, considerando seus atributos florais e sua fenologia de floração. Os dados foram coletados no município de Mucugê, de outubro de 2005 a agosto de 2006, durante expedições bimestrais em área de cerrado ralo, denominado localmente como "Gerais de Mucugê" (13º 07'15,7"S; 41º 34'53,6"W). Foram registradas quais as espécies de beija-flores ocorrem, sua sazonalidade, suas interações agonísticas inter e intraespecíficas, quais as espécies de plantas visitam, seus atributos florais (morfometria floral, tipo e coloração da flor, concentração de néctar) e seu período de floração. Oito espécies de beija-flores foram registradas: Phaethornis pretrei, Chlorostilbon lucidus, Heliactin bilophus, Eupetomena macroura, Colibri serrirostris, Calliphlox amethystina, Chrysolampis mosquitus e Anopetia gounellei - as três primeiras, residentes na área. Apenas 21 interações agonísticas foram observadas, nas quais Heliactin bilophus esteve envolvido em 12 delas. Esta espécie de beijaflor forrageou o maior número de espécies de plantas (nove espécies), das quais cinco espécies são ornitófilas, e foi considerada a espécie organizadora desta guilda de polinizadores nesta área. Onze espécies de plantas foram utilizadas por beija-flores, das quais sete ornitófilas. O padrão fenológico de floração estimado foi sequencial e contínuo, garantindo recursos aos beija-flores residentes durante todo o ano.

In the northern portion of the Espinhaço Range, records of hummingbird communities and their plants are restricted to rocky fields ("campo rupestre") and dry lands ("caatinga") habitats. This study aimed to identify the flower resources used by hummingbirds in a savannah area at Chapada Diamantina. With this purpose we described hummingbirds' seasonality and agonistic interactions, and floral attributes and flowering phenology of their plant resources. The surveys were carried out at "Gerais de Mucugê" (13º 07'15,7"S; 41º 34'53,6"W) in Chapada Diamantina, municipality of Mucugê, state of Bahia, Brazil. Twelve expeditions were undertaken on a bi-monthly basis between October, 2005 and August, 2007 at an open savannah area. Field activities included observations of hummingbird species, their behavior, and the frequency of their visits; as well as the plant species they visited, their floral attributes, size of corollas, and the flowering period. Eight species of hummingbirds were recorded: Phaethornis pretrei, Chlorostilbon lucidus, Heliactin bilophus, Eupetomena macroura, Colibri serrirostris, Calliphlox amethystina, Chrysolampis mosquitus and Anopetia gounellei - the first three species were residents. We observed 21 agonistic interactions, in which Heliactin bilophus was involved in 12 of them. This species of hummingbird visited the largest number of plant species (nine species), most of which were considered ornithophilous (five species), and it was considered the organizer of the pollinator's guild of the study area. Eleven species of plants were used by hummingbirds, of which seven were considered ornithophilous. The plant community presented a continuous flowering, providing year-round resource for resident hummingbirds.

Flowers visited by hummingbirds in an urban Cerrado fragment, Mato Grosso do Sul, Brazil

Hummingbirds are the main vertebrate pollinators in the Neotropics, but little is known about the interactions between hummingbirds and flowers in areas of Cerrado. This paper aims to describe the interactions between flowering plants (ornithophilous and non-ornithophilous species) and hummingbirds in an urban Cerrado remnant. For this purpose, we investigated which plant species are visited by hummingbirds, which hummingbird species occur in the area, their visiting frequency and behavior, their role as legitimate or illegitimate visitors, as well as the number of agonistic interactions among these visitors. Sampling was conducted throughout 18 months along a track located in an urban fragment of Cerrado vegetation in Campo Grande, Mato Grosso do Sul, Brasil. We found 15 species of plants visited by seven species of hummingbirds. The main habit for ornithophilous species was herbaceous, with the predominance of Bromeliaceae; among non-ornithophilous most species were trees from the families Vochysiaceae and Malvaceae. Hylocharis chrysura was the hummingbird that visited the largest number of plant species and also attended the greater number of agonistic events. The high proportion (66.7%) of non-ornithophilous species visited by hummingbirds in the present study was similar to that found in other communities analyzed in Brazil. The fact that ornithophilous species in the area does not offer resources continuously throughout the year should induce hummingbirds to search for alternative resources, and contribute to the high proportion of non-ornithophilous species visited. In general, the floral form was not a barrier to floral visits by hummingbirds, although morphological characteristics of flowers from some plant species may be restrictive. Tabebuia aurea, for example, presents flowers with long corollas, hindering the access to floral resources by the pollinators, what may favor the occurrence of illegitimate visits by hummingbirds. Despite of being a small fragment of Cerrado vegetation, the studied remnant can be considered an important refuge, sheltering a great richness of hummingbird species comparable to several forested areas in Brazil.

Os beija-flores são os principais vertebrados polinizadores na região Neotropical, mas pouco ainda se conhece sobre as interações entre beija-flores e flores em áreas de Cerrado. O objetivo deste estudo foi descrever as interações entre espécies de plantas em floração (ornitófilas e não-ornitófilas) e beija-flores, em um fragmento urbano de Cerrado. Para isso, investigamos quais espécies de plantas são visitadas por beija-flores, quais espécies de beija-flores ocorrem na área, seu comportamento e frequência de visitas, sua atuação como visitante legítimo ou ilegítimo, assim como o número de interações agonísticas entre essas aves. Foram realizados 18 meses de amostragem ao longo de uma trilha localizada em um fragmento urbano de Cerrado em Campo Grande, Mato Grosso do Sul, Brasil. Foram encontradas 15 espécies de plantas visitadas por sete espécies de beija-flores. O principal hábito para as espécies ornitófilas foi herbáceo, com a predominância da família Bromeliaceae; entre as não-ornitófilas o principal hábito foi o arbóreo, com a predominância das famílias Vochysiaceae e Malvaceae. Hylocharis chrysura foi o beija-flor que realizou o maior número de visitas às flores e o que participou de maior número de ocorrências agonísticas. A elevada proporção (66,7%) de espécies não-ornitófilas visitadas por beija-flores no presente estudo também vem sendo reportada em outras comunidades analisadas no Brasil. O fato de as espécies ornitófilas da área estudada não oferecerem recurso de forma contínua ao longo de todo o ano deve induzir os beija-flores a procurar recursos alternativos, e contribuir para a alta proporção de espécies não-ornitófilas visitadas. De modo geral, a forma floral não foi obstáculo às visitas dos beija-flores, apesar de as características morfológicas de algumas espécies de plantas poderem ser restritivas. Tabebuia aurea, por exemplo, tem flores de corola longa, o que dificulta o acesso ao néctar pelos beija-flores, podendo favorecer a ocorrência de visitas ilegítimas. Apesar de ser um fragmento de Cerrado pequeno, o remanescente estudado pode ser considerado um importante refúgio, abrigando riqueza de espécies de beija-flores comparável à de diversas formações florestais do Brasil.

Community-wide assessment of pollen limitation in hummingbird-pollinated plants of a tropical montane rain forest.

BACKGROUND AND AIMS: Although pollen limitation of reproduction (PL) has been widely studied, our understanding of its occurrence in tropical communities, especially for bird-pollinated plants, is underdeveloped. In addition, inclusion of both quantity and quality aspects in studies of PL are generally lacking. Within hummingbird-pollinated plants, a prediction was made for higher PL for the quality than quantity aspects and a minor effect of temporal variation because hummingbirds are constant and efficient pollen vectors but they may transfer low quality pollen. METHODS: Field hand and open pollination experiments were conducted on 21 species in a tropical montane rain forest over 2 years. The quantity (fruit set and seeds per fruit) and quality (seed weight and germination) aspects of reproduction were assessed as the response to open pollination relative to outcross hand pollination. The relationships between the effect size of quantity and quality aspects of reproduction and predictive plant features (self-incompatibility, autogamy, density and pollinator specialization level) were assessed with phylogenetic generalized linear models. KEY RESULTS: Just over half of all the species expressed PL for one or more response variables. On average, the severity of PL was strong for one quality variable (seed germination; 0·83), but insignificant for another (seed weight; -0·03), and low to moderate for quantity variables (0·31 for seeds per fruit and 0·39 for fruit set). There was only a minor contribution of temporal variation to PL within the studied species. Common predictors of PL, i.e. phylogenetic relatedness, self-incompatibility, autogamy, plant density and pollinator specialization level, did not adequately explain variation in PL within this community. CONCLUSIONS: Despite the measurable degree of PL within these hummingbird-pollinated plants, the causes of pollen quality and quantity insufficiency are not clear. Variables other than those tested may contribute to PL or causes of PL may vary among species and cannot adequately be accounted for when assessed from the within-community perspective.

The community of hummingbirds (Aves: Trochilidae) and the assemblage of flowers in a Caatinga vegetation / A comunidade de beija-flores (Aves: Trochilidae) e a assembleia de flores em uma área de Caatinga

We studied hummingbirds and their food plants in an area of caatinga vegetation. We specifically examined their seasonal use of this habitat, migratory and non-migratory status, their foraging strategies and community roles The study was conducted in an area of arboreal-shrub caatinga, located in the Serra do Pará, municipality of Santa Cruz do Capibaribe, state of Pernambuco in northeastern Brazil. Field work was undertaken during 12 expeditions on a monthly basis between June, 2007 and May, 2008. Five species of hummingbirds were recorded visiting flowers in the community studied. Three were considered residents: Chlorostilbon lucidus (Shaw, 1812), Eupetomena macroura (Gmelin, 1788), and Heliomaster squamosus (Temminck, 1823). Hummingbirds visited 31 species of plants, of which only five presented attributes related to ornithophily. C. lucidus visited 29 plant species, including all ornithophilous species, and it was the most aggressive, defending territories. Among hummingbirds, C. lucidus may be considered the principal pollinator. Hummingbirds may also be acting as pollen vectors for some of the plant species not identified as ornithophilous. The hummingbird guilds varied among the plant species used as floral resources, as well as in their frequency of visits. Differences in plant species abundance, hummingbird preference, competitive exclusion or flowering seasonality are factors likely to influence those variations.

Propôs-se estudar os beija-flores e as espécies de plantas utilizadas como recurso alimentar em uma área de caatinga, estudando especificamente a sazonalidade das espécies de beija-flores nesse habitat, os status migratório e não migratório, as suas estratégias de forrageamento e os papéis comunitários. O estudo foi conduzido em uma área de caatinga arbóreo-arbustiva, localizada na Serra do Pará, município de Santa Cruz do Capibaribe, Estado de Pernambuco, no nordeste do Brasil. Os trabalhos de campo foram realizados durante 12 expedições mensais entre junho de 2007 e maio de 2008. Cinco espécies de beija-flores foram registradas visitando flores na comunidade estudada. Três espécies foram consideradas residentes: Chlorostilbon lucidus (Shaw, 1812), Eupetomena macroura (Gmelin, 1788) e Heliomaster squamosus (Temminck, 1823). Os beija-flores visitaram 31 espécies de plantas, das quais apenas cinco apresentaram atributos relacionados à ornitofilia. C. lucidus visitou 29 espécies de plantas, incluindo todas as ornitófilas, assim como também foi a espécie mais agressiva, defendendo territórios. Entre os beija-flores, C. lucidus pode ser considerado como o principal polinizador. Os beija-flores podem estar atuando como vetores de pólen para algumas espécies de plantas não identificadas como ornitófilas. As guildas de beija-flores variaram entre as espécies de plantas utilizadas como recurso floral, assim como nas suas frequências de visitas. Diferenças na abundância das espécies de plantas, na preferência por parte dos beija-flores, na exclusão competitiva ou na sazonalidade de floração são fatores que podem ter influência sobre essas variações.

The community of hummingbirds (Aves: Trochilidae) and the assemblage of flowers in a Caatinga vegetation

We studied hummingbirds and their food plants in an area of caatinga vegetation. We specifically examined their seasonal use of this habitat, migratory and non-migratory status, their foraging strategies and community roles The study was conducted in an area of arboreal-shrub caatinga, located in the Serra do Pará, municipality of Santa Cruz do Capibaribe, state of Pernambuco in northeastern Brazil. Field work was undertaken during 12 expeditions on a monthly basis between June, 2007 and May, 2008. Five species of hummingbirds were recorded visiting flowers in the community studied. Three were considered residents: Chlorostilbon lucidus (Shaw, 1812), Eupetomena macroura (Gmelin, 1788), and Heliomaster squamosus (Temminck, 1823). Hummingbirds visited 31 species of plants, of which only five presented attributes related to ornithophily. C. lucidus visited 29 plant species, including all ornithophilous species, and it was the most aggressive, defending territories. Among hummingbirds, C. lucidus may be considered the principal pollinator. Hummingbirds may also be acting as pollen vectors for some of the plant species not identified as ornithophilous. The hummingbird guilds varied among the plant species used as floral resources, as well as in their frequency of visits. Differences in plant species abundance, hummingbird preference, competitive exclusion or flowering seasonality are factors likely to influence those variations.

Propôs-se estudar os beija-flores e as espécies de plantas utilizadas como recurso alimentar em uma área de caatinga, estudando especificamente a sazonalidade das espécies de beija-flores nesse habitat, os status migratório e não migratório, as suas estratégias de forrageamento e os papéis comunitários. O estudo foi conduzido em uma área de caatinga arbóreo-arbustiva, localizada na Serra do Pará, município de Santa Cruz do Capibaribe, Estado de Pernambuco, no nordeste do Brasil. Os trabalhos de campo foram realizados durante 12 expedições mensais entre junho de 2007 e maio de 2008. Cinco espécies de beija-flores foram registradas visitando flores na comunidade estudada. Três espécies foram consideradas residentes: Chlorostilbon lucidus (Shaw, 1812), Eupetomena macroura (Gmelin, 1788) e Heliomaster squamosus (Temminck, 1823). Os beija-flores visitaram 31 espécies de plantas, das quais apenas cinco apresentaram atributos relacionados à ornitofilia. C. lucidus visitou 29 espécies de plantas, incluindo todas as ornitófilas, assim como também foi a espécie mais agressiva, defendendo territórios. Entre os beija-flores, C. lucidus pode ser considerado como o principal polinizador. Os beija-flores podem estar atuando como vetores de pólen para algumas espécies de plantas não identificadas como ornitófilas. As guildas de beija-flores variaram entre as espécies de plantas utilizadas como recurso floral, assim como nas suas frequências de visitas. Diferenças na abundância das espécies de plantas, na preferência por parte dos beija-flores, na exclusão competitiva ou na sazonalidade de floração são fatores que podem ter influência sobre essas variações.

Pollination biology and reproduction of Seemannia sylvatica (Kunth) Hanstein (Gesneriaceae) in the Serra da Bodoquena National Park, Mato Grosso do Sul / Biologia da polinização e reprodução de Seemannia sylvatica (Kunth) Hanstein (Gesneriaceae) no Parque Nacional da Serra da Bodoquena, Mato Grosso do Sul

In Brazil, the family Gesneriaceae is represented by 23 genera and approximately 200 species. Seemannia sylvatica is an herb that occurs in dense populations in the riverbeds at Serra da Bodoquena. Goals of this study were to report the floral biology (on the first five days of anthesis), as well as to determine the breeding system and the pollinators of S. sylvatica. Data collection was conducted from June 2005 to July 2006 through monthly field trips, lasting for five days. Data on floral biology, breeding system and on the floral visitors were taken from individuals located along a track 2500 m long, in riparian forest of Salobrinha river. Flowers of S. sylvatica are tubular, red, with no perceptive odor and lasted more than five days (ca. 10 - 20 days in individuals transferred to an urban garden and kept in vases). Seemania sylvatica is protandrous, and the male phase occurred between the first and the fourth days of anthesis, while the female one started in the fifth day. Mean nectar volume secreted was 4.77 ± 3.2 µl, with a significative variation among flowers of different ages. Otherwise, nectar concentration average was 9.71 ± 4.41%, and did not varied significantly in flowers of different ages. The flowers of S. sylvatica were pollinated mainly by the hummingbirds Phaethornis pretrei and Thalurania furcata, and pierced by the bee Ceratina chloris. The butterfly Parides anchises orbygnianus was considered an occasional pollinator of these flowers. Seemannia sylvatica is self-compatible, since fruit set occurred on the experiments of spontaneous self-pollination, manual self-pollination, cross-pollination and open pollination (control). The protandry, coupled with the pattern of nectar production, characterized by low volume and solute concentration, which induces the pollinators to visit different flowers in a given circuit foraging, act maximizing the likelihood of cross-pollination in S. sylvatica. Moreover, the high proportion of fruit set by autogamy is an important strategy considering that S. sylvatica is visited by few species, being pollinated mainly by P. pretrei. Therefore, in the absence of these visitors, the formation of fruits may be achieved.

No Brasil, a família Gesneriaceae é representada por 23 gêneros e cerca de 200 espécies. Seemannia sylvatica é uma espécie herbácea que ocorre em densas populações nos leitos de rios da região da Serra da Bodoquena. Os objetivos deste estudo foram conhecer a biologia floral (nos primeiros cinco dias de antese), determinar o sistema reprodutivo e os polinizadores de S. sylvatica. A coleta de dados foi realizada no período de junho de 2005 a julho de 2006 através de viagens mensais a campo, com duração de cinco dias. Dados sobre a biologia floral, o sistema reprodutivo e sobre os visitantes florais foram tomados em indivíduos localizados ao longo de uma trilha de 2500 m de extensão, em área de mata ciliar do rio Salobrinha. As flores de S. sylvatica são tubulosas, vermelhas, inodoras e duram mais de cinco dias (ca. 10 - 20 dias em indivíduos transferidos para jardim e mantidos em vasos). Seemannia sylvatica apresenta protandria, sendo que a fase masculina ocorreu entre o primeiro e o quarto dia de antese e a feminina a partir do quinto dia. O volume médio de néctar secretado foi de 4,77 ± 3,2 µl, tendo variado significativamente em flores de diferentes idades. Por outro lado, a concentração média do néctar foi de 9,71 ± 4,41%, e não houve diferença significativa nas diferentes idades da flor. As flores de S. sylvatica foram polinizadas principalmente pelos beija-flores Phaethornis pretrei e pelas fêmeas de Thalurania furcata, e pilhadas pela abelha Ceratina chloris. A borboleta Parides anchises orbygnianus foi considerada polinizadora ocasional dessas flores. Seemannia sylvatica é autocompatível, havendo formação de frutos nos experimentos de autopolinização espontânea, autopolinização manual, polinização cruzada e controle. A protandria, aliada ao padrão de produção de néctar em S. sylvatica, caracterizado pelo baixo volume e concentração de solutos, que induz os polinizadores a visitarem flores diferentes num dado circuito de forrageamento, agem maximizando a probabilidade de ocorrência da polinização cruzada. Por outro lado, a alta proporção de frutos formados por autogamia é uma estratégia importante tendo em vista que S. sylvatica é visitada por poucas espécies, sendo polinizada principalmente por P. pretrei. Portanto, na ausência desses visitantes, a formação de frutos pode ser assegurada.

Flowering phenology and pollination of ornithophilous species in two habitats of Serra da Bodoquena, Mato Grosso do Sul, Brazil

The aim of this study is to describe interactions between hummingbirds and ornithophilous species at Serra da Bodoquena in midwest Brazil, with focus on flowering phenology and pollination of these plant species. In two habitats, gallery forest and semi-deciduous forest, data on flowering phenology of ornithophilous species were collected monthly over 14 months. In addition, data on morphology and floral biology, as well as visitor frequency and hummingbird behavior, were recorded. The studied community contained eight ornithophilous plant species and six hummingbird species. The ornithophilous species flowered throughout the year, and the greatest abundance of flowers was at the end of the rainy season and the beginning of the dry one. The herit huingbird Phaethornis pretrei and feales of Thalurania furcata, were the most similar in floral resource use. Acanthaceae is the most representative family of ornithophilous plant species in Serra da Bodoquena and, thus, represents the main food source for hummingbirds. Ruellia angustiflora is especially important because it flowers continuously throughout the year and is a significant food resource for P. pretrei, which is the main visitor for this plant guild.

O objetivo deste estudo é descrever as interações entre beijaflores e espécies ornitófilas na Serra da Bodoquena na região Centro-Oeste do Brasil, com foco na fenologia de floração e polinização destas espécies vegetais. Em dois habitats, mata ciliar e floresta semi-decídua, dados de fenologia de floração de espécies ornitófilas foram coletados mensalmente ao longo de 14 meses. Além disso, dados de morfologia e biologia floral bem como a frequência dos visitantes e o comportamento dos beija-flores foram registrados. A comunidade estudada contém oito espécies de plantas ornitófilas e seis espécies de beija-flores. As espécies ornitófilas floresceram todo o ano, e a maior abundância de flores foi no final da estação chuvosa e início da seca. O beija-flor eremita Phaethornis pretrei e a fêmea de Thalurania furcata foram os mais similares no uso dos recursos florais. Acanthaceae é a família mais representativa das espécies vegetais ornitófilas na Serra da Bodoquena e representa a principal fonte de recurso para os beija-flores. Ruellia angustiflora é especialmente importante porque floresce continuamente ao longo do ano e é uma importante fonte de recurso para P. pretrei, que é o principal visitante floral para esta guilda de plantas.