A new combination in Maranthes (Chrysobalanaceae)

Maranthes, previously known in the Neotropics only from Panama, has recently been collected in Nicaragua and Costa Rica. Prior to publication of the Chrysobalanaceae of theFlora de Nicaragua, the new combinationMaranthes panamensis (Standl.) Prance & F. White is made and based onCouepia panamensis, previously considered conspecific with the AsiaticM. corymbosa Blume.     

A New Record of a Host-Parasitoid Interaction: Hymenoepimecis veranii Lofredo & Penteado-Dias, 2009 (Hymenoptera: Ichneumonidae) Parasitizing Araneus orgaos Levi, 1991 (Araneae: Araneidae)

The genus Hymenoepimecis only occurs in the Neotropics. In some species of this genus, the larval stage modifies the behavior of the spider hosts, inducing then to construct a modified web. The wasp Hymenoepimecis veranii has been previously described as an ectoparasitoid of the spider Araneus omnicolor. This study provides detailed information about the natural history of the host-parasitoid interaction involving this wasp with a new host, the spider Araneus orgaos (Araneae: Araneidae), which occurs sympatrically with A. omnicolor.     

Domestication of cardamom (Elettaria cardamomum) in Western Ghats, India: divergence in productive traits and a shift in major pollinators

Background and Aims

Elettaria cardamomum, a highly priced spice, is native to the Western Ghats of South India. Wild populations still occur in isolated patches in their natural habitats; however, much of today''s commercial product comes from cultivated sources. There is no information on domestication-related traits of this species; the main objective of this study was to compare wild and cultivated populations of cardamom in terms of vegetative and reproductive features in order to identify domestication syndromes and to examine whether the two populations have developed reproductive barriers.

Methods

Two wild populations and five cultivated plantations were used for the present study. Vegetative and floral traits, flowering phenology, pollination biology and breeding systems of wild and cultivated populations were compared. Effective pollinators amongst floral visitors were identified by confirming pollen transfer as well as by fruit set following their visit to virgin flowers. Manual pollinations were carried out in order to study the breeding systems of the two populations and reproductive barriers, if any, between them.

Key Results

Several productive traits including the number of branches, number of inflorescences, and total number of flowers per clump, number of flowers that open each day, the duration of flowering, the length of the flower and the amount of nectar per flower are significantly greater in cultivated cardamom. The principal pollinators in wild cardamom are solitary bees, Megachile sp. and two species of Amegilla, whereas those in cultivated cardamom are the social bees Apis dorsata, A. cerana and Trigona iridipennis. Both the wild and cultivated populations are self-compatible and there are no reproductive barriers between the two populations.

Conclusions

Domestication in cardamom has brought about significant changes in vegetative and reproductive traits and a shift in effective pollinators from native solitary bees to social bees. The shift in pollinators seems to be due to the availability of a large number of flowers for prolonged periods in cultivated cardamom that can attract and sustain social bees, rather than due to co-evolution of the flower and the pollinator.Key words: Elettaria cardamomum, wild cardamom, domestication, Amegilla sp., Apis cerana, Apis dorsata, Megachile sp., pollination efficiency, solitary bees, social bees     

Floral divergence and temporal pollinator partitioning in two synchronopatric species of <Emphasis Type="Italic">Vigna</Emphasis> (Leguminosae-Papilionoideae)

Exclusivity of pollinators, temporal partitioning of shared pollinators and divergence in pollen placement on the shared pollinators’ bodies are mechanisms that prevent interspecific pollen flow and minimize competitive interactions in synchronopatric plant species. We investigated the floral biology, flower visitors, pollinator effectiveness and seasonal flower availability of two syntopic legume species of the genus Vigna, V. longifolia and V. luteola, in ‘restinga’ vegetation of an island in southern Brazil. Our goal was to identify the strategies that might mitigate negative consequences of their synchronous flowering. Vigna longifolia and V. luteola were self-compatible, but depended on pollinators to set seeds. Only medium to large bees were able to trigger the ‘brush type’ pollination mechanism. Vigna longifolia, with its asymmetrical corolla and hugging mechanism, showed a more restrictive pollination system, with precise sites of pollen deposition/removal on the bee’s body, compared to V. luteola, with its zygomorphic corolla and cymbiform keel. There was a daily temporal substitution in flower visitation by the main pollinators. Vigna longifolia and V. luteola had overlapping flowering phenology but the densities of their flowers fluctuated, resulting in a seasonal partitioning of flower visitation. The differences in corolla symmetry and mainly the temporal partitioning among pollinators throughout the day and the flowering season proved to be important factors in maintaining the synchronopatry of V. longifolia and V. luteola.     

Pollination ecology and breeding systems of five Gesneria species from Puerto Rico

Background and Aims

The genus Gesneria diversified in the Greater Antilles giving rise to various floral designs corresponding to different pollination syndromes. The goal of this study was to characterize the pollination and breeding systems of five Puerto Rican Gesneria species.

Methods

The study was conducted in Arecibo and El Yunke National Forest, Puerto Rico, between 2003 and 2007. Floral visitors were documented by human observers and video cameras. Floral longevity and nectar production were recorded for the five study species. Tests for self-compatibility and autonomous selfing were conducted through hand-pollination and bagging experiments.

Key Results

Floral phenology and nectar production schedules agree with nocturnal (in bell-shaped flowered G. pedunculosa and G. viridiflora subsp. sintenisii) or diurnal pollination syndromes (in tubular-flowered G. citrina, G. cuneifolia and G. reticulata). Nectar concentration is consistently low (8–13 %) across species. Gesneria citrina and G. cuneifolia are exclusively pollinated by hummingbirds, while Gesneria reticulata relies mostly on autonomous self-pollination, despite having classic ornithophilous flowers. A variety of floral visitors was recorded for the two species with bell-shaped flowers; however, not all visitors have the ability to transfer pollen. Bats are the primary pollinators of G. pedunculosa, with bananaquits probably acting as secondary pollinators. For G. viridiflora subsp. sintenisii, both bats and hummingbirds contact the flower''s reproductive organs, thus, this species is considered to be a generalist despite its nocturnal floral syndrome. All species are self-compatible but only tubular-flowered Gesneria are capable of autonomous self-pollination.

Conclusions

The visitation patterns described in this study fit the predicted hummingbird and bat pollination syndromes and support both specialization and generalization of pollination systems in Puerto Rican Gesneria. Specialization is associated with low pollinator visitation, particularly by hummingbirds, which may explain the occurrence of autonomous selfing mechanisms in tubular-flowered species.Key words: Autonomous selfing, bat pollination, breeding systems, Gesneria, hummingbird pollination, Puerto Rico     

Flowering phenology of invasive alien plant species compared with native species in three Mediterranean-type ecosystems

Background and Aims

Flowering phenology is a potentially important component of success of alien species, since elevated fecundity may enhance invasiveness. The flowering patterns of invasive alien plant species and related natives were studied in three regions with Mediterranean-type climate: California, Spain and South Africa''s Cape region.

Methods

A total of 227 invasive–native pairs were compared for seven character types across the regions, with each pair selected on the basis that they shared the same habitat type within a region, had a common growth form and pollination type, and belonged to the same family or genus.

Key Results

Invasive alien plant species have different patterns of flowering phenology from native species in the three regions. Whether the alien species flower earlier, later or at the same time as natives depends on the climatic regime in the native range of the aliens and the proportion of species in the invasive floras originating from different regions. Species invading at least two of the regions displayed the same flowering pattern, showing that flowering phenology is a conservative trait. Invasive species with native ranges in temperate climates flower earlier than natives, those from Mediterranean-type climates at the same time, and species from tropical climates flower later. In California, where the proportion of invaders from the Mediterranean Basin is high, the flowering pattern did not differ between invasive and native species, whereas in Spain the high proportion of tropical species results in a later flowering than natives, and in the Cape region early flowering than natives was the result of a high proportion of temperate invaders.

Conclusions

Observed patterns are due to the human-induced sympatry of species with different evolutionary histories whose flowering phenology evolved under different climatic regimes. The severity of the main abiotic filters imposed by the invaded regions (e.g. summer drought) has not been strong enough (yet) to shift the flowering pattern of invasive species to correspond with that of native relatives. It does, however, determine the length of the flowering season and the type of habitat invaded by summer-flowering aliens. Results suggest different implications for impacts at evolutionary time scales among the three regions.Key words: Biological invasions, flowering phenology, genetic inertia, Cape Floristic Region, California, Spain, Mediterranean-type ecosystems, water availability, climatic origin     

The interplay between inflorescence development and function as the crucible of architectural diversity

Background

Most angiosperms present flowers in inflorescences, which play roles in reproduction, primarily related to pollination, beyond those served by individual flowers alone. An inflorescence''s overall reproductive contribution depends primarily on the three-dimensional arrangement of the floral canopy and its dynamics during its flowering period. These features depend in turn on characteristics of the underlying branching structure (scaffold) that supports and supplies water and nutrients to the floral canopy. This scaffold is produced by developmental algorithms that are genetically specified and hormonally mediated. Thus, the extensive inflorescence diversity evident among angiosperms evolves through changes in the developmental programmes that specify scaffold characteristics, which in turn modify canopy features that promote reproductive performance in a particular pollination and mating environment. Nevertheless, developmental and ecological aspects of inflorescences have typically been studied independently, limiting comprehensive understanding of the relations between inflorescence form, reproductive function, and evolution.

Scope

This review fosters an integrated perspective on inflorescences by summarizing aspects of their development and pollination function that enable and guide inflorescence evolution and diversification.

Conclusions

The architecture of flowering inflorescences comprises three related components: topology (branching patterns, flower number), geometry (phyllotaxis, internode and pedicel lengths, three-dimensional flower arrangement) and phenology (flower opening rate and longevity, dichogamy). Genetic and developmental evidence reveals that these components are largely subject to quantitative control. Consequently, inflorescence evolution proceeds along a multidimensional continuum. Nevertheless, some combinations of topology, geometry and phenology are represented more commonly than others, because they serve reproductive function particularly effectively. For wind-pollinated species, these combinations often represent compromise solutions to the conflicting physical influences on pollen removal, transport and deposition. For animal-pollinated species, dominant selective influences include the conflicting benefits of large displays for attracting pollinators and of small displays for limiting among-flower self-pollination. The variety of architectural components that comprise inflorescences enable diverse resolutions of these conflicts.     

四川黄龙沟少花鹤顶兰繁殖成功特征

少花鹤顶兰(Phaiu delavayi)是多年生、多次结实的具有克隆能力的地生兰科植物,是中国特有种。目前少花鹤顶兰开花物候、花寿命、繁殖成功等生物学特征尚不清楚,而这些资料是开展少花鹤顶兰进化和保护生物学研究的基础。利用2005-2007年四川黄龙沟少花鹤顶兰的调查数据,对少花鹤顶兰繁殖成功特征进行了研究。结果表明黄龙沟少花鹤顶兰每个花序的平均花朵数为3(1-7)朵。叶和花的形态指标在年季间无显著变异。2005-2007年3年间的开花物候没有明显的差异,花期始于6月中旬,于7月底至8月初结束,持续约6-7周,80%-90%的花在7月初的开花高峰期开放,属花集中开放模式。花寿命与是否授粉密切相关,成功授粉的花寿命比没有授粉的花寿命短。少花鹤顶兰是自交亲和的,但其结实完全依赖于两种熊蜂的传粉,不存在自动自花授粉和无融合生殖现象。柱头可授性和花粉活力可维持15 d左右。繁殖成功率年季间的变化很大,并表现出逐年下降的趋势,花粉移走率为18%-51%,自然结实率为10%-36%。繁殖成功下降的趋势可能与黄龙沟喷洒农药有关。     

Petal micromorphology and its relationship to pollination

• The characteristics of petal epidermal conical cells affect the quality of the signals perceived by various pollinators. This study aimed to identify variations in micromorphological characteristics of flower petals and their relationship to melittophily, ornithophily and chiropterophily pollination systems.
• The petals of 11 species were analysed using scanning electron microscopy and optical microscopy and the micromorphological traits were described, measured and compared using Tukey's test, PCA and cluster analysis.
• Unlike chiropterophily, all melittophilous and some ornithophilous species possessed adaxial epidermal conical cells. Cluster grouping separated chiropterophilous flowers from melittophilous and ornithophilous. PCA analysis showed that the two morphometric profile of conical cells was the attribute that most strongly influenced the grouping of species. When considering the data set of the three pollination systems, melittophilous and ornithophilous plants were more similar to each other than they were to chriopterophilous species. The distance between conical cell apices is an important parameter in interactions with pollinators.
• This study facilitated recognition of smoothing pollinator resource access through petal micromorphological characteristics. Further research regarding the biometry of micromorphological traits related to pollination is required.

     

Distribution and evolution of C4 syndrome inRhynchospora (Rhynchosporeae-Cyperaceae)

In order to elucidate the evolution of C₄ syndrome, the taxonomic relationships, leaf anatomy, and ecological and global distribution of C₃ and C₄ species in the genusRhynchospora were investigated. The anatomical observation for 181 species revealed that 26 C₄ species occurred within theCapitatae group of the subgenusHaplostyleae, a natural group showing highly advanced morphological characteristics, together with several C₃ species. In spite of there being rather few C₄ species, they possessed two kinds of Kranz anatomical structure differing from each other in the location of Kranz cells. Some C₃ species ofCapitatae showed radial arrangement in mesophyll cells surrounding vascular bundles, which is distinguished from typical non-Kranz anatomy. The C₄ species extended their ecological ranges from wet habitats to dry savanna grasslands, while the C₃ species showed the best development in wet habitats. The C₃ species were widespread from tropical to temperate regions with partial range extension into subarctic regions of both hemispheres, showing conspicuously high concentration of species in the New World, but being absent from arid climatic regions. The C₄ species were distributed mostly in tropics and subtropics, showing two separate distributional centers in South and Central America and in Tropical Asia and Australia. The range of C₄ species was nearly completely included in the C₃ range. In conclusion, it seems that inRhynchospora the C₄ syndrome evolved relatively recently, and arose in at least two separate phylogenetic trends in the tropics and the subtropics, more probably in the Neotropics.     

The assembly of plants used as nectar sources by hummingbirds in a Cerrado area of Central Brazil

Studies on hummingbird–plant interactions commonly use a pollination approach emphasizing mutualistic relationships. But floral resources are often used opportunistically by these birds. Plant–pollinator assemblies and pollination sustainability will depend both on the well-adapted plants and other potential floral resources. The Cerrado, Neotropical savannas of Central Brazil, has ca. 7.5 % of its flora supposedly adapted to hummingbird pollination. But detailed information about flowers effectively used by hummingbirds at community level is still lacking. Hence, we recorded all plant species visited by hummingbirds, to determine how these nectariferous flowers were distributed in time and space in different plant formations of a Cerrado area, and also the hummingbird species that visit them. The study was conducted between March 2007 and December 2008 in the Panga Ecological Station. Data regarding flowering phenology, floral morphology and visitation were collected monthly. Forty-six nectariferous species from 39 genera and 17 families were recorded, most with annual flowering dynamics and tubular flowers. But only 21 species had a combination of traits fitting classic ornithophilous syndrome. For the remaining species hummingbird visitation was ascertained from observations at the study site or other sites in the region. Eight hummingbird species occurred in the area and were recorded visiting directly 36 plant species. The study area presented a relatively low number of ornithophilous plants, but a great habitat diversity and many non-ornithophilous plants that hummingbirds used as nectar sources. Therefore, in the studied Cerrado, the diversity of environments and nectariferous plants favour the maintenance of resident and migrant hummingbirds.     

Contrasting breeding systems in twoEriotheca (Bombacaceae) species of the Brazilian cerrados

The pollination biology and breeding systems ofEriotheca pubescens andE. gracilipes have been studied. These two species occur as trees in cerrado vegetation, the neotropical savannas of Central Brazil, with partially sympatric distributions. They have similar phenology and floral structure, although the flowers ofE. pubescens are larger. Both species have nectar flowers pollinated by largeAnthophoridae bees but the main pollinators of each species differ in size. The species have markedly different breeding systems: late-acting self-incompatibility inE. gracilipes and apomixis stimulated by pollination inE. pubescens.     

Phenology and Pollination Ecology of Three Brazilian Fig Species (Moraceae)

The phenology and pollination ecology of three native fig species were studied in southeastern Brazil. Populations displayed continual syconia production, with one species showing intra-tree flowering asynchrony. Pollination of the fig flowers was necessary for the development of the syconia; lack of pollination induced abortion of syconia. All three species follow the general pattern of pollination known for figs, but the behavior of the pollinator wasps, Pegoscapus spp., differed in some aspects from those of other neotropical and paleotropical fig wasps, mainly with respect to pollen loading and unloading during pollination. The longevity of Pegoscapus wasps outside the syconium was about two days.     

Glutamate-gated chloride channel subunit cDNA sequencing of Cochliomyia hominivorax (Diptera: Calliphoridae): cDNA variants and polymorphisms

The New World screwworm (NWS) Cochliomyia hominivorax (Coquerel) is one of the major myiasis-causing flies that injures livestock and leads to losses of ~US$ 2.7 billions/year in the Neotropics. Ivermectin (IVM), a macrocyclic lactone (ML), is the most used preventive insecticide for this parasite and targets the glutamate-gated chloride (GLUCLα) channels. Several authors have associated altered GluClα homologues to MLs resistance in invertebrates, although studies about resistance in NWS are limited to other genes. Here, we aimed to characterise the NWS GluClα (ChGluClα) cDNA and to search for alterations associated with IVM resistance in NWS larvae from a bioassay. The open reading frame of the ChGluClα comprised 1,359 bp and encoded a sequence of 452 amino acids. The ChGluClα cDNAs of the bioassay larvae showed different sequences that could be splice variants, which agree with the occurrence of alternative splicing in GluClα homologues. In addition, we found cDNAs with premature stop codons and the K242R SNP, which occurred more frequently in the surviving larvae and was located close to mutation (L256F) involved in ML resistance. Although these alterations were in low frequency, the ChGluClα sequencing will allow further studies to find alterations in the gene of resistant natural populations.     

Generalist passerine pollination of a winter-flowering fruit tree in central China

Background and Aims

Winter-flowering plants outside the tropics may experience a shortage of pollinator service, given that insect activity is largely limited by low temperature. Birds can be alternative pollinators for these plants, but experimental evidence for the pollination role of birds in winter-flowering plants is scarce.

Methods

Pollinator visitation to the loquat, Eriobotrya japonica (Rosaceae), was observed across the flowering season from November to January for two years in central China. Self- and cross-hand pollination was conducted in the field to investigate self-compatibility and pollen limitation. In addition, inflorescences were covered by bird cages and nylon mesh nets to exclude birds and all animal pollinators, respectively, to investigate the pollination role of birds in seed production.

Results

Self-fertilization in the loquat yielded few seeds. In early winter insect visit frequency was relatively higher, while in late winter insect pollinators were absent and two passerine birds (Pycnonotus sinensis and Zosterops japonicus) became the major floral visitors. However, seed-set of open-pollinated flowers did not differ between early and late winter. Exclusion of bird visitation greatly reduced seed-set, indicating that passerine birds were important pollinators for the loquat in late winter. The whitish perigynous flowers reward passerines with relatively large volumes of dilute nectar. Our observation on the loquat and other Rosaceae species suggested that perigyny might be related to bird pollination but the association needs further study.

Conclusions

These findings suggest that floral traits and phenology would be favoured to attract bird pollinators in cold weather, in which insect activity is limited.     

Nectar by day and night:Siphocampylus sulfureus (Lobeliaceae) pollinated by hummingbirds and bats

Most species of the neotropical genusSiphocampylus are believed to be bird-pollinated. The pollination biology ofSiphocampylus sulfureus was studied in a montane region in SE Brazil. This species has features intermediate between ornithophilous and chiropterophilous syndromes: it presents a striking combination of yellowish flowers with strong odour (chiropterophilous features), and diurnal anthesis and sucrose-dominated nectar (ornithophilous features). Major pollinators were hummingbirds by day, and a phyllostomid bat by night.Siphocampylus sulfureus may be viewed as a recent derivate from the presumed ornithophilous stock within sect.Macrosiphon, and thus benefits from the activity of both diurnal and nocturnal vertebrate pollinators.Dedicated to DrIlse Silberbauer-Gottsberger and Prof. DrGerhard Gottsberger for their pioneer contribution to floral biology in Brazil.     

Reproductive success of non-rewarding Cypripedium japonicum benefits from low spatial dispersion pattern and asynchronous flowering

Background and Aims

Outcrossing animal-pollinated plants, particularly non-rewarding species, often experience pollinator limitation to reproduction. Pollinator visitation is affected by various factors, and it is hypothesized that reproduction in non-rewarding plants would benefit from low spatial flower abundance and asynchronous flowering. In order to test this hypothesis, the influence of spatial pattern and flowering phenology on male and female reproductive success (RS) was investigated in a non-rewarding orchid, Cypripedium japonicum, in central China over two flowering seasons.

Methods

The probabilities of intrafloral self-pollination and geitonogamy caused by pollinator behaviours were estimated from field observations. Pollinator limitation was evaluated by hand-pollination experiments. RS was surveyed in different spatial flower dispersal patterns and local flower densities. The effects of flowering phenological traits on RS were assessed by univariate and multivariate regression analyses.

Key Results

Hand-pollination experiments revealed that fruit production was strongly pollen limited throughout the entire reproductive season – over two seasons, 74·3 % of individuals set fruit following hand pollination, but only 5·2–7·7 % did so under natural conditions. Intrafloral self-pollination and geitonogamy within the potential clones might be rare. Both male and female fitness were substantially lower in clustered plants than in those growing singly. An increase in local conspecific flower density significantly and negatively influenced male RS, but had no effect on female RS. Phenotypic selection analysis indicated that individuals flowering earlier have the greatest probability of RS. Over 85 % of sampled flowering individuals had a flowering synchrony value >0·7; however, highly synchronous flowering was not advantageous for RS, as indicated by the negative directional selection differentials and gradients, and by the positive quadratic selection gradients.

Conclusions

These results support the hypothesis that, as a consequence of density-dependent selection, low spatio-temporal flower abundance is advantageous for attracting pollinators and for reproduction in natural populations of non-rewarding C. japonicum.Key words: Cypripedium japonicum, pollen limitation, spatial dispersal pattern, flowering synchrony, reproductive success, selection differential, selection gradient, deceptive flower     

钝叶柃不同性别花的花部形态与传粉特征比较

据有关资料记载,柃属(Eurya Thunb.)植物属于雌雄异株植物,目前仅在柃木(Eurya japonica Thunb.)中有过两性花的报道。近年的调查发现,钝叶柃(Eurya obtusifolia H.T.Chang)也有性别变异,存在两性花。在对其性别特征及功能研究的基础上,进一步跟踪了钝叶柃的开花和传粉过程,对不同性别花的花部形态和传粉特征进行了比较分析。在重庆市北碚区选取了4个样地,测定了花部形态、花朵朝向、花粉活力、柱头可授性、花粉对水的耐受性、单花花粉量和单花泌蜜体积等形态和传粉相关指标,并对其开花动态、传粉昆虫种类和昆虫传粉行为进行了仔细观察,还进行了套袋试验。结果发现钝叶柃不同性别花的花部形态和传粉特征既有一些共同点,又存在着明显差异,性别变异株则呈现出雌雄植株间的过渡特征。钝叶柃是一种花期短,花小而多,开花同步性高的植物,雌花和雄花色味相同。该植物的主要传粉方式为虫媒,主要传粉者为两种蜜蜂科昆虫,但风媒也在其传粉中起着一定作用。该植物不同性别花的主要差异有:1)雄花呈灯笼状,花瓣不反卷,雌花辐射状,花瓣反卷;2)雄花较雌花大;3)雄花倾向于垂直朝下,雌花倾向于斜向下朝向枝条末端;4)雌花寿命较雄花长。钝叶柃在开花和传粉上的许多特征都在一定程度上体现了其对雌雄异株性系统的适应。相应地,传粉者在不同性别植株上的行为也存在一定差异。钝叶柃不同性别花在形态上的差异是其周围各种生物因素及非生物因素共同作用的结果,其中传粉昆虫和雨水的选择可能在这些差异的塑造中起着重要作用。