Rodrigo B. Singer

Pollination by Sexual Mimicry in Mormolyca ringens: A Floral Chemistry that Remarkably Matches the Pheromones of Virgin Queens of Scaptotrigona sp.

The chemical composition of some volatile (2-heptanol) and nonvolatile constituents (a homologous 9-alkene/alkane series) of Mormolyca ringens flowers and Scaptotrigona sp. queen waxes (homologous 9-alkene/alkane series) and cephalic extracts (homologous series of 2-alkanols, including 2-heptanol) involved with the pseudocopulation or sexual mimicry in Orchidaceae pollination is compared. The similarity in chemical composition of flowers and insects is assigned to the chemically induced copulatory activity in Scaptotrigona males.

The chemistry of pollination in selected Brazilian Maxillariinae orchids: floral rewards and fragrance.

We report the chemical composition of the floral rewards and the fragrance of 10 Maxillariinae (Orchidaceae) species. The species that offer rewards (labellar secretions) are usually scentless, the rewards being collected by bees. Chemical analyses revealed that the major chemical class of compounds present in the labellar secretions are triterpenoids. The rewardless Maxillariinae flowers were usually scented, and chemical analyses of their volatiles revealed that they were composed of mono and sesquiterpenoids.

The pollination ofStenorrhynchos lanceolatus (Aublet) L. C. Rich. (Orchidaceae: Spiranthinae) by hummingbirds in southeastern Brazil

Hummingbird pollination is documented for a natural population ofStenorrhynchos lanceolatus Aublet. L. C. Rich. occurring in Rio de Janeiro State, southeastern Brazil. At the study site the plants are pollinated byPhaethornis eurynome (Phaethorninae),Thalurania glaucopis (females only) andLeucochloris albicollis (Trochilinae). The plants offer nectar as a reward and the pollinaria become stuck to the surface of the hummingbirds bill while it is probing the flowers. The orchid population received a few (0–4) hummingbird visits per day, with about 83% of the flowers being pollinated. In spite of the low frequency of visits, the granular structure of the pollinarium plus the behaviour of the most frequent pollinators, which tend to visit all the fresh-looking flowers of each inflorescence, a very high fruiting success was promoted. Experimental evidence suggests that the pollinaria may remain up to 6.30 hours on the hummingbirds bill, enhancing the chances of cross-pollination and long-distance pollen flow.

Typifications and New Synonymies in Capanemia (Orchidaceae, Oncidiinae)

Abstract.  Capanemia Barb. Rodr. (Orchidaceae, Oncidiinae) currently includes 17 epiphytic, predominantly Brazilian species. As part of an ongoing revision of this genus, we herein propose new synonyms and typifications for several taxa. After a thorough revision of both herbarium material and many living specimens in cultivation collected in southern and southeastern Brazil, we herein recognize only seven species, six of which are treated here: C. brachycion (Griseb.) Schltr., C. carinata Barb. Rodr., C. gehrtii Hoehne, C. micromera Barb. Rodr., C. superflua (Rchb. f.) Garay, and C. therezae Barb. Rodr; the seventh species, C. adelaidae Porto & Brade, is recognized as valid but not treated here, since no taxonomic or nomenclatural problems were detected regarding this species. New synonymies are proposed: C. ensata Pabst is referred to C. gehrtii; C. angustilabia Schltr., C. australis (Kraenzl.) Schltr., C. lossiana L. Kollmann, C. perpusilla Schltr., C. riograndensis Pabst, and C. spathuliglossa Pabst are referred to C. micromera; and C. fluminensis Pabst is referred to C. therezae. Lectotypes are proposed for C. angustilabia, C. carinata, C. micromera, C. perpusilla, C. spathuliglossa, and C. therezae. A neotype is proposed for C. hatschbachii Schltr.

Floral features, pollination biology and breeding system of Chloraea membranacea Lindl. (Orchidaceae: Chloraeinae)

BACKGROUND AND AIMS The pollination biology of very few Chloraeinae orchids has been studied to date, and most of these studies have focused on breeding systems and fruiting success. Chloraea membranacea Lindl. is one of the few non-Andean species in this group, and the aim of the present contribution is to elucidate the pollination biology, functional floral morphology and breeding system in native populations of this species from Argentina (Buenos Aires) and Brazil (Rio Grande do Sul State). METHODS Floral features were examined using light microscopy, and scanning and transmission electron microscopy. The breeding system was studied by means of controlled pollinations applied to plants, either bagged in the field or cultivated in a glasshouse. Pollination observations were made on natural populations, and pollinator behaviour was recorded by means of photography and video. KEY RESULTS Both Argentinean and Brazilian plants were very consistent regarding all studied features. Flowers are nectarless but scented and anatomical analysis indicates that the dark, clavate projections on the adaxial labellar surface are osmophores (scent-producing glands). The plants are self-compatible but pollinator-dependent. The fruit-set obtained through cross-pollination and manual self-pollination was almost identical. The main pollinators are male and female Halictidae bees that withdraw the pollinarium when leaving the flower. Remarkably, the bees tend to visit more than one flower per inflorescence, thus promoting self-pollination (geitonogamy). Fruiting success in Brazilian plants reached 60·78 % in 2010 and 46 % in 2011. Some pollinarium-laden female bees were observed transferring pollen from the carried pollinarium to their hind legs. The use of pollen by pollinators is a rare record for Orchidaceae in general. CONCLUSIONS Chloraea membrancea is pollinated by deceit. Together, self-compatibility, pollinarium texture, pollinator abundance and behaviour may account for the observed high fruiting success. It is suggested that a reappraisal and re-analysis of important flower features in Chloraeinae orchids is necessary.

Brasiliorchis: A New Genus for the Maxillaria picta Alliance (Orchidaceae, Maxillariinae)

ABSTRACT Brasiliorchis R. Singer, S. Koehler & Carnevali is here proposed to include the orchid species formerly recognized in the Maxillaria picta alliance, an orchid group mostly endemic to the Atlantic Rain Forest Biome, in south and southeastern Brazil. The new genus is supported by both morphological features and ongoing molecular studies. The new genus is easily diagnosed by its sulcate to ridged, bifoliate pseudobulbs and its long-lasting, campanulate, rewardless flowers. The pollinaria of these flowers are normally devoid of stipes. Formal diagnosis of the genus and 13 taxonomic combinations are presented: Brasiliorchis barbozae (Loefgren) R. Singer, S. Koehler & Carnevali, B. chrysantha (Barbosa Rodrigues) R. Singer, S. Koehler & Carnevali, B. consanguinea (Klotzsch) R. Singer, S. Koehler & Carnevali, B. gracilis (Loddiges) R. Singer, S. Koehler & Carnevali, B. heismanniana (Barbosa Rodrigues) R. Singer, S. Koehler & Carnevali, B. kautskyi (Pabst) R. Singer, S. Koehler & Carnevali, B. marginata (Lindley) R. Singer, S. Koehler & Carnevali, B. phoenicanthera (Barbosa Rodrigues) R. Singer, S. Koehler & Carnevali, B. picta (Hooker) R. Singer, S. Koehler & Carnevali, B. polyantha (Barbosa Rodrigues) R. Singer, S. Koehler & Carnevali, B. porphyrostele (Reichenbach f.) R. Singer, S. Koehler & Carnevali, B. schunkeana (Campacci & Kautsky) R. Singer, S. Koehler & Carnevali, and B. ubatubana (Hoehne) R. Singer, S. Koehler & Carnevali. Lectotypes are designated for B. barbozae, B. chrysantha, B. heismanniana, B. phoenicanthera, B. picta, and B. polyantha. A neotype is proposed for B. consanguinea. In addition, a key to distinguish Brasiliorchis from other sympatric bifoliate orchids within Brazilian Maxillariinae is presented.

Typifications and taxonomic notes in species of Brazilian Goodyerinae and Spiranthinae (Orchidaceae) described by José Vellozo and Barbosa Rodrigues

A total of 46 lectotypes, one neotype and one epitype are designated for species of Goodyerinae and Spiranthinae originally described by Jose Mariano da Conceicao Vellozo and Joao Barbosa Rodrigues. Moreover, three new previously accepted names are treated as synonyms.

A comparative survey of floral characters in Capanemia Barb. Rodr. (Orchidaceae: Oncidiinae).

BACKGROUND AND AIMS Capanemia Barb. Rodr. comprises seven species that mostly inhabit the Brazilian Atlantic Rain Forest domain. The genus currently consists of two sections: Capanemia Cogn. and Planifolia Pabst, distinguished on the basis of leaf shape. We compare the floral morphology and anatomy of all species to determine whether separation into sections is supported by floral characters. METHODS Both fresh flowers and herbarium specimens were investigated, and column and pollinarium features, together with the presence or absence of floral rewards, recorded. Anatomical features were examined using both light microscopy and scanning electron microscopy. KEY RESULTS AND CONCLUSIONS With the sole exception of Capanemia therezae, all species shared a distinctive set of floral characters. Flowers were mostly white or yellowish-white and fragrant, and column wings were positioned parallel to the labellum, concealing the stigmatic cavity. Pollinaria had proportionally long tegular stipes and clavate to reniform pollinia, whereas the labellum possessed a conspicuous indument of trichomes, but was devoid of nectar or any other secretion that might function as a food-reward. Capanemia therezae, however, was exceptional in having greenish, unscented flowers with short, rounded and divergent column wings and an exposed stigmatic cavity. Its pollinaria had proportionally short tegular stipes and round pollinia, whereas the labellum lacked trichomes. Droplets of nectar were evident on the adaxial surface of the labellum, adjacent to the callus. Floral features did not support the currently accepted sectional division of Capanemia. If ongoing phylogenetic studies demonstrate that both sections are indeed monophyletic, then these taxa should be distinguished solely on the basis of foliar features.

Stingless Bees: Chemical Differences and Potential Functions in Nannotrigona testaceicornis and Plebeia droryana Males and Workers

Cuticular wax, abdominal and cephalic extracts of foraging workers and males of Nannotrigona testaceicornis and Plebeia droryana, from the “Aretuzina” farm in São Simão, SP, Brazil, were analyzed by GC-MS. The principal constituents were hydrocarbons, terpenes, aldehydes, esters, steroids, alcohols, and fatty acids. Interspecific differences for both cuticular wax and cephalic extracts were found. The composition of cuticular wax and cephalic extracts was similar at the intraspecific level, with minor component differences between males and workers. Abdominal extracts differentiated sexes (male and worker) at the intraspecific and interspecific levels. The main chemical components in abdominal extracts of N. testaceicornis workers and males were geranylgeranyl acetate and (Z)-9-nonacosene, respectively. The principal components of abdominal extracts from P. droryana workers and males were tetradecanal and unsaturated fatty acids (linoleic and linolenic acids), respectively. A secondary alcohol, (S)-2-nonanol, was detected in Plebeia droryana males only, but not in workers. Preliminary field experiments showed that (S)-(+)-2-heptanol and (S)-(+)-2-heptanol/ (S)-(+)-2-nonanol (1:1) attracted workers of P. droryana, N. testaceicornis, and Frieseomelitta silvestrii. However, males did not respond suggesting that these compounds do not function as alarm or recruitment pheromones . In addition, racemic mixtures were inactive.

Further Disentangling of a Taxonomic Puzzle: Maxillaria ramosa, Ornithidium pendulum, and a New Species, O. elianae (Orchidaceae)

ABSTRACT McIllmurray and Oakeley (2004) demonstrated that the name Maxillaria ramosa has been misapplied to Ornithidium pendulum since 1967, and possibly corresponds to M. cassapensis. We refer Ornithidium ochraceum, O. loefgrenii, and Maxillaria spathulata to the synonymy of O. pendulum (in addition to the already recognized synonyms O. dichotomum and Scaphyglottis tafallae), and designate a lectotype for O. dichotomum. Anew species from Venezuela and the Guianas (Ornithidium elianae), previously confused with O. pendulum, is described. An updated description of O. pendulum is presented along with a review of its complicated taxonomic history and the first record of this species for Costa Rica.