Emerson Ricardo Pansarin

Biologia floral, melitofilia e influência de besouros Curculionidae no sucesso reprodutivo de Grobya amherstiae Lindl. (Orchidaceae: Cyrtopodiinae)

The phenology, floral morphology, pollination mechanisms and reproductive biology of Grobya amherstiae Lindl. were studied in two populations located in altitudinal forests at Serra do Japi, Jundiai, Sao Paulo State, Brazil. The flowering occurs in summer and lasts about one month (part of February and March). The flowers of an inflorescence open almost simultaneously, in the morning, and each lasts about seven to eight days. The flowers release a honey-like fragrance. At both populations G. amherstiae was pollinated by Paratetrapedia fervida Smith (Anthophoridae) bees, which collect floral oils produced by trichomatic elaiophores at the apex of the lip and the column basis. At one of the populations, besides bees individuals of a Curculionid beetle of the genus Montella were recorded, which perform self-pollination on the majority of the flowers. Grobya amherstiae is self-compatible but pollinator dependent. The females of Montella sp. oviposit in the ovary and their larvae consume the seeds. However, the number of fruits parasitized by the larvae is low when compared with the amount of fruits produced. Since natural fruit set is low, the beetles contribute positively for the reproductive success of G. amherstiae at least in one of the populations.

Reproductive biology and pollination mechanisms of Epidendrum secundum (Orchidaceae). Floral variation: a consequence of natural hybridization?

The phenology, flower morphology, pollination mechanism and reproductive biology of Epidendrum secundum were studied in a semi-deciduous forest at the Serra do Japi (SJ), and in the Atlantic rain forest of Picinguaba, both natural reserves in the State of São Paulo, southeastern Brazil. E. secundum flowers all year round, with a flowering peak between September and January. This species is either a lithophytic or terrestrial herb in the SJ, whereas, in Picinguaba, it grows mainly in disturbed areas along roadsides. E. secundum is pollinated by several species of diurnal Lepidoptera at both study sites. In Picinguaba, where E. secundum is sympatric with E. fulgens and both share the same pollinators, pollen transference between these two species was recorded. E. secundum is self-compatible but pollinator-dependent. It is inter-compatible with E. fulgens, producing fertile seeds. In contrast to the population of the SJ, in the Picinguaba region, floral morphology is quite variable among plants and some individuals present flowers with characteristics in-between both sympatric species, suggesting that natural hybridization occasionally occurs. The anthropogenic perturbation is probably the cause of the occurrence of E. secundum in the Picinguaba region, enabling its contact with E. fulgens.

Biologia reprodutiva e polinização em Epidendrum paniculatum Ruiz & Pavón (Orchidaceae)

Epidendrum paniculatum Ruiz & Pavon occurs in Central and South America. The populations studied grows on rocks of semidecidual forests at the Serra do Japi (Sao Paulo State - Brazil). The flowers are green and white, and fragrant during the day and the night. In the study area, the pollinators are Ithomiinae butterflies and diurnal moths of the family Arctiidae, both reported to collect alkaloids of certain flowers. The tests performed revealed, however, that alkaloids are not present in flowers of E. paniculatum. The pollinators are attracted by the flowers of this species probably due to fragrance and nectar production. The treatments carried out revealed a high level of self-incompatibility within the flowers of E. paniculatum. Due to the tendency of many Lepidoptera to remain at specific micro-habitats, the occurrence of self-pollination is very common. The high level of self-incompatibility, combined with pollinator inefficiency, promotes a strong loss of pollen and consequently low fruit set. The small number of fruits produced is derived from cross-pollination. This fact plus to the production of thousands of seeds dispersed by wind in each fruit, probably is sufficient to maintain of the number individuals constant in the region, genetic variation, and extensive distribution of E. paniculatum.

Biologia reprodutiva e polinização de duas espécies de Polystachya Hook. no Sudeste do Brasil: evidência de pseudocleistogamia em Polystachyeae (Orchidaceae)

Phenology, floral biology, pollinators, breeding system and natural fruit set of Polystachya estrellensis Rchb. f. and P. concreta (Jacq.) Garay & H. R. Sweet were studied in mesophytic forests at Serra do Japi, and in mangroves at a seashore plain at Picinguaba, respectively. Both study areas are natural reserves in southeastern Brazil. Both species flower in summer, are epiphytes and produce terminal inflorescences with up to 150 non-resupinate flowers. The flowers produce a citric fragrance, mainly in the warmest hours of the day. Both species are pollinated by solitary and social small native bees, which collect pseudopollen from the lip of the flowers. The pollinarium is placed frontally on the head of the bees, when they are collecting pseudopollen. Polystachya estrellensis and P. concreta are self-compatible. The majority of flowers of P. estrellensis (96,7%) is cleistogamous, while P. concreta produces only chasmogamous flowers. The cleistogamous flowers of P. estrellensis present dimensions and number of floral elements identical to the chasmogamous, a phenomenon called pseudocleistogamy. The chasmogamous flowers of P. estrellensis, as well as all flowers of P. concreta are pollinator dependent. The natural fruit set of P. estrellensis was higher than that of P. concreta as a consequence of pseudocleistogamy. In mesophytic forests of the Serra do Japi, in which the fruit set of several orchid species is low, mainly because of pollinator scarcity, the strategy presented by P. estrellensis is an important factor that increases the reproductive success of this species, compared with to the non-autogamous members of Epidendroideae that occur in the same region.

Biologia floral de Cleistes macrantha (Barb. Rodr.) Schltr. (Orchidaceae: Vanilloideae: Pogoniinae)

Cleistes macrantha (Barb. Rodr.) Schltr. is widely distributed in Atlantic rain forests in south and southeastern Brazil, occurring in anthropogenic disturbed areas and in restinga vegetation. Aspects of the floral biology of C. macrantha were investigated in the Intervales nature reserve, in the interior of Sao Paulo state. This species offers nectar as reward and is pollinated principally by bumblebees. The nectar is secreted before the anthesis of the flowers, with no posterior secretion. Hermit hummingbirds can also act as pollinators. A previous visit of a bumblebee, however, is necessary for pollen deposition on their bills. Bumblebees are responsible for most cross-pollinations. The hummingbirds perform mainly self-pollination. Preliminary treatments reveal that C. macrantha is self-compatible, but a pollinator is necessary for successful pollination. In spite of the self-compatibility observed, ecological factors favor cross-pollination in this species. This study makes too, a comparison of the floral biology of C. macrantha with what is known about the genera of the North American-Asiatic clade in Pogoniinae.

Pollination biology of three Brazilian species of Micranthocereus Backeb. (Cereeae, Cactoideae) endemic to the “Campos rupestres”

Summary: n The genus Micranthocereus includes nine endemic Brazilian species distributed in the states of Bahia, Minas Gerais, Goiás and Tocantins. In the present study the floral biology of M. flaviflorus, M. streckeri and M. purpureus from “campo rupestre” vegetation of the Chapada Diamantina, Bahia, was investigated. Data on floral morphology and nectar production (concentration and volume) were collected throughout anthesis. Flowers of all species are tubular and present coloured perianth-segments. Nectar is accumulated within a nectar-chamber, located inside the floral tube. Flowers of M. flaviflorus and M. streckeri are predominantly nocturnal, opening in the night (at about 7 p.m.). Each flower lasts c.36 hours, with a concentration of sugar in the nectar between approximately 18–24%. Both species present floral features typical for ornithophily, and were pollinated by the hummingbird Chlorostilbon aureoventris, whose visits occurred in regular intervals and were characterized by territorialist behaviour. Species of bees and butterflies were also observed visiting flowers of M. flaviflorus and M. streckeri. M. streckeri was additionally visited by the hummingbird Phaethornis squalidus, mainly in the afternoon. Flowers of M. purpureus are nocturnal, and each flower lasts c.17 hours and present longer corollas with wider diameter than those of the other two species studied; sugar concentration in the nectar was about 21–22%. Three sphingid and one bat species were observed visiting flowers of M. purpureus, with a greater frequency of visits of the sphingids. Pollen viability was high (80–90%) and similar between the three species of Micranthocereus studied.