Pollination ecology of Swartzia apetala Raddi var. apetala (leguminosae-papilionoideae)

Abstract

The pollination ecology of Swartzia apetala Raddi var. apetala was studied in the restinga of Maricá, State of Rio de Janeiro, Brazil. S. apetala var. apetala is a shrub with asynchronic annual blooming, between the months of November and April (hot-rainy season). Each plant can exhibit more than one blooming episode in this period. Their flowers are hermaphrodites, apetalous, heterantherous, odoriferous, and the pollen represents the only reward offered to visitors. It is pollinized by species of Centris and Xylocopa, solitary and polyletic bees, which collect the pollen by means of vibratory movements. Other bees such as Apis mellifera, Pseudaugochloropsis graminea and Trigona spinipes are only pollen-thieves. In this variety of Swartzia vibrating is an efficient method to collect pollen from the anthers despite non-poricidal dehiscence.. The flowering phenology and the behavior of visitors influence the rate of outcrossing.<br>A ecologia da polinização de Swartzia apetala Raddi var. apetala foi estudada na restinga de Maricá, Estado do Rio de Janeiro, Brasil. S. apetala var. apetala é um arbusto com floração do tipo anual assincrônica, entre os meses de novembro e abril (estação quente- chuvosa). Cada planta pode apresentar mais de um episódio de floração neste período. As flores são hermafroditas, apétalas, heterândricas, odoríferas e o polem constitui a única recompensa oferecida aos visitantes. É polinizada por espécies de Centris e Xylocopa, abelhas solitárias e poliléticas, que coletam o polem através do método de vibração. Nesta variedade de Swartzia a vibração é um método eficiente de coleta de polem apesar das anteras apresentarem deiscência rimosa. Outras abelhas, como Apis mellifera, Pseudaugochloropsis graminea e Trigona spinipes, são pilhadoras de pólen. A fenologia da floração e o comportamento dos visitantes florais influenciam a taxa de fertilização cruzada

Pollination biology of melittophilous legume tree species in the Atlantic Forest in Southeast Brazil

“…This kind of floral morphology can thus limit the spectrum of visitors able to forage on flowers and may work as a strategy for effective pollination. Pollen deposition on different areas of the pollinator's body in the studied Senna and Swartzia species is a result of heteranthery, an attribute already recorded for other Swartzia species (Lopes & Machado 1996;Moço & Pinheiro 1999), in various genera of the tribe Cassiinae (Dulberger 1981;Gottsberger & Silberbauer-Gottsberger 1988;Westerkamp 2004) and in at least 20 families (Endress 1994;Vallejo-Marín et al 2010). Heteranthery, resulting in functional separation of pollen for feeding and pollen for pollination, has been considered an evolutionary response to assure pollination while feeding voracious foraging bees (Vogel 1978;Buchmann 1983;Luo et al 2008;Vallejo-Marín et al 2009;Papaj et al 2017).…”

“…The medium to large-sized bees observed in this study have been reported as pollinators of several other legume species with medium and large-sized flowers: Euglossina species are the main pollinators of Swartzia pickelli (Lopes & Machado 1996), and Xylocopa and Centridini bees of Swartzia apetala (Moço & Pinheiro 1999) and of several Senna species (Carvalho & Oliveira 2003), as well as several Cassiinae species with pollen flowers (Dulberger 1981;Gottsberger & Silberbauer-Gottsberger 1988). These cohorts of buzz-collectors have also been reported as pollinators of several Caesalpinioideae with nectar flowers (Cocucci et al 1992;Lewis & Gibbs 1999), and most of them are important pollinators of many canopy tree species of Neotropical forests Bawa 1985a;1990).…”

“…Self-incompatibility has been suggested as prevalent in tropical trees (Bawa 1974;Bawa et al 1985b). In fact, several tropical Leguminosae tree species, such as Swartzia pickelli (Lopes & Machado 1996) and Swartzia apetala (Moço & Pinheiro 1999) in the north-eastern Atlantic rainforest, Pseudopiptadenia contorta (Prata-deAssis-Pires & Freitas 2008) and S. multijuga (Wolowski & Freitas 2010) in a montane Atlantic rainforest, Senna silvestris (Carvalho & Oliveira 2003) and Copaifera langsdorffi (Freitas & Oliveira 2002), both in the Brazilian savanna, and Caesalpinia calycina (Lewis & Gibbs 1999) in the caatinga, have been demonstrated as self-incompatible. However, since the number of treated flowers and individuals in this study was low, more experiments are necessary to detect the mating-system of these species.…”

“…Again, the pollination of these species shows a relationship between the size of the bees and the flowers; S. oblata flowers have both large-and medium-sized bees as pollinators, whereas the larger flowers of S. simplex are probably only effectively pollinated by the largest Xylocopa species. Bees of similar size categories were also recorded as the main pollinators of S. pickelli and S. apetala (Lopes & Machado 1996;Moço & Pinheiro 1999).…”

Biologia floral de Manilkara subsericea e de Sideroxylon obtusifolium (Sapotaceae) em restinga

“…Essas mesmas características estão presentes em grãos de pólen de fl ores com deiscência poricida (Silva et al 2002) ou com deiscência rimosa (Moço & Pinheiro 1999), que dependem da vibração dos estames a fi m de que o pólen seja transferido das anteras para o polinizador.…”