Kátia Maria Medeiros de Siqueira

Ecologia da polinização do maracujá-amarelo, na região do vale do submédio São Francisco

This study describes aspects of floral biology and the reproductive system of Passiflora edulis f. flavicarpa (Passifloraceae), including foraging patterns of the floral visitors in the region of Sao Francisco Valley. The study was carried out in irrigated orchards in the Manicoba Project, in Juazeiro-BA, during 2005 and 2006. The floral anthesis occurred between midday and 1 pm. Flower closing started at 6 pm and finished around 1 am. The time for style deflexion was 71,4 ± 12,4 min, about 5% of the flowers remained with the style undefexed. The stigmas were receptive during the entire anthesis and the pollen grains presented 94% viability. The nectar volume was in average 100 µL, with 48% of sugar concentration . The average number of pollen grains/flower was 140,595 ± 34,175 and 426 ± 77 of ovules/ovary. The highest rates were obtained after manual crossed pollination (74%), confirming the existence of a system of self-incompatibility. We registered 10% of flowers with four stigmas, which when manually pollinated, produced bigger fruits with a higher number of seeds (477,7 ± 76,8). We found a positive correlation between the number of seeds and the weight of the fruits. The flower visitors were Apis mellifera, Trigona spinipes, Xylocopa grisescens, X. frontalis and X. cearensis. A. mellifera and T. spinipes being pollen and nectar robbers, respectively. Bees of the genus Xylocopa were more frequent during the dry season and A. mellifera during the wet season. The effective pollinators were X. grisescens and X. frontalis. We found that they were limited in number in the studied areas. However they were found to be more frequent in other plant species during the rainy season which indicates that these plant species compete with the passion fruit for pollination service.

Estudo comparativo da polinização de Mangifera indica L. em cultivo convencional e orgânico na região do Vale do Submédio do São Francisco

O presente estudo foi desenvolvido durante os anos de 2005/2006, em plantio comercial de mangueira, da variedade Tommy Atkins, na Fazenda Frutex, em Petrolina-PE, objetivando verificar a biologia floral, bem como o estudo comparativo sobre o comportamento, a frequencia e a sazonalidade dos visitantes florais em cultivo orgânico e convencional. As inflorescencias da mangueira apresentam flores masculinas e hermafroditas, na proporcao de 2:1, com predominância das primeiras na base da panicula. A antese e diurna, assincronica, com liberacao de forte odor adocicado. As flores apresentam dicogamia, caracterizada pela deiscencia das anteras 24h apos a antese. A producao de nectar e continua e em pequenas quantidades, em media 0,045 µL por flor. Quanto aos visitantes florais foram registradas 21 especies, pertencentes as ordens: Diptera, Hymenoptera, Lepidoptera e Odonata. Apis mellifera foi a especie mais frequente nos dois tipos de cultivo. Dentre os dipteros, destacaram-se Belvosia bicincta (17,7%) e Musca domestica (10,2%) como as mais frequentes em cultivo convencional e orgânico, respectivamente. A diversidade e o numero de visitas foram maiores em cultivo orgânico. A utilizacao de agrotoxicos durante a floracao reduziu a frequencia de visitas das abelhas em 50% e dos dipteros em 20%. Devido ao seu comportamento, frequencia e ativo deslocamento nas inflorescencias, A. mellifera foi considerada como o polinizador mais eficiente da cultura para a regiao do Vale do Submedio Sao Francisco.

Comparação do padrão de floração e de visitação do meloeiro do tipo amarelo em Juazeiro-BA¹

The work was conducted in an experimental area of UNEB in Juazeiro, Bahia, Brazil, in 2010 and 2011, with the aim of describing aspects of phenology, floral biology and performance of floral visitors of melon type yellow, to contribute to the management of hives of Apis mellifera L., in the region of the Sao Francisco Valey. In November 2010, an average of 22,7±2,6 days of blooming were observed, with emission of exclusively male flowers until the second day, and emission of hermaphrodite flowers for 16 days. In May 2011, the average blooming days was 19,3±4,3 and male flowers production only until the fourth day and hermaphrodite flowers production for 20 days. The average number of flowers per plant and the sex ratio were 96,2±4,2 and 1:16 in November 2010, and 67,1±17,7 and 1:19, in May 2011, respectively. The hermaphrodite flowers had higher nectar volume than the male ones in both periods, and this could be the probable cause of the higher number of visits received by such floral type. The highest number of visits occurred in the morning, and pollen collection was especially high from 7:00 am to 11:00 am.

EVALUATION OF FLORAL CHARACTERISTICS OF MELON HYBRIDS (Cucumis melo L.) IN POLLINATOR ATTRACTIVENESS

Floral morphology and biology are important characteristics for plant-pollinator interactions and may influence the behavior of these agents. This study aimed to determine which floral attributes of different melon hybrids influence this interaction and, consequently, their attractiveness in simultaneous crops. The study was conducted in the region of Petrolina, State of Pernambuco (PE)/Juazeiro, State of Bahia (BA) and Mossoro, State of Rio Grande do Norte (RN), in areas with the following melon hybrids: Yellow type, Piel de Sapo, Cantaloupe and Galia. For studies on floral morphology and biology, hermaphrodites and male flowers of each hybrid were analyzed for their size and nectar chamber size, pollen and nectar production, anthesis time and flower lifespan. Floral visitors were observed simultaneously in hybrids of three types of melon, from 5:00 a.m. to 6:00 p.m., in the two study sites. Evaluations of the corolla diameter and flower height indicated that the hermaphrodite flowers were larger in size than male flowers in all types of melon investigated, in both study sites. As for nectar chamber, male flowers are larger in width, but smaller in height, compared to hermaphrodite flowers. Regarding the volume of nectar, differences were found between floral types for the hybrids evaluated, in the two study sites; the hermaphrodite flowers produced 2-7 times more nectar than male flowers in all studied hybrids. Observations of visits of Apis mellifera to areas with simultaneous flowering of the three types of melon demonstrated differences in the frequency of visits between hybrids, floral type and foraged resource. Flowers of the hybrids Piel de Sapo and Cantaloupe exhibited larger corolla diameter, larger dimensions of the nectar chamber and greater supply of resources for foraging, which could explain the higher number of visits of bees to their flowers in the sites studied.

Foraging of Honeybees (Apis mellifera) on Flowers of Yellow Melon (Cucumis melo): Duration of Visits

Studying the pollinators’ foraging behaviour is quite important for pollination. Time spent by the pollinator in floral handling is one of the aspects of this behaviour. Honeybees ( Apis mellifera ) are the main responsible for the pollination of melon ( Cucumis melo ), but there are few studies on their foraging, mainly in the region of Petrolina, state of Pernambuco, and Juazeiro, state of Bahia, in Brazil. This study aimed to compare bee visitation to hermaphrodite (HF) and male (MF) flowers in a crop area where different number of hives were used. For each floral type, 10 flowers were observed, in each experiment (0, 1, 2 or 3 hives). The duration of bee visits (n = 10) was registered in three times of the day: 8 a.m., 11 a.m., and 4 p.m. In general, HF received significantly longer visits than MF, in all experiments, except when using one hive. In fact, significant correlations were found between the duration of visits and number of hives for HF, but not for MF. This is probably related to the attractiveness of HF and to the availability of floral resources. The studies of duration of pollinator’ visits are relevant in agriculture and should be considered when evaluating the efficiency of pollination in melon.