RESUMO Este trabalho analisou visitantes florais de Turnera subulata Sm. (Turneraceae) em área antropizada na Bahia (Campus UEFS), com foco nos potenciais polinizadores, na produção de frutos e sementes e na influência dos fatores climáticos nesta interação. O estudo foi realizado durante seis meses em 2018 e 2019. Foram observados aspectos da biologia floral e comportamento do visitante. As flores de T. subulata duraram aproximadamente seis horas e durante este período foram expostas aos visitantes em diferentes intervalos para avaliar o pico de formação dos frutos. Os visitantes mais frequentes foram as abelhas Apis mellifera Linnaeus, 1758, Trigona sp., Augochlora sp. e Protomeliturga turnerae (Ducke, 1907). O pico de forrageamento ocorreu pela manhã, coincidindo com o momento de maior formação de frutos e sementes, e com o maior número de flores abertas. Tanto as abelhas exóticas quanto as nativas atuaram como potenciais polinizadores, sendo consideradas complementares no processo de polinização das flores.

ABSTRACT This work analyzed floral visitors of Turnera subulata Sm. (Turneraceae) within an anthropized area in Bahia (UEFS Campus), focusing on potential pollinators, fruit and seed production and the influence of climatic factors on this interaction. The study was carried during six months in 2018 and 2019. Aspects of floral biology and visitor behavior were observed. Turnera subulata flowers lasted approximately six hours and during this period they were exposed to visitors at different intervals to assess the peak time of fruit formation. The most frequent visitors were the bees Apis mellifera Linnaeus, 1758, Trigona sp., Augochlora sp. and Protomeliturga turnerae (Ducke, 1907). The foraging peak occurred in the morning, coinciding with the time of greatest formation of fruits and seeds, and with the time of greatest number of open flowers. Both exotic and native bees acted as potential pollinators, being considered complementary in the flower pollination process.

ABSTRACT The application of sewage sludge (SS) in agriculture is a practice used worldwide, and it is commonly applied in sugarcane to supply nutrients, with beneficial effects on crop productivity and soil; but SS can increase sorption and decrease desorption of herbicides. However, in tropical soils such as in Brazil, there are no studies regarding the behavior of pre-emergent herbicides, mainly aminocyclopyrachlor and mesotrione, in SS-amended soil. The aim of the present study was to determine the effect of municipal SS applied in agriculture on the sorption–desorption of aminocyclopyrachlor and mesotrione in clay soil. Aminocyclopyrachlor (pyrimidine-2-14C-aminocyclopyrachlor) and mesotrione (cyclohexane-2-14C-mesotrione) sorption–desorption was evaluated using a batch equilibrium method. Soil was amended at 0% (control – unamended), 0.1%, 1%, and 10% (w∙w–1) of air-dried SS corresponding to 1.2, 12, and 120 t∙ha–1. The Freundlich Kf sorption values of aminocyclopyrachlor and mesotrione were similar for all treatments, ranging from 1.07 to 1.45 and 3.48 to 4.25 µmol (1–1/n) L1/n∙kg–1, respectively. Overall, the lowest Kd sorption value of these herbicides was reported for SS-amended soil (1%), while in the SS-amended soil (10%) it was higher than unamended soil. The H value for aminocyclopyrachlor was ~1 (no hysteresis) and for mesotrione was on average 0.4 (hysteresis occurring). In conclusion, the present study indicates that SS applied in any crop to supply nutrients can slightly affect the sorption–desorption of aminocyclopyrachlor and mesotrione, but this small difference does not affect the bioavailability of these herbicides for weed control.

ABSTRACT: Pollination depends on morphological and behavioural adjustments between visitors and plants. Some plant species as Ipomoea bahiensis (Convolvulaceae) provide nectar and pollen to visitors and occur in anthropic areas, therefore becoming an important source of resources for the maintenance of native pollinating insects. However, what is the efficiency of each floral visitor species for the pollination of this plant species? What morphological and behavioural characteristics determine the pollinators? In this regard, this study evaluated the I. bahiensis flower and visitor morphology in a semi-arid area and the foraging behaviour of these floral visitors. Also, the efficiency rate of potential pollinators was quantified. Bees and butterflies visited the flowers of I. bahiensis, but the bees Melitoma spp., Apis mellifera (Linnaeus, 1758), and Pseudaugochlora pandora (Smith, 1853) were the most frequent visitors. These species presented medium-sized and compatible with the floral tube width. In addition to the size, these bees presented behaviour that favoured the contact with the reproductive structures of the flower, as evidenced by the efficiency test of the flower visits. Although butterflies often collect nectar from the flowers, they do not present characteristics that could result in pollination. Hence, medium-sized bees played the role of efficient pollinator of I. bahiensis.

ABSTRACT The family Convolvulaceae is widely distributed in tropical regions, mainly in open areas. Convolvulaceae flowers are characterized mainly by being beautiful and ephemeral, attracting many flower visitors that belong to different taxonomic groups. This work aimed to investigate the interactions between insects and flowers of Jacquemontia bracteosa (Convolvulaceae), focusing on the pollination efficiency, in an area in the Brazilian semiarid. From November 2011 to October 2012, floral biology of J. bracteosa was investigated as well as the flower visit frequency, behavior, and morphology of floral visitors. The flowers of J. bracteosa are white, showy and open early in the morning, lasting less than 12 hours, with fruiting occurring both by selfing and outcrossing fecundation. A total of 337 specimens insects were collected on J. bracteosa flowers during the field observations. The Neotropical bee, Ancyloscelis apiformis, was considered the most efficient pollinator of J. bracteosa. This bee showed appropriate behavior, high frequency (64% of the total sample), and was constant on the flowers. Furthermore, they arrived soon when the flowers began to open and presented 90% of efficiency in tests of flower pollination of J. bracteosa. Other native bee species also visited the flowers of J. bracteosa and may be considered potential pollinators because they presented behavior and morphology compatible with the flowers. This study suggests that maintenance of weeds or ruderal plants, especially those that also have ornamental potential in anthropic area, may be an option for the preservation of local native pollinators, which are threatened by environmental degradation.

Several studies have been conducted with bees of the subtribe Euglossina using odor baits as attractants. The objective of this study was to analyze the daily activity pattern of visits by males of four species of Eulaema - Eulaema nigrita Lepeletier, 1841, Eulaema flavescens (Friese, 1899), Eulaema cingulata (Fabricius, 1804) and Eulaema bombiformis (Packard, 1869) - to vanillin and benzyl acetate baits, and their relationship with climatic and environmental factors throughout the day in different months of the year in a tropical forest fragment in Bahia. Eulaema nigrita was the most frequent species on vanillin baits and E. flavescens was the most frequent species on benzyl acetate baits. The highest frequency of visits was observed in February and December. Activities started between 5:00 and 9:00 h. In February and November, visits of E. nigrita to the bait were observed daily, following a bimodal pattern. The same activity pattern was observed for E. bombiformis in December. Males of four species of Eulaema occurred in all remaining months in a unimodal daily activity pattern, with a higher frequency before 9:30 h. The correlation between the visiting activity to odor baits and climatic factors was low. This result can be due to bee flight activity occurring within a range of adequate climatic variation, particularly temperature, which in our study ranged from 23 to 32ºC. Daily activity patterns of Euglossina males on odor baits can represent patterns of flower fragrance collection under natural conditions, with visits usually at the time of highest production.

As espécies de Vochysia são neotropicais e apresentam flores que podem ser visitadas por abelhas, beija-flores e borboletas. Este estudo teve como objetivo a análise das interações entre as flores de Vochysia lucida e seus visitantes florais, em uma área de restinga no Estado da Bahia, Brasil. V. lucida é uma espécie arbórea e apresenta inflorescências do tipo racemo, com cerca de 100 a 170 flores. As flores são zigomorfas, amarelas e foram consideradas melitófilas. O néctar floral é produzido e estocado em esporão, localizado no cálice. O pico de floração de V. lucida ocorreu em novembro e dezembro. Durante o estudo as flores abriam às 6:00 h, quando o estigma já estava receptivo. Na abertura da flor a antera já não estava mais presente e os grãos de pólen estavam depositados na parede do estilete, ocorrendo apresentação secundária de pólen. As pétalas caíam no final da tarde, por volta das 17:00 h. Os beija-flores embora freqüentes nas flores de V. lucida foram considerados visitantes oportunistas. Entre os visitantes florais registrados, as abelhas de grande porte foram consideradas os polinizadores mais eficientes, especialmente Xylocopa frontalis, por ter morfologia e comportamento adequados para contatar as estruturas reprodutivas da flor, durante as coletas de néctar, e por sua elevada freqüência de visita.

Vochysia species are Neotropical and present flowers that can be visited by bees, hummingbirds, and butterflies. This study aimed to analyze the interactions between the flowers of Vochysia lucida and their floral visitors in an area of restinga in Bahia State, Brazil. V. lucida is an arborescent species and presents inflorescences of the type raceme, with about 100 to 170 flowers. The flowers are zygomorphic, yellow-coloured, and considered mellitophilous. The floral nectar is produced and stored in the spur, which is localized at the calyx. The flowering peak of V. lucida was in November and December. All through the study the flowers opened at 6 h., when the stigma was already receptive. At flower opening the anther was already not more present and the pollen grains were deposited in the wall of the style, occurring secondary presentation of pollen. Petals dropped in the end of the afternoon about 17:00 h. The hummingbirds, although frequent in the flowers of V. lucida, were considered as opportunistic visitors. Among the recorded floral visitors, the large bees were regarded the most efficient pollinators, especially Xylocopa frontalis, because it has suitable morphology and behavior to contact the reproductive structures of the flower, during nectar collections, and for its high visiting frequency.

As abelhas do gênero Xylocopa Latreille, 1802 são comuns em ecossistemas de restingas em acelerada fase de degradação e são importantes polinizadores deste ecossistema. Elas nidificam especialmente em madeira morta ou apodrecida. As atividades relacionadas à construção e estrutura dos ninhos de Xylocopa (Schoenherria) subcyanea Perez, 1901 na restinga do litoral norte da Bahia, Brasil, foram observadas em 43 ninhos ativos de X. subcyanea, em diferentes fases de desenvolvimento, em dois troncos apodrecidos. A fase de fundação ou reuso no primeiro tronco foi em agosto e a fase de provisionamento das células nos ninhos, em ambos troncos, em janeiro. As principais atividades foram escavações no tronco, entrada e saída dos ninhos, permanência na entrada do ninho, entrada com pólen e desidratação de néctar. Foi observado horário preferencial ao longo do dia para as atividades de entrada e saída dos ninhos, sendo estas influenciadas pelos horários do nascer e pôr do sol. Ninhos abandonados foram reusados por X. subcyanea e Centris tarsata SMITH, 1874. Os ninhos ativos eram ocupados por quatro diferentes abelhas adultas. Geralmente, uma abelha ficava na entrada do ninho. A estrutura do ninho foi descrita.

Bees of the genus Xylocopa Latreille, 1802 are frequent in sandbank ecosystems under accelerated degradation. They nest especially in dead or rotted wood. The nest construction and nest structure of Xylocopa (Schoenherria) subcyanea Perez, 1901 were studied in a sandbank from Bahia's north littoral, Brazil. We observed 43 active nests, under different stages of development, in two dead logs. The main activities were excavation of the logs, entering and leaving nest, permanence in the nest entrance, entering with pollen, and nectar dehydration. Preferential times along the day were observed for entering and leaving nest, showing influence of sunrise and sunset times. Abandoned nests were reused by X. subcyanea and Centris tarsata Smith, 1874. Active nests were occupied by four different adult bees. An individual frequently stayed at nest entrance, adopting a defensive behavior. The nest structure was described.

As flores de Krameria bahiana B.B. Simpson produzem principalmente óleo como recurso floral para seus visitantes. Abelhas coletoras de óleo usualmente apresentam adaptações morfológicas e comportamentais para sua coleta. Este estudo teve como objetivo a análise das interações entre as flores de K. bahiana e as abelhas visitantes, visando a eficiência da polinização, em uma área de restinga na Bahia. De fevereiro/2001 a fevereiro/2002 e de maio a outubro/2002 foram realizadas observações sobre a fenologia e morfologia das plantas e comportamento dos visitantes florais. As flores das inflorescências são zigomórficas, pequenas, de cor rosa e apresentam um par de pétalas modificadas em elaióforos epiteliais, as quais são responsáveis pela produção de óleo. As flores foram visitadas especialmente por abelhas do gênero Centris, C. leprieuri Spinola, C. tarsata Smith, C. trigonoides Lepeletier e C. pulchra Moure, Oliveira & Viana. Essas espécies coletam apenas óleo nas flores, raspando os elaióforos, posteriormente transferindo o recurso para a escopa localizada na tíbia e basitarso das pernas posteriores. Durante esta ação, as abelhas freqüentemente contatam as estruturas reprodutivas das flores, resultando na polinização. C. leprieuri foi a abelha mais freqüente durante este estudo, sendo considerada o polinizador efetivo. Megachile dentipes Vachal também visitou as flores de K. bahiana, coletando apenas pólen. Entretanto, estas abelhas foram consideradas polinizadoras esporádicas por não serem freqüentes nas flores de K. bahiana nos meses de observação.

The flowers of K. bahiana mainly produce oil as floral resource for their visitors. Oil collecting bees usually show morphological and behavioral adaptation for their collection. This study focused on the analysis of interactions between the flowers of K. bahiana and their visiting bees, aiming for the efficiency of the pollination, in an area of the Coastal Sand Plains of Bahia State, Brazil. From February/2001 to February/2002 and from May to October/2002 observations were accomplished about the phenology and morphology of the plants and the floral visitors' behavior. The flowers of the inflorescences are zigomorphic, small sized, pink and present a pair of petals modified in epithelial elaiophores, which are responsible for the production of oil. These flowers were visited especially by bees of the genus Centris: C. leprieuri Spinola, C. tarsata Smith, C. trigonoides Lepeletier and C. pulchra Moure, Oliveira & Viana. The bees collected only oil in the flowers, by scratching the elaiophores and then transferring it to scopa located on the tibia and basitarsus of the hind legs. During those actions, the bees often contact the reproductive structures of the flowers, resulting in pollination. C. leprieuri was the most frequent bee during this study, thus considered the effective pollinator. Megachile dentipes Vachal also visited the flowers of K. bahiana, collecting only pollen. However, these bees were considered sporadic pollinators because they were not frequent in the flowers of K. bahiana in the months of observation.

As flores de Comolia ovalifolia apresentam anteras poricidas e seu pólen serve como fonte protéica a um grupo específico de abelhas, capaz de extrair o pólen das anteras através de vibração. O florescimento de C. ovalifolia e a atividade das abelhas mais freqüentes foram observadas de janeiro a dezembro/2001. Os picos de florescimento de C. ovalifolia ocorreram nos meses de março/2001 e entre setembro e novembro/2001. As flores de C. ovalifolia foram visitadas por 16 espécies de abelhas, sendo as mais freqüentes Centris leprieuri (Spinola), Xylocopa subcyanea Pérez, Centris sp., Euglossa sp. e Florilegus similis Urban. Entre elas, C. leprieuri destacou-se com 89% das visitas e sua atividade forrageira anual coincidiu com a floração de C. ovalifolia. Além disso, essa abelha apresentou tamanho adequado e comportamento eficiente na coleta e transferência de pólen para o estigma, sendo considerada polinizador legítimo dessas flores.

The flowers of Comolia ovalifolia present poricidal anthers and their pollen serve as protein source to a specific group of bees, able to extract the pollen from the anthers through vibration. From January to December /2001, we observed the flowering of C. ovalifolia and the activity of the most frequent bees throughout the year. The peaks of flowering of C. ovalifolia occurred in March and from September to November/2001. The flowers of C. ovalifolia were visited by 16 species of bees, being the most frequent Centris leprieuri (Spinola), Xylocopa subcyanea Pérez, Centris sp., Euglossa sp. and Florilegus similis Urban. Among these, C. leprieuri was the most frequent visitor in the flowers (89%) and its foraging period overlapped with the blooming of C. ovalifolia. This bee presented adequate size and efficient behavior in pollen collection and transfer to the stigma, being considered an effective pollinator of the flowers.

Populations of Ludwigia elegans (Carnb.) Hara were examined in Aluminio (600m) and Campos do Jordão (1520m), in the State of São Paulo. Flowers of both populations are self-incompatible and dependent on bees for pollination. Flowers of Ludwigia elegans at the Aluminio site were visited by about 30 different species of bees, and those at Campos do Jordão by 10. These results can be related to climatic differences at the two sites, especially temperature, due to their difference in altitude. Inspite of the difference in the absolute number of bee species seen at each site, Tetraglossula anthracina (Michener, 1989) (Colletidae) can be considered a specialized and efficient pollinator in both areas, since it visited these flowers frequently and showed many morphological and behavioral adaptations for pollen and nectar collection.