Abstract An integrated approach considering facies, isotopic, and palynological analyses of lake sediments from the Serra Norte de Carajás, southeastern Amazonia, is presented in this work to refine paleoclimate and paleohydrological changes based on upland lake sediments during the late Quaternary. The sediments have a fining-upward deposition cycle typical of upland swamps/lakes. The origin of organic matter is autochthonous mainly related to C3 terrestrial plants, macrophytes and algae. The pollen records of Hedyosmum during the Early Pleistocene suggest lower temperatures than those observed along Holocene. In the transitional period between the Pleistocene and the Holocene, rainfall decreased, causing the retraction of the flooded area, favoring the development of marshy conditions. The Late and Middle Holocene were marked by higher temperatures and lower humidity. Afterward, the increased pollen concentration from canga and forest vegetation, macrophytes, palms, and algae suggested increased humidity in the Early Holocene. The relative contribution of forest pollen along the records indicated that drier conditions were not strong enough for an extensive expansion of canga over forested areas. facies isotopic Carajás Amazonia Quaternary finingupward fining upward swampslakes swamps lakes swamps/lakes C plants decreased area Afterward vegetation palms areas

Abstract The study aimed to analyze the honey of Melipona subnitida to identify the plants visited by these bees in colonies installed in a restinga vegetation in Maranhão state. Honey was collected monthly from July/2017 to June/2018. The honey samples were submitted to the acetolysis method and the pollen grains were analyzed qualitatively and quantitatively. The pollen analysis of honey resulted in 54 pollen types and 26 families. The largest pollen variety was registered in Fabaceae. Quantitative analyzes of pollen grains in honey samples revealed that three were monofloral, in July/2017 with Avicennia germinans honey and December/2017 and January/2018 with Copaifera martii honey. In the other months, the heterofloral honeys. Melipona subnitida proved to be general in food gathering. Knowing the flora used by M. subnita contributes to the meliponiculturists to improve the handling of the colonies, the increase and quality in the production of honey.

ResumenCentris (Hemisiella) dichrootricha es una especie de abeja solitaria neotropical, que anida en cavidades preexistentes y vive en la selva tropical. El presente estudio describe la biología de anidación de C. dichrootricha y su preferencia de nidificación por áreas en Cerrado y Bosque de Galería. El área de estudio se localiza en el Parque Estadual de Mirador, municipio de Formosa da Serra Negra, Maranhão. El método empleado fue el de nidos trampa de madera de diferentes diámetros, 6, 8, 10, 12, 14 y 16 mm, colocándose 300 nidos trampa por área. Las trampas fueron monitoreadas mensualmente y todos los nidos terminados fueron recogidos y sustituidos por otros vacíos. Los nidos completos fueron llevados al laboratorio para analizar el desarrollo de la abeja, la emergencia, las características de los nidos y la presencia de parásitos. La especie ocupó 29 nidos de los diámetros de 8, 10, 12 y 14 mm. Emergieron 87 individuos de C. dichrootricha. Los nidos fueron parasitados por tres especies: Mesocheira bicolor (Apinae), Coelioxys sp. (Megachilinae) y Antrax sp. (Diptera). En el Bosque de Galería se presentó la mayor nidificación (72.4 %) y en el Cerrado solamente 27.6 %, de esta forma, hubo diferencias significativas entre los hábitats (χ² = 5.56; p < 0.05; G. L.= 1). Los nidos fundados en el bosque de galería presentaron 80.9 % de sedimento originario del Cerrado. Las hembras fueron significativamente más grandes que los machos (F1, 76 = 595.19; p < 0.001). Hubo 11 tipos de polen pertenecientes a seis familias. Los tipos de polinización de la familia Malpighiaceae fueron los más representativos, con cuatro especies: Byrsonima crassifolia, B. rotunda, B. spicata y Heteropterys sp. C. dichrootricha mostró preferencia por nidificar en cavidades con diámetros variados y en el bosque de galería. El presente estudio contribuye con la descripción de los hábitos de nidificación y la biología de la especie para las áreas de Cerrado en la región centrosur de Maranhão. C. dichrootricha utilizó en su mayoría recursos provenientes del Cerrado, tanto sedimento para construir el nido, como material polínico y aceite floral. Estós datos indican que el bosque de galería y el Cerrado están intrínsecamente relacionados con el mantenimiento y conservación de C. dichrootricha.

Abstract:The Neotropical bee Centris (Hemisiella) dichrootricha is a solitary bee that nests in pre-existing cavities that occur in the rain forest. This study describes the nesting biology of C. dichrootricha and its preference for nesting in Cerrado and gallery forest habitats. The study was conducted from January 2012 and December 2013, in Mirador State Park in the municipality of Formosa da Serra Negra, Maranhão State, Brazil. For this, wooden trap-nests of 6, 8, 10, 12, 14 and 16 mm in diameter were used; a total of 300 trap-nests were placed in the gallery forest and Cerrado areas, respectively. Traps were monitored monthly and all completed nests were collected and replaced with empty ones. The nests were then taken to the laboratory to analyze bee development and emergence, nests characteristics and parasites presence. The species used 29 of the trap-nests, which had diameters of 8, 10, 12 and 14 mm. A total of 87 C. dichrootricha specimens emerged. The nests were parasitized by two bee species, Mesocheira bicolor (Apinae) and Coelioxys sp. (Megachilinae), and one fly species, Antrax sp. (Diptera). The highest nesting incidence of 72.4 % was observed in the gallery forest, whereas only 27.6 % in the Cerrado; this difference in habitat use was significant (χ² = 5.56; p < 0.05; DF = 1). For the nests that were built in the gallery forest, 80.9% of the soil originated from the Cerrado. The females were significantly larger than the males (F1, 76 = 595.19; p < 0.001). There were 11 pollen types that belonged to six families. Pollen of the family Malpighiaceae was most frequently used, with four species represented (Byrsonima crassifolia, B. rotunda, B. spicata and Heteropterys sp.). C. dichrootricha showed a preference for nesting in cavities of various diameters in gallery forest sites. The present study provides a novel description of the nesting habits and biology of C. dichrootricha in habitats of Central/Southern Maranhão. C. dichrootricha primarily used resources from the Cerrado, including soil to build their nests, pollen and floral oils; we concluded that gallery forest and Cerrado areas are intrinsically related to the maintenance of local populations of this species. Rev. Biol. Trop. 64 (3): 1041-1056. Epub 2016 September 01.

Os Centridini compreendem cerca de 176 espécies distribuídas principalmente nas regiões tropicais da América. Mesmo considerados polinizadores-chave na manutenção de muitas espécies vegetais, dados sobre sua bionomia são ainda restritos. Há relatos sobre a nidificação de 11 espécies, das 21 diagnosticadas como polinizadoras do murici, Byrsonima crassifolia L. Kunth, uma espécie valiosa para o biomonitoramento. Um estudo da biologia de nidificação de Centris flavifrons (Friese) foi conduzido no Maranhão durante o período de atividade dos adultos (maio a dezembro). Os ninhos estavam agregados. As fêmeas escavaram seus ninhos em solo plano e compactado. Quinze ninhos ativos foram escavados, sendo que em apenas seis foram encontradas células. O túnel era simples, sem ramificações, com uma única célula na sua porção terminal, situada entre 25 cm e 50 cm de profundidade. Foi observada atividade noturna na construção dos ninhos. A análise polínica do aprovisionamento de quatro células permitiu identificar 23 espécies florais, das quais seis espécies de Malpighiaceae. Foram registradas seis espécies florais que ainda não haviam sido encontradas visitando C. flavifrons: Lecythis lurida (Miers) Mori, Hymenea courbaril L., Myrcea sp., Protium sp., Tetrapterys sp. e Thalisia sp.

The Centridini has almost 176 species distributed mainly in the tropic regions of America. Although they are considered key pollinators in the maintenance of many vegetal species, data about their bionomics are restrict. Nesting activity is known for 11 species, out of the 21 that are considered pollinators of murici, Byrsonima crassifolia L. Kunth, a valuable biomonitoring specie. A study of the nesting biology of Centris flavifrons (Friese) was conducted in the state of Maranhão, Brazil, during the active period of the adults (May through December). Nests were aggregated. The females excavated their nests on flat surfaces of hard soils. Fifteen nests were dug and we only found cells in six of them. The nests architecture consisted of a single unbranched tunnel, with only one cell in the vertical position at the end, which was 25 cm to 50 cm away from the entrance. Nocturnal activity was observed in the nests building. The pollen analysis of the contents of four cells allowed to identify 23 floral species, six of them Malpighiaceae. Six floral species were registered visiting C. flavifrons by the first time: Lecythis lurida (Miers) Mori, Hymenea courbaril L., Myrcea sp., Protium sp., Tetrapterys sp. and Thalisia sp.