Celso Feitosa Martins

Diversidade de Euglossinae (Hymenoptera, Apidae) em dois fragmentos de Mata Atlântica localizados na região urbana de João Pessoa, Paraíba, Brasil

The use of fragrances to attract males of Euglossinae bees has been an important tool to increase the knowledge of the group. In the Northeastern of Brazil, studies on euglossine bees are still uncommon, mainly in urban areas. The goals of this study are to identify the Euglossinae species composition, to know the diversity and the community structure of Euglossinae species, verify their preferences for different fragrances and evaluate the phenology of these species, in two Atlantic Forest fragments of the city of Joao Pessoa, Paraiba state, Brazil. Bees were sampled at 15 days intervals, over the course of one year, from 8:00 to 17:00 hours, through the use of traps baited with seven types of fragrances. In both areas, 1082 individuals belonging to nine species were sampled. None significant difference of diversity and relative abundance of bees between fragments were observed. Eucalyptol was the most attractive fragrance. Bees were more abundant between 8:00 and 9:00 AM. Visits to the fragrances were more frequent from the middle of dry season to the beginning of the rainy season and positively correlated with the monthly mean temperature. Most species of bees visited all the baits over the year, but the number of attracted males was highest in April.

Abelhas e vespas solitárias em ninhos-armadilha na Reserva Biológica Guaribas (Mamanguape, Paraíba, Brasil)

The trap-nesting bees of Guaribas Biological Reserve were studied during one year. Three areas with different vegetation types were sampled, open savanas, closed forest, and a mosaic of these two types. Twelve species of trap-nesting bees were observed, four of which are parasites. The most abundant species were Centris tarsata (Smith, 1879), C. analis (Fabricius, 1804), Tetrapedia diversipes KJug, 1810, and Mesocheira bicolor (Fabricius, 1804). Nesting of Centris tarsata and Mesocheira bicolor occurred mainly during the dry season, while Centris analis and Tetrapedia diversipes did not show any seasonal preferences. Mesocheira bicolar occurred only in the nests of C. tarsata, parasitizing more than 50% of the nests and representing 23.2% of the individuais emerged in the host nests. The mosaic area yielded a greater abundance and diversity. Comparing the sampling methods of trap-nests and entomological nets, conducted simultaneously in the same area, in relation to diversity of trap nesting bees, it was observed a great similarity in terrns of composition and differences of abundance in species sampled. Some hypothesis are discussed to explain a reason for the greater diversity and abundance of the mosaic area in relation to the other areas.

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.

Species richness and seasonality of spiders (Arachnida, Araneae) in an urban Atlantic Forest fragment in Northeastern Brazil

Species richness and forest seasonality of spiders in an urban fragment of Northeastern Brazil were investigated. Mata do Buraquinho is a remnant of Atlantic Rain Forest where no spider inventories have ever been made. Samplings during dry and wet seasons were carried out in order to establish if seasonality influences species richness and complementarily of the spider fauna. Pitfall traps, nocturnal collections, and beating tray samples were used to access a multi-guild spider fauna. Spider species were estimated using first order Jackknife method. Four hundred samples were obtained, resulting in 1681 adult spiders. A total of 166 species were recorded and 211 were estimated. No significant differences for species richness were observed between both periods, and the captured species were the same according to the complementarily coefficients. The fragmentation hypothesis as factor of biota impoverishment was not tested, but future investigations on this topic are suggested in the complex of forest remnants in João Pessoa.

Espécies arbóreas utilizadas para nidificação por abelhas sem ferrão na caatinga (Seridó, PB; João Câmara, RN)

In Rio Grande do Norte, a caatinga region of North-eastern Brazil, the nesting opportunities that trees offer to stingless bees (Meliponinae) were studied. Samples consisted mostly of tree trunks, which were kept by Meliponinae beekeepers. Nearly 13 per cent of observed nests were in living trees in the field. Seven species of stingless bees, totalling 227 nests, were encountered in 12 tree species. More than 75.0% of stingless bees were found in two tree species being Caesalpinia pyramidalis (Caesalpiniaceae, 41.9%) and Commiphora leptophloeos (Burseraceae, 33.9%). Furthermore, all bee species nidify in C. pyramidalis. A great part of the nests in trunks were of Melipona subnitida, (N = 130) of which 50.0% was found in C. leptophloeos and 22.3% in C. pyramidalis. M. asilvai was predominantly found in C. pyramidalis (92.3%, N = 39). Besides this survey was mainly directed to bee species with beekeping importance, data shows the huge relevance of these two plant species for nesting by stingless bees in the caatinga.

Composição e sazonalidade de espécies de Euglossina (Hymenoptera: Apidae) em mata e duna na Área de Proteção Ambiental da Barra do Rio Mamanguape, Rio Tinto, PB

By using artificial fragrances as baits, we studied richness, composition, abundance and seasonality of Euglossina species in two areas (forest and dune) in the Environmental Protection Area of the Mamanguape River Bar, State of Paraiba, Brazil, between August 2002 and July 2004. Bees were attracted with wads of absorbent paper containing each of the fragrances: benzyl acetate, ionone beta, skatole, eucalyptol, eugenol and vanillin, and captured with insect net. We collected a total of 3,132 males of nine species of Euglossina. On both areas, Euglossa cordata (L.) and Eulaema nigrita Lepeletier were present throughout the year and were the most abundant species in the forest and the first one was the most abundant specie at the dune. Concerning to the composition, the Atlantic Rainforest areas in Paraíba State were more similar among themselves, the same occurring to the dune areas in Paraíba and Bahia States. In the forest, Euglossina species showed higher seasonality, being more abundant during the drier period, specially E. cordata. At the dune, species were homogeneously distributed in the dry and rainy periods.

Africanized honey bees pollinate and preempt the pollen of Spondias mombin (Anacardiaceae) flowers

The invasion of generalist Africanized honey bees may change certain plant–pollinator interactions. We evaluated the preemption by honey bees and the exploitative competition with native bees on a tree with nocturnally dehiscent small flowers. Our main objectives were to quantify pollen production and harvesting, to verify whether honey bees exploitatively compete with native bees and to identify the effective pollinators of Spondias mombin. The nocturnally dehiscent flowers were pollen depleted by honey bees and attracted various nocturnal and diurnal bee species. A threefold increase in native bee abundance was produced by delaying pollen availability and by preventing the preemption of pollen by honey bees. The results suggest that honey bees reduce the foraging benefit of late-arriving native bees. Honey bees and Scaptotrigona aff. tubiba were regarded as the main effective pollinators of S. mombin due to their abundance, behavior, and ability to visit a large number of flowers.

Spillover of trap-nesting bees and wasps in an urban-rural interface

A mismatch of resource availability in certain periods can lead to spillover of insects between habitats, resulting in temporal differences in insect diversity. Urban gardens are important anthropogenic habitats but it is unknown whether, when and why spillover of beneficial insects occurs between gardens and agricultural habitats. We used trap nests for Hymenoptera to monthly monitor bee and wasp abundance and species richness in 12 gardens and 12 rapeseed fields. Half of the gardens and rapeseed fields were located in the urban–rural interface and bordered each other (a garden paired with a rapeseed field) and the other half were isolated in the rural landscape (isolated rapeseed fields) and in the urban city centre (isolated gardens). In general, gardens in the urban–rural interface comprised the highest richness of bees and wasps. The abundance of bees but not of wasps was highest in paired habitats and peaked at full rapeseed blooming, indicating that mass-flowering rapeseed offers foraging resources for bees nesting in adjacent gardens. Thus, bees nest and increase their populations in both areas, benefiting from the mass-flowering resource in the agricultural habitat as well as the nesting resources from gardens, suggesting spillover of bees but not of wasps between paired gardens and rapeseed fields. Our study highlights the value of gardens in the urban–rural interface for the biodiversity of functionally important insects. Implementing urban gardening and small-scale agriculture in cities and suburban habitats can promote local pollinator populations and benefit adjacent croplands.

Gene Variation, Population Differentiation, and Sociogenetic Structure of Nests of Partamona seridoensis (Hymenoptera: Apidae, Meliponini)

Gene variation and the differentiation of two populations of Partamona seridoensis (Hymenoptera: Apidae: Meliponini) from the Caatinga biome, a semiarid ecosystem unique to Brazil, were estimated through allozymic and microsatellite analyses. These populations exhibited similar low degrees of enzyme gene variation. Observed genotype frequencies at the allozyme and microsatellite loci were in accordance with Hardy–Weinberg equilibrium in the two populations. Both markers demonstrated that the two populations are not genetically homogeneous and must be considered distinct populations. The occurrence of private alleles at the allozyme and microsatellite loci corroborates this differentiation, sustaining the hypothesis of a low level of interpopulation gene flow. The phenotypic segregations clearly demonstrated that the progeny inside each nest were the result of mating between the queen of the colony and only one male.