Solange Cristina Augusto

Acerola pollinators in the savanna of Central Brazil: temporal variations in oil-collecting bee richness and a mutualistic network

We present parameters to support the conservation and management of Acerola pollinators. We monitored pollinator visits to this fruit shrub in a Brazilian savanna and identified the pollinator’s other food resources. Twenty-three species of pollinators were sampled. Although there were temporal variations in visitor frequency, satisfactory levels of fruit set were obtained. This temporal variation promoted a compensatory effect on plant reproduction as the pollinator species were replaced during the course of flowering. The analysis of pollen loads showed grains of 16 plant species and four pollen types belonging to seven families that formed a network with a nested pattern. Such a network suggests that generalist plants must be available in the crop vicinity. The data presented suggest the natural viability of cultivating Acerola in the savannas of Central Brazil and the importance of natural lands for providing nesting resources and to enhance the bee diversity in agroecosystems.

Task allocation and interactions among females in Euglossa carolina nests (Hymenoptera, Apidae, Euglossini)

Multifemale nests of Euglossa carolina were studied to investigate task allocation during nest reactivations according to both the females’ size and order of emergence. The study was carried out at the campus of the University of São Paulo, Ribeirão Preto, Brazil, from January, 1990 to March, 1992. The activities of the females were recorded during the reactivation processes in eight nests maintained in observation boxes. The size of each female was determined by measuring the forewing length and the maximum width of the head. Nest reactivations were performed by one or more females in the presence or absence of a female that had participated in a previous reactivation process. Usually, the first emerging females remained in the nests and established associations in which the oldest became dominant. All nestmates had mated, and developed ovaries and did not differ in size. Task allocation was recognized by behavioral characteristics, namely, agonism and oophagy in cells oviposited by other females.

Bee diversity in Tecoma stans (L.) Kunth (Bignoniaceae): importance for pollination and fruit production.

Tecoma stans (L.) Kunth is an exotic plant in Brazil, commonly distributed in urban areas, which is considered an invasive species in crop and pasture areas. In this study, the floral biology and the behavior of bees in flowers of T. stans from three urban areas in southeastern Brazil were investigated. In all study sites, T. stans was an important food resource to the Apoidea to 48 species of bees. Centris tarsata Smith and Exomalopsis fulvofasciata Smith (Hymenoptera: Apidae) were the effective pollinators more abundant, while Scaptotrigona depilis Moure (Hymenoptera: Apidae) was the more frequent robber species. The most part of T. stans visitors (87.5%) exploited exclusively nectar, which varied in sugar concentration depending on the day period and flower phase. In all flower stages, higher averages of nectar concentration (26.4% to 32.7%) occurred from 10 am to 2 pm. The presence of osmophore in the petals and protandry were detected. In two urban areas the number of visitors varied significantly during the day. The greatest abundance of pollinators occurred when pollen availability was higher and flowers showed receptive stigma, which could be contributing to the reproductive success of T. stans. The results indicate that the production of fruits increased in plants that received a higher number of effective pollinators.

The Use of Trap-Nests to Manage Carpenter Bees (Hymenoptera: Apidae: Xylocopini), Pollinators of Passion Fruit (Passifloraceae: Passiflora edulis f. flavicarpa)

ABSTRACT Carpenter bees are the main pollinators of passion fruit, a crop classified as vulnerable to pollinator decline because it is strictly self-incompatible. We investigated cost-effective management strategies to increase the presence of female carpenter bees in passion fruit orchards by using trap-nests in bee shelters. Transfers of nests containing females of X. frontalis and X. grisescens between different sites were significantly more successful when the nests contained brood cells. Supplying a bee shelter with a combination of suitably sized empty bamboo stalks and active nests of carpenter bees can increase the population of actively nesting bees by >200% during the course of 23 mo, as a consequence of the emergence of brood from the introduced nests and the attraction of bees from the surroundings. In conclusion, our methods lead to improved success of introducing, increasing and maintaining carpenter bees populations for the pollination of passion fruit crops.

Diversity of the euglossine bee community (Hymenoptera, Apidae) of an Atlantic Forest remnant in southeastern Brazil

Diversity of the euglossine bee community (Hymenoptera, Apidae) of an Atlantic Forest remnant in southeastern Brazil. Euglossine bees, attracted to scent baits of cineole, eugenol and vanillin, were collected with entomological nets, from December 1998 to November 1999. Samplings were carried out once a month simultaneously by two collectors positioned in two different sites in an Atlantic Forest remnant in northeastern Sao Paulo state, Brazil. A total of 859 male euglossine bees, belonging to 13 species and four Euglossini genera were collected. Of the total sample, 506 (12 species) males were captured at site A and 353 (10 species) were collected at site B.In both sites, Euglossa pleosticta Dressler, 1982 was the most abundant species (45.79%), followed by Eulaema nigrita Lepeletier, 1841 (20.79%). The results of this study supply new information about the diversity of orchid bee fauna in Atlantic Forest remnants as well as show that more than one site is needed to sample these bees in a fragmented landascape.

Nesting and use of pollen resources by Tetrapedia diversipes Klug (Apidae) in Atlantic Forest areas (Rio de Janeiro, Brazil) in different stages of regeneration

Nesting and use of pollen resources by Tetrapedia diversipes Klug (Apidae) in Atlantic Forest areas (Rio de Janeiro, Brazil) in different stages of regeneration. The nesting in trap-nests and use of pollen sources in larval food by Tetrapedia diversipes Klug, 1810 (Apidae) was compared between regenerating areas of Atlantic Forest. The study was conducted between April 2008 and October 2009 at Uniao Biological Reserve, Rio de Janeiro, Brazil. T. diversipes nested in 66 trap-nests and showed a peak of nesting during the months of highest rainfall. The most frequent pollen type in brood cells during the wet season was Dalechampia sp. 1. During the dry season, the type Ludwigia sp. was the most frequent, followed by Dalechampia sp. 2. The high frequency of Dalechampia and Ludwigia species in the larval food, observed in both habitats and in the two seasons could be considered relevant for T. diversipes, suggesting highly selective diet based primarily on two plant species unrelated, but similar in size of pollen grains.

Larval food sources of Centris (Heterocentris) analis (Fabricius, 1804) (Hymenoptera: Apidae), an oil-collecting bee

Pollen analysis of larval food allows identification of plants used as nest provision sources. Considering the importance of Centris analis in pollination, we aimed to identify its plant sources, food niche width in Cerrado, and analyze the use of sources between cool/dry and warm/wet seasons. We sampled 22 nests collected in two areas from February 2008 to October 2009. Heteropterys spp. (Malpighiaceae) were the main pollen sources, but Byrsomia spp. (Malpighiaceae), Banisteriopsis malifolia (Malpighiaceae), Solanum lycocarpum (Solanaceae) and Machaerium spp. (Leguminosae) were also important food sources. There was no difference in the use of the sources between the seasons (F1,100 = 0.001; p = 0.979). Despite the high number of pollen types (n = 14) the food niche widths were low, H = 0.777 and H = 0.949, which can be explained by the dominance of some food items. Hence, C. analis use, profusely, a few plants as food sources that could be considered conservation targets.

The orchid bee fauna in the Brazilian savanna: do forest formations contribute to higher species diversity?

The Neotropical savanna is characterized by a set of different phytophysiognomies occurring in a wide expanse of Brazilian lands. Based on the known higher diversity of orchid bees in forests rather than in savanna formations, we hypothesized that the occurrence of forest formations inside the Brazilian savanna increases the diversity of euglossine bees in that domain and that there are species more associated with these environments. To test this hypothesis, we sampled the euglossine fauna in eight forest and woody savanna remnants and analyzed their community structure. We sampled 1,010 males of 13 species of orchid bees. Bee abundance and species richness ranged from 30 to 341 individuals and from 4 to 12 species, respectively. The forest remnants showed the highest diversity indices and species richness. Our data suggest that some species of Euglossa are mainly associated with forest remnants. We concluded that environmental heterogeneity in the Neotropical savanna contributes to higher diversity of euglossine and that some species are more frequently found in forested habitats. Additionally, considering that some sampled species are typical of the Atlantic and Amazon forests, our data reinforce the hypothesis that forest environments inside the Brazilian savanna can be considered bio-corridors for orchid bees.

Nidificação de Euglossa (Euglossa) melanotricha Moure (Hymenoptera: Apidae) no solo do cerrado

Nests of euglossine bees are difficult to found in nature, with descriptions available for only 20% of known species. A nest of Euglossa (Euglossa) melanotricha Moure found inside a cavity in the ground at a Cerrado area in Uberlândia, Minas Gerais state, is described. Comparisons of nesting behavior and social structure with those reported for Euglossa (Euglossa) cordata (L.) and Euglossa (Euglossa) townsendi Cokerell are presented and discussed.

Bigger and sweeter passion fruits: effect of pollinator enhancement on fruit production and quality

Brazil stands out as the world’s largest producer of yellow passion fruit, a species of economic interest which, due to its self-incompatibility, depends on pollinators for fruit formation. The main pollinators of passion fruit are large solitary bees of the genus Xylocopa, commonly known as carpenter bees, which are potential candidates for management. Passion fruit crops exhibit a low density of pollinators and, consequently, a reduction in production. To improve management techniques of X. frontalis and X. grisescens, the general aim of this study was to evaluate the effect of pollinator enhancement on pollination services in passion fruit crop areas. Our results demonstrated that pollinator enhancement was an efficient way to minimize pollination deficit in passion fruit crops, as it promoted the production of a bigger and sweeter fruits. Data obtained in our study are essential to consolidate management techniques for carpenter bees in passion fruit crops.