We identified native bees that are floral visitors and potential pollinators of tomato in Cerrado areas, described the foraging behavior of these species, and verified the influence of the visitation of a solitary bee on the quantity and quality of fruits. Three areas of tomato crops, located in Minas Gerais, Brazil, were sampled between March and November 2012. We collected 185 bees belonging to 13 species. Exomalopsis (Exomalopsis) analis Spinola, 1853 (Hymenoptera: Apidae) was the most abundant. Ten species performed buzz pollination. Apis mellifera L. 1758 (Hymenoptera: Apidae) and Paratrigona lineata (Lepeletier, 1836) (Hymenoptera: Apidae) could also act as pollinators. The fruit set and number of seeds obtained from the pollination treatment by E. analis were higher than those in the control group. Our results allowed the identification of potential tomato pollinators in Cerrado areas and also contributed information regarding the impact of a single species (E. analis) on fruit set and quality. Although most of the visiting bees show the ability for tomato pollination, there is an absence of adequate management techniques, and its usage is difficult with the aim of increasing the crop production, which is the case for E. analis. Species such as Melipona quinquefasciata, P. lineata, and A. mellifera, which are easy to handle, are not used for pollination services. Finally, it is suggested that a combination of different bee species that are able to pollinate the tomato is necessary to prevent the super-exploitation of only a single species for pollination services and to guarantee the occurrence of potential pollinators in the crop area.

Stingless bees are abundant and diverse key actors in several plant-pollinator networks in the neotropics, but little is known about their natural history and ecology. This study aims to contribute to knowledge about the diversity and dispersion of stingless bees and discusses the importance of nesting substrates. It was carried out in the Araguari river valley in Minas Gerais, Brazil, where a nest site survey was conducted in an area of 100 ha during 11 alternate months from 2006 to 2008, for a total of 1,200 observation hours. Sixty-nine nests were found, belonging to 12 genera and 20 different species. Nests ofMelipona rufiventriswere by far the most abundant. Stingless bees nested more frequently in hollows of live trees (64%), and 11 different substrates were identified. Seventeen plant species were used as nesting substrates andAnadenanthera macrocarpa(Fabaceae) was the main host, encompassing 23% of the surveyed nests. The area studied is important for the maintenance of stingless bees because it provides nesting sites for them. Without nesting sites the reproductive division of colonies is compromised, affecting the nests' survival.

The use of stingless bees in greenhouses has provided tremendous benefits to diverse crops in terms of productivity and fruit quality. However, knowledge about management techniques in these environments is still scarce. The present study aimed to evaluate the adaptation of Melipona quadrifasciata Lepeletier, 1836 in a greenhouse of Lycopersicon esculentum Mill. for its potential use in pollinating this crop. Six nests of M. quadrifasciata were introduced in a greenhouse in Araguari, Minas Gerais state, Brazil. The development of colonies inside the greenhouse was investigated and the foraging behaviour of the workers was assessed before introduction into the greenhouse and again after the nests had been removed. The vital activities of colony maintenance were performed unevenly throughout the day inside and outside the greenhouse, but with confinement the daily period of foraging decreased and bees started collecting pollen from the flowers after approximately six months. The difficulty in orienting to and identifying flowers by the workers was attributed to sunlight diffusion and blockage of ultraviolet radiation caused by the cover on the greenhouse. Structural changes in the greenhouses, as well as improvements in management techniques, are required for better utilization of stingless bees for pollination of plant species grown in greenhouses.

Network of Bee-plant Interactions and Recognition of Key Species in Semideciduous Forest Introduction The scanty information about species richness, diversity, taxonomy, distribution and population dynamics, along with the impact of human activities on most bee species represent the major environmental issues that hinder the conservation of native areas in Latin America (Freitas et al., 2009). Determining the diversity of both the fauna and flora of many ecosystems is the starting point for specific investigations, such as assessing the role of pollinators in maintaining the flora (Anacleto & Marchini, 2005). The importance of this matter arises therefrom. Studies about networks of interactions between bees and plants are fundamental for the conservation and management of native pollinators habitat (Biesmeijer et al., 2005). Network approaches to ecological research emphasize the pattern of interactions among species, i.e., how the links (interactions) are systematized within the network, rather than only providing the identity of the species that constitute a community (Bascompte, 2009).

Stingless bees are considered particularly promising for use as commercial pollinators. However, studies testing the effectiveness of these bees in pollinating grape tomatoes in greenhouses are not yet available. This work aimed to analyze the floral biology of the grape tomato and evaluate whether the additional pollination performed by Melipona quadrifasciata Lepeletier generates an effective increase in production and improves the quality of this variety of tomato when grown in greenhouses. The research took place in two greenhouses located in Araguari, Minas Gerais state, Brazil. In one of them, we only used a mechanical method of pollination and, in the other, pollination by the mechanical method was associated with pollination performed by bees. The productivity was compared by recording the number of flowers and fruits formed on different branches, and tomato quality was assessed by analyzing their size, weight, number of seeds and total sugar content. Tomatoes originating from flowers visited by M. quadrifasciata workers produced about 47% more seeds and their concentration of sugar was approximately 14% higher. These results suggest that using M. quadrifasciata for tomato pollination shows to be promising, since their use as pollinators entails positive effects on fruit quality.