Pragas, doenças e condições ambientais que influenciam a sobrevivência e distribuição de abelhas

Abstract

Bees are the main pollinating agents of natural and agricultural ecosystems. They represent an important group for maintaining biodiversity and food production. However, in many parts of the world, an increasing decline and disappearance of bees has been recorded. This disappearance has been reported both for species of economic interest such as the Africanized honeybees Apis mellifera and meliponines, and for native solitary bees such as the bees of the tribe Euglossini. Although understudied in Brazil, some possible causes associated with this bee decline are related to the sanitary situation of the hives and to climate change. Thus, to reduce the knowledge gap and better understand the possible causes that may interfere in this decline of bees in the country, the research sought to investigate: Chapter 1. Assess the impacts of pests and pathogens on the decline of managed bees in Brazil; Chapter 2. To evaluate the influence of environmental variations found between in mesic and xeric habitats along a tropical mountain on the distribution of orchid bees.In the first chapter, the study showed that most of the hives found in the country had some kind of pest or showed some symptoms of diseases, which leads to colony losses. The main pests related to major losses in Apis mellifera hives were ants and wasps, while for meliponines were robber bees, ants and phorids flies. The main disease symptom causing hive losses for both groups was worker death. In this study, we also identified that both bee groups share similar pests and disease symptoms. The work also highlights that the misuse of management techniques can negatively influence bee health. In the second chapter, we observed a strong influence of altitudinal gradient and season on the composition and richness of Euglossini species. Lower altitudes, where higher temperatures and vegetation size were observed, showed a higher richness of Euglossini bees. During the rainy season, when there is a greater availability of floral resources and higher air humidity, we observed that xeric and mesic habitats showed similar values of richness and abundance of Euglossini bees. We also noticed that the mesic habitat is an environment that favors a similar richness and abundance of bee species between seasons. While in xeric habitats, richness and abundance were lower in the dry season when air humidity and temperature reduce. Overall, in this second chapter we generated novel knowledge about the relevance of mesic habitats along altitudinal gradients, predominantly xeric, on Euglossini bee diversity. Mesic environments maintain ideal conditions for the bees throughout the year, reinforcing the importance of these environments for the maintenance of these pollinators of great ecosystem relevance.

Both studies brought important scientific contributions, expanding the knowledge about the severity of the presence of pests and diseases in hives and about how Euglossini communities respond to environmental variations, useful to predict the impact of climate change, that can help mitigate the disappearance of bees and species conservation.