Stingless bees as bioindicators in Brazil

Juliana Almeida Braga, Rodrigo Morais Nunes, Maria Cristina Affonso Lorenzon

Keywords: Atlantic Forest Reserve, biodiversity, CCD, Mefipona quadrifasciata anthidiodes, meliponicutture, Nannotrigona testaceicornis, stingless bees, Tetragonisca angustula

Warning - loss of bees

Colony collapse disorder refers to the decline in numbers of Apis mellifera honey bee colonies. This decline is occurring in the USA and there are losses in European countries too. There has been speculation concerning the possible causes for this loss of colonies, and one of the hypotheses presented by researchers is environmental contamination. The risks generated for bees by the use of pesticides have been extensively discussed by ecologists and beekeepers, and 5 will be an important topic to be addressed at the Apimondia congress in France in September 2009.

The Atlantic Forest Reserve - rich in species

Brazil's Atlantic Forest Reserve is recognised as one of the planet’s 34 ‘biodiversity hot spots’ with many endemic species, but is in the process of degradation and extinction (Myers et a/, 2000).

The State of Rio de Janeiro, in south-east Brazil, hosts approximately 17% of the original forest cover in the form of forest fragments, whose bee fauna and flora are seriously threatened. Ramalho (2003) emphasised that the Forest's stingless bees represent approximately 70% of all the active bees in one area of the Reserve. The high indices of biological diversity and endemism of this biomass, subjected to the drastic reduction, make this ecosystem a priority for biodiversity conservation.

Meliponiculture

The keeping of stingless bees was established in fragments of the Atlantic Forest Reserve to promote its expansion as a hotbed for sustainability. Over eight months, meliponaria (apiaries for stingless bees) were installed in four locations of the Reserve, three on the mainland and one on an island, with each location at least 20 km apart. The species of bees were: Tetragonisca angustula (jatais), Nannotrigona testaceicornis (irais) and Melipona quadrifasciata anthidiodes(mandagaia).

One year before research began, colonies of Melipona were fed artificially to build them up. After the hives were installed they were reviewed every 15 days to ensure maintenance and production.

The meliponaria on the island had optimal conditions for rearing the jatais bees and mirins (which are tiny bees, less than 3 mm). The Region confirmed its aptitude for the production of honey and swarms. In the inland locations, the colonies of mandacaia, jatais and irais did not show satisfactory production, when compared to the island ones: the entrance tubes were fragile, and there was little movement from the bees, making them vulnerable to predators.

The jatafs and jrais colonies were stable for seven months without any honey collection. In the hives of Metipona the flux of food was so low that it did not permit maintenance and the honey and wax pots wereconsumed.

The apparent fragility of Melipona was a surprise to the researchers who considered the region good for production of this bee species. After three months of endeavour with artificial feeding, the colonies of Melipona stayed weak and finally they were transferred to another location 50 km away in a region that was more open and with less flora than the Atlantic Forest Reserve. Here the colonies of Melipona (see images overleaf) were kept with artificial feeding and the population grew. This suggests the existence of negative factors in the location in the Reserve.

Significance of this failure

Melipona are well adapted to the Atlantic Forest Reserve, yet their failure in an area that was apparently favourable in terms of flora, confirms the presence of negative factors such as forest fragmentation. In this Region agricultural practices are not well understood and the loss of colonies may be due to the use of pesticides.

Bees as bioindicators

Bees are considered good biological indicators for the occurrence of unfavourable conditions, or the presence of chemical substances in the environment in which they live, both through the high mortality rate of individual bees, and the presence of residues in their bodies and their products.

Studies have demonstrated that various pesticides are absorbed by the lipids of pollen grains. This toxicity can be maintained over a long period in the food that bees store in the combs, and can cause mortality in the brood and young bees for a long time, while the actual cause is hidden.

Nature in peril

The state of conservation of all the Brazilian biomass is of great concern. Of the 1.4 million km’ of the original Atlantic Forest Reserve, only 7.3% is left. This is made worse due to the fact that about 70% of the 169 million Brazilians live in the Region. In the past three decades, the biomass has suffered severe change.

The extinction of one species of bee can lead to the extinction of at least one economically-important tree. Therefore, the conservation of different habitats depends on the preservation of the bee populations. Apart from the necessity to strengthen the existing conservation areas, as well as the Creation of new ones, it is vital that sustainable use programmes, aiming at raising the ecological conscience of the local communities, are implemented.

Therefore it is necessary to make an appeal not only to governments at Federal, State and Municipal level, but to society as a whole, to start disseminating knowledge about the problems caused by deforestation, as well as the indiscriminate removal of bees from forest, that may lead to the extinction of the bees and, eventually to the extinction of the flora and fauna that depend directly or indirectly on these pollinating agents.

References

MYERS, N.; MITTERMEIER, R. A.; MITTERMEIER, C. G.; DA FONSECA; G. A. B. KENT, J. (2000) Biodiversity hotspots for conservation priorities. Nature (403) 6772: 853-858.

RAMALHO, M. (2003). Stingless bees mass flowering trees in the canopy of Atlantic Forest: a - tight relationship. Acta Botanica Brasil 18: 37-47.

More information on stingless bees on the BfD Website Information Portal topic Bee species and races