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Arapuá bee can also disperse over long distances

Image: FAPESP Agency

Trigona spinipes is a species of stingless bee native to Brazil. It is known as irapuá or arapuá, extremely aggressive and present in practically all of South America, which may be related to the capacity of the breeding bees of this species to disperse over long distances and colonize degraded habitats.

The researchers reached this finding recently, through a study carried out by the Institute of Biosciences of the University of São Paulo (IB-USP), in partnership with the University of Texas, in Austin, USA.

In this way, this species of bee can survive in heavily altered environments and act as a “rescue” pollinator, compensating for the decline of other native pollinators. The irapuás feed and pollinate flowers of several species of native plants, in addition to crops such as carrots, oranges, sunflowers, mangoes, strawberries, pumpkins, peppers and coffee.

In order to assess whether the loss and fragmentation of forest areas influence the dispersion and population dynamics of this species of bee, the researchers collected specimens of the insect in coffee farms associated with Atlantic Forest fragments and in urban areas of the city of Poços de Caldas, in the south of Minas Gerais.

Using state-of-the-art genetic sequencing tools, they developed new microsatellite markers – small regions of DNA that vary from one individual to another – and used these markers to genotype the collected bees.

Based on a series of software available in a laboratory specializing in landscape genetics in University of Texas, the researchers estimated the degree of genetic relationship between bees collected in environments with different levels of degradation.

By overlaying the genetic data of collected bees on maps with high resolution relief, type of land use and vegetation cover in the studied region, they were able to assess the influence of these factors on the gene flow (exchange of genetic information) among bees in the region .The objective was to assess whether forest cover, type of land use or elevation influenced the dispersal and genetic differentiation of the irapuás.

And the results showed that they are capable of dispersing over long distances, since no genetic differentiation was found between bees collected in a range of 200 kilometers – bees found in São Paulo and Poços de Caldas belonged to the same population, the Their gene flow was also unaffected by forest cover, type of land use or elevation, which indicates their ability to disperse both over preserved and deforested areas.

“This species of bee manages to maintain a high gene flow in different types of environments. Therefore, it can be considered a rescue pollinator, as it compensates for the decline of other native pollinators that are more sensitive to deforestation”, explained the author of the study.

The researchers found evidence of a recent population expansion of the irapuás, and it is very likely that the reason for this dispersion is precisely the deforestation of areas in the Atlantic Forest, together with the fact that they are good colonizers of degraded areas.

Another study recently published by another group of Brazilian researchers in early September, supported by the São Paulo State Research Support Foundation (Fapesp), compared interaction networks between bees and plants throughout Brazil. And the survey results indicated that the irapuás do better in degraded environments than in preserved ones. The reasons for this ability to disperse and resist are not fully known.