Research indicates 27 new records of native bees in soybean fields

A study led by Embrapa Genetic Resources and Biotechnology (DF), in southwestern Goiás, identified 27 new records of bee species associated with soybean cultivation in Brazil. These were among the 40 species found in plantations in the Rio Verde and Montividiu region and had never been previously mentioned in scientific literature. The research also indicates that the presence of wild bees in soybean fields can increase grain weight by an average of 7%. 

The results are published in the article "Bioinput Use and Native Vegetation Fragments are Associated With Higher Bee Community Evenness in Large-Scale Soybean Crops," in the Journal of Applied Entomology. Considering also the neighboring native forests, the survey identified a total of 53 bee species belonging to five families (Apidae, Andrenidae, Megachilidae, Colletidae, and Halictidae).

The study reinforces that the conservation of native forest patches surrounding crops, and consequently of pollinators, can bring benefits not only to biodiversity but also to agricultural production, indicating that the presence of these insects can contribute to increased soybean productivity.

The research also confirms that pollinator conservation represents not only a biodiversity conservation strategy, but also a way to contribute to productivity, production sustainability and, ultimately, food security, in line with ESG criteria that are increasingly present in the demands of international markets.

The "invisible filter" of chemical pesticides

Historically, the large-scale soybean production model has relied on the intensive use of broad-spectrum synthetic insecticides and fungicides. The major bottleneck in this system is its impact on non-target organisms. In attempting to combat specific pests, the massive application of conventional chemical pesticides ends up acting as a severe "environmental filter" on beneficial fauna. And Embrapa's research statistically confirms this phenomenon. 

Embrapa Genetic Resources and Biotechnology researcher Carmen Pires explains that, on farms with highly intensive chemical management, there has been a drastic drop in the so-called evenness of bee communities. In ecology, the term indicates how uniformly individuals are distributed among the different species present in an environment. In the areas evaluated, more intensive management was associated with a reduction in diversity, favoring a small number of species possibly more tolerant to stress, while more specialized and potentially more efficient pollination species ceased to occur.

However, scientists warn of a common methodological error that these community analyses can hide: assessing the health of a crop solely by the sheer abundance of insects can be misleading. “An area heavily sprayed with chemicals may show a high number of insects in a quick count, but almost all belong to a single resistant species. Functionally, the crop becomes a 'biodiversity desert,' vulnerable and dependent on constant artificial interventions,” explains Pires.

The advancement of bio-inputs and regenerative planting.

The good news is that there is a viable and economically advantageous escape route: farms that have integrated bio-inputs — such as bacteria and fungi with less environmental impact for biological pest control and soil fertilization — and reduced their dependence on highly toxic chemicals, have managed to maintain significantly more balanced, healthy, and functionally diverse bee communities.

The transition to biological hives, classified as Class IV environmental risk (low risk), avoids the extermination of wild bees and preserves the natural cycle. The ecological impact of this choice is visible in the life structure of the bees themselves: about 60% of the species identified in southwestern Goiás build their nests directly on the ground.

The researcher observes that, at this point, regenerative agriculture assumes a central role in preservation. According to her, practices that minimize soil disturbance and maintain mulch cover protect the underground nests of bees within the soybean field itself. "Without tractors destroying their shelters and without pesticides penetrating the soil, these bees can persist from one harvest to the next, ready to pollinate the next flowering," she says. 

Furthermore, the study found that most of the species collected (44,7%) have solitary lifestyles. Unlike social bees, which live in populous colonies and can be managed in hives by beekeepers (so-called assisted pollination), solitary bees depend exclusively on the good ecological conditions of the farm to survive. Therefore, the producer needs to adopt bee-friendly practices to keep them alive on the property. Otherwise, they will lose the productivity bonus that they offer for free.

The Cerrado can be the pollinating "lungs" of the farm

The research also explains the relationship of dependence between the forest and the crops. The fragments of native Cerrado vegetation adjacent to soybean plantations act as true ecological refuges and as "factories" of pollinators. Of the native bees collected in the neighboring forests, the most representative species was Ceratina duplocarinata, while in the soybean areas the genus Dialictus predominated.

The data revealed that physical proximity to the forest is a relevant factor. The greater the distance of the crop from the edges of native Cerrado vegetation, the lower the richness and abundance of native bees found on soybean flowers. The preserved forest functions as a permanent home, providing shelter, nesting sites for the 18% of species that nest in hollow tree trunks, and alternative food during periods when soybeans are not flowering. Without the neighboring forest, the bees cannot colonize commercial plantations.

The new records

The consolidated figures from the study reveal the extent of biodiversity found in southwestern Goiás. Of the 764 bees collected in the samplings, 89% were native Brazilian bees. Only 11% belonged to the exotic species Apis mellifera (the Africanized bee, widely known for its honey production).

Prior to this publication, scientific reviews accumulated up to 2018 recorded only 12 species of native bees associated, in some way, with soybeans in Brazilian territory. The new work by Embrapa significantly expanded this knowledge by documenting 40 bee species in cultivated soybean areas in southwestern Goiás, including 27 previously unpublished records of species visiting the flowers of the legume in the region.

To achieve this scientific precision, the researchers tested and compared different field methodologies, which led to another important methodological discovery. Traditional pan traps (technically called pan traps, painted blue to attract insects) proved more efficient at measuring actual biodiversity than classic entomological nets (the popular "butterfly nets").

Pan traps accounted for 95% of all captures in the study (728 individuals), identifying 33 distinct species. The active entomological net, in turn, recorded only 7 species. The study indicates that the exclusive use of nets underestimates the true biological richness of soybean farms, largely due to the density of plants and the discreet behavior of smaller native bees, which hinder collections.

"Embrapa's research, based on field data, confirms that the future of national agriculture depends on ecological balance. Pollinating insects are the invisible friends of crops, but inadequate management can put them at risk. Protecting native bees and the Cerrado that shelters them is, above all, preserving Brazil's economy and food security," concludes Pires. 

The study

Conducted by Embrapa Genetic Resources and Biotechnology, the study also involved collaboration with researchers from the University of Brasília (UnB), the Federal University of Bahia (UFBA), and the Federal Institute of Goiás – Rio Verde Campus (IF Goiano). The research is part of the Regenera Cerrado project, developed in partnership between research institutions, rural producers, and Cargill. The project evaluates the impacts of adopting regenerative agriculture practices on soil health, the occurrence of pests, and natural enemies in production areas in southwestern Goiás.