Brazil’s native bees are vital for agriculture, but are being killed by it

2020-06-01

When we think of bees, we don’t always recognize the huge diversity of species they represent. Almost all the honey we consume comes from western honey bees (Apis mellifera), a hybrid of European and African species. But there are another 20,000 different bee species in the world. Brazil alone has more than 300, and the vast majority, unlike western honey bees, don’t sting. The country has the world’s greatest diversity of this type of bee.

The importance of Brazil’s stingless bees is increasingly being acknowledged, since agricultural crops of high economic value depend on pollination by these insects. And beekeeping helps conservation: Keepers of Melipona, a genus of stingless bees, usually preserve local ecosystems and restore areas used in their activity, since native Brazilian bees depend on a healthy habitat to reproduce.

“Their appreciation is on the rise. Places that maintained the culture of native beekeeping can now make this an alternative for income generation,” says Jerônimo Villas-Bôas, author of a manual that addresses practices associated with stingless beekeeping in Brazil.

In the fine dining sector, Brazilian honey has already reached the kitchens of well-known chefs, including Alex Atala, whose São Paulo restaurant has two Michelin stars.

Products from Brazilian bees — honey, propolis, pollen, wax and royal jelly — have been known for centuries. Reports written in 1577 by Hans Staden, who lived among the Tupinambá people on the coast of what is today São Paulo state, mention three native bees used by indigenous people for medicine and food purposes — probably mandaçaia (Melipona quadrifasciata), mandaguari (Scaptotrigona postica) and jataí-amarela (Tetragonisca angustula).

“For my doctoral thesis, I tested honey from three stingless bee species: jataí, canudo [Scaptotrigona depilis] and borá [Tetragona elongata]”, says Raoni da Silva Duarte, who has a Ph.D. in entomology from the University of São Paulo (USP). “During in vitro tests, the honeys had antimicrobial effects against several pathogens that may cause diseases in humans.”

Native beekeeping is currently expanding in Brazil, for purposes ranging from scientific research to community-based honey production, with several benefits. “Beekeepers seek areas with preserved vegetation,” Villas-Bôas says. “Stingless beekeeping enables us to conserve the species involved and, indirectly, other animals in the ecosystem such as birds and mammals.”

According to the U.N. Food and Agriculture Organization (FAO), more than 75% of crops intended for human consumption depend on pollination.

Most plant species, whether cultivated or native, are pollinated by animals such as bats, moths, butterflies, wasps, beetles — and mainly bees. The Brazilian Platform for Biodiversity and Ecosystem Services (BPBES) estimates the value of the environmental pollination service for food production in the country at about 43 billion reais ($8 billion) per year, accounting for 44 cultivated and wild plants.

Certain plant species are pollinated only by Brazilian stingless bees. “They are chiefly responsible for pollinating native vegetation, providing cross-fertilization, which guarantees variability in plant species,” says Generosa Sousa Ribeiro, from the Melipona Beekeeping Department at the State University of Southwest Bahia (UESB). “Several plants need native species. For instance, the acerola cherry depends on solitary bees of the Centris genus.”

Evidence shows that establishing stingless bee colonies in agricultural areas has positive effects on production of coffee, canola, guava, apple, passion fruit, cucumber and oil palm, among other crops. For strawberry, pollination by the iraí bee (Nannotrigona testaceicornis) reduces fruit deformation. And a study shows that the uruçu-nordestina bee (Melipona scutellaris) plays a major role in orange tree pollination.

“The more we know about Brazilian stingless bees, the more important they become,” says Juliana Feres, a researcher and founding partner of Heborá, a platform that focuses on improving production of Brazilian honey by rural women.

Stingless bees also provide a specialized service known as buzz pollination. When they land on flowers, many species, whether social or solitary, can vibrate by contracting their thoracic muscles, thus releasing pollen from the flowers and benefiting crops such as tomatoes and eggplants.

Nevertheless, native species are still underused. Western honey bees are still preferred not just to produce honey but also to supplement pollination of agricultural crops, because farmers are familiar with their management and their population is abundant. The Thematic Report on Pollination, Pollinators and Food Production in Brazil shows the dangers of generalizing: several crops need specific pollinators.

Threats in the air

However, native stingless bees face a paradox: while they are important for agricultural activity, they are threatened by agriculture itself. “Our food production system is the main reason why bees are disappearing,” Villas-Bôas says. “Plant suppression affects their natural habitat. In addition, uniform landscapes do not provide the diverse diet that insects need. To make matters worse, there is abusive use of pesticides.”

When pesticides do not kill, they may decrease the longevity of bees, hamper their ability to return to the hive, interrupt the laying of eggs by the queen, prevent communication, disrupt work organization and division, and paralyze wings and legs, among other harmful effects that end up weakening or even decimating the hive.

“The populations [of stingless species] are much smaller than those of A. mellifera, which makes it difficult to reorganize these bees after continued spraying. In 2017, we collected samples in areas of mass spraying, and we found more than 10 pesticides that were lethal for native bees,” says Ribeiro from UESB.

Western honey bees are a priority in agrochemical tests conducted in Brazil, based on OECD protocols. However, some studies already show that stingless bees are more sensitive to pesticides than the ubiquitous western bees. “There are still few results, given the very serious damage that poisons have been causing to pollinators in recent decades,” Ribeiro says.

A 2018 publication by Brazil’s environmental protection agency, known as IBAMA, calls for more specific studies that are not restricted to a single species.

Other works have since followed. A study conducted by researchers at São Paulo State University (UNESP) and published in 2019 assessed the effect of dimethoate, which is used as an international reference in toxicity tests. It showed that the dosage to kill 50% of a population of uruçu-nordestina larvae is 320 times lower than the dosage that kills an equal percentage of A. mellifera larvae.

Also in 2019, at the University of São Paulo’s Luiz de Queiroz Higher School of Agriculture (Esalq-USP), another study showed that thiamethoxam, widely used in agriculture, and three other insecticides from the neonicotinoid group may cause behavioral changes in adult jataí bees, such as reducing flight speed and  distance traveled.

A 2016 article focused on S. postica showed that the active ingredient imidacloprid, used in insecticides, interferes with the behavior of that bee, affecting its ability to recognize food and restraining its movements in the field.

An indicator of how serious the issue of pesticide use in agriculture is — and its harmful effects on human health and pollination — is the fact that imidacloprid continues to be found in tests performed on food samples under the Program for Analysis of Pesticide Residues on Food from Brazil’s National Health Surveillance Agency (Anvisa). The latest edition of the report was published in December 2019.

Loss of pollinators in an ecosystem may be irreversible, and nothing is known about the possibility of natural recolonization. “Brazil’s bees have co-evolved with its native flora for a long time,” Duarte says. “Each plant has adapted to the benefits that some species provided to its reproduction. At the same time, bees have adapted to specific resources such as nectar, pollen, oils and resins. In other words, Brazilian flora and native bees are highly dependent on each other.”

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