Pollination services represent 10% of world’s agricultural production value

The importance of bees to food production and threats of extinction as a result of climate change were topics of a Biota-FAPESP Education Conference Cycle lecture.

By Karina Toledo

Agência FAPESP – Humans have explored honeybee colonies since prehistoric times, but only in recent years have we learned that the importance of these insects to human nutrition goes well beyond making the powerful natural sweetener.

“Actually, honey is a small sub-product when compared to the value of the pollination service provided by the bees, which corresponds to nearly 10% of the world’s agricultural production value,” said University of São Paulo (USP) professor Vera Lúcia Imperatriz Fonseca during her lecture at the second meeting of the 2014 Biota-FAPESP Conference Cycle held in São Paulo on March 20, 2014.

Scientists estimate that in 2007, for example, the total value of honey exported stood at US$ 1.5 billion. The value of pollination ecosystem services throughout the world was calculated at US$ 212 billion. The data were collected by several studies and have been compiled in a book entitled “Polinizadores no Brasil: contribuição e perspectivas para a biodiversidade, uso sustentável, conservação e serviços ambientais” (Pollinators in Brazil: contribution and prospects for biodiversity, sustainable use, conservation and environmental services), one of the winners of the 2013 Jabuti Prize.

The work is the fruit of the FAPESP thematic project “Biodiversity and sustainable use of pollinators, with emphasis on Meliponini bees,” coordinated by Fonseca as part of the Biota-FAPESP Program.

Plants and fruits are the principal foods that require insects for pollination (the production of each has an estimated value of € 50 billion). Next are the oilseed crops, stimulants (coffee and tea), almonds and spices. Studies say that, on average, the value of the cultures that do not depend on insect pollination is € 151 billion per year, whereas those that do depend on pollination are valued at € 761 billion.

“Nearly 75% of our food depends directly or indirectly on plants pollinated or improved by animal pollination. Of these, 35% depend solely on pollinators. In the rest of the cases, insects such as bees help to increase the fruit’s quality and yield,” said Fonseca, who is currently a visiting professor at the Federal Rural University of the Semiarid Region (UFERSA), in the state of Rio Grande do Norte.

Fonseca went on to say that recent studies have shown that even crops such as canola (pollinated by the wind) and soybean (considered self-pollinating) produce between 20% to 40% more per hectare when they receive support from colonies of bees of the species Apis mellifera or when the crops are planted alongside remaining areas of native vegetation.

“When jatai bees are used to pollinate strawberry plants in protected environments, for example, there is a 70% reduction in the number of poorly formed fruit in some cultivars. Another crop that may benefit from pollination in protected environments is the tomato plant, which needs bees, such as those of the genus Melipona, that cause the flowers to vibrate. In general, bees increase the production of seeds, serve the habitat, make agricultural systems more sustainable, bring great benefits to the environment, and promote other ecosystem services that allow preservation of the biodiversity and water resources,” said Fonseca.

Climate change

Although the demand for pollination services performed by bees has been growing at the same rate as world agricultural production, the habitats favorable to maintaining these insects have been diminishing every year. Such misalignment has resulted in a phenomenon that scientists have recently named colony collapse disorder (CCD).

According to Fonseca, the syndrome involving the disappearance of the bees was first detected in 2007 in the Northern Hemisphere. Currently, in that region, the loss has been approximately 30% of the colonies each year and has required the importation of bees from other locations to promote agricultural pollination. Europe has also suffered from the phenomenon, which Brazil began to detect in 2011.

“Renting a bee colony for pollination can cost up to US$ 200 in the United States because producers know that the profits generated by the service will be much higher. And there are not enough bees. This is the global trend because we are increasingly planting crops that depend on bees for their production,” explained Fonseca.

Among the factors identified as causes for the disappearance of the bees is the improper use of herbicides and pesticides, deforestation following the use of the soil for large monocultures, and the migration of colonies.

“Pesticides, when they don’t kill bees outright, weaken them and reduce the time spent foraging (searching for food). Moreover, bees have to go farther in search of food when native vegetation is replaced by monoculture crops because there are fewer types of flowers. The migration of colonies, in turn, could increase competition for food among the species and foster the spread of disease,” explained Fonseca.

The scenario, already bleak, tends to worsen with the arrival of a new problem: global climate change. The basis of the difficulty is that the pollinators, as well as the plants that maintain their colonies, have a geographical distribution radius that is influenced by temperature and rainfall.

“Predictions by the United Nations Intergovernmental Panel on Climate Change (IPCC) for northeastern Brazil, for example, call for a 4º C increase in temperature over the next 50 years. This increase is expected to strongly impact the areas in which bees occur. We’ve performed species distribution modeling studies and studies that use pollen analysis of the food collected by the bees to learn which plants they are visiting. These tools allow us to conduct a floral resource utilization analysis, and, with the help of the Brazilian flora herbaria, we have modeled the principal sources of food. By cross-referencing the data, we can identify the most important natural areas to be rebuilt and preserved and plan a mitigation program. This program is planned so that, in 40 or 50 years, the bees will have a place to live,” explained Fonseca.

Bee diet

For the purpose of preserving important natural areas for attracting and maintaining the bees used in agricultural production, researcher Cláudia Inês da Silva of the Federal University of Ceará (UFC) has devoted herself to studying the dietary habits of carpenter bees (of the genus Xylocopa) and other bees that are important for pollinating passion fruit. Several of her findings were presented during her lecture at the second meeting of the 2014 Biota-FAPESP Education Conference Cycle.

“We selected the passion fruit because it is of high economic importance to Brazil, which contributes more than 60% of the world’s production of passion fruit. The fruit is typically grown on family farms and experiences huge fluctuations in production, mainly due to handling and raw material costs. And pollination has a direct influence on these production costs,” said Silva.

According to the researcher, knowledge of the insects that visit the flowers of the passion fruit plant is significantly lacking among the rural producers. This lack of knowledge is substantial in terms of the biology of the plant and its reproductive system, which is completely dependent upon pollination by bees.

“In the case of the passion fruit, not all bees are beneficial. Some, such as Apis mellifera, are very small and only gather the nectar and the pollen but do not promote pollination. It’s important to understand the needs of each crop and preserve the most appropriate pollinator,” said Silva.

A study conducted at the Department of Rural Economics at the Federal University Viçosa estimated that in an area of 2.3 hectares of passion fruit crops, the services provided by carpenter bees (Xylocopa) reduce production costs by approximately R$ 33,000 per hectare every three years.

However, despite their importance, the carpenter bees are often killed by the farmers, who consider them aggressive, Silva stated. “They’re afraid that the bees will eat the flowers, destroy the crop and ruin the fences where they usually build their nests. They think the carpenter bees are beetles,” she said.

During her doctoral studies at the Federal University of Uberlândia (UFU) under the advisorship of Paulo Eugênio de Oliveira, Silva identified 112 species of plants used to nourish the carpenter bees. Some of the most important are considered by farmers to be weeds (species of the genera Senna and Solanum) and are often removed from the surroundings.

“Based on this study, we have prepared a proposal to enrich and restore the plants that are important for attracting and maintaining these bees. Beginning with a study of the bees’ diet, we have planned a current and future scenario in order to identify potential areas for growing passion fruit,” Silva said.

The information has helped her to compile the book “Manejo dos Polinizadores e Polinização de Maracujá” (Management of passion fruit pollinators and pollination), which is expected to be released soon, with support from the Ministry of the Environment.