There are over 22,000 species of wild bees worldwide, with around 1,100 found in Spain. Photo: Blanca Arroyo

By Nerea Montes

Today, as we mark World Bee Day, it’s a moment to recognize how vital these insects are to our ecosystems and our everyday routines. However, when we think of bees—or pollinators in general—one species tends to dominate our imagination: the honey bee (Apis mellifera), widely used in beekeeping and known for its honey production and complex social structure centered around a queen and her workers. Yet, this species represents only a tiny fraction of a much broader reality.

In fact, over 22,000 species of bees have been identified globally, and about 1,100 of them inhabit Spain. Unlike their domesticated cousin, most wild bees are solitary—they don’t form hives, don’t produce honey, and remain largely unknown to the society.

Given this hidden diversity and the many threats pollinators face, it is crucial to understand their ecological roles and the factors putting them at risk. That’s the focus of a scientific team at the Doñana Biological Station, led by researcher Ignasi Bartomeus and specializing in community ecology. This group studies how plants and their pollinators interact, and how global change can affect the structure and functioning of these communities.

Pollinators are essential to ecosystem survival by enabling plant reproduction through fruit and seed production. But their importance goes even further—they are vital to something that directly affects us: food production.

Beyond the honey bee

International organizations like IPBES highlight that 75% of the crops we consume—from citrus fruits to apples—depend on insect pollinators to bear fruit. And it’s not just the honey bee doing the work. Many wild bee species, along with butterflies, flies, and beetles, also contribute. In fact, a 2024 study by the Doñana Biological Station in collaboration with research centers in the U.S. and Argentina found that wild insects are just as important as honey bees for crop production.

This raises an urgent question: What are the consequences of pollinator biodiversity loss? Researchers at the Basque Centre for Climate Change (BC3) in Bilbao, together with scientists at the Doñana Biological Station, recently examined how this gradual decline could impact not only crops but also wild plant species.

“At a global level, we’ve seen that the progressive loss of wild pollinating insects has a greater negative impact on plant reproduction than the decline of managed pollinators like the honey bee,” says predoctoral researcher Maddi Artamendi in her latest study. “Our findings highlight the importance of conserving biodiversity and the urgency of mitigating climate change as a driver of species loss.” This is why studying pollinator diversity and assessing their conservation status is so important.

Monitoring in Doñana

In this context, the Doñana Biological Station has been a pioneer in Spain in establishing long-term monitoring of wild bee populations and their relationships with plants. With over ten years of continuous sampling in the Doñana Natural Area, these efforts are helping scientists understand the conservation status of pollinator populations and whether they are being threatened by climate change or habitat destruction.

“In the past eleven years, we've observed a decline in wild bee populations, especially in the last two years,” notes entomologist Francisco P. Molina, who has led the monitoring since its inception. “Factors like drought, extreme temperatures, and even flooding due to heavy rains could be behind this decline, though we still don’t fully understand which of these environmental factors is having the greatest impact.”

These environmental pressures don’t just affect insect survival directly—they also threaten the timing of their interactions with the plants they visit. Wild bees live for just one to three weeks and emerge only once a year. Once their cycle is complete—mating and laying eggs—the adults die and won’t be seen again until the following year. For these bees, synchronizing their emergence with flowering plants is crucial for accessing food and reproducing.

In a study currently under review, predoctoral researcher Nerea Montes Pérez analyzed long-term data from Doñana and found that this timing—called phenological synchrony—has subtly shifted over time. She observed that maximum temperatures and winter rainfall are key factors that influence when bees emerge and when plants bloom. “These results give us a foundation for understanding what to expect if climate change continues to intensify,” she explains.

From Doñana to Europe

In the face of these challenges, international responses are beginning to take shape. Across Europe, the first steps are being taken to implement pollinator monitoring programs in every EU country. A recently launched pilot project for a European Pollinator Monitoring Framework aims to assess the abundance and distribution of wild bees and other pollinators across the continent. This kind of data is critical for designing effective conservation policies and actions.

Moreover, funding for pollinator biodiversity research, conservation, and protection has increased—targeting natural environments as well as agricultural and urban areas.

But research alone is not enough. It's also essential to share this knowledge with the public. Raising awareness about biodiversity and the role of pollinators is increasingly urgent. Numerous initiatives are promoting accessible educational content—from field guides for identifying species to citizen science activities like Bioblitz events and audiovisual materials that help bring pollination science to a broader audience.

“I think it’s crucial to raise awareness and make the effort to share the research we do, because conserving species and natural spaces is everyone’s responsibility,” says Nerea Montes. She recently participated in the 'Yo investigo, yo soy CSIC’ contest. In her video Polinder, she uses creative analogies to explain how plants and pollinators interact. “Initiatives like this help us, from the beginning of our research careers, to develop the ability to communicate science in a relatable way,” she adds.

An urgent ecological challenge

Conserving wild bees and other pollinators is one of the most pressing ecological challenges of our time. Their role in plant reproduction, ecosystem health, and food production is indispensable—yet they are often overlooked by society.

In a world facing climate change and habitat loss, it’s increasingly urgent to strengthen research efforts, improve environmental management, and raise public awareness about the importance of these pollinating insects. Learning about wild bees, studying their behaviors, sharing their stories, and spreading this knowledge are essential steps toward ensuring their survival.

Reference

Artamendi, M., Martin, P. A., Bartomeus, I., & Magrach, A. (2025). Loss of pollinator diversity consistently reduces reproductive success for wild and cultivated plants. Nature Ecology & Evolution, 9(2), 296-313. https://doi.org/10.1038/s41559-024-02595-2

Potts, S. G., Bartomeus, I., Biesmeijer, K., Breeze, T., Casino, A., Dauber, J., ... & Zhang, J. (2024). Refined proposal for an EU pollinator monitoring scheme. https://dx.doi.org/10.2760/2005545

Reilly, J., Bartomeus, I., Simpson, D., Allen‐Perkins, A., Garibaldi, L., & Winfree, R. (2024). Wild insects and honey bees are equally important to crop yields in a global analysis. Global Ecology and Biogeography, 33(7), e13843. https://doi.org/10.1111/geb.13843

Potts, S. G., Ngo, H. T., Biesmeijer, J. C., Breeze, T. D., Dicks, L. V., Garibaldi, L. A., ... & Vanbergen, A. (2016). The assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services on pollinators, pollination and food production. https://www.ipbes.net/assessment-reports/pollinators