Today, May 20, World Bee Day is celebrated, designated by the United Nations Organization (UN). And this year they request that emphasis be placed on the importance that these organisms have in food production and sustainable development. To celebrate and give a little visibility to this environmental problem that we face on a planetary scale see this video.
It's important to remember that not all bees are honey bees. Bees, recognized as the most effective pollinating species, are mostly wild. Of the 20 thousand species of bees that we know, only Apis mellifera and some bumblebees of the genus Bombus are domestic species.
The work recently published by Francisco Sánchez-Bayo and Kris A.G. Wyckhuys (2019), reveals dramatic rates of decline that could lead to the extinction of 40% of the world's insect species (terrestrial and aquatic) in the coming decades. According to this work, pollinator species such as lepidoptera (butterflies and moths) and hymenoptera (where bees are included) are among the most affected groups of terrestrial insects.
THE MAIN THREATS TO THE DIVERSITY OF THE WILD POLLINATORS
The main causes of the decline of wild pollinators are directly or indirectly related to human activity, and may even act together by multiplying their negative effect on these species (Sih et al 2004, Gill et al 2012, Sánchez-Bayo and Wyckhuys 2019). Understand what factors are limiting pollinators and why it will give us the keys to correct certain practices that endanger their survival.
Changes in land use that reduce pollinator resources: The loss, fragmentation and degradation of the natural and semi-natural habitat caused by human changes in land use (agriculture, livestock and urbanization) is one of the fundamental causes of the decline of pollinators around the world.
The use of pesticides is associated with a loss in the abundance and diversity of pollinators (Siqueira et al., 2008; Carvalheiro et al., 2010, 2012; Woodcock et al., 2017). Under this evidence, the application of insecticides such as neonicotinoids (derived from nicotine) or fipronil was partially restricted in the European Union in 2013 (European Commission 2013a, 2013b).
Emerging infectious diseases: Pollinators are exposed to a wide range of parasites, parasitoids and pathogens. The latter include protozoa, fungi, bacteria and viruses. It is considered that the pathogens that give rise to emerging infectious diseases (EIDs) are those that carry a higher risk for the survival of pollinators.
Managed species: To increase agricultural production there are management strategies based on the introduction of honey bee hives (Apis mellifera) and some species of bumblebees (Bombus), at the moment that their flowering requires it (Free 1993). The measure can have negative effects on native wild insect populations, if there is a significant increase in the abundance of these managed species or there is a shortage of floral resources.
Climate change is widely recognized as one of the main threats to biodiversity, and pollinators are not unaware of this impact. Climate change is affecting pollinators causing displacements in the areas of distribution of species spatial and temporal mismatches with plants that interact due to the increasing temperatures.