The use of pesticides and the destruction of their habitat leads to population collapse pollinators from all over the world, with the resulting danger to food safety and ecosystems. However, these factors are not the only threats these animals face.
Human activities have drastically changed the environment sensory pollutantssuch as noise or artificial light, which can change the behavior and capabilities of living things by introducing new stimuli or modifying natural stimuli.
For example the pollutants in the airLike the ozone (O3) and the nitrate radicals (NO3) oxidants, they break down the chemical compounds that produce floral aromas. A lot of pollinators of plants travel long distances, attracted by these scents, as they search for food.
An international team of scientists, led by the University of Washington (USA), analyzed the impact of these anthropogenic pollutants on the hawk moth’s sense of smell (Manduca Friday).
To do this, they monitored the pollination of night primroses (Oenothera pallida), a very popular garden plant, native to North America. These desert flowers emit a strong floral aroma that attracts a rich diversity of flowers pollinators. The oxidized aromas were the result a 70% drop in visits to the flowers by these insects, which probably reduced fruiting and plant fitness.
Pollinators flee from air pollutants
“Our work can undoubtedly be extrapolated to other species pollinatorsespecially those that rely on the detection of floral scents to locate food and come out at night, when nitrate radicals are most abundant in the atmosphere,” explains Joel A. Thornton, co-author of the study and researcher in the department . of Sciences: Atmospheres in the American Institute.
Nitrate radicals (NO3) are produced in the atmosphere by chemical reactions between ozone (O3) and nitrogen dioxide (NO2). Anthropogenic activities related to combustion of the fuel They are a major source of nitrogen oxides and part of the cause of ozone.
“Ozone has natural sources, but is also enhanced by anthropogenic emissions of nitrogen oxides and volatile organic compounds. In areas where both ozone and nitrogen dioxide are high, nitrate radical production will increase,” Thornton adds.
NO3 changes odors and affects pollinators
The work combined field observations in the east of the Washington state and laboratory experiments. “Are moths They have one of the most sensitive olfactory systems, comparable to that of the dog. Their olfactory neurons are located in the antennae and nose and detect odorants before transmitting this information to the brain,” says Jeff Riffell, who leads the research at the same university.
According to the findings, NO3 was much more reactive than O3 and selectively oxidized a specific subset of monoterpenes – components of the volatile essences of flowers – and into the floral fragrance that moths falcon that they use to recognize the flower.
“The kind pollinators that we study, the moths nocturnal fliers, they are especially important for flowers that open at dusk. These insects can fly between 40 and 80 km in one night. They are found throughout North America, making them an excellent model system for different areas as they are similar to other moth species from South America and Europe,” Riffell argues.
According to Thornton, it is possible that these disruptions could also occur during the day due to nitrogen oxide pollution: “Other previous work has shown this. Nitrate radicals are short-lived during the day due to their destruction by sunlight and reactions with other radicals during the day. However, nitrogen oxides during the day can enhance both ozone and the hydroxyl radical (a fragment of water vapor), both reactive toward monoterpenes, the same components of floral aroma that we consider important for the location of flowers throughout part of the environment. pollinators”.
On a global scale, the authors of this work point out that many urban areas have sufficient O3 and not3 air pollution, which significantly reduces the distance at which pollinators can perceive floral aroma.
