The use of pesticides and the destruction of their habitat are leading to the disappearance of pollinators worldwide, threatening food security and ecosystems. However, these factors are not the only threats these animals face.
Human activities have drastically changed the environment sensory pollutantsB. Noise or artificial light, which can change the behavior and performance of living beings by introducing new stimuli or changing natural stimuli.
For example, air pollutants such as ozone (EITHER3) and that Nitrate radicals (NO3) Oxidants, they break down the chemical compounds that produce floral aromas. Many plant pollinators travel long distances in search of food, attracted by these smells.
An international team of scientists led by the University of Washington (USA) analyzed the effects of these anthropogenic pollutants on the hawkmoth’s ability to smell (Manduca sixth).
Our work can also be applied to other species of pollinators, such as those that rely on detecting floral scents to find food and come out at night.
To do this, they monitored the Pollination by evening primrose (Oenothera pallida), a very popular garden plant native to North America. These desert flowers exude a strong floral aroma that attracts a wide variety of pollinators. Oxidized aromas emerged a 70% decrease in visits to the flowers by these insects, which likely affected fruit production and plant health.
“Our work can undoubtedly be transferred to other pollinator species, particularly those that rely on floral scent detection to find food and emerge at night, when nitrate radicals are most abundant in the atmosphere,” he explains to SINC. Joel A ThorntonCo-author of the study and researcher in the Department of Atmospheric Sciences of the American institution.
Nitrate radicals (NO3) are formed in the atmosphere by chemical reactions between ozone (O3) and nitrogen dioxide (NO2). Anthropogenic activities related to Fuel combustion They are a main source of nitrogen oxides and are partly responsible for the formation of ozone.
“Ozone has natural sources but is also enhanced by anthropogenic emissions of nitrogen oxides and volatile organic compounds. In regions where both ozone and nitrogen dioxide are high, the production of nitrate radicals is increased,” he adds. Thornton.
Evening primrose during the field study. /Jeremy Chan
How NO3 changes smells
The work combined field observations in the East Washington and laboratory experiments. “These moths have one of the most sensitive olfactory systems, rivaling that of dogs. Their olfactory neurons are located in the antennae and nose and detect odors before relaying that information to the brain,” he tells SINC. Jeff Riffelwho is leading the study 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 produced the floral scent that hawkmoths use to recognize the flower.
“The pollinator species we studied, night-flying moths, are particularly important for flowers that open at dusk. These insects can fly between 40 and 80 km in a single night. “They are found throughout North America, making them an excellent model system for different areas because they are similar to other moth species from South America and Europe,” argues Riffell.
Accordingly ThorntonIt is possible that these disorders could also occur during the day in connection with nitrogen oxide pollution: “Other previous work has shown this.” Nitrate radicals only last for a short time during the day because they are destroyed by sunlight and react with other daytime radicals. However, during the day, nitrogen oxides can enhance both ozone and the hydroxyl radical (a fragment of water vapor), both of which respond to monoterpenes, the same components of floral aroma that we identify as important for floral location for a subset of pollinators. ”
At a global level, the authors of this work point out that many urban areas have sufficient O3 and not3 Air pollution, for example, to significantly reduce the distance from which pollinators can detect the aroma of flowers.
Hawk butterfly on a flower. / Ron Wolf
Reference:
JK Chan et al. “Olfaction in the Anthropocene: NO3 negatively affects floral scent and nocturnal pollination.” Science.