Air Pollution Renders Flower Odors Unattractive to Moths

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A team of researchers from the Max Planck Institute for Chemical Ecology in Jena, Germany, and the University of Virginia, USA, has studied the impact of high ozone air pollution on the chemical communication between flowers and pollinators.

A team of researchers from the Max Planck Institute for Chemical Ecology in Jena, Germany, and the University of Virginia, USA, has studied the impact of high ozone air pollution on the chemical communication between flowers and pollinators. They showed that tobacco hawkmoths lost attraction to the scent of their preferred flowers when that scent had been altered by ozone. This oxidizing pollutant thus disturbs the interaction between a plant and its pollinator, a relationship that has evolved over millions of years. However, when given the chance, hawkmoths quickly learn that an unpleasantly polluted scent may lead to nutritious nectar (Journal of Chemical Ecology, September 2020, DOI: 10.1007/s10886-020-01211-4).

Pollination is a critical ecosystem service, one that is performed mainly by insects. Flowers attract insects using floral scents, which are chemical signals that the pollinators can have an innate preference for. This preference is the result of the co-evolutionary relationship between flowers and their pollinators that has evolved over millions of years.

For about 20 years, the term "Anthropocene" has been used in the scientific community to refer to the geological epoch in which humans are responsible for many changes in biological and atmospheric processes. However, until recently, little has been known about the effects of anthropogenic climate change and atmospheric pollution on natural environmental odors that drive chemical communication between organisms.

Read more: Max Planck Institute of Chemical Ecology

A tobacco hawkmoth (Manduca sexta) drinking nectar from a flower of the tobacco species Nicotiana alata. The nocturnal moth locates its food source by smelling the odor or seeing the strikingly bright color of the flowers. The visual signals of the plant to be pollinated, paired with M. sexta's ability to associate new smells with nectar rewards, may help the insect to compensate for the interference in chemical communication caused by high ozone levels in the air. (Photo Credit: Anna Schroll)