A research study has found that air pollution makes it more difficult for insects to find flowers. Air pollution is changing the scent of flowers, reports New Scientist in February 2024.
The scent molecules released by flowers smell different before and after pollutants are detected in the surrounding air. The University of Washington in Seattle in the United States has been conducting research on the impact of pollution on insects and flower pollination.
Researcher Jeff Riffell said that, in recent years, there has been a growing interest in ‘sensory pollution’ which arises from human activity that can change wildlife behaviour by changing or introducing new stimuli.” He said that noise pollution, for example can change bird songs, but little is known about air pollution’s effect on the way animals detect scents.
Scents are important to wildlife survival because scents inform animals about the location of food, other animals in the area, danger, people, and so on. Therefore, Jeff Riffell and his colleagues investigated the effects of anthropogenic pollutants on plant pollinators – such as insects.
The researchers focused on ozone and nitrate radicals which are pollutants created by the interaction of vehicle emissions and gases in the air. Both are known to react with compounds emitted by flowers, altering their smell.
The researchers collected the compounds released by the Pale Evening-Primrose (Oenothera pallida) which is a desert flower in North America. They found that both pollutants – ozone and nitrate – changed the scent of the Primrose flowers.
They exposed the White-Lined Sphinx Hawk Moth (Hyles lineata) to the flowers emitting their natural scent and to the polluted flowers (with degraded scent). The Hawk Moth visited the polluted flowers 70% less often than they visited the naturally-scented flowers. Additionally, the distance that the Hawk Moth could sense the flowers decreased from 2 kilometres to a few hundred metres.
Jeff Riffell thinks that the moth’s reduction in visits to flowers that are polluted may have a negative effect on the wider eco-system because the decline in moth visits could result in 28% less fruit appearing on a plant. Insects are needed to pollinate flowers so that they can bear fruit.
Photographer: Martina Nicolls
Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM