Air pollution has a worse effect on insects than previously thought, negatively affecting their health and reproduction systems even in remote geographical areas, scientists have discovered.
The work, done in collaboration by the University of Melbourne (Australia), the University of California Davis (USA), and Beijing Forestry University (PRC), showed that due to the air pollution from industry, bushfires, transport, insects antennae becomes contaminated and this reduces their ability to locate food and mates.
“Our research shows that it also reduces insects’ crucial ability to detect odours for finding food and mates.
“This could result in declining populations, including after bushfires and in habitats far from the pollution source.
Prof. Elgar also highlighted the importance of keeping the insect population healthy.
“As well as being fascinating creatures, many insects play a critical role in pollinating plants—including almost all the crops we rely on for food—and breaking down decaying material and recycling nutrients.”
Insects are particularly affected, according to Dr. Ittai Renan, director of Israel’s National Ecosystem Assessment Program and head of the Applied Entomology Lab in the Steinhardt Museum at Tel Aviv University, who was not involved in this study.
He said whether insects will ultimately adapt to these new pollution levels remains to be seen and warned that collapsing insect populations could be dangerous.
“The collapse of the insect population, which is the largest and oldest group of animals on Earth, is also linked to the disappearance of entire species and a decrease in the overall insect population,” he said.
Study’s Findings
The researchers conducted a series of experiments where they collected 25 houseflies from each of the groups, which included contaminated flies (exposed to different levels of ambient air pollution in Beijing), a control group (not-contaminated flies) and wild flies. Then they measured the density of Particulate matter (PM) on the flies.The researchers found that the PM contaminates were predominantly on the housefly antennas, then their head, legs and abdomens. The density of the particles on the antennae was recorded to be seven times higher in the flies exposed to 12 hours of ambient air pollution compared to the flies kept in the clean air.
The PM-contaminated antennae of the flies consistently compromised their ability to detect odour. This affected the capacity of the male and female houseflies to respond to odours of food, as well as to sex-specific pheromones.
Looking deeper into the impact of the pollution on the houseflies, the scientists found that PM exposure changed even the gene expression level, concluding that the pollutants have the potential to affect the metabolic pathways, like glucose, amino acid and fatty acid metabolism, as well as the circadian rhythm.
Insects’ antennae are a very important part of their anatomy as they have receptors that can detect odour molecules for food, and reproduction.
“When their antennae become clogged with pollution particles, insects struggle to smell food, a mate, or a place to lay their eggs, and it follows that their populations will decline,” said Prof. Elgar.
“About 40 percent of Earth’s landmass is exposed to particle air pollution concentrations above the World Health Organisation’s recommended annual average.
“Surprisingly, this includes many remote and comparatively pristine habitats and areas of ecological significance—because particulate material can be carried thousands of kilometres by air currents.”
How Does Air Pollution Affect Insects
Air pollution can have significant effects on insects, which play crucial roles in ecosystems as pollinators, decomposers, and as a vital food source for other animals.Here are some of the ways in which air pollution can impact insects.
Insects, like other organisms, breathe in oxygen from the air. Air pollutants such as particulate matter, nitrogen oxides, and sulphur dioxide can damage their respiratory systems, making it harder for them to breathe. This can lead to reduced growth, reproduction, and species survival rates.
Insects rely on chemical cues for various behaviours, such as finding food, mates, and suitable habitats. Air pollution can disrupt these chemical signals, making it difficult for insects to navigate their environment and carry out essential activities.
Air pollution can harm plant life by depositing pollutants on leaves and altering soil chemistry. Since many insects depend on plants for food and shelter, the degradation of their habitats can lead to population declines.
Many insects have symbiotic relationships with microorganisms that aid in digestion or provide essential nutrients. Air pollution can disturb these relationships, impacting the insects’ ability to obtain necessary nutrients from their food.
Many insects, such as bees and butterflies, are important pollinators for plants. Air pollution can impair their ability to forage for nectar and pollen, affecting plant reproduction and potentially leading to food chain disruptions.
Air pollution can interfere with insect reproductive processes. For example, pollutants may affect the development of eggs, larvae, and pupae, leading to reduced reproductive success and population decline.
The various impacts of air pollution on insects can lead to declines in population sizes. This has cascading effects on ecosystems, as many other species rely on insects for food.
Insects are often small and exposed to the elements, making them susceptible to direct harm from air pollutants. Certain pollutants can lead to tissue damage, reduced lifespan, and increased mortality rates.
Mitigating air pollution through efforts like reducing emissions and improving air quality can contribute to the well-being of insect populations and the ecosystems they support.
