Air pollution affects health in India

Pollution also affects insects : Dirty air makes bees sick

Air pollution damages the health of bees and other insects. This is what a research team led by Geetha Thimmegowda from the National Center for Biological Sciences in Bangalore reports in the journal "PNAS".

Even medium fine dust concentrations reduce the number of flower visits in giant honey bees, impair a number of body functions and increase the death rate.

Experiments on fruit flies confirm the observations and suggest that they also apply to other insects. In India, one of the most important fruit and vegetable producers in the world, the World Health Organization (WHO) located in 2019 nine of the ten most polluted cities in the world.

1800 bees examined

For three years, the researchers examined more than 1,800 giant honey bees in four differently polluted locations in the metropolis with a population of 13 million.

This species of bees Apis dorsata, also lives in cities, produces more than 80 percent of Indian honey and pollinates around 700 different plants. The team concentrated on four locations with different levels of particulate matter, but otherwise comparable.

The lightly polluted areas had mean concentrations of fine dust with a grain size of less than 10 micrometers of 28 and 34 micrograms per cubic meter. It was 46 micrograms at the moderately contaminated site and 99 micrograms at the heavily contaminated site. The limit in India is 60 micrograms per cubic meter.

Damage even with medium fine dust pollution

In the respective areas, the researchers always collected the hornet-sized bees in the morning from the blossoms of yellow trumpet flowers (Tecoma stans) that bloom all year round and are pollinated by giant honey bees.

The researchers registered at the moderately and heavily polluted locations fewer flower visits by bees and the bees collected there died much faster than the animals from areas with better air quality.

Investigations of legs, wings and antennae showed that the animals there were actually exposed to a much higher level of fine dust, arsenic, lead, tungsten and aluminum, which changed breathing, the number of blood cells, immune reactions and gene activity.

Since air pollution also left similar traces on fruit flies, the researchers assume that other insects are also affected - even with moderate particulate matter pollution of 50 micrograms per cubic meter. (Walter Willems, dpa)

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