Using more advanced research techniques than previously employed, researchers at the University of Reading have dug deep into the question how seriously air quality affects the ability of insects to pollinate.
An assumption has built up recently that air pollution could mask the volatile organic compounds (VOCs) that flowers emit to attract pollinators but no research had established the degree to which that happens.
A number of ‘free-air fumigation facilities’ were set up – eight metre diameter rings that emitted either diesel exhaust, ozone, diesel and ozone together or clean air. It was seen that the number of visits pollinators made to flowers within the polluted rings was dramatically lower than in the clean air environments.
By way of control, the researchers looked at the number of insects entering the various rings with flowers present and with no flowers at all. Because there was no difference seen between these two scenarios the team could determine that the pollutant itself was not repelling the insects, clearly suggesting that they simply found it more difficult to detect floral odour cues.
The real shock was the extent to which these odour cues were being disrupted, ‘The observed 60–90% reduction in flower visits by pollinators when exposed to diesel exhaust and ozone were more severe than we anticipated from previous laboratory studies and modelling.’
Most stable crops are wind pollinated but many fruits and vegetables require insects for pollination and low pollination results in lower yields and lower quality fruit.
Dr James Ryalls, a Research Fellow in the Centre for Agri-Environmental Research said: ‘Our study focused upon pollinators finding a flower, but insects use odours for a variety of interactions with each other and their environment. For example, pheromones are airborne odours produced by one insect to attract a mate of the same species. If pheromone communication is disrupted in a similar way it could result in insects struggling to find mates, which could have ramifications for insect biodiversity.’