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Lights for nocturnal pollinators
Finnish city unveils pollinator-safe streetlights ands celebrates ‘Night of the Pollinators’.
3 September 2024
A recent study shows the dramatic effects of artificial night-time lighting on insects.
The researchers, from the Senckenberg Biodiversity and Climate Research Center Frankfurt and the Johannes Gutenberg University in Mainz, found that light pollution caused profound changes in 1,564 larval genes of a species of midge.
The consequences are alarming: delayed development, increased oxidative stress and a drastically reduced reproductive capacity.
In the journal Environmental Pollution, the researchers warn of far-reaching ecological consequences and call for measures to reduce light pollution in order to protect biodiversity and the stability of ecosystems.
‘We are advised to avoid screen time before going to bed to avoid disturbing our sleep rhythm. Insects do not have this choice. Yet, artificial light not only negatively affects us humans, but these animals as well.’
PROF. DR MARKUS PFENNINGER
Study’s senior author, from the Senckenberg Biodiversity and Climate Research Center Frankfurt
Wherever people live, there is light: illuminated apartments, houses, streets, billboards, construction sites, office buildings or local landmarks. Particularly in cities, this turns night into day.
Together with a team of researchers from Senckenberg and the Johannes Gutenberg University in Mainz, Pfenninger studied the effect of artificial night-time light on the midge species Chironomus riparius.
These insects, with a body length of 7 to 8 millimetres, are a species with an extremely high ecological importance, as many animals in water, on land and in the air depend on the midges as a source of food.
The short lifecycle of around 30 days also makes chironomids an ideal study subject for eco-evolutionary experiments.
‘In our study, we combined state-of-the-art gene expression analyses with detailed lifecycle experiments to reveal the consequences of light pollution for midge populations and to understand their underlying molecular mechanisms.’
LINDA EBERHARDT
Doctoral student and the study’s first author
The study’s results are alarming: the larvae of Chironomus riparius that were exposed to artificial light at night exhibited changes in 1,564 of their genes.
‘We found a clear deviation in the expression of genes that control fundamental biological processes, e.g., the circadian rhythm, moulting and oxidative stress. This indicates that artificial light at night has profound effects on the physiology – the life processes in the cells, tissues, and organs – of insects.’
LINDA EBERHARDT
Doctoral student and the study’s first author
According to the study, the increase in oxidative stress also leads to altered larval development, a prolonged development time and, above all, a drastically reduced reproductive capacity.
‘The impact on reproductive capacity is particularly alarming. The population growth rate decreased significantly under the influence of night-time lighting in our experiments. A reduction in fertility can lead to a significant decline in population size, thus affecting the entire ecosystem.’
PROF. DR MARKUS PFENNINGER
Study’s senior author, from the Senckenberg Biodiversity and Climate Research Center Frankfurt
The findings of the study underline the importance of the natural light-dark cycle for insects and illustrate the potentially far-reaching consequences of light pollution.
Given the central role of insects in food webs, the effects of artificial night-time light on insect populations could trigger cascading effects throughout the entire ecosystem.
The researchers strongly recommend implementing measures to reduce light pollution in order to minimise the negative impact on insects and the environment.
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