Lights cause moths to evolve, according to articles in Science Shots 12 April 2016 and ScienceDaily 13 April 2016 and Biology Letters 12 April 2016, doi: 10.1098/rsbl.2016.0111. Moths are nocturnal but are well known for being attracted to bright lights. This is usually fatal for the moths, as they can be burned by the heat from the lights, or become more visible to predators. Swiss zoologists from the Universities of Basel and Zurich have tested two populations of moths to see if there are long term consequences to living in artificially lit night environments.
The researchers collected 10 different groups of larvae of the ermine moth Yponomeuta cagnagella, some from cities with lots of bright lights, and others from rural areas with very little artificial light, and reared them until they metamorphosed into adult moths. They then tested the adult moths for their “flight-to-light” response. They found “moth populations from urban areas with high, globally relevant levels of light pollution over several decades show a significantly reduced flight-to-light behaviour compared with populations of the same species from pristine dark-sky habitats”.
According to ScienceDaily, “The study results suggest that natural selection has changed the animals’ behaviour. Flight-to-light propensity is disadvantageous for moths in light polluted areas. Adapted moths avoid the light and thus have a survival advantage”.
According to Science Shots, “Overall, moths from the light-polluted populations had a 30% reduction in the flight-to-light behaviour, indicating that this species is evolving, as predicted, to stay away from artificial lights.”
According to ScienceDaily, “The study results suggest that natural selection has changed the animals’ behaviour”. The researchers suggest the decrease in flight-to-light behaviour is due to “reduced mobility”, i.e. the moths are flying less. This may enable the moths to survive, but the scientists commented: “As nocturnal insects are of eminent significance as pollinators and the primary food source of many vertebrates, an evolutionary change of the flight-to-light behaviour thereby potentially cascades across species interaction networks”.
The Science Shots article is entitled “Your porchlight is causing moths to evolve”.
Editorial Comment: Did you spot it? If the decreased flight-to-light moths are less mobile in general, then they are not feeding as much, not pollinating flowers and not finding mates. The long term outcome will be fewer moths in cities. Therefore, whatever currently unknown change has occurred in the moths’ genes causing the decreased flight-to-light response, it won’t improve the species as a whole, and certainly won’t make it evolve into a new species.
The decreased flight-to-light behaviour in these moths certainly is a change, and seems to be a degenerate one, but it is not evolution. The moths are still the same species. Even if the loss of flight-to-light response in cities produces survival advantage for individual moths in a highly artificial environment full of hazards like bright burning lights, for the moth species over all, it is not an advantage, and while any original flight-to-light moths remain on the planet they can refurbish the population at any time.
This change is an example of selection – artificial rather than natural, but as we have said many times, selection is not evolution. Selection only chooses from already existing options – in this case pre-existing less active moths in cities, and pre-existing more active moths in the countryside. In a natural environment the “flight-less” moths would be at a disadvantage to the more active moths, who would find more flowers to feed from, and more mates to reproduce with. Therefore, less mobile moths would eventually be eliminated in the country as well. In either place, selection is removing living things, not making new ones. (Ref. natural selection, insects, Lepidoptera)
Evidence News, vol. 16, No. 7
27 April 2016
Creation Research Australia