Street Lights Are Preventing Moths From Doing Their Job

As bee and butterfly populations fall dramatically in Europe and North America, another crucial pollinator is experiencing severe declines of its own: the moth. Reams of research have been done to understand and stem the nightmarish mixture of diseases and parasites, climate change, pesticide use, and probably other unknown factors hammering the daytime pollinators upon which we rely on so much for our foods, but little has been done on the nighttime ones.

So British scientists studied moths’ pollinating behaviors in the United Kingdom and discovered that these insects have another unique adversary: streetlamps, which disrupt their pollinating by luring them away from flowers and plants. Their findings are published today in the scientific journal Global Change Biology.

The team of ecologists, from Newcastle University in the UK, took to the night in Oxfordshire, to observe the pollinating behaviors of moths around roads in both lit and unlit areas of farmland. They found that in lit areas, the number of moths flitting around at ground level near the flowers and crops was half that of the number of moths found at ground level in unlit areas.

Where were the others? Fluttering frantically around and sometimes accidentally frying themselves in streetlamps. In these lit areas there was also a significant decrease in the diversity of moth species flying around the ground near plants—25 percent less, to be exact. Further, the British scientists also discovered that only 1 in 4 of the fuzzy insects captured around streetlamps were carrying pollen, indicating that these lights could be affecting nighttime pollination.

We all know that moths are attracted to light—you’ve probably experienced some banging against the screen of an open window in the summer time—and it is this attraction that draws them away from their nighttime duties of pollinating. Even if they don’t fry, a night spent exhaustingly fluttering around a lamp like one possessed is a night not spent pollinating plants. Callum Macgregor, lead researcher of the study, explained in a statement that “Where there are street lights, our research indicates that the moths are being attracted upwards, away from the fields and hedgerows. This is likely to cause disruption of nighttime pollination by moths.”

One in every three bites of food taken worldwide depends on pollinators for a successful harvest. And while bees and butterflies (particularly bees which alone account for $15 billion of the value of US agriculture) are crucial orchestrators of this process, their nighttime brethren, moths, are too. Yet moths, like the daytime pollinators, are also in severe decline, particularly across the UK and Europe, which can have severe knock-on effects within an ecosystem; not just with plant pollinations, but with other organisms like birds and bats, that rely on the protein filled insects for food. Ecologist Darren Evans, co-author of the study, noted that falling pollinator populations represent “a process that is being damaged on two fronts—night and day—and together the impact could be significant.”