When we think of pollinators, we tend to only consider bees and butterflies. But when the Sun goes down, the night shift takes over – moths, beetles, and bugs are a vital component in the pollination of many crops we take for granted. However, it has now been found that artificial lights can dramatically impact their ability to do so.
Researchers previously assumed that insects that pollinate flowers during the night tend to rely on scent to navigate the dark and flit from flower to flower as they collect their sweet reward. But this has neglected the role that vision may play for these nocturnal creatures.
A new study, published in Nature, found that artificial lights reduce the number of pollinators that visit flowers in fields at night, and that this significant cut in nocturnal pollinators may have a knock-on effect to those that come out in the day. The research highlights the impact that light pollution has on the insects we rely on for agriculture, something that may have been overlooked.
In a series of experiments, the researchers recorded how many pollinators visited two separate patches of field, one that was left dark and another that had been lit with lights equivalent to street lamps. They found that the one bathed in artificial lights received a staggering 62 percent fewer pollinators than the one left in the dark.
In the last 20 years alone, light emissions have rocketed by 70 percent, most prominently in urban areas. The authors think it likely that in these regions, most night-time pollinators have already disappeared.
Yet more worryingly, the researchers also found that the plants pollinated by insects at night were also visited more by pollinators during the day. The authors think that somehow the nocturnal pollinators indirectly promote the day-flying ones. How or why this occurs is still unknown, but the researchers suggest that it may have something to do with the plants gaining some sort of fitness advantage after being visited at night.
This, however, underlines the seriousness that the loss of night-time pollinators may have not only on the environment and nature, but also on our ability to produce enough food to feed an increasingly urbanized world.