Scientists have discovered that moths may play a much broader role as plant pollinators than previously suspected.
A joint study involving Butterfly Conservation, the Universities of York, Newcastle and Hull and Centre for Ecology & Hydrology, suggests moths have an important but overlooked ecological role – dispensing pollen over large distances under the cover of darkness.
The team caught moths at a farm in East Yorkshire in the summer of 2015 and used a recently-developed method called DNA metabarcoding to identify the different types of pollen they carried.
Dr Callum Macgregor, who led the study as part of his PhD research funded by NERC and Butterfly Conservation, said: “Using cutting-edge techniques to distinguish between different pollen types allowed us to gain new insight into the species of plants which are important nectar resources for moths – and therefore might benefit from pollination after dark.”
“Over half of the plant species we detected were not previously known to be visited by moths. It was particularly interesting that moths were carrying pollen from many of the same plant species that are visited by bees, hoverflies and butterflies.”
Pollen grains from agricultural crops such as peas, soybean and oil-seed rape were detected on multiple moths, despite a lack of previous evidence to suggest that moths are beneficial for commercial crops in the UK. In total pollen from 33 different plants was detected.
Dr Macgregor added: “Our study highlights the fact that we need to think seriously about the benefits of moths to plants and agricultural systems. While bees are excellent pollinators, they will only travel within the local environment of the nest.”
“Moths appear to complement the work of bees and can carry pollen over greater distances as they don’t have the same ties to a particular part of the landscape. Potentially, this might help to prevent inbreeding among plants.”
The new approach revealed that over one-third (34%) of all the individual moths examined at the farm were carrying pollen. Noctuid moths, such as the Dark Arches, Smoky Wainscot, Large Yellow Underwing and the Common Rustic/Lesser Common Rustic group were found to be transporting pollen from the greatest number of different plant species.
In addition to pollen from local wild plants and crops, the researchers also detected pollen from popular garden plants suggesting that moths may have travelled several hundred metres from the nearest gardens.
The study also compared the effectiveness of using the new DNA-based techniques compared to traditional use of light microscopes to detect and determine the identity of pollen grains. DNA metabarcoding detected pollen on significantly more individual moths than traditional techniques, identified more plant species from pollen samples and more interactions between nocturnal moths and plant species.
Project supervisor Dr Darren Evans, from Newcastle University’s School of Natural and Environmental Sciences, said: “Using new methods to analyse pollen enabled us to learn much more about our undervalued nocturnal ecosystems.”
“The results demonstrate for the first time that moths could even pollinate some agricultural crops. This highlights a need for more research into the role of moths as ecosystem service providers.”
Richard Fox, Associate Director of Recording and Research at Butterfly Conservation and a co-supervisor of Dr Macgregor’s research, added “This study and others that formed part of Callum’s PhD have shone a much needed light on the underappreciated role of nocturnal moths as plant pollinators in Britain and around the world. Butterfly Conservation is delighted to support and collaborate in such important research.”
Reference: Macgregor, C.J., Kitson, J.J.N., Fox, R., Hahn, C., Lunt, D.H., Pocock, M.J.O. & Evans, D.M. 2018. Construction, validation, and application of nocturnal pollen transport networks in an agro-ecosystem: a comparison using light microscopy and DNA metabarcoding. Ecological Entomology DOI: 10.1111/een.12674