title: Artificial nighttime light changes aphid-parasitoid population dynamics.
abstract: Artificial light at night (ALAN) is recognized as a widespread and increasingly important anthropogenic environmental pressure on wild species and their interactions. Understanding of how these impacts translate into changes in population dynamics of communities with multiple trophic levels is, however, severely lacking. In an outdoor mesocosm experiment we tested the effect of ALAN on the population dynamics of a plant-aphid-parasitoid community with one plant species, three aphid species and their specialist parasitoids. The light treatment reduced the abundance of two aphid species by 20% over five generations, most likely as a consequence of bottom-up effects, with reductions in bean plant biomass being observed. For the aphid Megoura viciae this effect was reversed under autumn conditions with the light treatment promoting continuous reproduction through asexuals. All three parasitoid species were negatively affected by the light treatment, through reduced host numbers and we discuss induced possible behavioural changes. These results suggest that, in addition to direct impacts on species behaviour, the impacts of ALAN can cascade through food webs with potentially far reaching effects on the wider ecosystem.
authors.affiliation: Centre for Ecology &Conservation, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, United Kingdom.
authors.forename: Dirk
authors.initials: D
authors.lastname: Sanders
authors.affiliation: Centre for Ecology &Conservation, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, United Kingdom.
authors.forename: Rachel
authors.initials: R
authors.lastname: Kehoe
authors.affiliation: Centre for Ecology &Conservation, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, United Kingdom.
authors.forename: Katie
authors.initials: K
authors.lastname: Tiley
authors.affiliation: Environment &Sustainability Institute, University of Exeter, Cornwall Campus Penryn, Cornwall, TR10 9EZ, United Kingdom.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Bennie
authors.affiliation: Environment &Sustainability Institute, University of Exeter, Cornwall Campus Penryn, Cornwall, TR10 9EZ, United Kingdom.
authors.forename: Dave
authors.initials: D
authors.lastname: Cruse
authors.affiliation: Environment &Sustainability Institute, University of Exeter, Cornwall Campus Penryn, Cornwall, TR10 9EZ, United Kingdom.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Davies
authors.affiliation: Centre for Ecology &Conservation, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, United Kingdom.
authors.forename: F J
authors.initials: FJ
authors.lastname: Frank van Veen
authors.affiliation: Environment &Sustainability Institute, University of Exeter, Cornwall Campus Penryn, Cornwall, TR10 9EZ, United Kingdom.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Gaston
mesh_terms: D000818:Animals; D001042:Aphids / Q000502:physiology / Q000528:radiation effects*; D044822:Biodiversity; D018533:Biomass; D017753:Ecosystem; D006790:Host-Parasite Interactions; D008027:Light; D027805:Phaseolus / Q000378:metabolism / Q000469:parasitology; D011157:Population Dynamics; D012621:Seasons