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.

Artificial Light at Night Reduces Daily Energy Expenditure in Breeding Great Tits (Parus major)

“…This is also true at our sites (Spoelstra et al in revision). Different light spectra could thus alter the balance between costs and benefits of light pollution for predator birds and their insect preys, an hypothesis that has already been suggested for other types of species interactions Sanders et al, 2015).…”

Transcriptome analysis of molecular mechanisms responsible for light-stress response in Mythimna separata (Walker)

“…Mortality of second instar larvae of M. separata was shown to be higher than in the third and fourth instar larvae after UV-A radiation34, and increased UV-A radiation of pupae could decrease the rate of adult emergence in this species34. As a major abiotic force, light has a wide range of biological effects on insects192447, which are known to be highly sensitive to artificial light23. Light can influence the physiology, behaviour, and reproduction of insects, especially nocturnal insects22232425, and these influences may vary depending on the wavelength of the light1927.…”

Assessing the effects of artificial light at night on biodiversity across latitude – Current knowledge gaps

“…Concerns initially came from astronomers, who warned about the loss of quality of the nocturnal sky, and spread to other fields. These effects range from the molecular (Honnen, Johnston, & Monaghan, 2016) to the community (Bennie et al, 2017;Rich & Longcore, 2006), and ecosystem level (Knop et al, 2017;Lewanzik & Voigt, 2014;Sanders et al, 2015). ALAN generates a broad array of effects on animals, and as far as we know to a lesser extent on plants and micro-organisms (Bennie, Davies, Cruse, Bell, & Gaston, 2017;ffrench-Constant et al, 2016;Hölker et al, 2015).…”

“…Because of the biological effects cited above, ALAN is expected to affect ecological processes like energy or nutrient fluxes or relationships in trophic networks (Bennie, Davies, Cruse, Inger, & Gaston, 2015;Gaston et al, 2013;Knop et al, 2017;Longcore & Rich, 2004;Macgregor, Evans, Fox, & Pocock, 2017;Mathews et al, 2015;Meyer & Sullivan, 2013;Miller et al, 2017;Perkin et al, 2011;Sanders et al, 2015). More generally, the synchronization between the components of any interspecific interactions can be altered Helm et al, 2017;Kronfeld-Schor, Visser, Salis, & Gils, 2017).…”