Changes in nocturnal insect communities in forest-dominated landscape relevant to artificial light intensity

Abstract

Background Artificial light at night has recently been identified as a major factor adversely affecting global insect diversity. Here, we compared the insect diversity in Gwangneung Forest Biosphere Reserve, specifically in the Korea National Arboretum (with no artificial light at night), with that of three nearby urban sites with a gradient of artificial light at night (five locations at each site). We analyzed the effects of the artificial night lighting index, mean annual temperature, and field light intensity (lux) at night on the insect community structure. Results The urban sites generally exhibited higher species richness and abundance as well as clear indicator species compared with the control site. The size distribution of the collected insects markedly differed between the control and the three urban sites. The abundance of herbivorous and omnivorous insects increased and decreased, respectively, with the increase in light intensity. Species richness of herbivorous and omnivorous insects was likely correlated with the field light intensity at night and artificial night lighting index, respectively. Conclusions This study demonstrates the association between nighttime environment and marked changes in insect community structure and revealed consequent transition of ecosystem services by changes in trophic group composition.

Artificial light at night may decrease predation risk for terrestrial insects

“…While global insect defaunation is thought to be partly a result of such mechanisms, the relationship between invertebrate abundance and ALAN is complex; evident in the mixed results of studies to date. While a recent study of terrestrial insects in hedgerows and grass margins found significantly lower abundance in habitats illuminated by streetlights than those not [12], further studies show correlations which are positive [13,14], species dependent [15][16][17] or non-significant [18]. Possible explanations include varying predation under ALAN.…”

Insects within bushes assemble and forage closer to artificial light at night

“…It has been suggested, for example, that the intrusion of light into otherwise dark night‐time environments disrupts insects' foraging behaviour (Cieraad et al, 2022; Tierney et al, 2017; van Langevelde et al, 2018) and decreases the nutritional bioavailability of their hostplants (Grenis & Murphy, 2019); but whether this ultimately affects herbivorous insect abundance is unclear. Some researchers have reported that, at broad scales, insects are less abundant near streetlighting (Boyes et al, 2021b), whilst others report abundance levels which are the same, species‐dependent, or greater near various forms of ALAN (Firebaugh & Haynes, 2020; Hakbong et al, 2021; Lockett et al, 2021; Manfrin et al, 2017; McMunn et al, 2019; Willmott et al, 2019).…”

Bats in the spotlight : Spatiotemporal response of foraging and commuting bats to anthropogenic light at night

“…However, some studies reported already changes in diet preferences in several bat species, including P. pipistrellus which also feed on Lepidoptera (Arlettaz et al, 2000;Rydell, 1992). As ALAN alters the assemblage compositions of invertebrates (Grubisic and van Grunsven, 2021;Hakbong et al, 2021), this could lead to cascading effects on the diet preferences of bats.…”