Sex-specific gene expression in the mosquito Culex pipiens f. molestus in response to artificial light at night

Abstract

BackgroundArtificial light at night (ALAN) is a typical feature of urban areas and most organisms living in urban or suburban habitats are exposed to low levels of ALAN. Light is one of the most important environmental cues that organisms use to regulate their activities. Studies have begun to quantify the influence of ALAN on the behavior and ecology of organisms, but research on the effects at the molecular level remains limited. Mosquitoes in the Culex pipiens complex (Diptera, Culicidae) are widespread and abundant in urban areas where they are potential disease vectors. It is thus of particular interest to understand how ALAN may influence biologically and ecologically relevant traits.ResultsWe used RNAseq to evaluate the transcriptome response in a Cx. pipiens f. molestus laboratory population that was exposed to near-natural light conditions (light:dark L16:D8 hours, “control”) and ALAN conditions with 3 h of constant low-level light at night (L16 + Llow3:D5 hours, “low-light”). The resulting transcripts were mapped to the reference genome of the closely related Culex quinquefasciatus. Female expression patterns differed significantly between control and treatment conditions at five genes although none showed an absolute fold change greater than two (FC > 2). In contrast, male expression differed at 230 genes (74 with FC > 2). Of these, 216 genes (72 with FC > 2) showed reduced expression in the low-light treatment, most of which were related to gametogenesis, lipid metabolism, and immunity. Of the 14 genes (two with FC > 2) with increased expression, only five had any functional annotation. There was a pronounced sex-bias in gene expression regardless of treatment, with 11,660 genes (51 % of annotated genes; 8694 with FC > 2; 48 % of annotated genes) differentially expressed between males and females, including 14 genes of the circadian clock.ConclusionOur data suggest a stronger response to artificial light by males of Cx. pipiens f. molestus than by females, and that a wide range of physiological pathways may be affected by ALAN at the molecular level. The fact that differences in gene expression appear to be sex-specific may have a strong influence at the population level.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-2336-0) contains supplementary material, which is available to authorized users.

Artificial light at night decreases biomass and alters community composition of benthic primary producers in a sub‐alpine stream

“…The use of ALAN is increasing worldwide and therefore the ecological consequences of light pollution are increasing as well (Pawson and Bader ). It is known that ALAN affects aquatic microorganisms (Poulin et al ; Hölker et al ), insects (Perkin et al b ; Honnen et al ), and fish (Riley et al ; Brüning et al ). Our study shows that artificial nocturnal illumination, with white LED, can also influence biomass and community composition of aquatic primary producers, the basal food resource for consumers.…”

“…So far, ecological effects of ALAN have been commonly examined at the level of single species (Gaston et al ) while fewer studies address higher ecological levels such as communities or ecosystems functions (e.g., Davies et al ; Becker et al ; Meyer and Sullivan ). Moreover, studies of ecological effects of ALAN have largely focused on terrestrial habitats, while the interest in aquatic systems is relatively recent (Perkin et al a ; Brüning et al ; Hölker et al ; Honnen et al ) despite the fact that freshwaters are often exposed to ALAN from adjacent urban and sub‐urban areas (Ceola et al ).…”

The impact of artificial light at night on nocturnal insects: A review and synthesis

“…Exposure to artificial light in the laboratory inhibits a variety of biological processes in nocturnal insects (e.g., Botha, Jones, & Hopkins, 2017), possibly due to a buildup of melatonin (Honnen, Johnston, & Monaghan, 2016;Jones, Durrant, Michaelides, & Green, 2015). In moths, constant light can inhibit female sex pheromone release (Fatzinger, 1973;Geffen, Groot, et al, 2015;Sower, Shorey, & Gaston, 1970), reduce male attraction (Geffen, Eck, et al, 2015), induce male sterility (Bebas, Cymborowski, & Giebultowicz, 2001;Giebultowicz, 2001;Riemann, Johnson, & Thorson, 1981), and disrupt female oviposition (Yamaoka & Hirao, 1981).…”

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).…”