Biology subjects

Cichon, M.

Publications and source records attributed to Cichon, M..

3 recordsLinked to original sources

bioRxiv2025

Artificial light at night consistently impacts avian physiology and behaviour: a meta-analysis

Artificial light at night (ALAN) is a major anthropogenic pressure across the tree of life, driving population declines in insects and reptiles. Avian responses to ALAN defy simple patterns, varying in direction and magnitude, and the consequences of these responses remain unresolved. We conducted a meta-analysis to test how ALAN alters physiological, behavioural and life history traits underpinning avian performance. We analysed 623 effect sizes from 36 studies in 30 species. We found consistent physiological and behavioural shifts under ALAN, while life-history traits were unaffected. ALAN disrupted molecular and endocrine processes, leading to reduced sleep, higher metabolic rate, and accelerated reproductive maturation. Behaviourally, daily activity was extended, with earlier onset, later offset, and increased nocturnal activity and foraging effort. ALAN effects were stronger in migratory species and more pronounced in adults and females than nestlings and males. Higher light intensities amplified activity shifts, ageing, and sleep disruption, whereas exposure below 2 lux had minimal impact. Birds appear to buffer ALAN effects through physiological and behavioural adjustments, minimising impacts on life-history traits, a paradox likely explained by phenotypic plasticity or evolutionary adaptation. We identified light intensity threshold and group-specific vulnerabilities, emphasizing the need for targeted conservation in our increasingly illuminated world.

ecology↗

bioRxiv2025

Awake and hungry: artificial light at night disrupts behaviour and reproductive ecology in a wild migratory bird

Artificial light at night (ALAN), a growing consequence of global urbanisation, disrupts natural light cues that regulate biological rhythms across taxa. However, the behavioural pathways linking ALAN exposure to broader ecological impacts remain poorly understood. Here, we experimentally introduced ALAN into nestboxes of a long-distance migratory bird, the collared flycatcher (Ficedula albicollis), breeding in Gotland, Sweden, to assess ALAN effects on development and reproductive ecology. Nestlings were exposed to ALAN from two days post-hatching until fledging, and we video-recorded parental and nestling activity over 24 hours on day 8 post-hatching. From a high-resolution behavioural dataset (32,100 nestling and 3,709 parental events), we found that ALAN-exposed nestlings begged more frequently and for longer at night compared to dark controls, revealing disrupted nocturnal behaviour. These effects cascaded to parental care: both females and males in ALAN nests extended their daily activity, initiating feeding earlier and terminating later, but traded off this extension by reducing their hourly feeding counts compared to parents in dark conditions. Consequently, nestlings under ALAN fledged at an older age and had a lower fledging rate after day eight post-hatching, despite no difference in total fledging numbers compared to controls. Our findings provide the first comprehensive experimental evidence that ALAN alters the behaviour of both parents alongside their offspring and reduces reproductive success in a long-distance migrant, a species group that increasingly encounters light pollution during nocturnal migration. ALAN, though directly affecting mainly nestlings and females in nestboxes, triggered socially-mediated responses that altered the circadian behaviour of entire bird families. This study underscores the need to consider behavioural disruption as a critical mechanism underlying the ecological impacts of ALAN in natural populations. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/658843v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@1808fborg.highwire.dtl.DTLVardef@1f5bfd1org.highwire.dtl.DTLVardef@104607borg.highwire.dtl.DTLVardef@5a3604_HPS_FORMAT_FIGEXP M_FIG Summary figure: Cascading effects of artificial light at night, an aspect of human-induced light pollution, on the behaviour and reproductive ecology of collared flycatchers C_FIG

ecology↗

bioRxiv2019

The great tit HapMap project: a continental-scale analysis of genomic variation in a songbird

A major aim of evolutionary biology is to understand why patterns of genomic diversity vary among populations and species. Large-scale genomic studies of widespread species are useful for studying how the environment and demographic history shape patterns of genomic divergence, and with the continually decreasing cost of sequencing and genotyping, such studies are now becoming feasible. Here, we carry out one of the most geographically comprehensive surveys of genomic variation in a wild vertebrate to date; the great tit (Parus major) HapMap project. We screened ca 500,000 SNP markers across 647 individuals from 29 populations, spanning almost the entire geographic range of the European great tit subspecies. We found that genome-wide variation was consistent with a recent colonisation across Europe from a single refugium in South-East Europe, with bottlenecks and reduced genetic diversity in island populations. Differentiation across the genome was highly heterogeneous, with clear "islands of differentiation" even among populations with very low levels of genome-wide differentiation. Low local recombination rate in the genome was a strong predictor of high local genomic differentiation (FST), especially in island and peripheral mainland populations, suggesting that the interplay between genetic drift and recombination is a key driver of highly heterogeneous differentiation landscapes. We also detected genomic outlier regions that were confined to one or more peripheral great tit populations, most likely as a result of recent directional selection at the range edges of this species. Haplotype-based measures of selection were also related to recombination rate, albeit less strongly, and highlighted population-specific sweeps that likely resulted from positive selection. These regions under positive selection contained candidate genes associated with morphology, thermal adaptation and colouration, providing promising avenues for future investigation. Our study highlights how comprehensive screens of genomic variation in wild organisms can provide unique insights into evolution.

evolutionary biology↗