Does exposure to artificial light at night impacts immunity and microbiome in natural populations of an amphibian?

The constant increase of urbanization and human activities worldwide is exposing animals and human to a multitude of stressful stimuli that disrupt physiological functions in organisms.

A major source of pollution nowadays, that affect 99% of the european territory and thus almost every organism in Europe, is light pollution (or ALAN, Artificial Light at Night).

Recent studies suggest that the immune function could be strongly disrupted by exposure to ALAN, but these results mostly comes from experimental studies conducted in laboratory conditions, and thus not realistic of real conditions of exposure to the light pollution.

Considering the current major biodiversity loss crisis, especially in amphibian taxa, it is crucial to know if the ability of wild organisms to mount appropriated immune respones and control infections is affected by this anthropic source of pollution.

Within an eco-immunological and One Health framework, this project has thus been designed to characterize for the first time, and totally in natura, the effects of ALAN on immunity, microbiome composition and infectious phenotype of a common nocturnal Vertebrate, the common toad (Bufo bufo).

Using 30 wild populations of common toads living on a natural gradient of exposure to ALAN in a french region, this project will characterize:(i) How exposure to ALAN impact toads immune phenotype, using multiple measures to precisely characterize the different immune components that may be differently affected. (ii) How exposure to ALAN impacts toads microbiome composition at the two main interfaces of skin and intestinal mucosa, characterizing bacterial and eukaryotic communities. (iii) If toads infectious phenotype is dependent of ALAN exposure, immune responses and microbiome composition - focussing on pathogens identified as a threat for amphibians in France.