I am a postoctoral researcher. My research mainly focusses on the effects of urbanisation on wildlife from an ecophysiological and evolutionary point of view.
2016-Now : Metals, Oxidative stress & Telomeres in great and blue tits
I am currently working at the Wild Urban Evolutionary & Ecology Lab (Center of New Technologies; University of Warsaw). Environmental disturbances can trigger new selective pressures, especially in urban areas in which human activities are likely to have the most drastic impacts. Chemical pollution such as trace metals are of particularly timely concern given their implication in several human diseases and their noxious effect on wildlife. I am testing whether oxidative stress 1) covaries with urbanisation level and 2) is associated with trace metal exposure. I am also investigating the effect of oxidative stress and trace metal exposure on great tit fitness parameters, telomere length and on genomic variation. This project is financed by a Polonez grant (Marie Curie cofund).
2015-2016 : Dispersal & Habitat choice in earthworms
Between 2015-2016, I had an assistant lecturer position at the Pierre & Marie Curie University. My research in the Institute of Ecology and Environmental Sciences aimed at investigating dispersal and habitat choice in earthworm in a context of urbanisation.
Dispersal is an ecological process that enables organisms to colonize new habitats and have access to resources which availability differ with time and space. Therefore, dispersal capacity shapes the capacity of an individual to escape a low quality habitat. Investigating dispersal behaviour is necessary to understand population dynamics and community structures. I experimentally demonstrated the importance of habitat quality and population density in the departure choice of epigeic earthworms (Chatelain & Mathieu 2017 Soil Biology and Biochemistry). My results also show that dispersal behaviour is highly variable between species, suggesting different evolutionary histories between species (for example due to different degrees of exposure to environmental disturbances).
Soil pollution due to anthropogenic activities is a relatively new but a significant disturbance to soil ecosystems. I tested experimentally the effects of trace metal concentrations in urban soils on habitat choice of three species of endogeic earthworms that originate either from an urban or a rural environment, to test whether 1) earthworms choose their habitat according to metal levels in the soil, and 2) metal accumulation and survival differ between urban and rural earthworms (in prep.). At the same time, I carried out a correlative study to understand how earthworms communities composition is shaped by trace metal concentrations in the soil of the parisian garden (analyses ongoing).
2012-2015: Metals & Plumage melanism in the feral pigeon
During my PhD (2012-2015), my research aimed at explaining melanin-based plumage polymorphism. More specifically, I tested the beneficial role of melanism in coping with high levels of trace metals.
Lead and zinc are the most abundant metal in urban areas. Understanding their effects on wildlife is a main challenge of the 21st century. I experimentally showed that lead exposure has consistent negative effects on the reproduction success (Chatelain et al. 2015 Global Change Biology, independently of parental hormones Chatelain et al. 2018 Ecotoxicology & Environmental safety), on some parameters of the immune response (Chatelain et al. 2016 Ecotoxicology) and on the transfer of antibodies into the eggs (Chatelain et al. 2016 Physiological and Biochemial Zoology) in the feral pigeon. On the contrary, zinc has positive effects on bird reproduction and physiology, and also compensates lead detrimental effects.
Interestingly, I found that zinc and lead concentrations in the feathers of the feral pigeon (Columba livia) increase with increasing plumage darkness. This result suggests that eumelanin, the pigment responsible for the black colouration of plumage, coat and skin in numerous animals, could allow animals to detoxify themselves by transferring a part of the metals circulating in their bloodstream in their feathers (Chatelain et al. 2014 Biology letters, Chatelain et al. 2015 Global Change Biology). Accordingly, juveniles exposed to lead are darker than their counterparts raised in a metal-free environment, suggesting a higher survival of dark pigeons compared to pale pigeons (Chatelain et al. 2015 Global Change Biology).
Altogether, those results suggest that melanism could be selected in urban area because of the higher ability of melanistic birds to cope with the deleterious effects of some trace metals. Thus, this mechnism could explain the higher frequency of dark pigeons in cities than in rural environments.
2012: The evolution of aposematism
During my master's internship (2012) in the Center for Behaviour and Evolution (Institute of Neuroscience, Newcastle University), supervised by Candy Rowe, I identified some parameters influencing predators' motivation to consume aposematic* and mimetic** prey. To do so, I carried out experimental studies on starlings (Sturnus vulgaris). First we showed that predation pressure on aposematic prey increases when decreasing temperature (Chatelain et al. 2013). This study gives an interesting answer to the temporal and geographical distribution of aposematic species. Second, we showed that predation pressure on the aposematic-mimic pair increases with increasing the nutrious content of the mimic. This result highlights the parasitic interaction between an aposematic species and its mimic when the two species have different nutritional values.
*aposematism is a defensive strategy that associates a conspicuous phenotype and the production of toxic compounds.
** a mimetic species is a species displaying a similar phenotype (i.e. shape, colouration or behaviour) as another species. In this case, the mimetic species exhibits the same conspicious phenotype as the aposematic species bus does not produce any toxic compounds.