Celine Le Bohec

Monaco Scientific Centre | CSM · Polar Biology Department

Gene expression can accelerate ecological divergence by rapidly tweaking the response of an organism to novel environments, with more divergent environments exerting stronger selection and supposedly, requiring faster adaptive responses. Organisms adapted to extreme environments provide ideal systems to test this hypothesis, particularly when compa...

Introductory paragraph Advances in medicine and food security have contributed to an increase in human lifespan ¹ . Yet, the associated rise in sedentary behaviour and in obesity 2,3 already threatens these gains ⁴ . Indeed, a growing body of evidence supports the central role of nutrient sensing and energy management pathways in regulating ageing...

New data from Adélie Land reveals that similar declines in the survival of juvenile Adélie penguins have emerged at distant locations around Antarctica, and receding sea ice could be at play.

Emperor penguins (Aptenodytes forsteri) are under increasing environmental pressure. Monitoring colony size and population trends of this Antarctic seabird relies primarily on satellite imagery recorded near the end of the breeding season, when light conditions levels are sufficient to capture images, but colony occupancy is highly variable. To cor...

Suspected cases of Highly Pathogenic Avian Influenza (H5N1) were detected in Adelie penguins and Antarctic shags at the southernmost latitude so far in Antarctica, at two breeding sites out of 13 visited, using highly specific PCR assay. These first records mark the progression of the H5N1 panzootic into Antarctica.

Like many polar animals, emperor penguin populations are challenging to monitor because of the species' life history and remoteness. Consequently, it has been difficult to establish its global status, a subject important to resolve as polar environments change. To advance our understanding of emperor penguins, we combined remote sensing, validation...

Gene expression can accelerate ecological divergence by rapidly tweaking the response of an organism to novel environments, with more divergent environments exerting stronger selection and, supposedly, requiring faster adaptive responses. Organisms adapted to extreme environments provide ideal systems to test this hypothesis, particularly when comp...

Emperor penguins are one of the seabird species most vulnerable to climate change in Antarctica, as they depend on stable sea ice for breeding and molting. Recent extremes of warming have taken to the lowest records of sea ice in West Antarctica in 2022 and 2023, raising concerns to the extent that emperor penguins have been affected. We evaluated...

Emperor penguins ( Aptenodytes forsteri ) are under increasing environmental pressure. Monitoring colony size and trends of this Antarctic seabird relies primarily on satellite imagery recorded near the end of the breeding season, when illumination levels are sufficient to capture images, but colony occupancy is highly variable. To correct populati...

Automatic monitoring of wildlife is becoming a critical tool in the field of ecology. In particular, Radio‐Frequency IDentification (RFID) is now a widespread technology to assess the phenology, breeding and survival of many species. While RFID produces massive datasets, no established fast and accurate methods are yet available for this type of da...

Purifying selection is the most pervasive type of selection, as it constantly removes deleterious mutations arising in populations, directly scaling with population size. Highly expressed genes appear to accumulate fewer deleterious mutations between divergent species' lineages, pointing towards gene expression as an additional driver of purifying...

Automatic monitoring of wildlife is becoming a critical tool in the field of ecology. In particular, Radio-Frequency IDentification (RFID) is now a widespread technology to assess the phenology, breeding, and survival of many species. While RFID produces massive datasets, no established fast and accurate methods are yet available for this type of d...

Systematic long-term studies on ecosystem dynamics are largely lacking from the East Antarctic Southern Ocean, although it is well recognized that they are indispensable to identify the ecological impacts and risks of environmental change. Here, we present a framework for establishing a long-term cross-disciplinary study on decadal timescales. We a...

To protect the unique and rich biodiversity of the Southern Ocean, conservation measures such as marine protected areas (MPAs) have been implemented. Currently, the establishment of several additional protection zones is being considered based on the known habitat distributions of key species of the ecosystems including emperor penguins and other m...

An increasing number of marine animals are equipped with biologgers, to study their physiology, behaviour and ecology, often for conservation purposes. To minimise the impacts of biologgers on the animals’ welfare, the Refinement principle from the Three Rs framework (Replacement, Reduction, Refinement) urges to continuously test and evaluate new a...

Microplastic (<5 mm; MP) pollution has been an emerging threat for marine ecosystems around the globe with increasing evidence that even the world's most remote areas, including Antarctica, are no longer unaffected. Few studies however, have examined MP in Antarctic biota, and especially those from Antarctic regions with low human activity, meaning...

Systematic long-term studies on ecosystem dynamics are largely lacking for the East Antarctic Southern Ocean, although it is well recognized that such investigations are indispensable to identify the ecological impacts and risks of environmental change. Therefore, here we develop a framework for establishing a long-term cross-disciplinary study and...

Although mitochondrial DNA has been widely used in phylogeography, evidence has emerged that factors such as climate, food availability, and environmental pressures that produce high levels of stress can exert a strong influence on mitochondrial genomes, to the point of promoting the persistence of certain genotypes in order to compensate for the m...

The eco-evolutionary history of penguins is profoundly influenced by their shift from temperate to cold environments. Breeding only in Antarctica during the winter, the Emperor penguin appears as an extreme outcome of this process, with unique features related to insulation, heat production and energy management. However, whether this species actua...

Reproductive success can improve with experience, which increases with age in many long-lived species. Signals that provide reliable information about age are therefore of importance for mate choice and consequently are under sexual selection. In birds, these are often vocal signals as well as visual signals in the form of plumage coloration. King...

An increasing number of marine animals are equipped with biologgers, to study their physiology, behaviour and ecology, often for conservation purposes. To minimise the impacts of biologgers on the animals′ welfare, the Refinement principle from the Three Rs framework (Replacement, Reduction, Refinement) urges to continuously test and evaluate new a...

The period of emancipation, when juvenile seabirds change from a terrestrial existence to a life at sea, is associated with many challenges. Apart from finding favourable foraging sites, they have to develop effective prey search patterns and physiological capacities that enable them to capture sufficient prey to meet their energetic needs. Animals...

To protect the unique Southern Ocean biodiversity, conservation measures like marine protected areas (MPAs) are implemented based on the known habitat distribution of ecologically important species. However, distribution models focus on adults, neglecting that immatures animals can inhabit vastly different areas. Here, we show that current conserva...

Penguins are the only extant family of flightless diving birds. They currently comprise at least 18 species, distributed from polar to tropical environments in the Southern Hemisphere. The history of their diversification and adaptation to these diverse environments remains controversial. We used 22 new genomes from 18 penguin species to reconstruc...

Camera traps for motion-triggered or continuous time-lapse recordings are readily available on the market. For demanding applications in ecology and environmental sciences, however, commercial systems often lack flexibility to freely adjust recording time intervals, suffer from mechanical component wear, and can be difficult to combine with auxilia...

Aim The conservation of biodiversity is hampered by data deficiencies, with many new species and subspecies awaiting description or reclassification. Population genomics and ecological niche modelling offer complementary new tools for uncovering functional units of phylogenetic diversity. We hypothesize that phylogenetically delineated lineages of...

Over evolutionary time, pathogen challenge shapes the immune phenotype of the host to better respond to an incipient threat. The extent and direction of this selection pressure depends on the local pathogen composition, which is in turn determined by biotic and abiotic features of the environment. However, little is known about adaptation to local...

Background: The astonishing variety of sounds that birds can produce has been the subject of many studies aiming to identify the underlying anatomical and physical mechanisms of sound production. An interesting feature of some bird vocalisations is the simultaneous production of two different frequencies. While most work has been focusing on songb...

Like all birds, penguins undergo periodic molt, during which they replace old feathers. However, unlike other birds, penguins replace their entire plumage within a short period while fasting ashore. During molt, king penguins (Aptenodytes patagonicus) lose half of their initial body mass, most importantly their insulating subcutaneous fat and half...

We argue the need to improve climate change forecasting for ecology, and importantly, how to relate long-term projections to conservation. As an example, we discuss the need for effective management of one species, the emperor penguin, Aptenodytes forsteri. This species is unique amongst birds in that its breeding habit is critically dependent upon...

Camera images and video recordings are simple and non-invasive tools to investigate animals in their natural habitat. Quantitative evaluations, however, often require an exact reconstruction of object positions, sizes, and distances in the image. Here, we provide an open source software package to perform such calculations. Our approach allows the...

The view from the south is, more than ever, dominated by ominous signs of change. Antarctica and the Southern Ocean are intrinsic to the Earth system, and their evolution is intertwined with and influences the course of the Anthropocene. In turn, changes in the Antarctic affect and presage humanity's future. Growing understanding is countering popu...

The view from the south is, more than ever, dominated by ominous signs of change. Antarctica and the Southern Ocean are intrinsic to the Earth system, and their evolution is intertwined with and influences the course of the Anthropocene. In turn, changes in the Antarctic affect and presage humanity's future. Growing understanding is countering popu...

While migratory seabirds dominate ecotoxicological studies within the Arctic, there is limited knowledge about exposure and potential effects from circulating legacy and emerging contaminants in species who reside in the high-Arctic all year round. Here, we focus on the case of the Mandt's Black guillemot (Cepphus grylle mandtii) breeding at Kongsf...

The upwelling hypothesis has been proposed to explain reduced or lack of population structure in seabird species specialized in food resources available at cold-water upwellings. However, population genetic structure may be challenging to detect in species with large population sizes, since variation in allele frequencies are more robust under gene...

Microsatellites analyzed for Humboldt penguins: Range of fragment size in base pairs (bp) (S), annealing temperature (AT), total number of alleles (Na), expected (He) and observed heterozygosity (Ho), Chi-Square from Hardy-Weinberg Equilibrium (HWE), probability from HWE (p). (DOCX)

Hardy-Weinberg test to each locus from colonies of Humboldt penguin at Pacific coast. (DOCX)

Discriminant function DAPC from Humboldt penguin, based on 10 microsatellites. (DOCX)

Pairwise RST based on genotypes of 10 microsatellite loci (below) and Nm based on RST (above) for Humboldt penguins. Significant values (P<0.05) are in bold. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta...

Sex ratio of Humboldt penguin for each colony at Pacific coast. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Frequency of migrant male and female from first generation among colonies, and in gray proportion of philopatric rate. CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Skyline plot of Humboldt penguin from Pacific coast to D-loop mtDNA and RAG1 nDNA. (DOCX)

Bottleneck summary results from SMM, IAM and TPM mutation model through Wilcoxon test, mean heterozygosity (He); mean k. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Results delta K´Evano implemented by Haverst web. (DOCX)

MicrossatelitesHumboldtPenguindataset- complete microsatellites data set for Humboldt penguin. (TXT)

Pairwise ϕST based on mtDNA (below) and RAG1 (above) for Humboldt penguins. Significant values (P<0.05) are in bold. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Number of migrants of Humboldt penguin estimated based on RST from 9 microsatellites. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Bayesian STRUCTURE of the Humboldt penguin, delta K = 2 and K = 3, using admixture and no-admixture model. (DOCX)

In less than one century, the once-abundant Peruvian diving petrel has become the first endangered seabird of the Humboldt Current System (HCS). This small endemic petrel of the South American Pacific coast is now an important indicator of ongoing habitat loss and of the success of local conservation policies in the HCS - an ecoregion designated as...

Darwin’s finches are an iconic example of adaptive radiation. The size and shape of the beaks of different finch species are diversified for feeding on different size seeds and other food resources. However, beaks also serve other functions, such as preening for the control of ectoparasites. In diverse groups of birds, the effectiveness of preening...

Emperor penguins (Aptenodytes forsteri) are highly adapted to the harsh conditions of the Antarctic winter: they are able to fast for up to 134 days during breeding. To conserve energy, emperor penguins form tight groups (huddles), which is key for their reproductive success. The effect of different meteorological factors on the huddling behaviour,...

During breeding, king penguins do not build nests, however they show strong territorial behaviour and keep a pecking distance to neighbouring penguins. Penguin positions in breeding colonies are highly stable over weeks and appear regularly spaced, but thus far no quantitative analysis of the structural order inside a colony has been performed. In...

Range shift is the primary short-term species response to rapid climate change, but it is often hampered by natural or anthropogenic habitat fragmentation. Different critical areas of a species’ niche may be exposed to heterogeneous environmental changes and modelling species response under such complex spatial and ecological scenarios presents wel...

In the context of sexual selection, animals have developed a variety of cues conveying information about the sex of an individual to conspecifics. In many colonial seabird species, where females and males are monomorphic and do not show obvious differences in external morphology, acoustic cues are an important signal for individual and sex recognit...

1. Long-term photographic recordings of animal populations provide unique insights in ecological and evolutionary processes. However, image acquisition at remote locations under harsh climatic conditions is highly challenging. 2. We present a robust, energetically self-sufficient and remote-controlled observatory designed to operate year-round in...

La recherche et le développement de techniques de pointe nous permettent d’observer la nature et la faune sauvage en toute discrétion et en toute intimité. Les objets connectés donnent accès à des données inédites, inaccessibles jusqu'à présent du fait de fortes contraintes logistiques, de performances trop faibles, ou bien encore de biais inhérent...

King penguin colonies present an acoustically rich environment due to the highly vocal nature of these birds and the large abundance of birds within a colony (100.000 + ). Individual identification in adults and chicks is based on vocal signals. Penguins can recognize the call of their partner or chick even among thousands of calling individuals. H...

Little is known about the early life at sea of marine top predators, like deep-diving king penguins (Aptenodytes patagonicus), although this dispersal phase is probably a critical phase in their life. Apart from finding favourable foraging sites, they have to develop effective prey search patterns as well as physiological capacities that enable the...

The Strategic Plan for Biodiversity, adopted under the auspices of the Convention on Biological Diversity, provides the basis for taking effective action to curb biodiversity loss across the planet by 2020—an urgent imperative. Yet, Antarctica and the Southern Ocean, which encompass 10% of the planet’s surface, are excluded from assessments of prog...

Range shift is the primary short-term response of species to rapid climate change but it is hampered by natural or anthropogenic habitat fragmentation. Fragmented habitats expose different critical areas of a species niche to heterogeneous environmental changes resulting in uncoupled effects. Modelling species distribution under complex real-life s...

Defining reliable demographic models is essential to understand the threats of ongoing environmental change. Yet, in the most remote and threatened areas, models are often based on the survey of a single population, assuming stationarity and independence in population responses. This is the case for the Emperor penguin Aptenodytes forsteri, a flags...

The variability in individual fitness within a population is likely to be mediated through individual foraging ability and tactics, themselves linked to age- or experience-related processes, but also to differences in individual quality. Not only age, experience, and quality but also sex-related foraging strategies should particularly play an impor...

Growing evidence suggests that telomeres, non-coding DNA sequences that shorten with age and stress, are related in an undefined way to individual breeding performances and survival rates in several species. Short telomeres and elevated shortening rates are typically associated with life stress and low health. As such, telomeres could serve as an i...

According to life-history theory, individuals are expected to maximize their number of offspring while minimizing costs on their survival. In long-lived species, breeding season usually occurs once a year and mature individuals can therefore breed every year. However, several strategies are found among these species, breeding attempts regularly occ...

How genetic diversity is maintained in philopatric colonial systems remains unclear, and understanding the dynamic balance of philopatry and dispersal at all spatial scales is essential to the study of the evolution of coloniality. In the King penguin, Aptenodytes patagonicus, return rates of post-fledging chicks to their natal sub-colony are remar...