Maxime Pineaux, Thomas Merkling, Etienne Danchin, Scott Hatch, David Duneau, Pierrick Blanchard, Sarah Leclaire. (2020). Sex and hatching order modulate the association between MHC-II diversity and fitness in early-life stages of a wild seabird (Vol. 29).
Abstract: Genes of the major histocompatibility complex (MHC) play a pivotal role in parasite resistance, and their allelic diversity has been associated with fitness variations in several taxa. However, studies report inconsistencies in the direction of this association, with either positive, quadratic or no association being described. These discrepancies may arise because the fitness costs and benefits of MHC diversity differ among individuals depending on their exposure and immune responses to parasites. Here, we investigated in black-legged kittiwake (Rissa tridactyla) chicks whether associations between MHC class-II diversity and fitness vary with sex and hatching order. MHC-II diversity was positively associated with growth and tick clearance in female chicks, but not in male chicks. Our data also revealed a positive association between MHC-II diversity and survival in second-hatched female chicks (two eggs being the typical clutch size). These findings may result from condition-dependent parasite infections differentially impacting sexes in relation to hatching order. We thus suggest that it may be important to account for individual heterogeneities in traits that potentially exert selective pressures on MHC diversity in order to properly predict MHC–fitness associations.
Keywords: divergent allele advantage fitness heterozygote advantage immunity Ixodes uriae parasite-mediated selection
Programme: 1162
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Estelle Cateau, Antoine Leclerc, Noémie Cartier, Isabel Valsecchi, Éric Bailly, Ronan Le Senechal, Margaux Becerra, Brice Le Gallou, Rose-Anne Lavergne, Adélaïde Chesnay, Jean-Patrice Robin, Carolyn Cray, Nicolas Goddard, Milan Thorel, Jacques Guillot, Baptiste Mulot, Guillaume Desoubeaux. (2022). Aspergillosis in a colony of Humboldt penguins (Spheniscus humboldti) under managed care: a clinical and environmental investigation in a French zoological park (Vol. 60).
Abstract: Aspergillosis is pervasive in bird populations, especially those under human care. Its management can be critically impacted by exposure to high levels of conidia and by resistance to azole drugs. The fungal contamination in the environment of a Humboldt penguin (Spheniscus humboldti) group, housed in a French zoological park next to numerous large crop fields, was assessed through three serial sessions of surface sampling in nests, in 2018–20: all isolates were counted and characterized by sequencing. When identified as Aspergillus fumigatus, they were systematically screened for resistance mutations in the cyp51A gene and tested for minimal inhibitory concentrations (MICs) determination. At the same time, the clinical incidence of aspergillosis was evaluated in the penguin population by the means of systematic necropsy and mycological investigations. A microsatellite-based analysis tracked the circulation of A. fumigatus strains. Environmental investigations highlighted the substantial increase of the fungal load during the summer season (>12-fold vs. the other timepoints) and a large overrepresentation of species belonging to the Aspergillus section Fumigati, ranging from 22.7 to 94.6% relative prevalence. Only one cryptic species was detected (A. nishimurae), and one isolate exhibited G138S resistance mutation with elevated MICs. The overall incidence of aspergillosis was measured at ∼3.4% case-years, and mostly in juveniles. The analysis of microsatellite polymorphism revealed a high level of genetic diversity among A. fumigatus clinical isolates. In contrast, one environmental strain appeared largely overrepresented during the summer sampling session. In all, the rural location of the zoo did not influence the emergence of resistant strains.- The incidence of aspergillosis in the penguin population of a French zoo was found elevated, mostly in juveniles.- The fungal contamination was high in the surrounding environment, especially at the end of summer.- Globally, a great level of genetic diversity was observed, except for one clonal strain.
Programme: 119
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Philip Bertrand, Joël Bêty, Nigel G. Yoccoz, Marie-Josée Fortin, Hallvard Strøm, Harald Steen, Jack Kohler, Stephanie M. Harris, Samantha C. Patrick, Olivier Chastel, P. Blévin, Haakon Hop, Geir Moholdt, Joséphine Maton, Sébastien Descamps. (2021). Fine-scale spatial segregation in a pelagic seabird driven by differential use of tidewater glacier fronts (Vol. 11).
Abstract: In colonially breeding marine predators, individual movements and colonial segregation are influenced by seascape characteristics. Tidewater glacier fronts are important features of the Arctic seascape and are often described as foraging hotspots. Albeit their documented importance for wildlife, little is known about their structuring effect on Arctic predator movements and space use. In this study, we tested the hypothesis that tidewater glacier fronts can influence marine bird foraging patterns and drive spatial segregation among adjacent colonies. We analysed movements of black-legged kittiwakes (Rissa tridactyla) in a glacial fjord by tracking breeding individuals from five colonies. Although breeding kittiwakes were observed to travel up to ca. 280 km from the colony, individuals were more likely to use glacier fronts located closer to their colony and rarely used glacier fronts located farther away than 18 km. Such variation in the use of glacier fronts created fine-scale spatial segregation among the four closest (ca. 7 km distance on average) kittiwake colonies. Overall, our results support the hypothesis that spatially predictable foraging patches like glacier fronts can have strong structuring effects on predator movements and can modulate the magnitude of intercolonial spatial segregation in central-place foragers.
Keywords: Behavioural ecology Biogeography
Programme: 330
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Stephanie Jenouvrier, Judy Che-Castaldo, Shaye Wolf, Marika Holland, Sara Labrousse, Michelle LaRue, Barbara Wienecke, Peter Fretwell, Christophe Barbraud, Noah Greenwald, Julienne Stroeve, Philip N. Trathan. (2021). The call of the emperor penguin: Legal responses to species threatened by climate change (Vol. 27).
Abstract: Species extinction risk is accelerating due to anthropogenic climate change, making it urgent to protect vulnerable species through legal frameworks in order to facilitate conservation actions that help mitigate risk. Here, we discuss fundamental concepts for assessing climate change risks to species using the example of the emperor penguin (Aptenodytes forsteri), currently being considered for protection under the US Endangered Species Act (ESA). This species forms colonies on Antarctic sea ice, which is projected to significantly decline due to ongoing greenhouse gas (GHG) emissions. We project the dynamics of all known emperor penguin colonies under different GHG emission scenarios using a climate-dependent meta-population model including the effects of extreme climate events based on the observational satellite record of colonies. Assessments for listing species under the ESA require information about how species resiliency, redundancy and representation (3Rs) will be affected by threats within the foreseeable future. Our results show that if sea ice declines at the rate projected by climate models under current energy system trends and policies, the 3Rs would be dramatically reduced and almost all colonies would become quasi-extinct by 2100. We conclude that the species should be listed as threatened under the ESA.
Keywords: climate risk assessments Endangered Species Act foreseeable future population projections redundancy and representation (3Rs) resiliency sea ice projections species distribution treatment of scientific uncertainty
Programme: 109
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Anaïs Janc, Christophe Guinet, David Pinaud, Gaëtan Richard, Pascal Monestiez, Paul Tixier. (2021). Fishing behaviours and fisher effect in decision-making processes when facing depredation by marine predators (Vol. 28).
Abstract: Fishers aim to optimise cost–benefit ratios of their behaviour when exploiting resources. Avoidance of interactions with marine predators (i.e. their feeding on catches in fishing gear, known as depredation) has recently become an important component of their decisions. How fishers minimise these interactions whilst maximising fishing success is poorly understood. This issue is addressed in a sub-Antarctic, long-line fishery confronted with extensive depredation by sperm whales Physeter macrocephalus and killer whales Orcinus orca by examining a 15-year data set. Whereas a broad range of behaviours was identified from spatio-temporal and operational descriptors, none combined high fishing success with low frequency of interactions. With experience, fishers favoured exploitation of productive patches with high frequencies of interactions over avoidance behaviours. Such decisions, although potentially optimal in the short term, are likely to intensify pressures on fish stocks and impact depredating whales. Therefore, the present study provides additional evidence to inform management decisions pertaining to the coexistence between fisheries and marine predators.
Keywords: experience individual perceptions optimal foraging theory skipper behaviour sustainability of fish stocks whale–fisheries interactions
Programme: 109
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Mathieu Casado, Amaelle Landais, Ghislain Picard, Laurent Arnaud, Giuliano Dreossi, Barbara Stenni, Frederic Prié. (2021). Water Isotopic Signature of Surface Snow Metamorphism in Antarctica (Vol. 48).
Abstract: Water isotope ratios of ice cores are a key source of information on past temperatures. Through fractionation within the hydrological cycle, temperature is imprinted in the water isotopic composition of snowfalls. However, this signal of climatic interest is modified after deposition when snow remains at the surface exposed to the atmosphere. Comparing time series of surface snow isotopic composition at Dome C with satellite observations of surface snow metamorphism, we found that long summer periods without precipitation favor surface snow metamorphism altering the surface snow isotopic composition. Using excess parameters (combining D,17O, and 18O fractions) allow the identification of this alteration caused by sublimation and condensation of surface hoar. The combined measurement of all three isotopic compositions could help identifying ice core sections influenced by snow metamorphism in sites with very low snow accumulation.
Keywords: excess Ice cores metamorhism Paleoclimate water isotopes
Programme: 1110
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Alexander Kokhanovsky, Simon Gascoin, Laurent Arnaud, Ghislain Picard. (2021). Retrieval of Snow Albedo and Total Ozone Column from Single-View MSI/S-2 Spectral Reflectance Measurements over Antarctica (Vol. 13).
Abstract: We proposed a simple algorithm to retrieve the total ozone column and snow properties (spectral albedo and effective light absorption path) using the high spatial resolution single–view MSI/S-2 measurements over Antarctica. In addition, the algorithm allows the retrieval of the snow grain size on a scale of 10–20 m. This algorithm should be useful for the understanding of intra-pixel total ozone and snow albedo variability in complement to satellite observations performed on a much coarser spatial resolution scale (0.3–1 km and even larger spatial scales).
Keywords: albedo inverse problems light scattering radiative transfer snow snow grain size
Programme: 1110
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M. Paar, B. Lebreton, M. Graeve, M. Greenacre, R. Asmus, H. Asmus. (2019). Food sources of macrozoobenthos in an Arctic kelp belt: trophic relationships revealed by stable isotope and fatty acid analyses (Vol. 615).
Abstract: Arctic kelp belts, made of large perennial macroalgae of the order Laminariales, are expanding because of rising temperatures and reduced sea ice cover of coastal waters. In summer 2013, the trophic relationships within a kelp belt food web in Kongsfjorden (Spitsbergen) were determined using fatty acid and stable isotope analyses. Low relative proportions of Phaeophyta fatty acid trophic markers (i.e. 20:4(n-6), 18:3(n-3) and 18:2(n-6)) in consumers (3.3-8.9%), as well as low 20:4(n-6)/20:5(n-3) ratios (<0.1-0.6), indicated that Phaeophyta were poorly used by macrozoobenthos as a food source, either fresh or as detritus. Relatively high δ13C values measured in macrozoobenthos (-22.5 to -16.1‰) ruled out an important role of erect Rhodophyta, which were much more 13C depleted (-37.1 to -35.8‰). Instead, δ13C values and relatively high abundances of typical diatom (14:0, 16:1(n-7), 20:5(n-3)) and flagellate (18:4(n-3), 22:6(n-3)) fatty acid trophic markers in consumers pointed out an important use of microalgae, likely of pelagic and benthic origin (i.e. senescent phytoplankton bloom, eroded epiphytes and suspended epilithic material). The use of these food resources may be fostered by their trapping under the kelp canopy.
Keywords: Detritus Food web Macroalgae Macrofauna Polar coastal ecosystem Trophic markers
Programme: 1190
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Thomas G Wilson, Elisa Goffo, Yann Alibert, Davide Gandolfi, Andrea Bonfanti, Carina M Persson, Andrew Collier Cameron, Malcolm Fridlund, Luca Fossati, Judith Korth, Willy Benz, Adrien Deline, Hans-Gustav Florén, Pascal Guterman, Vardan Adibekyan, Matthew J Hooton, Sergio Hoyer, Adrien Leleu, Alexander James Mustill, Sébastien Salmon, Sérgio G Sousa, Olga Suarez, Lyu Abe, Abdelkrim Agabi, Roi Alonso, Guillem Anglada, Joel Asquier, Tamas Bárczy, David Barrado Navascues, Susana C C Barros, Wolfgang Baumjohann, Mathias Beck, Thomas Beck, Nicolas Billot, Xavier Bonfils, Alexis Brandeker, Christopher Broeg, Edward M Bryant, Matthew R Burleigh, Marco Buttu, Juan Cabrera, Sébastien Charnoz, David R Ciardi, Ryan Cloutier, William D Cochran, Karen A Collins, Knicole D Colón, Nicolas Crouzet, Szilard Csizmadia, Melvyn B Davies, Magali Deleuil, Laetitia Delrez, Olivier Demangeon, Brice-Olivier Demory, Diana Dragomir, Georgina Dransfield, David Ehrenreich, Anders Erikson, Andrea Fortier, Tianjun Gan, Samuel Gill, Michaël Gillon, Crystal L Gnilka, Nolan Grieves, Sascha Grziwa, Manuel Güdel, Tristan Guillot, Jonas Haldemann, Kevin Heng, Keith Horne, Steve B Howell, Kate G Isaak, Jon M Jenkins, Eric L N Jensen, Laszlo Kiss, Gaia Lacedelli, Kristine Lam, Jacques Laskar, David W Latham, Alain Lecavelier des Etangs, Monika Lendl, Kathryn V Lester, Alan M Levine, John Livingston, Christophe Lovis, Rafael Luque, Demetrio Magrin, Wenceslas Marie-Sainte, Pierre F L Maxted, Andrew W Mayo, Brian McLean, Marko Mecina, Djamel Mékarnia, Valerio Nascimbeni, Louise D Nielsen, Göran Olofsson, Hugh P Osborn, Hannah L M Osborne, Roland Ottensamer, Isabella Pagano, Enric Pallé, Gisbert Peter, Giampaolo Piotto, Don Pollacco, Didier Queloz, Roberto Ragazzoni, Nicola Rando, Heike Rauer, Seth Redfield, Ignasi Ribas, George R Ricker, Martin Rieder, Nuno C Santos, Gaetano Scandariato, François-Xavier Schmider, Richard P Schwarz, Nicholas J Scott, Sara Seager, Damien Ségransan, Luisa Maria Serrano, Attila E Simon, Alexis M S Smith, Manfred Steller, Chris Stockdale, Gyula Szabó, Nicolas Thomas, Eric B Ting, Amaury H M J Triaud, Stéphane Udry, Vincent Van Eylen, Valérie Van Grootel, Roland K Vanderspek, Valentina Viotto, Nicholas Walton, Joshua N Winn. (2022). A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterized with CHEOPS (Vol. 511).
Abstract: We report the discovery and characterization of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in the Transiting Exoplanet Survey Satellite (TESS) photometry. To characterize the system, we performed and retrieved the CHaracterising ExOPlanets Satellite (CHEOPS), TESS, and ground-based photometry, the High Accuracy Radial velocity Planet Searcher (HARPS) high-resolution spectroscopy, and Gemini speckle imaging. We characterize the host star and determine $T{\rm eff, \star }=4734\pm 67\,\mathrm{ K}$, $R{\star }=0.726\pm 0.007\, \mathrm{ R}{\odot }$, and $M{\star }=0.748\pm 0.032\, \mathrm{ M}{\odot }$. We present a novel detrending method based on point spread function shape-change modelling and demonstrate its suitability to correct flux variations in CHEOPS data. We confirm the planetary nature of both bodies and find that TOI-1064 b has an orbital period of Pb = 6.44387 ± 0.00003 d, a radius of Rb = 2.59 ± 0.04 R⊕, and a mass of $M{\rm b} = 13.5{-1.8}^{+1.7}$ M⊕, whilst TOI-1064 c has an orbital period of $P{\rm c} = 12.22657^{+0.00005}_{-0.00004}$ d, a radius of Rc = 2.65 ± 0.04 R⊕, and a 3σ upper mass limit of 8.5 M⊕. From the high-precision photometry we obtain radius uncertainties of ∼1.6 per cent, allowing us to conduct internal structure and atmospheric escape modelling. TOI-1064 b is one of the densest, well-characterized sub-Neptunes, with a tenuous atmosphere that can be explained by the loss of a primordial envelope following migration through the protoplanetary disc. It is likely that TOI-1064 c has an extended atmosphere due to the tentative low density, however further radial velocities are needed to confirm this scenario and the similar radii, different masses nature of this system. The high-precision data and modelling of TOI-1064 b are important for planets in this region of mass–radius space, and it allow us to identify a trend in bulk density–stellar metallicity for massive sub-Neptunes that may hint at the formation of this population of planets.
Programme: 1066
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Alexander Winterl, Sebastian Richter, Aymeric Houstin, Anna P. Nesterova, Francesco Bonadonna, Werner Schneider, Ben Fabry, Céline Le Bohec, Daniel P. Zitterbart. (2020). micrObs – A customizable time-lapse camera for ecological studies (Vol. 8).
Abstract: 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 auxiliary sensors such as GPS, weather stations, or light sensors. We present a robust time-lapse camera system that has been operating continuously since 2013 under the harsh climatic conditions of the Antarctic and Subantarctic regions. Thus far, we have recorded over one million images with individual cameras. The system consumes 122 mW of power in standby mode and captures up to 200,000 high-resolution (16 MPix) images without maintenance such as battery or image memory replacement. It offers time-lapse intervals between 2 s and 1 h, low-light or night-time power saving, and data logging capabilities for additional inputs such as GPS and weather data.
Keywords: Automated camera system Collective behavior Ecology Image processing Remote sensing Wildlife monitoring
Programme: 137
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