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Yves Le Bras, Joffrey Jouma’a, Baptiste Picard, Christophe Guinet. (2016). How Elephant Seals (Mirounga leonina) Adjust Their Fine Scale Horizontal Movement and Diving Behaviour in Relation to Prey Encounter Rate (Vol. 11).
Abstract: Understanding the diving behaviour of diving predators in relation to concomitant prey distribution could have major practical applications in conservation biology by allowing the assessment of how changes in fine scale prey distribution impact foraging efficiency and ultimately population dynamics. The southern elephant seal (Mirounga leonina, hereafter SES), the largest phocid, is a major predator of the southern ocean feeding on myctophids and cephalopods. Because of its large size it can carry bio-loggers with minimal disturbance. Moreover, it has great diving abilities and a wide foraging habitat. Thus, the SES is a well suited model species to study predator diving behaviour and the distribution of ecologically important prey species in the Southern Ocean. In this study, we examined how SESs adjust their diving behaviour and horizontal movements in response to fine scale prey encounter densities using high resolution accelerometers, magnetometers, pressure sensors and GPS loggers. When high prey encounter rates were encountered, animals responded by (1) diving and returning to the surface with steeper angles, reducing the duration of transit dive phases (thus improving dive efficiency), and (2) exhibiting more horizontally and vertically sinuous bottom phases. In these cases, the distance travelled horizontally at the surface was reduced. This behaviour is likely to counteract horizontal displacement from water currents, as they try to remain within favourable prey patches. The prey encounter rate at the bottom of dives decreased with increasing diving depth, suggesting a combined effect of decreased accessibility and prey density with increasing depth. Prey encounter rate also decreased when the bottom phases of dives were spread across larger vertical extents of the water column. This result suggests that the vertical aggregation of prey can regulate prey density, and as a consequence impact the foraging success of SESs. To our knowledge, this is one of only a handful of studies showing how the vertical distributions and structure of prey fields influence the prey encounter rates of a diving predator.
Keywords: Foraging Predation Acceleration Animal behavior Predator-prey dynamics Seals Swimming Water columns
Programme: 109
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T. Ouisse, M. Laparie, M. Lebouvier, D. Renault. (2017). New insights into the ecology of Merizodus soledadinus, a predatory carabid beetle invading the sub-Antarctic Kerguelen Islands (Vol. 40).
Abstract: Our knowledge of the main determinants of invasion success is still incomplete. Among these factors, the effects of biological traits, including fecundity, longevity and dispersal in newly colonised regions, are pivotal. However, while numerous studies have considered ecological and evolutionary impacts of non-native species, their biology often remains understudied. Despite the continuous geographic expansion of Merizodus soledadinus (Coleoptera: Carabidae) at the Kerguelen Islands over recent decades, the main life-history parameters of this species are unknown. We determined adult longevity under controlled conditions, monitored seasonal activity through pitfall trappings, and analysed temporal variations of egg load and body reserves in field-collected individuals. The median adult life span (LT50) was 241 days, with maximum longevity of 710 days (N = 500). Females carried eggs throughout the year (8.94 ± 3.56 eggs per female), and it was not possible to pinpoint any clear egg-laying period. Year-round trappings demonstrated continuous activity of adults over seasons, with a peak during the austral summer that may arguably be associated with higher temperatures. Body stores (glycogen and proteins) did not vary significantly through the year, suggesting that adults feed continuously despite different prey availability between summer and winter, possibly via diet shifts. The amount of triglycerides increased at onset of summer, which may be associated with higher summer locomotor activity and/or more intense predation and reproduction.
Programme: 136
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David Renault, Mathieu Laparie, Shannon J. McCauley, Dries Bonte. (2018). Environmental Adaptations, Ecological Filtering, and Dispersal Central to Insect Invasions (Vol. 63).
Abstract: Insect invasions, the establishment and spread of nonnative insects in new regions, can have extensive economic and environmental consequences. Increased global connectivity accelerates rates of introductions, while climate change may decrease the barriers to invader species? spread. We follow an individual-level insect- and arachnid-centered perspective to assess how the process of invasion is influenced by phenotypic heterogeneity associated with dispersal and stress resistance, and their coupling, across the multiple steps of the invasion process. We also provide an overview and synthesis on the importance of environmental filters during the entire invasion process for the facilitation or inhibition of invasive insect population spread. Finally, we highlight important research gaps and the relevance and applicability of ongoing natural range expansions in the context of climate change to gain essential mechanistic insights into insect invasions.
Programme: 136
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L. T. Ellis, C. Ah-Peng, M. Aleffi, K. Baráth, M. Brugués, E. Ruiz, W. R. Buck, I. V. Czernyadjeva, P. Erzberger, L. B. Fantecelle, G. F. Peñaloza-Bojacá, C. A. T. Araújo, B. A. Oliveira, A. S. Maciel-Silva, N. J. M. Gremmen, S.-L. Guo, T. A. Hedderson, E. February, N. Wilding, V. Hugonnot, M. Kırmacı, H. Kürschner, M. Lebouvier, A. Mesterházy, R. Ochyra, M. Philippe, V. Plášek, Z. Skoupá, S. Poponessi, D. Gigante, R. Venanzoni, K. K. Rawat, V. Sahu, A. K. Asthana, M. S. Sabovljević, A. D. Sabovljević, A. Schäfer-Verwimp, S. Wierzcholska. (2017). New national and regional bryophyte records, 50 (Vol. 39).
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L. T. Ellis, M. Aleffi, H. Bednarek-Ochyra, V. A. Bakalin, M. Boiko, J. A. Calleja, V. E. Fedosov, M. S. Ignatov, E. A. Ignatova, R. Garilleti, T. Hallingbäck, N. Lönnell, N. Hodgetts, T. Kiebacher, J. Larraín, M. Lebouvier, M. Lüth, V. Mazimpaka, B. Vigalondo, F. Lara, R. Natcheva, M. Nobis, A. Nowak, J. D. Orgaz, J. Guerra, J. Pantović, N. Nikolić, M. S. Sabovljević, A. D. Sabovljević, O. Yu Pisarenko, V. Plášek, Z. Skoupá, S. Poponessi, M. Privitera, M. Puglisi, M. Skudnik, Q. H. Wang. (2017). New national and regional bryophyte records, 51 (Vol. 39).
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Alice Gadea, Pierre Le Pogam, Grichka Biver, Joël Boustie, Anne-Cécile Le Lamer, Françoise Le Dévéhat, Maryvonne Charrier. (2017). Which Specialized Metabolites Does the Native Subantarctic Gastropod Notodiscus hookeri Extract from the Consumption of the Lichens Usnea taylorii and Pseudocyphellaria crocata? (Vol. 22).
Abstract: Notodiscus hookeri is the only representative of terrestrial gastropods on Possession Island and exclusively feeds on lichens. The known toxicity of various lichen metabolites to plant-eating invertebrates led us to propose that N. hookeri evolved means to protect itself from their adverse effects. To validate this assumption, the current study focused on the consumption of two lichen species: Usnea taylorii and Pseudocyphellaria crocata. A controlled feeding experiment was designed to understand how the snail copes with the unpalatable and/or toxic compounds produced by these lichen species. The occurrence of two snail ecophenotypes, represented by a mineral shell and an organic shell, led to address the question of a metabolic response specific to the phenotype. Snails were fed for two months with one of these lichens and the chemical profiles of biological samples of N. hookeri (i.e., crop, digestive gland, intestine, and feces) were established by HPLC-DAD-MS and compared to that of the lichens. N. hookeri appears as a generalist lichen feeder able to consume toxic metabolite-containing lichens, independently of the ecophenotype. The digestive gland did not sequester lichen metabolites. The snail metabolism might be based on four non-exclusive processes according to the concerned metabolites (avoidance, passive transport, hydrolysis, and excretion).
Keywords: Notodiscus hookeri Pseudocyphellaria crocata Usnea taylorii chemical ecology Crozet Archipelago lichens snails
Programme: 136
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L. T. Ellis, E. Agcagil, M. Kırmacı, M. Aleffi, V. A. Bakalin, H. Bednarek-Ochyra, B. Cykowska-Marzencka, M. Stryjak-Bogacka, G. F. P. Bojaca, L. B. Fantacelle, C. A. T. Araújo, A. S. Maciel-Silva, J. Bruno Silva, J. A. Calleja, M. J. Cano, J. Castillo Diaz, R. Gabriel, N. Dias dos Santos, J. Enroth, P. Erzberger, R. Garilleti, M. Hájek, L. Hedenäs, P. Heras, M. Infante, T. Kiebacher, A. Koczur, R. Krawczyk, J. Kučera, M. Lebouvier, M. Lüth, V. Mazimpaka, B. Vigalondo, F. Lara, J. Nagy, Cs Németh, A. Kovács, M. Nobis, M. Węgrzyn, P. Wietrzyk, N. Norhazrina, A. Vanderpoorten, A. Nowak, S. Poponessi, D. Gigante, R. Venanzoni, V. Plášek, S. Rangel Germano, A. Schäfer-Verwimp, C. Sérgio, D. Claro, C. A. Garcia, S. Shirzadian, S. Akhoondi Darzikolaei, A. Stebel, M. Suleiman, K.-T. Yong, V. M. Virchenko, G. Vončina, Y.-J. Yoon, H.-G. Choi, J. H. Kim. (2016). New national and regional bryophyte records, 49 (Vol. 38).
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Damien Ertz, Alan Fryday, Imke Schmitt, Maryvonne Charrier, Magdalena Dudek, Martin Kukwa. (2016). Ochrolechia kerguelensis sp. nov. from the Southern Hemisphere and O. antarctica reinstated from the synonymy of O. parella (Vol. 280).
Abstract: Ochrolechia kerguelensis Ertz & Kukwa is described as new to science from the subantarctic islands of Kerguelen. It is characterized by pruinose ascomata, usually 4-spored asci, large ascospores of 50–90 × 32–56 µm, the production of gyrophoric acid only in the apothecia and the lack of variolaric acid. A photobiont with cells containing orange guttules such as in trentepohlioid algae is recorded for the first time in the genus Ochrolechia, being present in O. austroamericana and O. kerguelensis. Ochrolechia antarctica is reinstated from the synonymy of O. parella and treated as a distinct species. Chemical and morphological differences between these taxa are discussed. Ochrolechia chilensis and O. deceptionis are treated as synonyms of O. antarctica. The phylogenetic placement of O. antarctica, O. austroamericana and O. kerguelensis is investigated using mtSSU rDNA sequences and a Bayesian analysis. A key to all fertile, saxicolous Ochrolechia species with a C+ red epihymenium occurring in the Southern Hemisphere is presented.
Keywords: biodiversity Fungi Pertusariales subantarctic islands taxonomy
Programme: 136
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Hullé M., Buchard C., Renault D., Lebouvier M., Vernon P. (2017). Distribution patterns of invertebrate species introduced into the sub-Antarctic Kerguelen Islands.
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Gadea A., Le Lamer A.-c., Fanuel M., Boustie J., Charrier M., Le Dévéhat F. (2017). Overcoming specialized metabolites by gaining essential nutrients: a lichen/snail case study.
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