Investigating the relationship between pollination strategies and the size-advantage model in zoophilous plants using the reproductive biology of Arum cylindraceum and other European Arum species as case studies

The size-advantage model (SAM) explains the temporal variation of energetic investment on reproductive structures (i.e. male and female gametes and reproductive organs) in long-lived hermaphroditic plants and animals. It proposes that an increase in the resources available to an organism induces a higher relative investment on the most energetically costly sexual structures. In plants, pollination interactions are known to play an important role in the evolution of floral features. Because the SAM directly concerns flower characters, pollinators are expected to have a strong influence on the application of the model. This hypothesis, however, has never been tested. Here, we investigate whether the identity and diversity of pollinators can be used as a proxy to predict the application of the SAM in exclusive zoophilous plants. We present a new approach to unravel the dynamics of the model and test it on several widespread Arum (Araceae) species. By identifying the species composition, abundance and spatial variation of arthropods trapped in inflorescences, we show that some species (i.e. A. cylindraceum and A. italicum) display a generalist reproductive strategy, relying on the exploitation of a low number of dipterans, in contrast to the pattern seen in the specialist A. maculatum (pollinated specifically by two fly species only). Based on the model presented here, the application of the SAM is predicted for the first two and not expected in the latter species, those predictions being further confirmed by allometric measures. We here demonstrate that while an increase in the female zone occurs in larger inflorescences of generalist species, this does not happen in species demonstrating specific pollinators. This is the first time that this theory is both proposed and empirically tested in zoophilous plants. Its overall biological importance is discussed through its application in other non-Arum system

CASE – Centre Asie du Sud-Est

Andrée Feillard, chargée de recherche au CNRS L’Asie du Sud-Est : approches pluridisciplinaires Si l’Asie du Sud-Est des réseaux et des échanges a été massivement présente dans les contributions de cette année, un autre thème a été particulièrement prégnant, c’est celui de la religion qui constitue également l’un des axes principaux des travaux du CASE, qu’il s’agisse de l’Islam indonésien, étudié par Michael Feener (Asia Research Institute, National University of Singapore) et Greg Barton (M..

CASE – Centre Asie du Sud-Est

Pierre-Yves Manguin, directeur d’études à l’EFEOÉric Bourdonneau, maître de conférences à l’EFEO Histoire et archéologie de l’ancienne Asie du Sud-Est Thématique 1 (Pierre-Yves Manguin) : Les premiers « âges du commerce » dans l’ancienne Asie du Sud-Est : échanges, réseaux, marchés Les systèmes politiques côtiers de l’Asie du Sud-Est, à compter des environs du Ve siècle av. notre ère, se sont développés au gré des fluctuations des échanges maritimes, à l’échelle de la région, entre les deux r..

Centre Asie du Sud-Est – CASE

Andrée Feillard, chargée de recherche au CNRS L’Asie du Sud-Est : approches pluridisciplinaires Ce séminaire pluridisciplinaire a réuni les membres du Centre Asie du Sud-Est (CASE) et les étudiants avancés. L’objectif principal est d’examiner les processus à l’œuvre dans la constitution d’une aire culturelle qui, par-delà sa diversité culturelle et religieuse, tente de s’élaborer comme une communauté politique. Dirigé par Andrée Feillard, le séminaire a été animé plusieurs fois en coopération..

CASE – Centre Asie du Sud-Est

Pierre-Yves Manguin, directeur d’études à l’EFEOÉric Bourdonneau, maître de conférences à l’EFEO Histoire et archéologie de l’ancienne Asie du Sud-Est Thématique 1 (Pierre-Yves Manguin) : Les premiers « âges du commerce » dans l’ancienne Asie du Sud-Est : échanges, réseaux, marchés Les systèmes politiques côtiers de l’Asie du Sud-Est, à compter des environs du Ve siècle av. notre ère, se sont développés au gré des fluctuations des échanges maritimes, à l’échelle de la région, entre les deux r..

MONDORAL - Pourquoi faut-il raconter des histoires ? OPUS 2. : Table ronde 14h30 - 16h30

Fonds audiovisuel du programme ESCoM-AAR (Equipe Sémiotique Cognitive et nouveaux Médias - Archives Audiovisuelles de la Recherche; 2001 - 2016).MONDORAL et l'ODEON - Théâtre de l'Europe vous invitent au grand jeu des questions-réponses par le moyen d'histoires. Le sujet est toujours : pourquoi faut-il raconter des histoires ? il s'agit cette fois d'interroger la notion de transmission, sa nécessité, la métamorphose de ses formes, son adaptation au monde de demain. Quatre parties se succèdent, accueillant chacune, sous l'oeil attentif d'un modérateur, huit participants disposant de dix minutes pour exposer leur point de vue par un récit, une anecdote ou un conte. Ces propositions seront ensuite mises en débat et revisitées à la lumière de tout ce qui a été partagé. C'est à travers ce mode ludique et sérieux d'investigation que nous espérons découvrir avec vous les chemins encore possibles vers ce qui nous rassemblerait et qui s'apparenterait à nos rêves. MONDORAL est un programme d'actions autour du conte et des arts de la parole. Il réunit quatre établissements, le Conservatoire de Littérature Orale à Vendôme, La Maison du Conte de Chevilly-Larue, le Centre des Arts du Récit en Isère, et l'association Paroles Traverses Festival Mythod à Rennes. Mondoral s'est donné pour mission de mettre en visibilité l'art du conteur aujourd'hui sous ses formes multiples et foisonnantes et de contribuer à la transmission et à l'enrichissement du patrimoine immatériel oral, narratif et littéraire de la société

50-year seasonal variability in East African droughts and floods recorded in central Afar lake sediments (Ethiopia) and their connections with the El Niño-Southern Oscillation

International audienceUnderstanding past and present hydrosystem feedbacks to global ocean-atmospheric interactions represents one of the main challenges to preventing droughts, extreme events, and related human catastrophes in the face of global warming, especially in arid and semiarid environments. In eastern Africa, the El Niño-Southern Oscillation (ENSO) was identified as one of the primary drivers of precipitation variability affecting water availability. However, the northern East African Rift System (EARS) still suffers from the underrepresentation of predictive and ENSO teleconnection models because of the scarcity of local to regional historical or palaeo-data. In this paper, we provide a 50-year seasonal flood and drought chronicle of the Awash River catchment from the study of laminated sediment from Gemeri and Afambo lakes (central Afar region, Ethiopia) with the aim of reconstructing the magnitude of regional hydroclimatic events. Pluricentimetric micro-laminated lithogenic facies alternating with plurimillimetric carbonate-enriched facies are investigated in both lakes. We couple dating methods including radiocarbon, short-lived radionuclides, palaeomagnetic field variations, and varve counting on both lake deposits to build a high-resolution age model and to discuss the regional hydrosedimentary dynamics of the Awash River over the last ~ 700 years with a focus on the last 50 years. Using a multiproxy approach, we observe that following a multicentennial enhanced hydrological period, the two lakes have experienced a gradual decrease in river load inflow since 1979 CE, attaining extreme drought and high evaporative conditions between 1991 and 1997 CE. In 2014, the construction of a dam and increased agricultural water management in the lower Awash River plain impacted the erodibility of local soils and the hydrosedimentary balance of the lake basins, as evidenced by a disproportionate sediment accumulation rate. Comparison of our quantitative reconstruction with (i) lake water surface evolution, (ii) the interannual Awash River flow rates, and (iii) the El Niño 3.4 model highlights the intermittent connections between ENSO sea surface temperature anomalies, regional droughts, and hydrological conditions in the northern EARS. Copyright

Investigating the relationship between pollination strategies and the size-advantage model in zoophilous plants using the reproductive biology of Arum cylindraceum and other European Arum species as case studies

The size-advantage model (SAM) explains the temporal variation of energetic investment on reproductive structures (i.e. male and female gametes and reproductive organs) in long-lived hermaphroditic plants and animals. It proposes that an increase in the resources available to an organism induces a higher relative investment on the most energetically costly sexual structures. In plants, pollination interactions are known to play an important role in the evolution of floral features. Because the SAM directly concerns flower characters, pollinators are expected to have a strong influence on the application of the model. This hypothesis, however, has never been tested. Here, we investigate whether the identity and diversity of pollinators can be used as a proxy to predict the application of the SAM in exclusive zoophilous plants. We present a new approach to unravel the dynamics of the model and test it on several widespread Arum (Araceae) species. By identifying the species composition, abundance and spatial variation of arthropods trapped in inflorescences, we show that some species (i.e. A. cylindraceum and A. italicum) display a generalist reproductive strategy, relying on the exploitation of a low number of dipterans, in contrast to the pattern seen in the specialist A. maculatum (pollinated specifically by two fly species only). Based on the model presented here, the application of the SAM is predicted for the first two and not expected in the latter species, those predictions being further confirmed by allometric measures. We here demonstrate that while an increase in the female zone occurs in larger inflorescences of generalist species, this does not happen in species demonstrating specific pollinators. This is the first time that this theory is both proposed and empirically tested in zoophilous plants. Its overall biological importance is discussed through its application in other non-Arum systems