Éditeur(s) : HAL CCSD Laboratoire Arago
Résumé : International audience
As it is unlikely that successful settlement is solely a matter of chance (i.e. tofind a suitable habitat), one of the greatest challenges facing the fish larvae is how to locate therelatively rare patches of coral reef habitat on which they settle and ultimately reside as adults.The answer must lie partly in the sensory modalities of fishes at settlement. Habitat selection isonly possible if fish larvae could detect some environmental cues to select a suitable reef habitatat settlement. The present review aims at providing the latest works dealing with informationperception in coral reef fish larvae at settlement. Two decades ago, it was generally assumedthat larval behaviors and sensory abilities at settlement were considered too feeble to significantlyaffect dispersal outcomes. Several recent studies showed that recognition of suitable reefhabitats by fish larvae at settlement is based on a combination of visual, chemical and acousticcues. The first part of our review shows the main advances in the knowledge of visual, chemicaland acoustic cues used by fish larvae to detect an island, a reef, a micro-habitat, a conspecific orsome predators. The second part of our review deals with the effect of imprinting and/or innatecapabilities. The third part focuses on the different cues used at different scales and underlinessome contradictory results about the distance of transmission and detection of chemical andacoustic cues in coral reefs. Finally, as global and regional environmental changes have stressedcoral reefs to such an extent that they are either destroyed or in decline, the fourth part presentsthe effects of both anthropogenic and environmental stressors on information perception andresponse capacities in coral reef fish larvae. If polluted seawater disrupts the larval abilities tofind a suitable reef habitat, fish larvae may spend more time in the planktonic environment,resulting in increased energetic costs and predation risk, and consequently a lower larval settlement.We hypothesise that as the stability of fish communities is dependent, in part, on the stabilityof social interactions, the disruption of “larvae-habitat relationships” can have major consequencesfor larval settlement into adult population with further repercussions for the ecosystemas a whole. Overall, larval settlement of coral reef fish is an excellent example of the complexityof interactions between an organism and its environment as without perceiving environmentalcues, fish larva would have very little chance of selecting a suitable reef habitat. Moreover,understanding the relationship between reef state and settlement potential will allow managementplanning for the maintenance of coral reefs that are increasingly degraded.
ISSN: 0240-8759

hal-01191776
https://hal-univ-perp.archives-ouvertes.fr/hal-01191776

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Until recently, our ability to implement and assess spatial marine management approaches has been limited by a lack of information regarding processes that bind marine ecosystems, including habitat locations, larval and adult movement, trophic interactions, and fisher behavior. However, recent advances in habitat-mapping technologies, genetics, marine microchemistry, animal tracking and numerical modeling have greatly enhanced our knowledge of these processes. Although these advances have yet to be fully integrated into management decisions, they have the potential to revolutionize spatial marine management. Nevertheless, this revolution will require advances in our ability to share and integrate data into models of marine ecosystems.
ISSN: 1877-3435

hal-00609464
https://hal.archives-ouvertes.fr/hal-00609464
DOI : 10.1016/j.cosust.2010.02.002

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Color polymorphism is widespread in animals and can be associated with temporary adjustments to environmental variables (phenotypic plasticity). In teleost fishes, one of the most remarkable examples of color plasticity is background adaptation in flatfishes. However, such rapid and complete changes in body color and pattern remain relatively unreported in other species. The convict surgeonfish Acanthurus triostegus is a gregarious species whose body color pattern consists of black vertical bars on a whitish body. Here, we describe an entirely reverse body color pattern (white vertical bars on a blackish body) that we observed in some A. triostegus juveniles in a nursery area at Moorea Island, French Polynesia. In aquaria, we determined that change from one color pattern to the other is rapid, reversible, and corresponds to phenotypic plasticity associated with aggressive behavior.
ISSN: 0722-4028

hal-01628304
http://hal.upmc.fr/hal-01628304
http://hal.upmc.fr/hal-01628304/document
http://hal.upmc.fr/hal-01628304/file/Besson_2017_Complete_and_rapid.pdf
DOI : 10.1007/s00338-017-1631-4

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : The suitability of the natural 15N abundance and of total N concentration of leaves as indicators of the type of plant N nutrition in a rain forest of French Guiana were tested. Leaf samples from primary legume species, non-legumes (pioneer species) and from the non-N2-fixing species Dicorynia guianensis were analyzed. Both '15N and total leaf N varied widely (m1 r '15N (‰) r 7 and 1 r leaf N(%) r 3.2) suggesting possible distinctions between diazotrophic and non-fixing plants. The '15N also revealed two statistically distinct groups of non-N2-fixing species ('15N = 5.14 - 0.3 vs '15Nv=v1.65 - 0.17) related to the different ecological behaviors of these species in the successional processes. We conclude that the '15N signature of plant leaves combined with their total N concentration may be relevant indicators for identifying functional groups within the community of non-N2-fixing species, as well as for detecting diazotrophy. Despite the variability in the '15N of the non-N2-fixing species, N2-fixing groups can still be identified, provided that plants are simultaneously classified taxonomically, by their leaf '15N and total N concentration and by the presence or absence of nodules. The variability in the '15N of the non-fixing species is discussed.
ISSN: 0029-8549

hal-01031454
https://hal.archives-ouvertes.fr/hal-01031454
DOI : 10.1007/s004420050846

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The seasonal patterns of conceptions and births differ between geographic areas. Several potential determinants of this variation have been identified, including biological, environmental and behavioral elements, but festive events are rarely mentioned. We investigated the possible association between the carnival and seasonal fertility variations in the French West Indies. We ran a retrospective registry-based study. The data were extracted from the registry of all births on Guadeloupe between 2000 and 2011 (n = 74,412), and from the Maternity Birth Register of the University Hospital, for all pregnancies of at least 14 completed weeks of gestation (observable conceptions) with an outcome recorded between 2007 and 2010 (n = 8,425). We compared data during and outside the carnival period for each year, including 2009, when there was no carnival due to a 44-day general strike. In all years other than 2009, the weekly number of births was higher for pregnancies initiated during the carnival period than for pregnancies initiated at other times, and the weekly number of observable conceptions was higher during the carnival period than at other times. Our findings support the hypothesis that carnivals in the French West Indies are associated with an increase in the number of conceptions and subsequent births.
ISSN: 1932-6203

hal-01485778
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01485778
DOI : 10.1371/journal.pone.0173102
PUBMED : 28253323

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
When fish larvae recruit back to a reef, chemical cues are often used to find suitable habitat or to find juvenile or adult conspecifics. We tested if the chemical information used by larvae was intentionally produced by juvenile and adult conspecifics already on the reef (communication process) or whether the cues used result from normal biochemical processes with no active involvement by conspecifics (“spying” behavior by larvae). Conspecific chemical cues attracted the majority of larvae (four out of the seven species tested); although while some species were equally attracted to cues from adults and juveniles (Chromis viridis, Apogon novemfasciatus), two exhibited greater sensitivity to adult cues (Pomacentrus pavo, Dascyllus aruanus). Our results indicate also that spying cues are those most commonly used by settling fishes (C. viridis, P. pavo, A. novemfasciatus). Only one species (D. aruanus) preferred the odour of conspecifics that had had visual contact with larvae (communication).
ISSN: 1631-0691

hal-01212899
https://hal-univ-perp.archives-ouvertes.fr/hal-01212899
DOI : 10.1016/j.crvi.2015.05.004

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Studies on the periodicity of wood formation provide essential data on tree age and factors related to the control of tree growth. The aim of this work was to investigate the cambial phenology and its relation with leaf phenology and climatic seasonality in two tropical rainforest species belonging to the genus Parkia known for having a contrasted leaf phenology. From wood samples collected at 15 day intervals from April 2009 to February 2012 in five trees of both species, we quantified cambial activity by counting layers of cells in cambial zone, enlarging cells zone and wall thickening cells zone from wood prepared anatomical micro sections. In the same time, we observed leaf shedding behaviors in the crown of the studied trees. In both species, cambial activity was significantly reduced during leafless period. However, the cambial activity of P. velutina was not affected by seasonality while in P. nitida, we found a significant positive effect of the dry season on cambial activity. This diminution of activity associated to leaf shedding occurred annually during the dry season in P. nitida whereas the trees were not synchronous in time for P. velutina. On the contrary that is often admitted, the rest cambial period can be independent of environmental restriction such as dry season. Leaf phenology remains the best proxy to estimate cambial activity.
ISSN: 0931-1890

hal-01135166
https://hal.archives-ouvertes.fr/hal-01135166
https://hal.archives-ouvertes.fr/hal-01135166/document
https://hal.archives-ouvertes.fr/hal-01135166/file/Art_Morel_al_Seasonal_variations_phenological_traits_2015.pdf
DOI : 10.1007/s00468-015-1177-4

Éditeur(s) : HAL CCSD The Austrian Society of Entomofaunistics (ÖGEF)
Résumé : International audience
ISSN: 1994-4136

hal-01086782
https://hal-agroparistech.archives-ouvertes.fr/hal-01086782