Search results for " Reproduction"
showing 10 items of 282 documents
Modes, mechanisms and evidence of bet hedging in rotifer diapause traits
2016
In this contribution, we review our knowledge on bet-hedging strategies associated with rotifer diapause. First, we describe the ecological scenario under which bet hedging is likely to have evolved in three diapause-related traits in monogonont rotifer populations: (1) the timing of sex (because diapausing eggs are produced via sexual reproduction), (2) the sexual reproduction ratio (i.e. the fraction of sexually reproducing females) and (3) the timing of diapausing egg hatching. Then, we describe how to discriminate among bet-hedging modes and discuss which modes and mechanisms better fit the variability observed in these traits in rotifers. Finally, we evaluate the strength of the empiri…
Local Recruitment in the Greater Flamingo: A New Approach Using Capture- Mark-Recapture Data
1997
International audience; Although the establishment of new individuals in the breeding component of a population is an essential feature of population regulation, only a few attempts have been made to test biological hypotheses about recruitment. Most previous studies rely on ad hoc calculations or are flawed with unwarranted assumptions about survival. We use a recently developed approach, based on capture-mark-recapture, in which analysis of local recruitment is similar to a time-reversed analysis of survival. The basic data set consists of capture histories viewed in reverse order, with initial capture at year of birth, and subsequent observations corresponding to years when the animal ha…
Interaction between Medicago truncatula and Pseudomonas fluorescens: evaluation of costs and benefits across an elevated atmospheric CO2.
2012
10 pages; International audience; Soil microorganisms play a key role in both plants nutrition and health. Their relation with plant varies from mutualism to parasitism, according to the balance of costs and benefits for the two partners of the interaction. These interactions involved the liberation of plant organic compounds via rhizodeposition. Modification of atmospheric CO2 concentration may affect rhizodeposition and as a consequence trophic interactions that bind plants and microorganisms. Positive effect of elevated CO2 on plants are rather well known but consequences for micoorganisms and their interactions with plants are still poorly understood. A gnotobiotic system has been devel…
Flexible timing of reproductive effort as an alternative mating tactic in black grouse (Lyrurus tetrix) males
2016
Alternative reproductive tactics often take the form of dichotomous behavioural phenotypes. Focusing attention on such obvious dichotomy means that flexible patterns of behaviour within tactics is largely ignored. Using a long-term dataset of black grouse (Lyrurus tetrix) lek behaviours, we tested whether there were fine-scale differences in reproductive effort (lek attendance, fighting rates) and whether these were related to age and phenotype. Yearling males increased their lek attendance and fighting rate to a peak when adult male effort was declining. Adults and yearlings allocated reproductive effort according to their body mass but this was unrelated to differences in timing of effort…
Population and reproductive dynamics of the polychaete Pygospio elegans in a boreal estuary complex
2016
Pygospio elegans is an opportunistic, wide-spread spionid polychaete that reproduces asexually via fragmentation and can produce benthic and pelagic larvae, hence combining different developmental modes in one species. We documented the density, size distribution, and reproductive activity of P. elegans at four sites in the Danish Isefjord-Roskilde Fjord estuary complex, where all modes of reproduction were reported. We compared population dynamics of this species to environmental parameters such as salinity, temperature, and sediment characteristics (grain size, sorting, porosity, water content, organic content, C/N). We observed that new cohorts—resulting either from sexual or asexual rep…
Communal nesting in the garden dormouse (Eliomys quercinus)
2017
Communal nesting has been described in many rodents including some dormouse species. In this study, we report the existence of this reproductive strategy in the garden dormouse Eliomys quercinus. Data was recorded by checking natural nests and nest-boxes from 2003 to 2013 in SE Spain. Pups and adults dormice found in nests were captured and marked. Overall, 198 nests were found: 161 (81.31%) were singular nests and 37 (18.69%) were communal nests. Communal nests were composed by different combinations of one up to three females together with one up to three different size litters. The number of communal nests varied from year to year in accordance with the number of singular nests and no se…
The Reproductive Strategy as an Important Trait for the Distribution of Lower-Trunk Epiphytic Lichens in Old-Growth vs. Non-Old Growth Forests
2021
(1) Research Highlights: The work studied the beta diversity patterns of epiphytic lichens as a function of their reproductive strategies in old-growth and non-old growth forests from the Mediterranean area. (2) Background and Objectives: The reproductive strategies of lichens can drive the dispersal and distribution of species assemblages in forest ecosystems. To further investigate this issue, we analyzed data on epiphytic lichen diversity collected from old-growth and non-old growth forest sites (36 plots) located in Cilento National Park (South Italy). Our working hypothesis was that the dispersal abilities due to the different reproductive strategies drove species beta diversity depend…
Settlement dynamics and recruitment responses of Mediterranean gorgonians larvae to different crustose coralline algae species
2020
International audience; Sessile marine species such as Anthozoans act as ecosystem engineers due to their three-dimensional structure. Gorgonians, in particular, can form dense underwater forests that give shelter to other species increasing local biodiversity. In the last decades, several Mediterranean gorgonian populations have been affected by natural and anthropogenic impacts which drastically reduced their size. However, some species showed unexpected resilience, mainly due to the supply of new individuals. To understand the mechanisms underlying recovery processes, studies on the first life history stages (i.e. larval dispersal, settlement and recruitment) are needed. In tropical cora…
Proteomics and Metabolomics Studies and Clinical Outcomes
2018
Abstract The application of proteomics and metabolomics to the field of human reproduction arose as a result of the need to identify new diagnostic and therapeutic tools that improve fertilization, implantation, and live birth rates in assisted reproduction cycles. A better understanding of the molecular mechanisms underlying the physiology of germ cells, embryos, and the endometrium has been made possible through the identification of their proteomic and metabolomic profiles. This has led to the discovery of specific biomarkers for the diagnosis, treatment, and counseling of several infertility-related conditions and for a more objective selection of the best gametes and embryos and the mo…
Second-generation preimplantation genetic testing for aneuploidy in assisted reproduction: a SWOT analysis.
2019
Second-generation preimplantation genetic testing for aneuploidy (PGT-A 2.0) in patients with an unfavourable reproductive and IVF prognosis is becoming common practice, with the aim of improving reproductive outcomes. However, there is still no clear evidence on the possible advantages and drawbacks with regard to this procedure. In this discussion paper, based on a SWOT (strengths, weaknesses, opportunities, threats) analysis, the different aspects of this strategy are evaluated. Current evidence suggests that PGT-A 2.0 should not at present have an indiscriminate application, but it might be indicated in cases in which the risk of aneuploidy is increased.