Subjects -> PALEONTOLOGY (Total: 43 journals)
Showing 1 - 21 of 21 Journals sorted alphabetically
Alcheringa: An Australasian Journal of Palaeontology     Hybrid Journal   (Followers: 6)
Ameghiniana     Open Access  
Annales de Paléontologie     Full-text available via subscription   (Followers: 4)
Annals of Carnegie Museum     Full-text available via subscription   (Followers: 1)
Boreas: An International Journal of Quaternary Research     Hybrid Journal   (Followers: 13)
Comptes Rendus Palevol     Open Access  
European Journal of Protistology     Hybrid Journal   (Followers: 5)
EvoDevo     Open Access   (Followers: 4)
Facies     Hybrid Journal   (Followers: 9)
Fossil Record     Open Access   (Followers: 5)
Geobios     Full-text available via subscription   (Followers: 4)
Geologica Saxonica     Open Access   (Followers: 7)
Historical Biology: An International Journal of Paleobiology     Hybrid Journal   (Followers: 9)
Ichnos: An International Journal for Plant and Animal Traces     Hybrid Journal  
International Journal of Speleology     Open Access   (Followers: 3)
Journal of Paleolimnology     Hybrid Journal   (Followers: 5)
Journal of Paleontology     Hybrid Journal   (Followers: 8)
Journal of Quaternary Science     Hybrid Journal   (Followers: 31)
Journal of Vertebrate Paleontology     Full-text available via subscription   (Followers: 8)
Marine Micropaleontology     Hybrid Journal   (Followers: 2)
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen     Full-text available via subscription   (Followers: 3)
Novitates Paleoentomologicae     Open Access   (Followers: 1)
Open Quaternary     Open Access  
Palaeogeography, Palaeoclimatology, Palaeoecology     Hybrid Journal   (Followers: 13)
Palaeontographica A     Full-text available via subscription   (Followers: 3)
Palaeontology     Hybrid Journal   (Followers: 17)
Palaeoworld     Hybrid Journal   (Followers: 3)
Paläontologische Zeitschrift     Hybrid Journal   (Followers: 4)
Paleobiology     Full-text available via subscription   (Followers: 6)
PaleoBios     Open Access   (Followers: 1)
Paleoceanography and Paleoclimatology     Full-text available via subscription   (Followers: 5)
Paleontological Journal     Full-text available via subscription   (Followers: 4)
Palynology     Hybrid Journal   (Followers: 1)
Papers in Palaeontology     Hybrid Journal  
Peer Community Journal     Open Access   (Followers: 8)
Quaternaire     Open Access   (Followers: 3)
Quaternary Research     Full-text available via subscription   (Followers: 19)
Quaternary Science Reviews     Hybrid Journal   (Followers: 26)
Review of Palaeobotany and Palynology     Hybrid Journal   (Followers: 1)
Revue de Micropaleontologie     Full-text available via subscription  
Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy)     Open Access   (Followers: 1)
Spanish Journal of Palaeontology     Open Access  
Swiss Journal of Palaeontology     Hybrid Journal   (Followers: 4)
Vertebrate Anatomy Morphology Palaeontology     Open Access   (Followers: 1)
Zitteliana     Open Access  
Similar Journals
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Peer Community Journal
Number of Followers: 8  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2804-3871
Published by Peer Community in (PCI) Homepage  [1 journal]
  • Capdevielle Dulac, Claire; Benoist, Romain et al. - Spontaneous
           parthenogenesis in the parasitoid wasp Cotesia typhae: low frequency
           anomaly or evolving process'

    • Abstract: Hymenopterans are haplodiploids and unlike most other Arthropods they do not possess sexual chromosomes. Sex determination typically happens via the ploidy of individuals: haploids become males and diploids become females. Arrhenotoky is believed to be the ancestral reproduction mode in Hymenopterans, with haploid males produced parthenogenetically, and diploid females produced sexually. However, a number of transitions towards thelytoky (diploid females produced parthenogenetically) have appeared in Hymenopterans, and in most cases populations or species are either totally arrhenotokous or totally thelytokous. Here we present the case of Cotesia typhae (Fernandez-Triana), a Braconidae that produces parthenogenetic females at a low frequency. The phenotyping of two laboratory strains and one natural population showed that this frequency is variable, and that this rare thelytokous phenomenon also happens in the wild. Moreover, mated females from one of the laboratory strains produce a few parthenogenetic daughters among a majority of sexual daughters. The analysis of daughters of heterozygous virgin females allowed us to show that a mechanism similar to automixis with central fusion is very likely at play in C. typhae. This mechanism allows some parts of the genome to remain heterozygous, especially at the chromosomes’ centromeres, which can be advantageous depending on the sex determination system involved. Lastly, in most species, the origin of thelytoky is either bacterial or genetic, and an antibiotic treatment as well as PCR experiments did not demonstrate a bacterial cause in C. typhae. The unusual case of low parthenogenetic frequency described in this species constitutes another example of the fascinating diversity of sex determination systems in Arthropods.
      PubDate: Wed, 22 Jun 2022 09:50:13 +000
       
  • Smit, Nikolaos; Baniel, Alice et al. - Sexual coercion in a natural
           mandrill population

    • Abstract: Increasing evidence indicates that sexual coercion is widespread. While some coercive strategies are conspicuous, such as forced copulation or sexual harassment, less is known about the ecology and evolution of intimidation, where repeated male aggression promotes future rather than immediate mating success with targeted females. Although known in humans, intimidation was recently reported in chimpanzees (Pan troglodytes) and chacma baboons (Papio ursinus), where males are regularly violent against females. Here, we investigate the nature of male coercive strategies in wild mandrills (Mandrillus sphinx), a primate living in large polygynandrous groups where severe male aggression towards females is rare and females can form coalitions against males. Yet, we found support for all three predictions of the sexual coercion hypothesis, namely that male aggression (1) specifically targets sexually receptive females, (2) inflicts costs to these females, and (3) increases male mating success in the long-term. These results hold true when considering only non-physical threats, or only severe aggression. Finally, we show that high-ranking females are most targeted by males, probably because of their higher reproductive performances, while high-ranking males are most coercive. These results indicate that sexual intimidation is widespread in sexually dimorphic and group-living mammals, and that males and females vary in their propensities to use, and to be exposed to sexual coercion, respectively.
      PubDate: Mon, 20 Jun 2022 07:47:14 +000
       
  • Poisot, Timothée - Dissimilarity of species interaction networks:
           quantifying the effect of turnover and rewiring

    • Abstract: Despite having established its usefulness in the last ten years, the decomposition of ecological networks in components allowing to measure their β-diversity retains some methodological ambiguities. Notably, how to quantify the relative effect of mechanisms tied to interaction rewiring vs. species turnover has been interpreted differently by different authors. In this contribution, I present mathematical arguments and numerical experiments that should (i) establish that the decomposition of networks as it is currently done is indeed fit for purpose, and (ii) provide guidelines to interpret the values of the components tied to turnover and rewiring. 
      PubDate: Mon, 13 Jun 2022 06:48:10 +000
       
  • Alan R., Rogers - Beating your Neighbor to the Berry Patch

    • Abstract: Foragers often compete for resources that ripen (or otherwise improve) gradually. What strategy is optimal in this situation' It turns out that there is no optimal strategy. There is no evolutionarily stable strategy (ESS), and the only Nash equilibrium (NE) is unstable: strategies similar to the NE can always invade.  But in spite of this instability, the NE is predictive. If harvesting attempts are costly or there are many competitors, the process tends to remain near the unstable NE.  In this case, the resource often goes unharvested. Harvesting attempts--when they happen at all--usually occur when the resource is barely ripe enough to offset costs. The more foragers there are, the lower the chance that the resource will be harvested and the greater its mean value when harvested. This counterintuitive behavior is exhibited not only by theoretical models and computer simulations, but also by human subjects in an experimental game.
      PubDate: Wed, 08 Jun 2022 06:47:47 +000
       
  • Duchenne, François; Porcher, Emmanuelle et al. - Controversy over the
           decline of arthropods: a matter of temporal baseline'

    • Abstract: Recently, a number of studies have reported somewhat contradictory patterns of temporal trends in arthropod abundance, from decline to increase. Arthropods often exhibit non-monotonous variation in abundance over time, making it important to account for temporal coverage in interpretation of abundance trends, which is often overlooked in statistical analysis. Combining four recently analysed datasets that led to contrasting outcomes, we first show that temporal abundance variations of arthropods are non-monotonous. Using simulations, we show non-monotony is likely to bias estimated linear abundance trends. Finally, analysing empirical data, we show that heterogeneity in estimated abundance trends is significantly related to the variation in temporal baseline of analysed time series. Once differences in baseline years, habitats and continents are accounted for, we do not find any statistical difference in estimated linear abundance trends among the four datasets. We also show that short time series produce more stochastic abundance trends than long series, making the dearth of old and long-term time series a strong limitation in the assessment of temporal trends in arthropod abundance. The lack of time series with a baseline year before global change acceleration is likely to lead to an underestimation of global change effects on biodiversity.
      PubDate: Wed, 08 Jun 2022 06:44:50 +000
       
  • Alan R., Rogers - An efficient algorithm for estimating population history
           from genetic data

    • Abstract: The Legofit statistical package uses genetic data to estimate parameters describing population history. Previous versions used computer simulations to estimate probabilities, an approach that limited both speed and accuracy. This article describes a new deterministic algorithm, which makes Legofit faster and more accurate. The speed of this algorithm declines as model complexity increases. With very complex models, the deterministic algorithm is slower than the stochastic one. In an application to simulated data sets, the estimates produced by the deterministic and stochastic algorithms were essentially identical. Reanalysis of a human data set replicated the findings of a previous study and provided increased support for the hypotheses that (a) early modern humans contributed genes to Neanderthals, and (b) a "superarchaic" population (which separated from all other humans early in the Pleistocene) was either large or deeply subdivided.
      PubDate: Tue, 07 Jun 2022 06:18:51 +000
       
  • Cantalapiedra-Hijar, Gonzalo; Morel, Isabelle et al. - Identifying cattle
           with superior growth feed efficiency through their natural 15N abundance
           and plasma urea concentration: A meta-analysis

    • Abstract: The objective of this study was to test two candidate biomarkers of feed efficiency in growing cattle. A database was built using performance data from 13 trials conducted with growing heifers, steers and young bulls and testing 34 dietary treatments. Different breeds were used with Charolais (37%), Simmental (15%), and cross-bred (40%) cattle being the most numerous. The database included 759 individual records for animal performance and laboratory data for N isotopic discrimination measured in plasma or muscle (Δ15Nanimal-diet; n = 749) and plasma urea concentration (n = 659). Feed conversion efficiency (FCE) and residual feed intake (RFI) criteria were calculated for a duration ranging between 56 and 259 d, depending on the trial. For FCE prediction, mixed models included the random effects of study, treatment within-study and pen within-study (i.e. contemporary group; CG) allowing these effects to be progressively excluded from the relationship. For RFI prediction, simple linear regressions were tested with the CG effect removed from biomarker values before analysis. Better models were obtained with Δ15Nanimal-diet compared to plasma urea concentration, irrespective of using mean or individual values and regardless of the feed efficiency criterion. Prediction error (0.027 kg/kg) from mixed-effect models using mean FCE and Δ15Nanimal-diet values would allow discrimination of 2 dietary treatments or production conditions in terms of FCE if they differ by more than 0.10 kg/kg. The Δ15Nanimal-diet values showed a negative and significant (P<0.001) relationship with FCE at the individual level and results highlighted that it is possible to significantly discriminate two animals randomly selected from the same CG if they differ by at least 0.06 kg/kg FCE. In addition, the top 20% highest and lowest animals within-CG in terms of RFI and FCE (extreme animals) showed significant (P<0.001) differences in Δ15Nanimal-diet values, while only extreme FCE animals could be discriminated when using plasma urea concentrations (P=0.002). No gain in feed efficiency prediction was observed when combining candidate biomarkers. However, when average daily gain data was combined with Δ15Nanimal-diet, the prediction of FCE at the individual level was strengthened compared to using only one of them, in which case average daily gain was the best single predictor. Our findings confirm that Δ15Nanimal-diet may be useful to form groups of animals for precision feeding when feed intake and body weight gain are not available. Further studies are warranted, however, to evaluate the usefulness of this promising biomarker for genetic selection.
      PubDate: Wed, 01 Jun 2022 11:27:02 +000
       
  • Lefort, Marie-Caroline; Cruickshank, Robert H. et al. - Corrigendum:
           Blood, sweat and tears: a review of non-invasive DNA sampling

    • Abstract: In the original article,Box 1 was not printed in its entirety, and two references were badly quoted in page 3 of the pdf and were missing in the reference list.
      PubDate: Wed, 25 May 2022 09:41:58 +000
       
  • Guiglielmoni, Nadège; Rivera-Vicéns, Ramón et al. - A deep dive into
           genome assemblies of non-vertebrate animals

    • Abstract: Non-vertebrate species represent about 95% of known metazoan (animal) diversity. They remain to this day relatively unexplored genetically, but understanding their genome structure and function is pivotal for expanding our current knowledge of evolution, ecology and biodiversity. Following the continuous improvements and decreasing costs of sequencing technologies, many genome assembly tools have been released, leading to a significant amount of genome projects being completed in recent years. In this review, we examine the current state of genome projects of non-vertebrate animal species. We present an overview of available sequencing technologies, assembly approaches, as well as pre and post-processing steps, genome assembly evaluation methods, and their application to non-vertebrate animal genomes.
      PubDate: Mon, 16 May 2022 06:54:30 +000
       
  • Demené, Arthur; Laurent, Benoît et al. - Chromosomal rearrangements with
           stable repertoires of genes and transposable elements in an invasive
           forest-pathogenic fungus

    • Abstract: Chromosomal rearrangements have been largely described among eukaryotes, and may have important consequences on evolution of species. High genome plasticity has been often reported in Fungi, which may explain their apparent ability to quickly adapt to new environments. Cryphonectria parasitica, causing the Chestnut blight disease, is an invasive fungal pathogen species associated with several recent host shifts during its successive introductions from Asia to North America and Europe. Previous cytological karyotyping and genomic studies suggested several chromosomal rearrangements which remains to be described in detail for this species. A serious limitation for valid genome comparisons is the access to robust genome assemblies that usually contain genomic regions of low complexity. We present a new de novo whole-genome assembly obtained from a new method of DNA extraction and long-reads sequencing Nanopore technology obtained from a Japanese isolate sampled in the native area of the species. The comparison with a recently published reference genome revealed stable gene and transposable elements (TEs) repertoires. We also showed that the C. parasitica genome is lowly compartmentalized, with a poor association between TEs and genes, such as those potentially involved in host interactions (i.e., genes coding for small secreted proteins or for secondary metabolites). This genome comparison, however, detected several large chromosomal rearrangements that may have important consequences in gene regulations and sexual mating in this invasive species. This study opens the way for more comparisons of high-quality assembled genomes, and questions the role of structural variations in the invasive success of this fungal pathogen species.
      PubDate: Fri, 13 May 2022 08:58:03 +000
       
  • Evin, Allowen; Bouby, Laurent et al. - Archaeophenomics of ancient
           domestic plants and animals using geometric morphometrics : a review

    • Abstract: Geometric morphometrics revolutionized domestication studies through the precise quantification of the phenotype of ancient plant and animal remains. Geometric morphometrics allow for an increasingly detailed understanding of the past agrobiodiversity and our ability to characterize large scale ancient phenotypes has led to what can be named archaeophenomics : the large scale phenotyping of ancient remains. This review describes advances in the bioarchaeological study of domesticated species and their wild relatives where their phenomes are quantified through geometric morphometrics. The two main questions addressed by archaeophenomics are i) taxonomic identification, including domestication signature, and ii) the inference of the spatio-temporal agrobiodiversity dynamics. Archaeophenomics is a growing field in bioarchaeology of domestic species that will benefit in the near future from advances in artificial intelligence and from an increasing interest in multiproxy approaches combining morphometric data with e.g. isotopes or archaeogenomics.
      PubDate: Thu, 12 May 2022 06:38:35 +000
       
  • Le Rouzic, Arnaud - Gene network robustness as a multivariate character

    • Abstract: Robustness to genetic or environmental disturbances is often considered as a key property of living systems. Yet, in spite of being discussed since the 1950s, how robustness emerges from the complexity of genetic architectures and how it evolves still remains unclear. In particular, whether or not robustness is independent to various sources of perturbations conditions the range of adaptive scenarios that can be considered. For instance, selection for robustness to heritable mutations is likely to be modest and indirect, and its evolution might result from indirect selection on a pleiotropically-related character (e.g., homeostasis). Here, I propose to treat various robustness measurements as quantitative characters, and study theoretically, by individual-based simulations, their propensity to evolve independently. Based on a simple evolutionary model of a gene regulatory network, I showed that five measurements of the robustness of gene expression to genetic or non-genetic disturbances were substantially correlated. Yet, robustness was mutationally variable in several dimensions, and robustness components could evolve differentially under direct selection pressure. Therefore, the fact that the sensitivity of gene expression to mutations and environmental factors rely on the same gene networks does not preclude distinct evolutionary histories of robustness components.
      PubDate: Tue, 26 Apr 2022 07:17:44 +000
       
  • Quéméner, Audrey; Dessauge, Frédéric et al. - The impact of housing
           conditions on porcine mesenchymal stromal/stem cell populations differ
           between adipose tissue and skeletal muscle

    • Abstract: Background. In pigs, the ratio between lean mass and fat mass in the carcass determines production efficiency and is strongly influenced by the number and size of cells in tissues. During growth, the increase in the number of cells results from the recruitment of different populations of multipotent mesenchymal stromal/stem cells (MSCs) residing in the tissues. We hypothesized that the impact of hygiene of housing conditions during growth on the proportions of MSCs in adipose tissue and skeletal muscle may differ between pigs with different residual feed intake (RFI), a measure of feed efficiency. Methods. At the age of 12 weeks, Large White pigs from two lines divergently selected for low and high RFI were housed in two contrasting hygiene conditions (good vs poor). After six weeks, pigs were slaughtered (n = 30; 5-9/group). Samples of subcutaneous adipose tissue and longissimus skeletal muscle were collected, and cells from the stromal vascular fraction (SVF), which includes mesenchymal stromal/stem cell populations, were isolated from each tissue. Adipose and muscle cell populations from the SVF were phenotyped by flow cytometry using antibodies that targeted different cell surface markers (CD45 to separate hematopoietic cells from MSCs; CD34, CD38, CD56 and CD140a to identify MSC populations with adipogenic and/or myogenic potential). Results. Adipose tissue and muscle shared some common MSC populations although MSC diversity was higher in muscle than in adipose tissue. In muscle, the CD45-CD56+CD34-CD140a+ and CD45-CD56+CD34+CD140a+ cell populations were abundant. Of these two cell populations, only the proportions of CD45-CD56+CD34+CD140a+ cells increased (P ≤ 0.05) in pigs housed in poor hygiene as compared with pigs in good hygiene conditions. For the CD45-CD56-CD34- cell population, present in low proportion, there was an interaction between hygiene condition and genetic line (P < 0.05) with a decrease in low RFI pigs housed in poor hygiene conditions. In adipose tissue, the two abundant MSC populations were CD45-CD56-CD34- and CD45-CD56+CD34-. The proportion of CD45-CD56-CD34- cells increased (P < 0.05) whereas the proportion of CD45-CD56+CD34- tended to decrease (P < 0.1) in pigs housed in poor conditions. This study shows that the proportions of some MSC populations were affected by hygiene of housing conditions in a tissue-dependent manner in pigs of both RFI lines. It suggests that MSCs may play a significant role in adipose tissue and skeletal muscle homeostasis and may influence later growth and body composition in growing animals.
      PubDate: Tue, 19 Apr 2022 07:42:05 +000
       
  • Blouet, Sylvain; Bramanti, Lorenzo et al. - Artificial reefs geographical
           location matters more than shape, age and depth for sessile invertebrate
           colonization in the Gulf of Lion (NorthWestern Mediterranean Sea)

    • Abstract: Artificial reefs (ARs) have been used to support fishing activities. Sessile invertebrates are essential components of trophic networks within ARs, supporting fish productivity. However, colonization by sessile invertebrates is possible only after effective larval dispersal from source populations, usually in natural habitat. While most studies focused on short-term colonization by pioneer species, we propose to test the relevance of geographic location, shape, age and depth of immersion on the ARs long-term colonization by species found in natural stable communities in the Gulf of Lion. We recorded the presence of five sessile invertebrates species, with contrasting life-history traits and regional distribution in the natural rocky habitat, on ARs with different shapes deployed during two immersion time periods (1985 and the 2000s) and in two depth ranges (<20m and >20m). At the local level (~5kms), neither shape, depth nor immersion duration differentiated ARs assemblages. At the regional scale (>30kms), colonization patterns differed between species, resulting in diverse assemblages. This study highlights the primacy of geographical positioning over shape, immersion duration and depth in ARs colonization, suggesting it should be accounted for in maritime spatial planning
      PubDate: Mon, 11 Apr 2022 12:27:39 +000
       
  • Ludwigia+grandiflora+subsp.+hexapetala&rft.title=Peer+Community+Journal&rft.issn=2804-3871&rft.date=2022&rft.volume=">Portillo Lemus, Luis O.; Harang, Maryline et al. - Late-acting
           self-incompatible system, preferential allogamy and delayed selfing in the
           heteromorphic invasive populations of Ludwigia grandiflora subsp.
           hexapetala

    • Abstract: Breeding system influences local population genetic structure, effective size, offspring fitness and functional variation. Determining the respective importance of self- and cross-fertilization in hermaphroditic flowering plants is thus important to understand their ecology and evolution. The worldwide invasive species, Ludwigia grandiflora subsp. hexapetala (Lgh) presents two floral morphs: one self-compatible short-styled morph (S-morph) and one self-incompatible long-styled morph (L-morph). In this study, we identified the breeding systems of western European experimental and natural populations of Lgh by comparing structural characteristics of pollen and style, by studying self- and cross-pollen tube elongations and the viability of the resulting seeds and seedlings in both floral morphs. Our results showed no differences in pollen shape and stigma surfaces no matter the floral morph. In the self-incompatible L-morph flowers, self-pollen tubes were stopped tardily, in the ovarian area, and were unable to fertilize the ovules. This first formal identification of a late-acting, prezygotic self-incompatible system (LSI) in Ludwigia genus contributes a case of LSI in an additional family within the Myrtales order. In the self-compatible S-morph flowers, self-pollen always succeeded to self-fertilize the ovules that nearly all developed into viable seedlings. However, cross-pollen tubes always elongated faster than self-pollen tubes in both morphs. S-morph individuals may thus advantage preferential allogamy over selfing when cross-pollen is available despite its self-compatibility. As expected in late-acting self-incompatible systems, L-morph flowers authorised 0.2‰ of selfed seeds during the uppermost flowering season, that increased to 1‰ at the end of the flowering season. Such delayed selfing resulted in a significant quantity of viable floating seeds. They may contribute to the local regeneration, seed bank and propagation of the L-morph, which may contribute to explain its invasion success worldwide. Management plans of Lgh would gain to consider the breeding systems we identified.
      PubDate: Wed, 06 Apr 2022 16:14:48 +000
       
  • Stemmelen, Alex; Paquette, Alain et al. - Insect herbivory on urban trees:
           Complementary effects of tree neighbours and predation

    • Abstract: Insect herbivory is an important component of forest ecosystems functioning and can affect tree growth and survival. Tree diversity is known to influence insect herbivory in natural forest, with most studies reporting a decrease in herbivory with increasing tree diversity. Urban ecosystems, on the other hand, differ in many ways from the forest ecosystem and the drivers of insect herbivory in cities are still debated. We monitored 48 urban trees from five species – three native and two exotic – in three parks of Montreal (Canada) for leaf insect herbivory and predator activity on artificial larvae, and linked herbivory with both predation and tree diversity in the vicinity of focal trees. Leaf insect herbivory decreased with increasing tree diversity and with increasing predator attack rate. Our findings indicate that tree diversity is a key determinant of multitrophic interactions between trees, herbivores and predators in urban environments and that managing tree diversity could contribute to pest control in cities.
      PubDate: Fri, 01 Apr 2022 15:22:58 +000
       
  • Tourneur, Jean-Claude; Cole, Claire et al. - Pre- and post-oviposition
           behavioural strategies to protect eggs against extreme winter cold in an
           insect with maternal care

    • Abstract: Depositing eggs in an area with adequate temperature is often crucial for mothers and their offspring, as the eggs are immobile and therefore cannot avoid exposure to sub-optimal temperatures. However, the importance of temperature on oviposition site selection is less clear when mothers can avoid these potential adverse effects by both moving their eggs after oviposition and providing other forms of egg care. In this study, we addressed this question in the European earwig, an insect in which mothers care for the eggs during several months in winter, frequently moving them during this period. We set up 60 females from two random natural populations (as this species often exhibits population-specific life-history traits and behaviours) under controlled thermal gradients, and recorded the temperature at which they built their nests, tested whether they moved their eggs after an experimental temperature change, and measured the effects on egg development and hatching rate. Our results demonstrate that females indeed select oviposition sites according to temperature, and can move their eggs to reach warmer temperatures. We also show that these warmer temperatures are necessary to ensure egg hatching. Although this set of behavioural thermoregulations is present in the two tested populations, we found a population-specific modality of expression. These included the range of temperatures explored before oviposition, temperature selected at oviposition and dynamics of egg transport following a temperature change. Overall, our study sheds light on a new post-oviposition strategy in female insects that overwinter with their eggs for coping with temperature changes. More generally, it also reveals that egg care and/or egg transport do not prevent behavioural thermoregulation via oviposition site selection and highlights the diversity of behaviours that insects can adopt to enhance their tolerance to global climate change.
      PubDate: Mon, 28 Mar 2022 14:11:26 +000
       
  • Mouton, Laurence; Henri, Hélène et al. - Analyses of symbiotic bacterial
           communities in the plant pest Bemisia tabaci reveal high prevalence of
           Candidatus Hemipteriphilus asiaticus on the African continent

    • Abstract: Microbial symbionts are widespread in insects and some of them have been associated with adaptive changes. Primary symbionts (P-symbionts) have a nutritional role that allows their hosts to feed on unbalanced diets (plant sap, wood, blood). Most of them have undergone genome reduction, but their genomes still retain genes involved in pathways that are necessary to synthesize the nutrients that their hosts need. However, in some P-symbionts, essential pathways are incomplete and secondary symbionts (S-symbionts) are required to complete parts of their degenerated functions. The P-symbiont of the phloem sap-feeder Bemisia tabaci, Candidatus Portiera aleyrodidarium, lacks genes involved in the synthesis of vitamins, cofactors, and also of some essential amino-acids. Seven S-symbionts have been detected in the B. tabaci species complex. Phenotypic and genomic analyses have revealed various effects, from reproductive manipulation to fitness benefits, notably some of them have complementary metabolic capabilities to Candidatus Portiera aleyrodidarium, suggesting that their presence may be obligatory. In order to get the full picture of the symbiotic community of this pest, we investigated, through metabarcoding approaches, the symbiont content of individuals from Burkina Faso, a West African country where B. tabaci induces severe crop damage. While no new putative B. tabaci S-symbiont was identified, Candidatus Hemipteriphilus asiaticus, a symbiont only described in B. tabaci populations from Asia, was detected for the first time on this continent. Phylogenetic analyses however reveal that it is a different strain than the reference found in Asia. Specific diagnostic PCRs showed a high prevalence of these S-symbionts and especially of Candidatus Hemipteriphilus asiaticus in different genetic groups. These results suggest that Candidatus Hemipteriphilus asiaticus may affect the biology of B. tabaci and provide fitness advantage in some B. tabaci populations.
      PubDate: Tue, 22 Mar 2022 16:13:39 +000
       
  • Bass, Ethan; Kessler, André - Comment on "Information arms race explains
           plant-herbivore chemical communication in ecological communities"

    • Abstract: Zu et al (Science, 19 Jun 2020, p. 1377) propose that an ‘information arms-race’ between plants and herbivores explains plant-herbivore communication at the community level. However, the analysis presented here shows that key assumptions of the proposed model either a) conflict with standard evolutionary theory or b) with our current understanding of plant-insect interactions and phytochemical evolution. We investigate whether specific conditional information might be more suitable as a fitness proxy than the community averages proposed by Zu et al. Finally, we show that the presented statistical patterns can be explained more parsimoniously (e.g. through a null model) without invoking an unlikely process of community selection.
      PubDate: Mon, 14 Mar 2022 16:22:23 +000
       
  • Achaz, Guillaume; Gangloff, Serge et al. - The quiescent X, the
           replicative Y and the Autosomes

    • Abstract: From the analysis of the mutation spectrum in the 2,504 sequenced human genomes from the 1000 genomes project (phase 3), we show that sexual chromosomes (X and Y) exhibit a different proportion of indel mutations than autosomes (A), ranking them X>A>Y. We further show that X chromosomes exhibit a higher ratio of deletion/insertion when compared to autosomes. This simple pattern shows that the recent report that non-dividing quiescent yeast cells accumulate relatively more indels (and particularly deletions) than replicating ones also applies to metazoan cells, including humans. Indeed, the X chromosomes display more indels than the autosomes, having spent more time in quiescent oocytes, whereas the Y chromosomes are solely present in the replicating spermatocytes. From the proportion of indels, we have inferred thatde novomutations arising in the maternal lineage are twice more likely to be indels than mutations from the paternal lineage. Our observation, consistent with a recent trio analysis of the spectrum of mutations inherited from the maternal lineage, is likely a major component in our understanding of the origin of anisogamy.
      PubDate: Thu, 03 Mar 2022 08:38:50 +000
       
 
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