Novel Insights into the Bovine Polled Phenotype and Horn Ontogenesis in Bovidae

Despite massive research efforts, the molecular etiology of bovine polledness and the developmental pathways involved in horn ontogenesis are still poorly understood. In a recent article, we provided evidence for the existence of at least two different alleles at the Polled locus and identified candidate mutations for each of them. None of these mutations was located in known coding or regulatory regions, thus adding to the complexity of understanding the molecular basis of polledness. We confirm previous results here and exhaustively identify the causative mutation for the Celtic allele (PC) and four candidate mutations for the Friesian allele (PF). We describe a previously unreported eyelash-and-eyelid phenotype associated with regular polledness, and present unique histological and gene expression data on bovine horn bud differentiation in fetuses affected by three different horn defect syndromes, as well as in wild-type controls. We propose the ectopic expression of a lincRNA in PC/p horn buds as a probable cause of horn bud agenesis. In addition, we provide evidence for an involvement of OLIG2, FOXL2 and RXFP2 in horn bud differentiation, and draw a first link between bovine, ovine and caprine Polled loci. Our results represent a first and important step in understanding the genetic pathways and key process involved in horn bud differentiation in Bovidae

An assessment of five cut-off channels of the Rhône River with adult and benthic caddisfly assemblages

A large-scale river restoration programme was launched on the French Rhône in 1998. Among other objectives, it seeks to enhance the lateral connectivity between the river and its floodplain and the diversity of secondary-channels. Caddisflies are recognized as valuable indicators to assess aquatic ecosystems in general but only few studies concerned adult caddisflies in the Rhône River. The aim of the study was to carry out a comparative assessment of five floodplain channels in one sector of the Upper-Rhône, on the basis of their caddisfly assemblages. Caddisflies were sampled in 2015 in the larval and adult stages via benthic samples and light-traps, respectively. Previous data were also available for both stages. The analyses were based on the species list and few habitat variables. They used diversity indices (specific richness, diversity, evenness, rarity), abundance distribution models and biological traits. Abundance classes combining larval and adult data were set up to better describe their distribution along the lateral connectivity gradient. Our results examplified how side-channels contribute to the maintenance of sector-scale aquatic biodiversity; especially through the lateral coexistence of species and assemblages otherwise typical for contrasted level of the longitudinal typology. The study also suggested i) that the interaction between lateral connectivity and year-to-year hydrological variations may be crucial in explaining changes in caddisfly abundances and ii) that the study of rank-abundance models along connectivity gradients may be of general interest in the study of floodplain diversity patterns

Lateral Connectivity In Large River Floodplains: From Invertebrate Community Prediction To Local Food Web Transfers

The particularly rich aquatic biodiversity of large river floodplains is structured by river dynamics and hydrological connectivity. Subjected to very high pressure from river uses and engineering (e.g. hydropower, dams, dykes), large rivers undergo physical (loss of diversity of floodplain habitats) and functional (loss of lateral hydrological connectivity) changes in their floodplain habitats. The significant degradation of these habitats and the associated biodiversity has led to a desire to limit the impacts of human activities and restore floodplain environments. The aim of the present thesis is to explore the relationship between hydrological connectivity and biological processes (taxonomic diversity and trophic transfers) in large river floodplains. To this end, a multidisciplinary (geomorphology, biology and ecology), multi-compartment (plankton, invertebrate and fish) and multi-scale (channel vs. floodplain) approach was adopted. Two floodplains of the French Upper Rhône comprising restored channels characterized by variable connectivity with the river were selected as study sites. The results confirm the strong influence of hydrological connectivity on the composition of invertebrate assemblages at both the individual channels and the entire floodplain. They also confirmed the aquatic invertebrate diversity varies in response to two components of the hydrological connectivity (upstream overflows with hydraulic constraints and so-called "slow" connections) at both spatial scales. Both flow components also proved to be effective to predict invertebrate diversity changes along a progressive alluviation and disconnection sequence after the reconnection with the main river of a previously isolated channel. At the floodplain scale, relationships between changes in the composition of invertebrate assemblages and thermal inertia in stagnant floodplain channels show that the benthic diversity of floodplains is also generated by the diversity of the water sources that feed them (surface water vs. ground water). Isotope analyses in juvenile fish revealed the dietary adaptation of these organisms to the fluctuations and scarcity of trophic resources in two floodplain fish nurseries. These results justified that environmental conditions at the base of the food web have a large influence on the YOY diet composition. Our study also demonstrated that changes in temporal patterns in water level variations (i.e. dam hydropeaking) can alter key ecosystem processes such as planktonic production and energy transfer through food webs. An innovative approach integrating light trapped adult caddisflies and statistical mixed models was proposed to decipher the role of species traits and habitats in mercury accumulation and transfer in a large river floodplain. This study revealed that variation of mercury concentrations between species was best explained by the larval feeding type, whereas the contributions of larval micro-habitat and forewing length (used as surrogate of adult body size) were minor. Moreover, caddisfly adults associated with the floodplain larval macrohabitat were, on average, 3 times less contaminated than those associated with the main river channel. These results demonstrated the strong effect of lateral connectivity and the likely impact of the composition of the dissolved organic matter in floodplains (that reduces the mercury bioavailability for biota) on mercury bioaccumulation and transfers. Overall, the findings of the present work revealed the influence of lateral hydrological connectivity on (i) the distribution of benthic invertebrates in the floodplain, (ii) the functionality of fish nurseries and (iii) the transfer of contaminants through the emergence of aquatic insects. These outcomes have major implications for the improvement of the existing practices of floodplain ecological restauration. Namely, they allow to anticipate taxonomic diversity in relation to natural evolution or abrupt change (e.g. by reconnection) in the level of hydrological connectivity of the floodplain channel. The influence of thermal inertia in floodplain invertebrate diversity offers important prospects for restoring vertical connectivity (raising the groundwater table level, limiting the bed incision, etc.). Our results also show that dams can contribute to the restoration effort. Flow releases from dams can be manipulated in order to mimic elements of natural flow regimes (upstream overflow and slow connections) in floodplains. Conversely, a low flow variability is a prerequisite for favourable plankton production and juvenile feeding in floodplain fish nurseries. Finally, our work highlighted certain links between lateral hydrological connectivity and biogeochemical cycles (organic matter, nutrients, contaminants) in restored floodplain channels

Head capsule observations in chironomid larvae and contaminant levels in a moderately contaminated small karstic stream, Jura Mountains, eastern France

Chironomid larvae are useful bioindicators to assess environmental degradation and pollution of freshwater ecosystems. Specifically, mouthparts deformities in chironomid larvae are considered as indicators of environmental stress (e.g. caused by water pollution). In this study, a total of 50 chironomid larvae from a small karstic stream were examined for cephalic/mouthpart deformities. Five years earlier, toxicological analysis were performed on stream sediment and bryophyta and revealed a significative pollution (trace metals, pesticides and as well organic contamination). The highest contaminant concentration was 59 (+/- 11.8) mg/kg for Zn in bryophyta and 960 µg/kg for fluoranthene in sediment. According SEQ-Eau (French System of Evaluating Water Quality), this pollution is sufficient to cause adverse effects on aquatic biota. Despite this contamination, no cephalic deformities were observed on both upstream (more contaminated, RVA1) and downstream stations (RVA2). Only a mechanical wear and some broken mentum have been detected on upstream station. These results may encourage reflections on the role of certain environmental variables (e.g. dissolved oxygen concentration, water temperature, dry period, substratum), microbial processes (e.g. methylation of contaminants) regarding the toxicity level, the uptake and the effects of contaminants and some physiological mechanisms (e.g. ecdysis) for their elimination

The female of Cyrnus cintranus McLachlan 1884 (Trichoptera: Polycentropodidae) in France

Cyrnus cintranus is one of five Cyrnus species with distribution ranges restricted to western Europe. In this paper, we redescribe the poorly defined female of C. cintranus. We also draw attention to the existence of a previously unmentioned morphological feature that aids significantly in the identification of the female of C. cintranus, separating it from the females of the other Cyrnus species. New data are provided on the distribution and ecology of this species

Assessment of the stream invertebrate β‐diversity along an elevation gradient using a bidimensional null model analysis

[Formula: see text] ‐Diversity, commonly defined as the compositional variation among localities that links local diversity (α‐diversity) and regional diversity (γ‐diversity), can arise from two different ecological phenomena, namely the spatial species turnover (i.e., species replacement) and the nestedness of assemblages (i.e., species loss). However, any assessment that does not account for stochasticity in community assembly could be biased and misinform conservation management. In this study, we aimed to provide a better understanding of the overall ecological phenomena underlying stream [Formula: see text] ‐diversity along elevation gradients and to contribute to the rich debate on null model approaches to identify nonrandom patterns in the distribution of taxa. Based on presence‐absence data of 78 stream invertebrate families from 309 sites located in the Swiss Alpine region, we analyzed the effect size of nonrandom spatial distribution of stream invertebrates on the [Formula: see text] ‐diversity and its two components (i.e., turnover and nestedness). We used a modeling framework that allows exploring the complete range of existing algorithms used in null model analysis and assessing how distribution patterns vary according to an array of possible ecological assumptions. Overall, the turnover of stream invertebrates and the nestedness of assemblages were significantly lower and higher, respectively, than the ones expected by chance. This pattern increased with elevation, and the consistent trend observed along the altitudinal gradient, even in the most conservative analysis, strengthened our findings. Our study suggests that deterministic distribution of stream invertebrates in the Swiss Alpine region is significantly driven by differential dispersal capacity and environmental stress gradients. As long as the ecological assumptions for constructing the null models and their implications are acknowledged, we believe that they still represent useful tools to measure the effect size of nonrandom spatial distribution of taxa on [Formula: see text] ‐diversity

Two new species of Bungona Harker, 1957 (Ephemeroptera: Baetidae) from Borneo, Indonesia

Two new species of Bungona, belonging to the subgenera Chopralla Waltz & McCafferty, 1987 and Centroptella Braasch & Soldán, 1980, are described based on larvae from Kalimantan (Borneo, Indonesia). Bungona (Centroptella) papilionodes n. sp. is the third species described for the subgenus. It can be distinguished from Bungona (Centroptella) longisetosa (Braasch & Soldán, 1980) and Bungona (Centroptella) soldani (Müller-Liebenau, 1983) by the length of the maxillary palp, the presence or absence of an additional small denticle on the lateral margin of the distal incisor, and the spination of the paraproct. This new report of the subgenus greatly increases its geographic range of distribution, as it was known only from Sri-Lanka and China. Bungona (Chopralla) bintang n. sp. is the seventh species described for the subgenus Chopralla and the second described from Borneo. It differs from others species of the subgenus and especially from Bungona (Chopralla) pusilla (Müller-Liebenau, 1984) (Borneo) by the combination of lacking hindwing pads, the particular spination of distal margins of tergites, and the shape of the maxillary palp. The two new species fit into the recently revised concepts of Chopralla and Centroptella and confirm the characters used to support these taxa as valid subgener

Size-Abundance Relationships of Freshwater Macroinvertebrates in Two Contrasting Floodplain Channels of Rhone River

Body size is perhaps the most fundamental property of an organism and its relationship with abundance is one of the most studied relationships in ecology. Although numerous studies have examined these relationships in local communities, few have investigated how they vary at different temporal and spatial scales. We investigated the relationship between body size and abundance of local macroinvertebrate communities in two floodplain channels of the French upper Rhone River. The two channels differ in their vegetation coverage (high vs. low vegetation) and hydrological regimes. The shapes of the size-abundance relationship were similar between channels on a yearly basis but differed when compared between months. The variation in local size-abundance relationships between months was related to variation in the functional diversity across time. Our findings suggest that local size-abundance relationships are able to quantitatively describe temporal changes in community structure, showing the importance of relating diversity with ecosystem function in a more realistic context.</p