Emerging Parasitic Protists: The Case of Perkinsea

The last century has witnessed an increasing rate of new disease emergence across the world leading to permanent loss of biodiversity. Perkinsea is a microeukaryotic parasitic phylum composed of four main lineages of parasitic protists with broad host ranges. Some of them represent major ecological and economical threats because of their geographically invasive ability and pathogenicity (leading to mortality events). In marine environments, three lineages are currently described, the Parviluciferaceae, the Perkinsidae, and the Xcellidae, infecting, respectively, dinoflagellates, mollusks, and fish. In contrast, only one lineage is officially described in freshwater environments: the severe Perkinsea infectious agent infecting frog tadpoles. The advent of high-throughput sequencing methods, mainly based on 18S rRNA assays, showed that Perkinsea is far more diverse than the previously four described lineages especially in freshwater environments. Indeed, some lineages could be parasites of green microalgae, but a formal nature of the interaction needs to be explored. Hence, to date, most of the newly described aquatic clusters are only defined by their environmental sequences and are still not (yet) associated with any host. The unveiling of this microbial black box presents a multitude of research challenges to understand their ecological roles and ultimately to prevent their most negative impacts. This review summarizes the biological and ecological traits of Perkinsea—their diversity, life cycle, host preferences, pathogenicity, and highlights their diversity and ubiquity in association with a wide range of hosts.

Modelling multivariate data using product copulas and minimum distance estimators: an exemplary application to ecological traits

Modelling and applying multivariate distributions is an important topic in ecology. In particular in plant ecology, the multidimensional nature of plant traits comes with challenges such as wide ranges in observations as well as correlations between several characteristics. In other disciplines (e.g., finances and economics), copulas have been proven as a valuable tool for modelling multivariate distributions. However, applications in ecology are still rarely used. Here, we present a copula-based methodology of fitting multivariate distributions to ecological data. We used product copula models to fit multidimensional plant traits, on example of observations from the global trait database TRY. The fitting procedure is split into two parts: fitting the marginal distributions and fitting the copula. We found that product copulas are well suited to model ecological data as they have the advantage of being asymmetric (similar to the observed data). Challenges in the fitting were mainly addressed to limited amount of data. In view of growing global databases, we conclude that copula modelling provides a great potential for ecological modelling.

Ubiquitous but Ignored? A Case of Water Beetle in Southeastern Europe

Although freshwater habitats, especially springs, are widely recognized as top-priority habitats for monitoring and conservation procedures, their fauna, especially water beetles, are still poorly studied in the southeastern part of Europe. Thus, the dominant water beetle in these habitats, E. bosnica (Zaitzev, 1908) (Insecta: Coleoptera: Elmidae), has been completely ignored and misidentified. This study represents the first review of its taxonomy and its population and ecological traits. Both published and unpublished data are presented and discussed, as well as the results of field sampling in 46 springs and other waterbodies conducted in this region from 2004 to 2019. The identification characters of the male genitalia and the first DNA barcode of the species are presented. The results confirm the close phylogenetic relationship of E. bosnica with E. aenea (Müller, 1806) and E. rioloides (Kuwert, 1890). The species proved to be a useful environmental descriptor and can easily be used as a biological indicator due to its easy identification. The species shows remarkable sensitivity to environmental conditions and inhabits sites that are potentially under increased anthropogenic pressure and could disappear at an alarming rate. Thus, karstic habitats should be included in future conservation and monitoring procedures in this part of Europe.

First Assessment of Nocturnal Lepidopteran Communities in the Forest Savannah Mosaic of the Plateaux Batéké, Southeastern Gabon

Lepidopterans are an important component of central African biodiversity. Indeed, they play an important role as plant pollinators, food source, bio-indicators, and even pests for local crops. However, almost nothing is known about these moths in central Africa, while they are being increasingly threatened by significant landscape changes due mainly to infrastructure constructions and climate change. So, the mosaic of forests and savannah in the Plateaux Batéké (southeastern Gabon) constitutes a unique opportunity to study how Lepidopteran communities might evolve along an ecological gradient with upcoming changes in forest cover in the region. A total of 2824 specimens, representing 14 distinct families or subfamilies, were sampled using light-trapping and sorted into morphospecies, while a subset of 95 samples was further investigated using both morphological and molecular methods. Community comparison of nocturnal Lepidopteran showed that there was a significant difference in terms of abundance only between sampling sessions. Indeed, this could be due to food availability between sampling sessions. In May and June in Gabon, most plants have flowers and fruits and moth families such as Geometridae and Sphingidae emerge at that time. The most represented family in our sampled specimens was the Geometridae, which prefers habitats with permanent river courses as is the case in our sampling area. However, a more comprehensive study using various trapping methods, during several seasonal cycles and with more replicates in each habitat type is needed for a better understanding of the community structure and ecological traits that characterize nocturnal Lepidopteran in the Plateaux Batéké of Gabon.

Chloroplast Genome Traits Correlate With Organismal Complexity and Ecological Traits in Chlorophyta

A positive relationship between cell size and chloroplast genome size within chloroplast-bearing protists has been hypothesized in the past and shown in some case studies, but other factors influencing chloroplast genome size during the evolution of chlorophyte algae have been less studied. We study chloroplast genome size and GC content as a function of habitats and cell size of chlorophyte algae. The chloroplast genome size of green algae in freshwater, marine and terrestrial habitats was differed significantly, with terrestrial algae having larger chloroplast genome sizes in general. The most important contributor to these enlarged genomes in terrestrial species was the length of intergenic regions. There was no clear difference in the GC content of chloroplast genomes from the three habitats categories. Functional morphological categories also showed differences in chloroplast genome size, with filamentous algae having substantially larger genomes than other forms of algae, and foliose algae had lower GC content than other groups. Chloroplast genome size showed no significant differences among the classes Ulvophyceae, Trebouxiophyceae, and Chlorophyceae, but the GC content of Chlorophyceae chloroplast genomes was significantly lower than that of Ulvophyceae and Trebouxiophyceae. There was a certain positive relationship between chloroplast genome size and cell size for the Chlorophyta as a whole and within each of three major classes. Our data also confirmed previous reports that ancestral quadripartite architecture had been lost many times independently in Chlorophyta. Finally, the comparison of the phenotype of chlorophytes algae harboring plastids uncovered that most of the investigated Chlorophyta algae housed a single plastid per cell.

Long-term population dynamics of Aphelenchoides besseyi on Oryza sativa in a paddy field, and changes in the pathological and ecological traits of the two populations

Summary An Oryza sativa cultivar inoculated with the white tip nematode, Aphelenchoides besseyi, was cultivated over 18 years to investigate the population dynamics of the nematode and the change in the virulence of nematodes and tolerance/resistance of plants. The mean number of living nematodes per seed (S) showed two peaks, each of which was followed by a 3-year decrease in the S value, during the initial 10 years. The annual reproduction curve between in year and in year t had a peak in a range of of <1.1. The incidence of white tip disease increased with increasing mean number of living nematodes seed−1 in the previous year, whereas the proportion of seeds with living nematodes increased with increasing mean number of living nematodes seed−1 in the current year. Inoculation tests of the nematode cohorts on the seedling cohorts derived from seeds harvested in the same or different years indicated that the initial 6-year interaction between the rice and nematode populations caused the nematodes to increase the incidence of white tip disease and to decrease the degree of seed swelling and the proportion of heavy seeds. On the other hand, the interaction caused the rice plants to prevent the incidence of disease from increasing and the degree of seed swelling and the proportion of heavy seeds from decreasing.

Stakeholders’ Interactions and Land Management Options in Bui Division, North West Region of Cameroon By

The lucid engagements of stakeholders in land management is an essential strategy in circumventing the stakes of land utilisation. This is symptomatic in ecumenes of intricate ecological traits with diverse stakeholders’ management interests. Bui Division of the North West Region of Cameroon, a citadel of stakeholders enmeshed and is manning their respective lands with signatures of rare plausible interaction options in a decentralisation framework. As such, the study sought to assess the stakeholders’ interaction options for land management in Bui Division. A historical and comparative research designs were used to obtain primary and secondary data from 1971-2021. This was through questionnaires, formal and informal interviews from 16.9% of population in 505 households and direct observations with consultation of published and unpublished documents. Data was analysed using inferential statistics with the Anova Test at 0.05 at a critical level and a df of 7 to determine the significant differences in stakeholders’ interaction options for land management. The results reveal the calculated values of 0.9, 8, 3.9, 3.6 and 8.3 higher than the tabulated ratios of 0.65, 0.000, 0.001, 0.002 and 0.000 respectively. This indicates that there were significant differences in stakeholders’ interaction options in land management based on stakeholders’ activities and interests. Multiple stakeholders’ collaborative and participatory interaction options were positively apt in diverse sectors of land management. The study posits that participatory interaction through multi-stakeholders’ involvements and collaborations are the best options to minimise the deprived perceptions of under representation of some stakeholders in land management platforms in Bui Division.