Parasitism, seasonality, and diversity of trombiculid mites (Trombidiformes: Parasitengona, Trombiculidae) infesting bats (Chiroptera) in Poland

The study aims to ascertain the diversity of trombiculid species associated with Chiroptera in Poland, and for the first time in the case of research on Central European Trombiculidae, we use both DNA and morphology in an integrative taxonomic approach to determine species identities of trombiculids. The research was carried out from 2015 to 2019. In total, 2725 larvae were collected from 300 specimens of bats belonging to 11 species. Deutonymphs were obtained through laboratory rearing of larvae; few larvae and deutonymphs were collected also from bats' daily roosts. The presence of trombiculid larvae on hosts was observed between July and April of the following year, with the highest numbers recorded in autumn, during bat swarming. Male bats were infested more often than females (16.4 vs. 6.6%). The highest infestation rate was recorded for Barbastella barbastellus, Myotis nattereri and Plecotus auritus, and the highest prevalence of chiggers (> 30%) for Myotis bechsteinii and P. auritus. The larvae found on bats occupied the areas with free access to the host’s skin: auricles, tragus, and snout. Morphological identification of specimens to the species level was hindered by the mosaic distribution of diagnostic traits. Morphological analyses indicated the presence of Leptotrombidium russicum and Leptotrombidium spp. in the examined material, whereas molecular analyses additionally suggested three other potential species assigned to the same genus based on the assessed scope of intrageneric variation (ASAP method). We argue that the identification of the parasitic larvae (chiggers) using morphological characters does not address the question of actual species boundaries, which, in turn, affects the inferences about host specificity and host range.

Diversity of Modes of Reproduction and Sex Determination Systems in Invertebrates, and the Putative Contribution of Genetic Conflict

About eight million animal species are estimated to live on Earth, and all except those belonging to one subphylum are invertebrates. Invertebrates are incredibly diverse in their morphologies, life histories, and in the range of the ecological niches that they occupy. A great variety of modes of reproduction and sex determination systems is also observed among them, and their mosaic-distribution across the phylogeny shows that transitions between them occur frequently and rapidly. Genetic conflict in its various forms is a long-standing theory to explain what drives those evolutionary transitions. Here, we review (1) the different modes of reproduction among invertebrate species, highlighting sexual reproduction as the probable ancestral state; (2) the paradoxical diversity of sex determination systems; (3) the different types of genetic conflicts that could drive the evolution of such different systems.

Parkin-independent mitophagy via Drp1-mediated outer membrane severing and inner membrane ubiquitination

Here, we report that acute reduction in mitochondrial translation fidelity (MTF) causes ubiquitination of the inner mitochondrial membrane (IMM) proteins, including TRAP1 and CPOX, which occurs selectively in mitochondria with a severed outer mitochondrial membrane (OMM). Ubiquitinated IMM recruits the autophagy machinery. Inhibiting autophagy leads to increased accumulation of mitochondria with severed OMM and ubiquitinated IMM. This process occurs downstream of the accumulation of cytochrome c/CPOX in a subset of mitochondria heterogeneously distributed throughout the cell (“mosaic distribution”). Formation of mosaic mitochondria, OMM severing, and IMM ubiquitination require active mitochondrial translation and mitochondrial fission, but not the proapoptotic proteins Bax and Bak. In contrast, in Parkin-overexpressing cells, MTF reduction does not lead to the severing of the OMM or IMM ubiquitination, but it does induce Drp1-independent ubiquitination of the OMM. Furthermore, high–cytochrome c/CPOX mitochondria are preferentially targeted by Parkin, indicating that in the context of reduced MTF, they are mitophagy intermediates regardless of Parkin expression. In sum, Parkin-deficient cells adapt to mitochondrial proteotoxicity through a Drp1-mediated mechanism that involves the severing of the OMM and autophagy targeting ubiquitinated IMM proteins.

The Evolution of Molybdenum Dependent Nitrogenase in Cyanobacteria

Nitrogen fixation plays a crucial role in the nitrogen cycle by helping to convert nitrogen into a form usable by other organisms. Bacteria capable of fixing nitrogen are found in six phyla including Cyanobacteria. Molybdenum dependent nitrogenase (nif) genes are thought to share a single origin as they have homologs in various phyla. However, diazotrophic bacteria have a mosaic distribution within the cyanobacterial lineage. Therefore, the aim of this study was to determine the cause of this mosaic distribution. We identified nif gene operon structures in the genomes of 85 of the 179 cyanobacterial strains for which whole genome sequences were available. Four nif operons were conserved in each diazotroph Cyanobacterium, although there were some gene translocations and insertions. Phylogenetic inference of these genes did not reveal horizontal gene transfer from outside the phylum Cyanobacteria. These results support the hypothesis that the mosaic distribution of diazotrophic bacteria in the cyanobacterial lineage is the result of the independent loss of nif genes inherited from common cyanobacterial ancestors in each lineage.

STATE OF CENOPOPULATIONS OF SOME RARE SPECIES OF PLANTS OF SAMARA REGION iN THE TERRITORY OF NATURE MONUMENT OF REGIONAL IMPORTANCE "SERNOVODNY SHIKHAN"

The condition of cenopopulations of four rare species ( Artemisia salsoloides , Hedysarum grandiflorum , Oxytropis floribunda , Stipa korshinskyi ) in the petrophytic steppes of the High Zavolzh'yе (High Transvolga, Samara region) was studied on the basis of the regularities of their spatial and ontogenetic structure. The data were processed using the software package R, which allows us to perform calculations of spatial statistics. Thus, stationarity, isotropy, and intensity of plant objects location were evaluated. The mosaic distribution of individuals of all species recorded within the boundaries of the study area was characterized. Using local density maps, the sparseness of individuals on the outskirts of the model site, caused by cattle grazing, was revealed. The behavior of the Ripley's function showed an independent distribution of species as a consequence of weak interspecies competition. The spatial pattern and age spectrum of the studied rare protected dominant species were analyzed. The absence of seedlings and senile plants due to exposure to unfavorable factors of exogenous nature was noted. The im-v and g states were the most numerous. In accordance with the behavior of the K(r) function, the random placement of the four predominant species was revealed, indicating their optimal location within the study area. Patterns of mutual placement of pregenerative and generative individuals of Artemisia salsoloides, Hedysarum grandiflorum, and Oxytropis floribunda were studied. Calculation of the Ripley's cross-function showed that individuals of different age groups of the described species are located independently from each other, demonstrating the absence of intraspecific competition. Undoubtedly, the spatial distribution of individuals of the plant species composing the phytocenosis is influenced both by grazing and by the features of the soil cover of the site, which is manifested by significant elimination of plants at the initial stages of ontogenesis. Nevertheless, the cenopopulations of rare species are stable, mature and promising, and the individuals are distributed in an optimal way that minimizes energy costs.

The second outbreak of the poplar leafminer Phyllonorycter populifoliella in St. Petersburg

Исследовались популяционные характеристики, факторы смертности и пищевые предпочтения минирующей листья тополя тополёвой нижнесторонней моли-пестрянки Phyllonorycter populifoliella (Treitshke, 1833) (Lepidoptera: Gracillariidae) в Санкт-Петербурге в связи с развитием второй в истории насаждений города вспышки массового размножения этого вредителя. В разных районах Санкт-Петербурга были заложены пробные площади с разной интенсивностью повреждения, варьирующей в среднем от 5,2 до 21,7 мин/лист. На каждой пробной площади в первые дни после начала лёта первого поколения (первая декада августа) срезались по две ветви в нижней части кроны с каждого дерева на которых анализировались мины 50 листьев для установления причин гибели и доли выживших особей. На всех пробных участках (за одним исключением) был один вид тополя - тополь берлинский Populus × berolinensis. Именно этот вид наиболее интенсивно повреждался Ph. populifoliella. Вспышка размножения в 2017-2019 гг., локализованная в Невском районе, постепенно распространяется по территории города, имея выраженный мозаичный характер,однако причины этой мозаичности распространения не ясны. Плотность популяции вредителя в Невском районе за последние годы существенно увеличилась. Наиболее успешно проходит развитие на деревьях с высокой плотностью популяции вредителя. С одного листа на таких участках вылетает 7 и более бабочек (36-52%) от начавших развиваться личинок), тогда как при меньшей плотности (в среднем 5 и 11 мин/лист) вылет составляет 8 и 19% соответственно. Это позволяет сделать предположение о ведущей роли состояния кормовых деревьев в развитии тополёвой моли. В отношении остальных факторов, влияющих на смертность, не удалось выявить их выраженного воздействия на плотность популяции. Population characteristics, mortality factors, and food preferences of the moth Phyllonorycter populifoliella (Treitshke, 1833) (Lepidoptera: Gracillariidae) mining leaves of poplar in St. Petersburg were studied under conditions of the second outbreak of this pest in the history of the urban plantings in St. Petersburg. In different districts of St. Petersburg, sample plots were established with different intensity of damage by the poplar leafminer, varying from 5.2 to 21.7 mines per leaf. On each sample plot, in the first days after the beginning of the flight of the first generation adults (the first ten days of August), two branches were cut in the lower part of the crown from each test tree, on which mines of at least 50 leaves were collected and analyzed to establish the causes of death and the proportion of the surviving individuals. With one exception, all sample plots were represented by one poplar species - the Berlin poplar Populus × berolinensis. This species was most intensively damaged by Ph. populifoliella . Outbreak in 2017- 2019 was initially localized in the Nevsky District and then gradually spread throughout the city, having the pronounced mosaic character, however, the reasons for the mosaic distribution of the outbreak are unclear. The density of the pest population has increased significantly in the Nevsky District over the past years. Development of the moth is most successful on trees with a high population density of the pest. Seven or more adult moths emerge from one leaf in such areas (36-52% of the larvae that begun to develop), while at a lower density (on average, 5-11 mines per leaf), the emergence was 8 and 19%, respectively. This finding allows us to assume the leading role of the state of forage trees in the development of the poplar leafminer. Contribution of the other factors affecting larval mortality was not possible to evaluate.

Re-evaluation of an early sphenacodontian synapsid from the Lower Permian of England

ABSTRACTThe holotypic isolated maxilla of the early sphenacodontian Haptodus grandis from the Cisuralian of England is revisited. A unique character combination includes haptodontine-grade traits like less specialised teeth and a high number of precanines, but at the same time a shortened lacrimal that is separated from the naris, which is strongly diagnostic of Sphenacodontoidea. As the specimen cannot be assigned to any known taxon, the new taxon Hypselohaptodus grandis gen. nov. is proposed. Comparison with other sphenacodontians reveals a mosaic distribution of maxillary features, most significantly regarding the precanine region. Preliminary character histories preclude Hypselohaptodus from Sphenacodontidae, but suggest a haptodontine-grade or basal therapsid position. The latter hypothesis is substantiated by an ecological model of episodic wet phases in an overall trend of aridification throughout the Permian, to explain the rareness of non-sphenacodontid sphenacodontians in the fossil record. Also from the early Permian of England, an isolated dentary has previously been assigned to Ophiacodon, but can be shown to be either a sphenacodontian, possibly affiliated with Hypselohaptodus, or a robust, Stereorhachis-like ophiacodontid. The absence of Ophiacodon in the intramontaneous Permian basis of Europe is explained by a narrow environmental tolerance range requiring limnic connection with lowland basins.

Sugarcane Mosaic Distribution, Incidence, Increase, and Spatial Pattern in Louisiana

Sugarcane mosaic is a historically important disease in Louisiana currently caused by sorghum mosaic virus (SrMV). Successful breeding for resistance reduced the disease to low incidence in commercial cultivars. However, mosaic was detected in experimental clone evaluations at multiple locations, leading to uncertainty concerning the current distribution and incidence in the state. Field surveys were conducted from 2016 to 2018 in breeding program yield trials and experimental clone seed cane increase fields. Mosaic symptomatic plants were observed in a newly released cultivar, HoCP 09-804, in three of five production areas, with incidences ranging from 0 to 10%. Mosaic also was observed in nine additional experimental clones. Single leaf samples were tested for SrMV using reverse transcription PCR. All symptomatic samples and a low percentage (0.3%) of asymptomatic samples tested positive for SrMV, confirming that it continues to be the causal species. Runs analysis detected aggregation of infected plants within at least 70% of rows in 94% of surveyed fields. The spatial pattern and geographical distribution of disease incidence suggested that infected seed cane was the source of the disease. Surveys conducted in the same fields of HoCP 09-804 through two subsequent crops detected disease incidence increases in some fields and decreases in the others in first ratoon, but observed incidence was lower compared with plant cane in all fields in second ratoon. The results indicated that disease increase owing to aphid transmission did not occur under the prevailing conditions.

Morphometrics and phylogeography of the cave-obligate land snail Helicodiscus barri (Gastropoda, Stylommatophora, Helicodiscidae)

Molecular studies have recently led to the detection of many cryptic species complexes within morphologically ambiguous species formerly undescribed by the scientific community. Organisms such as land snails are at a particularly higher risk of species misidentification and misinterpretation, in that gastropod systematics are based almost entirely on external shell morphology. Subterranean ecosystems are associated with especially high degrees of cryptic speciation, largely owing to the abiotic similarities of these systems. In this study, we attempt to diagnose the potential cryptic diversity in the troglobitic land snail Helicodiscusbarri. Land snails are generally associated with having low vagility, and as such this species’ broad, mosaic distribution indicates the misdiagnosis of this organism as a single species. We analyze both mitochondrial (16S, CO1) and nuclear (28S, H3) genetic data for 23 populations. Phylogeny for H.barri was reconstructed using both maximum-likelihood and Bayesian approaches to assess relationships among populations, and two species delimitation methods (mPTP and ABGD) were used to detect the presence of unique molecular operational taxonomic units (MOTUs). Species delimitation results revealed seven and sixteen MOTUs respectively, suggesting the presence of several cryptic lineages within H.barri. To assess how external shell morphology corresponds with patterns of genetic and environmental variation, two morphometric approaches were used incorporating 115 shells from 31 populations. Both morphometric approaches reveal a significant environmental influence on shell morphology, and one approach showed the significance of MOTU groups. We discuss the delimitation and morphometric results and additionally provide discussion on the taxonomic and conservation implications of this study.