Taxa Research Articles

Inconsistent identification of Apilactobacillus kunkeei-related strains obtained by well-developed overall genome-related indices

During a decade, overall genome related indices, including average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH), have been used as standards for the classification and identification of bacteria. On the other hand, a former study suggested that ANI-based classification is difficult for fructophilic lactic acid bacterium Apilactobacillus kunkeei. In the present study, the classification of Apilactobacillus spp., including A. kunkeei, was evaluated by multiple genome-based analyses. ANIb-based classification appropriately identified strains of Apilactobacillus spp., except for A. kunkeei-related strains. A number of strain pairings in A. kunkeei-related strains showed ANIb values around the threshold value of 95 %, based on which they were unable to be identified. On the other hand, dDDH provided clearer identification results for A. kunkeei-related strains but segmentalized them into a number of groups, while the validity of this segmentation was unclear. Certain strains shared similarities over the threshold with multiple species-level taxonomic groups in ANIb and dDDH. GTDB-Tk classifies the A. kunkeei-related strains into six species-level taxonomic groups without marked confusion, while the classification results differed from those obtained by ANIb and dDDH. The present study highlighted the inconsistent identification of A. kunkeei-related strains by the well-developed overall genome related indices, which would be a significant concern for bacterial taxonomy. Moreover, the rule adopted in GTDB-Tk, i.e., the classification of strains to taxa containing type strains showing the highest similarity, is recommended for introduction into ANIb- and GGDC-based classifications

Correlates of avian extinction timing around the world since 1500 CE

Avian extinctions have been relatively well documented in modern history, and in the past millennia, more bird species are known to have gone extinct than species in any other vertebrate class. We examined the biological correlates of extinction timing among 216 bird species that recently were either observed to go extinct or disappeared since 1500 CE, performing a novel analysis for examining the extinction trends of birds by modelling traits against the number of years since present day during which species have been extinct. We analyzed a broad range of traits and characteristics that have previously been associated with extinction and extinction risk in birds and compared the effects of these traits simultaneously against one another. In order to provide a more comprehensive and robust assessment of trait-based drivers of global bird loss in comparison to prior studies, we included extinct species recognized by any of the three major avian taxonomies as well those birds that lack recent confirmed sightings and are at least functionally extinct. We found that insular, flightless, larger-bodied, ecologically specialized species, as well as those with high aspect ratio wings, were likely to go extinct earlier in time. Besides identifying the key locations and time periods over the past five centuries where birds have gone extinct, and highlighting specific extinction-prone taxonomic groups, we provide a complete and unified dataset of traits used in this study that helps address the lack of extensive public data on modern extinct species.

Temporal and spatial dynamics of the non-indigenous bryozoan, Amathia verticillata, and its associated invertebrate community

The widespread non-indigenous bryozoan, Amathia verticillata primarily colonizes in coastal bays and harbors on anthropogenic structures. Although this habitat-forming bryozoan is widely recognized to house a variety of marine invertebrates within its structure, little is known about their spatiotemporal dynamics and their associated invertebrate community in Southern California, USA. Thus, we undertook a comprehensive yearlong study (July 2021-2022) in an urbanized estuary (Mission Bay, San Diego) to quantify A. verticillata percent cover and abiotic conditions at 6 stations with varying environmental conditions. The seasonal and spatial gradients in temperature and salinity within Mission Bay were as expected with seasonal hypersalinity typical of Mediterranean climate regions. The percent cover of A. verticillata was positively correlated with temperature with the highest percent cover found during the warmest periods, and higher average percent cover found in the warmer, eastern parts of Mission Bay. We also collected three replicate A. verticillata colonies to characterize the marine invertebrate community associated with this non-indigenous bryozoan. We identified 25 families, 24 genera, and 19 organisms to species belonging to the taxonomic groups: amphipods, isopods, tanaids, and polychaetes. Furthermore, we identified juvenile stages and ovigerous females living within A. verticillata. None of the identified invertebrate families contributed more than 21 % to the community. The seasonal growth and annual temporal patterns of A. verticillata may prevent competitively dominant species from becoming established within the invertebrate community and allow A. verticillata to harbor a diverse invertebrate community. Sphaeromatidae isopods were the most common family found in the bryozoan colonies, likely reflecting their broad environmental tolerances. Additionally, while some of the invertebrates found within A. verticillata were also non-indigenous species, more work needs to be done to determine if A. verticillata disproportionately supports these species over native species. Collectively, our results imply that A. verticillata functions as a nursery habitat on anthropogenic structures for peracarid crustaceans and polychaetes. Furthermore, A. verticillata assemble analogous communities across their distribution, which may indicate that invasions are homogenizing biota globally.

New mitochondrial genomes of three whip spider species from the Amazon (Arachnida, Amblypygi) with phylogenetic relationships and comparative analysis

The complete mitochondrial genomes of the whip spiders Charinus carajas, C. ferreus, and Heterophrynus longicornis were sequenced, annotated, and compared with other mitogenomes of whip spiders and arachnids. The three new mitogenomes have the 37 genes usually observed in Metazoa: 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), and two ribosomal RNAs (rRNAs), plus a non-coding control region (CR). Most PCGs presented an ATN start codon, except cox1 in both Charinus species, initiating with TTA. Most PCGs terminated with stop codons TAA or TAG, except nad5 of C. carajas and cox3 of H. longicornis, which presented an incomplete stop codon (T). The Ka/Ks ratios were less than one for all the PCGs, indicating these genes are under purifying selection. All the tRNAs, except for serine 1 (trnS1), had the typical cloverleaf-shaped secondary structure. All the phylogenetic analyses resolved Charinus carajas and C. ferreus as monophyletic groups. Nonetheless, we did not recover the monophyly of Heterophrynus longicornis. The phylogenies under partitioned models did not recover suprageneric taxonomic groups as clades, but the Bayesian inference under the CAT infinite mixture model recovered the family Phrynidae and the superfamily Phrynoidea as monophyletic groups.

Habitat dimensionality and feeding strategies but not temperature as determinants of body size-trophic structure relationship in a marine food web.

Disentangling the determinants of trophic structure is central to ecology. The capacity to capture subjugate and consume a prey (i.e. gape limitation) is a relevant limitation to acquire energy for most organisms, especially those in smaller size ranges. This generates a size hierarchy of trophic positions in which large organisms consume small ones. Body size is tightly correlated to gape limitation and explains a large fraction of variance in the body size-trophic position relationship. However, a considerable fraction of variance still remains to be explained. Consumer search space dimensionality (2D or 3D) and feeding strategies, temperature and the size structure of primary producers can alter the trophic structure, but tests based on information from natural food webs are scarce. We generated specific predictions about the body size trophic position relationship and evaluated them using information from a subtropical South Atlantic coastal marine ecosystem: benthic realm (2D, rocky shore and sandy beach) and the pelagic realm (3D). We characterized this marine coastal food web based on stable isotopes of carbon and nitrogen from 256 samples from primary producers (macroalgae and phytoplankton) to large predators (sand shark) in summer and winter. Consumer body size encompassed six orders of magnitude in weight from 10-2 to 6 × 104 g. Isotopic signal corresponded to an integration of carbon sources from basal consumers to top predators. The body size-trophic position relationship showed a linear positive association with different slopes for the benthic and pelagic environments. This implies a smaller predator prey size ratio for pelagic (3D) with respect to benthic consumers (2D) as theoretically expected. No seasonal differences were found in slopes and most of the overall variance in benthic environments was largely explained by feeding strategies of the different taxonomic groups. We provide an integrated evaluation on the role of body size, consumer search space and feeding strategy to understand the determinants of trophic position. Results demonstrate that integrating gape limitation hypothesis, the dimensionality of consumer search space and feeding strategies into a formal robust framework to understand trophic structure is feasible even in complex natural ecosystems.

Characterization of gut microbiota dynamics in an Alzheimer’s disease mouse model through clade-specific marker-based analysis of shotgun metagenomic data

Alzheimer’s disease (AD) is a complex neurodegenerative disorder significantly impairing cognitive faculties, memory, and physical abilities. To characterize the modulation of the gut microbiota in an in vivo AD model, we performed shotgun metagenomics sequencing on 3xTgAD mice at key time points (i.e., 2, 6, and 12 months) of AD progression. Fecal samples from both 3xTgAD and wild-type mice were collected, DNA extracted, and sequenced. Quantitative taxon abundance assessment using MetaPhlAn 4 ensured precise microbial community representation. The analysis focused on species-level genome bins (SGBs) including both known and unknown SGBs (kSGBs and uSGBs, respectively) and also comprised higher taxonomic categories such as family-level genome bins (FGBs), class-level genome bins (CGBs), and order-level genome bins (OGBs). Our bioinformatic results pinpointed the presence of extensive gut microbial diversity in AD mice and showed that the largest proportion of AD- and aging-associated microbiome changes in 3xTgAD mice concern SGBs that belong to the Bacteroidota and Firmicutes phyla, along with a large set of uncharacterized SGBs. Our findings emphasize the need for further advanced bioinformatic studies for accurate classification and functional analysis of these elusive microbial species in relation to their potential bridging role in the gut-brain axis and AD pathogenesis.

Transposable Element Diversity and Activity Patterns in Neotropical Salamanders.

Transposable elements (TEs) compose a substantial proportion of the largest eukaryotic genomes. TE diversity has been hypothesized to be negatively correlated with genome size, yet empirical demonstrations of such a relationship in a phylogenetic context are largely lacking. Furthermore, the most abundant type of TEs in genomes varies across groups, and it is not clear if there are patterns of TE activity consistent with genome size among different taxa with large genome sizes. We use low-coverage sequencing of 16 species of Neotropical salamanders, which vary ∼7-fold in genome size, to estimate TE relative abundance and diversity for each species. We also compare the divergence of copies of each TE superfamily to estimate patterns of TE activity in each species. We find a negative relationship between TE diversity and genome size, which is consistent with the hypothesis that either competition among TEs or reduced selection against ectopic recombination may result in lower diversity in the largest genomes. We also find divergent activity patterns in the largest versus the smallest genomes, suggesting that the history of TE activity may explain differences in genome size. Our results suggest that both TE diversity and relative abundance may be predictable, at least within taxonomic groups.

Short-term conservation education influences Ugandan adolescents' knowledge, attitudes and investment decisions.

Environmental education research methods often focus on measuring changes in people's attitudes toward conservation. While attitudes are an important indicator of change, it is critical to target incentivised behaviour because conservation efforts often involve behavioural changes that are costly to one's self (e.g., reducing water use, purchasing pricier alternatives). In the present study, we measured both attitudes and behaviours in a short-term conservation education program near the primate-rich Kibale National Forest in Western Uganda. Adolescents ( N = 59) participated in a three-hour curriculum over three weeks integrated into an after-school wildlife club. After almost 30 years of successful primate conservation education in this region, we chose a novel taxonomic group (bats) for this study. Our pre-registered study had two conditions: an experimental condition, in which students learned about bats as an important local pollinator species, and a control condition, in which students learned about the moon. Only the experimental condition emphasised conservation's delayed benefits. We compared attitudes, knowledge, and behaviours pre- and post- curriculum. To capture behaviour, we employed an investment task in which participants could invest their own resources in a 'fund' to support work relating to bats or the moon, depending on condition. Across both conditions, participants showed positive shifts in attitudes and knowledge from pre- to post-measures and showed increased investments in bat- and moon-related funds. These findings reveal that short-term conservation education influences adolescents' investment decisions as well as their attitudes and knowledge. Our method can easily be edited for conservation education of any species including endangered primates.

The “evolution” of the mitochondrial genome of the (<i>Phylloscopus borealis</i> sensu lato) occurs in its nuclear genome

Sequencing of a partial fragment of the ND5–cytb mithochondrial genes (1553 bp) and its nuclear copies was carried out to Phylloscopus borealis sensu lato, belonging to individual taxonomic groups from different parts of the range. It was shown that the majority of taxon-specific and unique mitochondrial substitutions in examinandus and xanthodryas forms were identical to those in nuclear copies of borealis mtDNA. Differences between mitochondrial haplotypes of examinandus and nuclear copies of mtDNA borealis were low (p = 0.02), at the same time the mtDNA genetic divergence in borealis–examinandus, borealis–xanthodryas and examinandus–xanthodryas significantly exceeded this value (p = 0.035, 0.044 and 0.046, respectively). A nuclear copy of the mitochondrial haplotype of the easternmost form of xanthodryas was first discovered in the nuclear genome of one borealis individual in the western part of the breeding range (Komi Republic). Alongside this, it was shown at the first time, the nuclear copies of xanthodryas mtDNA from Toyama Prefecture (Japan) were close to the mitochondrial haplotypes of borealis from Kytlym (Sverdlovsk region) (p = 0.018). Thus, the mutations emerging in the nuclear copies of mitochondrial genes are the source of most substitutions in the mitochondrial DNA of the studied forms. The origin of the mitochondrial haplotypes examinandus and xanthodryas from nuclear copies of mtDNA borealis and the close similarity of their nuclear genomes gives grounds to consider the mitogenomes of these forms as variants of the haplotype of the single species Ph. borealis sensu lato. With a high degree of probability, it can be argued that the divergence time of the haplotypes of the analyzed forms is significantly less than 2.5-3 million years, as previously assumed by a number of authors [Saitoh et al. 2010; Alström et al. 2011], and the “molecular clock” that do not take into account recombination events between the nuclear and mitochondrial genomes cannot be used in this case.

APPLICATION OF THE DNA BARCODING METHOD FOR IDENTIFICATION AND TAXONOMIC ANALYSIS OF THE LAMIACEAE FAMILY

The Lamiaceae family is one of the largest and most important among the aromatic plants, including many species with pronounced pharmacological properties. Plants of this family, such as mint, rosemary and thyme, are widely used in traditional and modern medicine due to their therapeutic and biochemical properties. The importance of correct species identification is emphasized by the need to preserve the biodiversity and sustainable use of the resources of this family. In this work, plants of Lamiaceae family growing in the territory of the Karaganda region were studied by DNA barcoding. The studies were conducted on the basis of nucleotide sequences of rbcL and trnH-psbA chloroplast DNA barcodes using the methods of paired genetic distances, BLASTn and phylogenetic tree based on the analysis of maximum parsimony. The high efficiency of the rbcL locus was demonstrated for the identification of higher taxonomic groups, such as subfamilies and tribes, while the intergenic spacer trnH-psbAhasproved to be effectiveat the level of speciesandgenus level.

Influence of vegetable knowledge in preschooler’s vegetable consumption: Veggies4myHeart project

Abstract Background Vegetable consumption among children is below recommended. Food rejection, especially vegetables, is common in preschool-aged children. Impoverished food knowledge is associated with this rejection. The Veggies4myHeart project aims to promote vegetable consumption and knowledge among preschoolers’. This study assesses the project’s effectiveness in increasing vegetable knowledge and consumption and whether increased knowledge influences vegetable consumption. Methods Veggies4myHeart is a prospective longitudinal study with children 2-6 years old attending preschools. Two preschools participated in a five-week intervention in the 2023/24 academic year. A distinctive pedagogical tool was tested in each preschool: a storybook and a digital game. Knowledge and vegetable consumption were assessed before and after the intervention. Knowledge was evaluated through a questionnaire with taxonomic categorization. Consumption was assessed by recording the portions of eight vegetables (carrot, lettuce, red cabbage, cucumber, tomato, onion, beetroot, and red bell pepper). Wilcoxon test was applied to compare vegetable knowledge and consumption before and after the intervention. Spearman’s correlation was used to examine the association between knowledge and vegetable consumption before and after the intervention. Results 98 children (55.1% female, mean age 4.15 ± 0.868 years) participated. Statistically significant increases in both knowledge and total vegetable consumption were observed post-intervention in both preschools (p < 0.001). A moderate correlation of 0.412 (p = 0.013) in the storybook group post-intervention suggests that increased knowledge may contribute to increased vegetable consumption. Conclusions This study demonstrates the potential of the Veggies4myHeart project as an effective strategy to promote knowledge about vegetables among preschool children, highlighting the critical role of educational interventions in promoting healthier dietary patterns. Key messages • To increase vegetable knowledge may lead to higher consumption in preschool children. • Veggies4myHeart demonstrated its effectiveness as an educational project for preschool children.

A field study of the molecular response of brown macroalgae to heavy metal exposure: An (epi)genetic approach

Our understanding of the relative contribution of genetic and epigenetic mechanisms to organismal response to stress is largely biased towards specific taxonomic groups (e.g. seed plants) and environmental stresses (e.g. drought and salinity). In previous work, we found intraspecific differences in heavy metal (HM) uptake capacity in the brown macroalgae Fucus vesiculosus. The molecular mechanisms underlying these differences, however, remained unknown. Here, we evaluated the concentrations of HMs, and characterized the genetic (single nucleotide polymorphisms) and epigenetic (cytosine DNA methylation) variability in reciprocal transplants of F. vesiculosus between two polluted and two unpolluted sites on the NW Spanish coast after 90 days. Genetic and epigenetic differentiation did not explain the phenotypic differentiation observed, possibly due to the combined effect of multiple environmental factors acting on the algae in their natural habitats. Nonetheless, we provide further evidence of intraspecific genetic differentiation in F. vesiculosus at short spatial scales, as well as first evidence of population-specific epigenetic changes in brown macroalgae in response to changes in environmental conditions (i.e. transplantation ex situ). We propose that both genetic and, to some extent, epigenetic mechanisms might impinge upon the adaptive potential of this species to environmental change, but this needs to be further addressed.

Veggies4myHeart – educational project to promote vegetable knowledge and consumption in preschoolers

Abstract Vegetable consumption among children is below recommended. Given the critical role of vegetable consumption in health promotion, it is essential to identify effective strategies to promote this intake. The Veggies4myHeart project aims to increase vegetable knowledge and consumption in preschool children through nutrition education strategies (NES). Veggies4myHeart is a prospective longitudinal study with children aged 2 to 6 years who attend preschools in the Leiria district. A questionnaire was applied to the parents to characterize the sample. NES were used: children’s story, digital game, vegetable-themed sticker booklet and the food wheel. The intervention consisted of 5 food education sessions, each focusing on one selected vegetable (lettuce, carrot, red cabbage, cucumber, and tomato). Sessions to assess knowledge and consumption of vegetables were held pre-and post-intervention. Knowledge was evaluated through a taxonomic categorization questionnaire. Consumption was assessed by recording the number of portions of each vegetable consumed. Wilcoxon test was used to compare pre-and post-intervention vegetable knowledge and consumption. ANOVA test was used to compare NES. Between 2018 and 2024, 649 children (52,5% female, mean age 4,36 ± 0,942) from 17 preschools participated. After the intervention, there was a statistically significant increase in vegetable knowledge (p < 0,001) and a statistically significant increase in the consumption of vegetables (p < 0,001). There are statistically significant differences between NES, with the digital game having greater vegetable knowledge (p < 0,001) and consumption (p < 0,001) than the others. The Veggies4myHeart project effectively increased vegetable knowledge and consumption in preschoolers. It is essential to continue the intervention to promote consumption and familiarity with vegetables, as well as the involvement of parents and preschool teachers, due to their prominent role as models for acquiring healthy eating habits. Key messages • The NES used proved useful, contributing to increased knowledge and consumption of vegetables. • The Veggies4myHeart project is an asset for preschool-aged children to become familiar with vegetables.

Microsatellites explorer: A database of short tandem repeats across genomes

Short tandem repeats (STRs) are widespread, repetitive elements, with a number of biological functions and are among the most rapidly mutating regions in the genome. Their distribution varies significantly between taxonomic groups in the tree of life and are highly polymorphic within the human population. Advances in sequencing technologies coupled with decreasing costs have enabled the generation of an ever-growing number of complete genomes. Additionally, the arrival of accurate long reads has facilitated the generation of Telomere-to-Telomere (T2T) assemblies of complete genomes. Nevertheless, there is no comprehensive database that encompasses the STRs found per genome across different organisms and for different human genomes across diverse ancestries. Here we introduce Microsatellites Explorer, a database of STRs found in the genomes of 117,253 organisms across all major taxonomic groups, 15 T2T genome assemblies of different organisms, and 94 human haplotypes from the human pangenome. The database currently hosts 406,758,798 STR sequences, serving as a centralized user-friendly repository to perform searches, interactive visualizations, and download existing STR data for independent analysis. Microsatellites Explorer is implemented as a web-portal for browsing, analyzing and downloading STR data. Microsatellites Explorer is publicly available at https://www.microsatellitesexplorer.com.

Microbiome associated to an H2-emitting zone in the São Francisco basin Brazil

BackgroundDihydrogen (H₂) natural gas is a clean and renewable energy source of significant interest in the transition to sustainable energy. Unlike conventional petroleum-based fuels, H₂ releases only water vapor upon combustion, making it a promising alternative for reducing carbon footprints in the future. However, the microbial impact on H₂ dynamics in H2-emitting zones remains unclear, as does the origin of H2 — whether it is produced at greater depths or within shallow soil layers. In the São Francisco Basin, soil hydrogen concentrations of approximately 200 ppm were identified in barren ground depressions. In this study, we investigated the microbiome associated with this area using the 16S rRNA gene sequencing, with a focus on metabolic processes related to H₂ consumption and production. Soil samples were collected from two monitored (< 1 m) depths – 10 cm and 1 m – in the emission zone, which is predominantly covered with pasture vegetation, and from an adjacent area with medium and small trees.ResultsOur findings suggest that the H2-emitting zone significantly influences the composition and function of the microbiome, with Bacillus emerging as the dominant genus. In contrast to typical Cerrado soil, we observed a higher prevalence of Actinobacteriota (∼ 40%) and Firmicutes (∼ 20%). Additionally, we identified an abundance of sporulating bacteria and taxonomic groups previously described as H2-oxidizing bacteria.ConclusionsThe H2-emitting zone in the São Francisco Basin presents a unique opportunity to deepen our understanding of the impact of H₂ on microbial communities. This study is the first to characterize a natural H2-associated bacterial community in Cerrado soil using a culture-independent approach.

An Inconvenient Truth: A Comprehensive Examination of the Added Value (or Lack Thereof) of Leadership Measures

AbstractThe leadership literature encompasses a bewildering array of leadership styles, with most studies focussing on the nature and consequences of a single leadership style in isolation. This isolationist approach has led researchers to mostly ignore the similarities between supposedly different leadership styles, and few studies have examined these overlaps empirically. To understand the extent of this problem, we use bifactor exploratory structural equation modelling to examine whether 12 dominant leadership measures capture shared variance and whether any variance unique to a particular style is related to theoretically and empirically established covariates. Moreover, we explore what the shared variance of these leadership measures may represent. Across seven samples, five countries, multiple organizational contexts, and 4000 respondents, the 12 leadership measures shared significant amounts of variance and did not systematically capture unique leadership‐related variance. Further analyses indicated this shared variance mainly represented the affective quality of the leader–follower relationship. The results reveal an inconvenient truth for leadership researchers who wish to differentiate styles, as the styles have much more in common than differences. Contrasting with previous recommendations to refine styles, we argue that a taxonomic leadership behaviour categories approach to leadership research is the most parsimonious way forward.

Towards a Taxonomy Machine: A Training Set of 5.6 Million Arthropod Images

The taxonomic identification of organisms from images is an active research area within the machine learning community. Current algorithms are very effective for object recognition and discrimination, but they require extensive training datasets to generate reliable assignments. This study releases 5.6 million images with representatives from 10 arthropod classes and 26 insect orders. All images were taken using a Keyence VHX-7000 Digital Microscope system with an automatic stage to permit high-resolution (4K) microphotography. Providing phenotypic data for 324,000 species derived from 48 countries, this release represents, by far, the largest dataset of standardized arthropod images. As such, this dataset is well suited for testing the efficacy of machine learning algorithms for identifying specimens into higher taxonomic categories.

Integrated Analysis of Metabolites and Microorganisms Reveals the Anthracnose Resistance Benefits from Cyanidin Mediated by Proteobacteria in Tea Plants.

Anthocyanins, key quality components of tea, act as an important bridge between plants and the environment due to their function on protecting plants from biotic and abiotic irritants. This study aimed to assess the interactions between anthocyanins metabolism and the environment. Purple (P) and green (G) leaves with different anthocyanin contents were inoculated with tea plant anthracnose. High-throughput metabolomics and 16S microbial diversity sequencing methods were used to screen the anthocyanin fractions of tea plant leaves responsive to anthracnose. The interconnections between metabolites and the resistance of phyllosphere microorganisms to fungal pathogens were then analyzed. The results showed that leaves with high anthocyanin content (0.14% of diseased area ratio) were less impacted by anthracnose infestation than leaves with low anthocyanin (3.12%). The cyanidin content decreased after infection in purple leaves (PR) and increased in green leaves (GR). The relative abundance of Cyanobacteria was suppressed by the significant enrichment of Proteobacteria after anthracnose infection in green leaves. However, there were no significant differences between these two groups of microorganisms in purple leaves. Collinear network analysis revealed a strong correlation between Cyanobacteria and Dihydrosorbinol and between Proteobacteria and cyanidin metabolites. Among them, OTU456 (Bosea) was identified as the key taxonomic group of bacterial communities in the green-infected leaf network. In summary, the anthracnose resistance benefits from cyanidin mediated by proteobacteria in tea plants. These results deepen our understanding of the regulation of secondary metabolism in tea plants and the formation of plant resistance.

Effects of tillage intensity and pesticide treated seeds on epigeal arthropod communities and weed seed predation in a maize-soybean rotation

Tillage practices and the use of pesticide seed treatments (PST) both have the potential to influence epigeal arthropod communities and the ecosystem services they provide, yet few studies have examined both factors in conjunction. A three-year field study (2017–2019) was conducted to assess the independent and interactive effects of tillage and pesticide seed treatments on epigeal arthropod communities and weed seed predation in a long-term row crop tillage intensity experiment located in southeastern New Hampshire, USA. Throughout the study, maize and soybean were planted in rotation with and without pesticide seed treatments (seed coatings containing a mixture of systemic and contact fungicides and neonicotinoid insecticides) under three tillage systems (full-, strip-, and no-till) in a randomized complete block design with four replications. Epigeal arthropod communities were sampled with pitfall traps from September to October 2018–2019 and weed seed predation was assessed over the same period each year from 2017–2019. A total of 1669 individual arthropods, representing 47 taxonomic groups, were observed over the course of the study. In 2018, epigeal arthropod communities differed based only on pesticide seed treatment. The opposite response was observed in 2019, as epigeal arthropod communities differed based only on tillage. Activity densities of Pterostichus melanarius (Illiger) were higher in the strip-till compared to full-till treatment in 2018. Annual levels of post-dispersal weed seed predation by invertebrates (% total seeds removed) varied based on tillage treatment in 2017 and 2019, but not in 2018, and ranged from as low as 6.1 % to as much as 27.2 % depending on year and treatment. These data provide evidence that both pesticide seed treatments and tillage systems can influence the communities of epigeal arthropods that inhabit annual row crop agroecosystems relatively late in the growing season, when the majority of pesticide residues have likely dissipated, and that the weed seed predation services provided by members of this community can be strongly negatively impacted by intensive tillage.

Host and habitat shape ectoparasite diversity on Mastomys natalensis and Mastomys coucha (Muridae).

Mastomys natalensis and M. coucha are commensal rodent species endemic to Africa. A recent taxonomic revision within Mastomys leaves the parasite–host list of M. natalensis questionable and that of M. coucha incomplete. The current study aimed to develop a better understanding of the ectoparasite diversity associated with the 2 distinct but closely related rodent species and to explore the influence of host and habitat type on ectoparasite infestations. Between 2014 and 2020, 590 rodents were trapped in 3 habitat types (village, agriculture and natural) across a wildlife-human/domestic animal interface. In total 48 epifaunistic species (45 ectoparasitic and 3 predatory) represented by 29 genera from 4 taxonomic groups (fleas, lice, mites and ticks) were recorded. Only 50% of the epifauna were shared between the 2 rodent species, with mites the most speciose taxon in both host species. The abundance of epifaunistic individuals, and also those of mites and fleas, were significantly higher on male M. natalensis, while ticks were significantly higher on reproductively active M. natalensis. For both rodent species, infestations by most epifaunistic taxa (on M. natalensis) and some taxa (on M. coucha) were significantly lower in the village as opposed to the less disturbed agricultural and natural habitat types. The study highlights the importance of host life history, even in closely related rodent species, in shaping parasite profiles and a loss of parasite diversity in more extreme anthropogenic habitats.