Differentiation Of Species Research Articles

Convergent evolution of the environmental adaptability of high‐elevation populations of waist‐shaped bugs

AbstractAimSimilar environmental selection pressures drive the occurrence of convergent evolution among species. However, studies on this phenomenon are scarce at the population level. Here, we used two waist‐shaped bugs to test the hypothesis that similar high‐elevation habitat environments could lead to similar genetic adaptations among populations of different species.LocationEast Asia.TaxaMalcus sinicus Štys, 1967 & Malcus insularis Štys, 1967.MethodsPopulation genetic structure was determined by phylogenetic and phylogeographical analyses. Demographic history was inferred by comparing simulated history models. Suitable habitat from the last interglacial period (LIG) to the present was predicted by ecological niche modelling (ENM). Convergent evolutionary processes were jointly assessed by the comparison of population ecological differences and the principal component analysis of environmentally related single‐nucleotide polymorphisms (SNPs).ResultsOur results showed that the land bridge in the Pleistocene helped ancestral populations of M. sinicus and M. insularis diffuse from mainland China to Taiwan Island. Subsequently, the geographical barrier imposed by the Taiwan Strait promoted the species differentiation. Geographic isolation and adaptive evolution jointly promoted the population differentiation in M. sinicus. Genetic similarity was found between the populations of M. sinicus in southwestern China (sin‐YN) and M. insularis on Taiwan Island (ins‐TW). Temperature‐related environmental factors and elevation were found to similarly and significantly clustered with ins‐TW and sin‐YN and were clearly distinguished from the other low−/mid‐elevation populations of M. sinicus (sin‐EA). Furthermore, the SNPs related to these environmental factors presented the same clustering results.Main ConclusionsOur study revealed a novel disjunct distribution pattern between southwestern China and Taiwan Island at the population level and provided evidence of convergent evolution of local populations in high‐elevation environments. Here, we revealed that similar environmental selection pressures can drive the occurrence of convergent evolution at the population level among different species.

Comprehensive study of allergenic tree species: Palynological insights enhanced by HPLC and GC-MS profiling.

Considering the limited data available on tree species in Uzbekistan, this research aimed to provide new insights. We gathered plant samples from different locations within Samarkand city and thoughtfully selected 15 tree species that represent the country's flora. Using scanning electron microscopy, we conducted comprehensive analyses of pollen morphology, revealing a diverse range of variations in the shapes, dimensions, and surface characteristics displayed by pollen grains. Distinct ornamentations such as micro-echinate, reticulate, rugulate, gemmate-verrucate, and verrucate-scabrate patterns facilitated the differentiation of species. These scanning electron microscopy findings enhance our comprehension of tree species diversity, adaptation, and ecological roles. In addition, leaf extracts were analyzed using HPLC and GC-MS, revealing a plethora of bioactive compounds, including catechins, chlorogenic acid, vanillic acid, and others. Furthermore, GC-MS analysis revealed the presence of seven key compounds, including 1-hexadecyne, 2-chloroethanol, 1,6-heptadiene, 2-methyl-, 5-bromoadamantan-2-one, ethyl 3-(3-pyridyl) propenoate, bis (2-ethylhexyl) phthalate, and quercetin. This study demonstrates the effectiveness of this method in assessing the quality of leaf extracts from tree species by examining both microscopic characteristics and chemical composition. This multifaceted approach has deepened our understanding of the characteristics and chemical compositions of these trees, thus contributing to a more profound appreciation of their ecological significance and potential applications.

Taxonomía del género Arachis (Leguminosae)

Taxonomía del género Arachis (Leguminosae)

Comprehensive species- and processing-specific peptide profiling of pasteurized, extended shelf-life and ultra-high temperature milk from cow, goat, sheep, buffalo, and mare

The present study aimed to identify endogenous milk peptides for species differentiation independent of heat exposure. Thus, comprehensive milk peptide profiles from five species and three types of heat treatments were analyzed by micro-flow liquid chromatography ion mobility quadrupole time-of-flight mass spectrometry (microLC-IM-QTOF) with subsequent database search leading to ≥ 3000 identified peptides. In the milks, 1154 peptides were unique for cow, 712 for sheep, 466 for goat, 197 for buffalo, and 69 for mare. Most peptides were detected in extended-shelf life (ESL) milk (2010), followed by ultra-high temperature (UHT) processed (1474) and pasteurized milk (1459 peptides), with 693 peptides present in all milk types. A blind test set of 64 samples confirmed eight species-specific, but heat-independent marker peptides in milk from cow, seven from goat, six from sheep, nine from buffalo, and three from mare. The generated peptide profiles can also be used to identify species- and heat-specific markers.

Ligilactobacillus cholophilus sp. nov., isolated from pickled potherb mustard (Brassica juncea Coss.).

Strain BD7642T was isolated from Chinese pickled potherb mustard (Brassica juncea Coss.) purchased from a local market in Shanghai, PR China. A polyphasic approach, including 16S rRNA gene sequence, housekeeping gene, average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), G+C content and phenotypic analyses, was employed to characterize strain BD7642T. Cells of the bacterium were short round rods, Gram-stain-positive, non-spore-forming and catalase-negative. The strain grew at 30-45 °C and pH 4.0-8.0. Optimum growth occurred at 35-40 °C and pH 6.0-7.0. The strain exhibited growth with salt (NaCl) concentrations of up to 5 % (w/v). The G+C content of the strain's genomic DNA was 31.37 mol%. The major fatty acids were C16 : 0, C18 : 1 c9 and summed feature 10 (C18 : 1 c11/t9/t6). 16S rRNA gene sequencing revealed that strain BD7642T represents a member of the genus Ligilactobacillus and it had high sequence similarity to Ligilactobacillus aviarius NBRC 102162T (96.73 %), Ligilactobacillus araffinosus LGM 23560 (96.66 %) and Ligilactobacillus salivarius JCM 1231T (95.82 %). The dDDH values between strain BD7642T and its phylogenetically related species within the genus Ligilactobacillus ranged from 12.6 to 25.4 %. The ANI values between strain BD7642T and its closely related taxa were far lower than the threshold (95 %-96 %) used for species differentiation. Results of phylogenetic, physiological and phenotypic characterization confirmed that strain BD7642T represents a novel species within the genus Ligilactobacillus, for which the name Ligilactobacillus cholophilus sp. nov. is proposed. The type strain is BD7642T (=CCTCC AB 2022398T=JCM 36074T).

Granulomatous dermatitis caused by Exserohilum mcginnisii infection in a cow.

A 5-y-old, Piedmontese cow had a 4-mo history of ongoing development of skin masses. This was the only cow affected in a herd of 20 cows. Up to 12, hairless, red-to-black, raised nodules-to-plaques were distributed along the dorsum and tail head. Biopsies were taken for histopathology and ancillary testing. An ulcerated skin section contained dermal infiltrates of eosinophils, plasma cells, neutrophils, macrophages, lymphocytes, and multinucleate giant cells, and pyogranulomas. Fungal hyphae were seen within the dermis, multinucleate giant cells, and pyogranulomas. In pyogranulomas, fungi were surrounded by a Splendore-Hoeppli reaction. Dematiaceous (pigmented) hyphae were rarely observed with H&E-stained and unstained (cleared and mounted) sections, but stained well with a Fontana-Masson stain. Exserohilum mcginnisii was identified by fungal culture, followed by PCR assay and sequencing. Exserohilum is a dematiaceous fungus that causes disease in humans and rarely in animals. The use of unstained sections and Fontana-Masson stain are important to demonstrate pigment because dematiaceous fungi have little melanin and appear as hyaline hyphae histologically. PCR assay and sequencing aid in the differentiation and classification of fungal species. To our knowledge, E. mcginnisii dermal granulomas have not been reported previously in cattle.

Paraboeazunyiensis (Gesneriaceae), a new species from north Guizhou, China.

A new lithophytic species, Paraboeazunyiensis T.Deng, F.Wen & R.B.Zhang (Gesneriaceae), inhabiting Karst rocks in northern Guizhou, China, is introduced and depicted in this study. It bears a resemblance to P.crassifolia (Hemsl.) B.L. Burtt, yet is distinguishable by its shorter filaments and staminodes, triangular ovate calyx segments, and ovaries surpassing the styles in length. Moreover, the phylogenetic tree constructed from nuclear DNA (ITS) and plastid DNA (trnL-F) data firmly support the differentiation of this novel species from P.crassifolia.

Impress of Climate Change in the Himalaya on Plant Evolution

Currently, species diversity has become a hotpot to biologist. Some researchers find mountains contribute disproportionately to Earth's terrestrial biodiversity, especially in the tropics, where there are unusually rich and confusing hot spots. But current assumptions about large-scale geographic patterns of species diversity cannot explain the extremely high biodiversity in mountain regions, especially in the tropics, where is characterized by a complex spatial configuration of terrain and climate. This paper focuses on three prominent and brief factors which impact species differentiation most in Himalaya to illuminate some researches up to now, include geographical, climatic, and biological. Geographic affect plant diversity by bring alien species, and format monsoon and plateau environment through uplift. Monsoon can advance the formation of landform also. Further, the period climate change can induce variation of endemic species, and the pollinator can impact variation by reproduction, thus the mismatch between pollinator and plants recently may lead the decline of certain species. Besides these, nowadays palynology evidence has become a credible two-way entry point to research plant evolution and climate change in the past era by authenticating how subspecies formatted. What’s more, because the vagaries of climate have prompted the breeding of endemic species, the rising temperature currently may alter the vegetation in alpine area.

A note on Scutellaria sieversii (Lamiaceae)

As a result of field research on the territory of Siberia and East Kazakhstan, viewing the collections stored in the Herbariums LE, MW, NSK, NS, TK, ALTB, MIM, as well as placed in the international JSTOR database, acquaintance with the protologue and type specimens, it was shown that the indication of the species Scutellaria sieversii from the section Lupulinaria for the flora of Siberia and Mongolia is erroneous. The species is found within the steppe zone, as well as in the northern part of the desert zone of East Kazakhstan. The discussion considers the morphological and ecological features of Siberian species from the section Lupulinaria and East Kazakhstan species S. krylovii, S. alberti, S. soongorica, closely related to S. sieversii. The most important diagnostic features in the differentiation of species are lifeform, the color of the corolla, the shape and pubescence of the leaf blade, and the pubescence of the erems. The diagnostic features of the species are given in the table and figures. The analysis of all characters showed that the accessions of Scutellaria sp. collected in Khakassia and previously referred to S. sieversii in literary sources should be attributed to S. supina s. l. For all studied species, information is provided on type specimens, ecological features, and general area.

Unveiling the potential of proteomics in addressing food and feed safety challenges.

The food and feed sector in Europe is rapidly evolving to address contemporary challenges, striving for fairer, safer, greener and more sustainable food systems. This includes the exploration of new protein sources for human consumption and animal feed such as protein derived from insects, algae or novel plant-derived proteins, and the re-evaluation of existing sources like processed animal protein (PAP). To generate reliable data on the diverse array of emerging protein sources for future food and feed safety assessments, a growing demand for the development and implementation of advanced analytical techniques exists. New approach methodologies (NAMs) including, mass spectrometry (MS)-based proteomics methods have been emerging as valuable techniques which potentially can be implemented in regulatory laboratory settings to complement conventional approaches in this realm. These MS-driven strategies have already proven their utility in diverse applications, including the detection of prohibited substances in feed, identification of allergens, differentiation of fish species in complex mixtures for fraud detection and the verification of novel foods and alternative protein sources. This EU-FORA programme was focused on three core objectives namely: (i) the training of the fellow in utilising MS-based proteomics for food and feed safety analyses, (ii) the involvement of the fellow in the development of standardised operating procedures (SOP) for targeted and non-targeted proteomic MS-based workflows for species and tissues specific PAP identification in a national reference laboratory (NRL) and (iii) the transfer and implementation of MS-based approaches and standardised protocols for PAP analysis at the fellow's home institution. Altogether, this programme facilitates the broadening and diversification of use of MS-based proteomic methodologies for reinforcing their significance within the domains of food and feed safety research and regulatory science applications.

Retracted: Electronic Nose for Differentiation and Quantification of Yeast Species in White Fresh Soft Cheese.

[This retracts the article DOI: 10.1155/2022/8472661.].

Germ‐soma differentiation and reproduction in a new species of early Cambrian acritarch

AbstractAs a significant evolutionary innovation, multicellularity has independently evolved multiple times throughout the evolutionary history of eukaryotes, making a substantial contribution to their diversity. In retracing the multicellularity of eukaryotes, deep‐time fossil records play an irreplaceable role. In this paper, we report a new acritarch Concavaesphaera ornata gen. et sp. nov. from the early Cambrian Kuanchuanpu biota (535 Ma). These fossils are generally spherical, with diameters ranging from 450 to 950 μm, and feature an envelope with complex ornament. Inside, there are two groups of cells varying in size. Larger cells are relatively fewer in number and each resides within a sac‐like cavity distributed along the inner wall of the envelope. Statistical data show a positive correlation between the diameter and cavity volume during the development of large cells. Small cells are numerous, have a diameter of about 15 μm, and fill the entire interior of the specimens. We interpret the large cells as reproductive cells and the small cells as somatic cells. These observations show that Concavaesphaera evolved multicellular complexity equivalent to that of modern Volvox, with germ‐soma differentiation and separation. Available evidence suggests that the similarities between Concavaesphaera and Volvox are more likely to be the result of convergent evolution. Therefore, Concavaesphaera may represent an extinct multicellular eukaryote which evolved during the Cambrian explosion and probably documented an independent innovation of multicellularity in eukaryotic evolutionary history. This implies that multicellularity evolved many more times in eukaryotes than previously estimated.

The Phylogenetic Characterization of Cockroaches (Insecta: Blattaria) in Türkiye and Determination of Their Vector Potential for Medically Important Parasites

This study was performed to investigate the phylogenetic characters of the cockroaches in XXX region for mitochondrial cytochrome c oxidase subunit I (mt-COI), mt-COII, and internal transcribed spacer-2 (ITS-2) gene regions, and to determine their mechanical transmission of medically important parasites. PCR-restriction fragment length polymorphism (RFLP) was performed using mt-COI, mt-COII, and ITS-2 DNA gene regions to identify cockroach species (n=220) collected from different regions. Differentiation of cockroach species was based on RFLP models using two restriction enzymes: AvaI and EciI. For phylogenetic analysis, mt-COI, mt-COII, and ITS-2 DNA barcode regions were amplified with standard primers. The amplicons obtained were purified and sequenced with PCR primers. According to PCR-RFLP, cockroach species were identified as Blattella germanica (n =105), Blatta orientalis (n = 86), and Periplaneta americana (n = 29). A total of 13 haplotypes were detected and Maximum likelihood (ML) analyses revealed that the sequences of all three species for the three gene regions showed monophyletic structuring. The cockroaches were examined for the presence of parasites. It was determined that of the 58 parasitic forms identified belonged to helminth species 46 (79.3%) and protozoan species and 12 (20.7%). The results showed that B. germanica (58.6%) had the highest prevalence, followed by Bl. orientalis (32.8%) and P. americana (8.6%). The study findings not only contribute to the molecular epidemiology of cockroaches but also confirm that they play an important role as mechanical vectors of protozoan and helminth parasites.

Genome-Wide Classification and Evolutionary Analysis of the KNOX Gene Family in Plants

The Knotted1-like homeobox (KNOX) gene family plays a pivotal role in regulating meristem activity, organ differentiation, and cell meristematic identity. However, there has been a lack of large-scale, systematic, and comprehensive comparative analyses to explore their expression patterns and evolutionary mechanisms. In this study, a total of 1425 KNOX genes were identified across 118 plant species. The result showed that higher plants exhibited a significantly higher abundance of KNOX genes compared to lower plants. Phylogenetic analysis revealed that all KNOX genes can be divided into two classes (class I and II) and evolved independently after species differentiation. An analysis of gene duplication or loss showed that gene loss was more common than gene duplication in lower plants within the KNOX gene family. These findings suggest that gene loss in the KNOX gene family occurs after events such as whole-genome duplication (WGD) or whole-genome triplication (WGT). In addition, conserved motif analysis was also conducted to uncover the evolutionary trajectories of KNOX genes. We found that three motifs (M1, M2, and M4) were present in nearly all KNOX genes, while four novel motifs (M7–M10) were lost in lower plants but present in higher plants. Moreover, the loss of certain motifs in the KNOX genes was also observed in higher plants, indicating sequence divergence in KNOX genes throughout evolution. To understand the expression patterns of KNOX genes, a gene expression pattern analysis was performed in A. thaliana and O. sativa. The results showed that class I KNOX genes exhibit conserved high expression in stems, suggesting their potential similar biological roles across different plant species and the conservation of their functions during evolution. Additionally, we analyzed the KNOX genes in the Citrus genus and closely related species, and we found that the number of KNOX genes evolved at a slower rate in these species, indicating a relatively conservative nature. In conclusion, this study provides valuable resources for the investigation of KNOX gene family evolution and function in plants.

Genomic epidemiology and heterogeneity of Providencia and their bla NDM-1-carrying plasmids

ABSTRACT Providencia as an opportunistic pathogen can cause serious infection, and moreover the emergence of multi-drug-resistant Providencia strains poses a potentially life-threatening risk to public health. However, a comprehensive genomic study to reveal the population structure and dissemination of Providencia is still lacking. In this study, we conducted a genomic epidemiology analysis on the 580 global sequenced Providencia isolates, including 257 ones sequenced in this study (42 ones were fully sequenced). We established a genome sequence-based species classification scheme for Providencia, redefining the conventional 11 Providencia species into seven genocomplexes that were further divided into 18 genospecies, providing an extensively updated reference for Providencia species discrimination based on the largest Providencia genome dataset to date. We then dissected the profile of antimicrobial resistance genes and the prevalence of multi-drug-resistant Providencia strains among these genocomplexes/genospecies, disclosing the presence of diverse and abundant antimicrobial resistance genes and high resistance ratios against multiple classes of drugs in Providencia. We further dissected the genetic basis for the spread of bla NDM-1 in Providencia. bla NDM-1 genes were mainly carried by five incompatible (Inc) groups of plasmids: IncC, IncW, IncpPROV114-NR, IncpCHS4.1-3, and IncpPrY2001, and the last three were newly designated in this study. By tracking the spread of bla NDM-1-carrying plasmids, IncC, IncpPROV114-NR, IncpCHS4.1-3, and IncpPrY2001 plasmids were found to be highly involved in parallel horizontal transfer or vertical clonal expansion of bla NDM-1 among Providencia. Overall, our study provided a comprehensive genomic view of species differentiation, antimicrobial resistance prevalence, and plasmid-mediated bla NDM-1 dissemination in Providencia.

Characterization and differentiation of forest species by seed image analysis: a new methodological approach

Biometric seed analysis can be used to characterize and differentiate forest species. However, forest species are generally studied using manual methods such as measurements with a digital caliper, which provides a limited amount of information on plant morphological characteristics, whereas agronomic species are analyzed using expensive and often inaccessible equipment. Thus, the objective of the present study was to demonstrate that seed image analysis and processing tools can help characterize and differentiate Brazilian forest species. For this purpose, the seeds of 155 forest species belonging to 42 families were photographed and analyzed to extract data on their morphometric descriptors using a new methodological approach. A total of 18 characteristics were assessed, namely eight dimensions, four shape characteristics, and six color characteristics. A set of approximately 1.827 million data was extracted from 101,521 seed images. Digital image processing efficiently characterized the studied seeds and the obtained characteristics allowed us to differentiate between species, including those belonging to the same botanical family and genus. Therefore, seed image analysis using the proposed methodology can be used to characterize, differentiate, and automatedly identify forest species in Brazil.

How Different Molecular Markers Estimate the Diversity of European Species of the Ganoderma Genus.

Based on published anatomical-morphological and ecological characteristics and phylogenetic evidence, six species of the Ganoderma genus are known to occur in Europe, namely, G. applanatum (Pers.) Pat., G. adspersum (Schulzer) Donk, G. pfeifferi Bres., G. resinaceum Boud., G. carnosum Pat., and G. lucidum (Curtis) P. Karst. Molecular markers (DNA sequences of selected genes or intergenic spacers) revolutionized our view of fungal variability. Every one of the four most frequently used molecular markers (ITS (internal transcribed spacer) and partial sequences of LSU (rRNA large subunit), tef1-α (translation elongation factor 1-alpha), and Rpb2 (RNA polymerase II second largest subunit)) provides a different view on the variability of European species of the Ganoderma genus. Both the lowest intraspecies variability and the best species differentiation (interspecies divergence) were observed for the LSU marker, and based on our data, this marker could be recommended for identification and species delineation in European Ganoderma spp. The sequences of the most frequently used ITS marker were unable to discriminate between G. lucidum and G. carnosum, and in general, this species pair showed the lowest interspecies divergence using all markers tested. Surprisingly, up to now, hidden variability has been detected in several Ganoderma spp., indicating the existence of possible cryptic taxa within the European Ganoderma morphospecies.

Clinicomycological profile of dermatophytosis in a tertiary care teaching hospital, Vadodara

Dermatophytosis is the most common type of cutaneous fungal infection seen in man infecting the superficial keratinized layer of the skin, hair and nails. The aim of the study is to isolate and identify the dermatophytes from clinically suspected cases of dermatophytosis, to determine the frequency of occurrence of various species of dermatophytes, to know the prevalence of age and sex of dermatophytosis in the locality.: The present study was carried out in the Department of Microbiology, Medical College and SSG Hospital, Vadodara. A total of 150 clinically diagnosed cases of dermatophytosis were taken for this study. Skin, hair and nail samples were aseptically collected and were subjected to KOH mount examination and culture. Differentiation of the dermatophyte species was performed based on the macroscopic and microscopic examination of culture and physiological test including urease test.: Tinea corporis (41.3%) was the commonest clinical type with a male to female ratio of 1.05:1. Out of these samples, dermatophytes were isolated in 108 cases with the overall isolation rate of 72%. Seven species of dermatophytes were isolated. 53 (49.1%) was the commonest species followed by 22(20.4%).: Identifying dermatophyte species and knowledge of their host preference and ecology play an important role in treating the patient. Correct and efficient laboratory methods for diagnosis of dermatophytosis is the need of the hour to provide correct and timely treatment and prevent the further spread and chronicity of the disease.

Phylogenetic distribution of malonate semialdehyde decarboxylase (MSAD) genes among strains within the genus Mycobacterium: evidence of MSAD gene loss in the evolution of pathogenic mycobacteria.

Despite the great diversity of malonate semialdehyde decarboxylases (MSADs), one of five subgroups of the tautomerase superfamily (TSF) found throughout the biosphere, their distribution among strains within the genus Mycobacterium remains unknown. In this study, we sought to investigate the phylogenetic distribution of MSAD genes of mycobacterial species via genome analysis of 192 different reference Mycobacterium species or subspecies retrieved from NCBI databases. We found that in a total of 87 of 192 strains (45.3%), MSAD-1 and MSAD-2 were distributed in an exclusive manner among Mycobacterium species except for 12 strains, including Mycobacterium chelonae members, with both in their genome. Of note, Mycobacterium strains better adapted to the host and of high virulence potential, such as the Mycobacterium tuberculosis complex, Mycobacterium leprae, Mycobacterium marinum, Mycobacterium ulcerans, and Mycobacterium avium subsp. paratuberculosis, had no orthologs of MSAD in their genome, suggesting MSAD loss during species differentiation in pathogenic slow-growing Mycobacterium. To investigate the MSAD distribution among strains of M. avium subspecies, the genome sequences of a total of 255 reference strains from the four subspecies of M. avium (43 of subspecies avium, 162 of subspecies hominissuis, 49 of subspecies paratuberculosis, and 1 of subspecies silvaticum) were further analyzed. We found that only 121 of 255 strains (47.4%) had MSADs in their genome, with none of the 49 M. avium subsp. paratuberculosis strains having MSAD genes. Even in 13 of 121 M. avium strains with the MSAD-1 gene in their genome, deletion mutations in the 98th codon causing premature termination of MSAD were found, further highlighting the occurrence of MSAD pseudogenization during species or subspecies differentiation of M. avium. In conclusion, our data indicated that there are two distinct types of MSADs, MSAD-1 and MSAD-2, among strains in the Mycobacterium genus, but more than half of the strains, including pathogenic mycobacteria, M. tuberculosis and M. leprae, have no orthologs in their genome, suggesting MSAD loss during host adaptation of pathogenic mycobacteria. In the future, the role of two distinct MSADs, MSAD-1 and MSAD-2, in mycobacterial pathogenesis or evolution should be investigated.

Silicon-based anti-herbivore defense in tropical tree seedlings.

Silicon-based defenses deter insect herbivores in many cultivated and wild grass species. Furthermore, in some of these species, silicon (Si) uptake and defense can be induced by herbivory. Tropical trees also take up Si and leaf Si concentrations vary greatly across and within species. As herbivory is a major driver of seedling mortality and niche differentiation of tropical tree species, understanding anti-herbivore defenses is pivotal. Yet, whether silicon is a constitutive and inducible herbivory defense in tropical forest tree species remains unknown. We grew seedlings of eight tropical tree species in a full factorial experiment, including two levels of plant-available soil Si concentrations (-Si/+Si) and a simulated herbivory treatment (-H/+H). The simulated herbivory treatment was a combination of clipping and application of methyl jasmonate. We then carried out multiple-choice feeding trials, separately for each tree species, in which leaves of each treatment combination were offered to a generalist caterpillar (Spodoptera frugiperda). Leaf damage was assessed. Three species showed a significant decrease in leaf damage under high compared to low Si conditions (by up to 72%), consistent with our expectation of Si-based defenses acting in tropical tree species. In one species, leaf damage was increased by increasing soil Si and in four species, no effect of soil Si on leaf damage was observed. Opposite to our expectation of Si uptake and defense being inducible by herbivory damage, simulated herbivory increased leaf damage in two species. Furthermore, simulated herbivory reduced Si concentrations in one species. Our results showed that tropical tree seedlings can be better defended when growing in Si-rich compared to Si-poor soils, and that the effects of Si on plant defense vary strongly across species. Furthermore, Si-based defenses may not be inducible in tropical tree species. Overall, constitutive Si-based defense should be considered part of the vast array of anti-herbivore defenses of tropical tree species. Our finding that Si-based defenses are highly species-specific combined with the fact that herbivory is a major driver of mortality in tropical tree seedling, suggests that variation in soil Si concentrations may have pervasive consequences for regeneration and performance across tropical tree species.