First assessment of the biodiversity of praying mantises (Insecta: Mantodea) in Cameroon with DNA barcoding

Praying mantises are the apex insect predators in many ecosystems, nevertheless they receive relatively less recognition in biodiversity reviews. We report a first survey of diversity of praying mantises in Cameroon, which is situated in the Congo Basin region, one of the richest biodiversity hotspots. Combination of light trapping with manual collecting resulted in 495 specimens representing 62 species. A total of eight species are novel for the country, at least five species are likely undescribed. DNA barcodes of 72 specimens representing every collected species were obtained, curated, and submitted to NCBI database. For eight species, barcodes are published for the first time. A maximum likelihood phylogenetic tree was created using all available barcodes of Mantodea of Central African subregion. The results obtained during this study stress the importance of combining traditional and molecular approaches during biodiversity assessments of often neglected taxa, the latter aiding in uncovering new species, resolving unknown morphological divergencies and assigning conspecifics.

The chromosome-level genome of Chinese praying mantis Tenodera sinensis (Mantodea: Mantidae) reveals its biology as a predator

BACKGROUND

The Chinese praying mantis, Tenodera sinensis (Saussure), is a carnivorous insect that preys on a variety of arthropods and small vertebrates, including pest species. Several studies have been conducted to understand its behavior and physiology. However, there is limited knowledge about the genetic information underlying its genome evolution, digestive demands, and predatory behaviors.

FINDINGS

Here we have assembled the chromosome-level genome of T. sinensis, representing the first sequenced genome of the family Mantidae, with a genome size of 2.54 Gb and scaffold N50 of 174.78 Mb. Our analyses revealed that 98.6% of BUSCO genes are present, resulting in a well-annotated assembly compared to other insect genomes, containing 25,022 genes. The reconstructed phylogenetic analysis showed the expected topology placing the praying mantis in an appropriate position. Analysis of transposon elements suggested the Gypsy/Dirs family, which belongs to long terminal repeat (LTR) transposons, may be a key factor resulting in the larger genome size. The genome shows expansions in several digestion and detoxification associated gene families, including trypsin and glycosyl hydrolase (GH) genes, ATP-binding cassette (ABC) transporter, and carboxylesterase (CarE), reflecting the possible genomic basis of digestive demands. Furthermore, we have found 1 ultraviolet-sensitive opsin and 2 long-wavelength-sensitive (LWS) opsins, emphasizing the core role of LWS opsins in regulating predatory behaviors.

CONCLUSIONS

The high-quality genome assembly of the praying mantis provides a valuable repository for studying the evolutionary patterns of the mantis genomes and the gene expression profiles of insect predators.

Chromosome number, sex determination, and meiotic chromosome behavior in the praying mantid Hierodula membranacea

Praying mantids are important models for studying a wide range of chromosome behaviors, yet few species of mantids have been characterized chromosomally. Here we show that the praying mantid Hierodula membranacea has a chromosome number of 2n = 27, and X₁X₁X₂X₂ (female): X₁X₂Y (male) sex determination. In male meiosis I, the X₁, X₂, and Y chromosomes of H. membranacea form a sex trivalent, with the Y chromosome associating with one spindle pole and the X₁ and X₂ chromosomes facing the opposite spindle pole. While it is possible that such a sex trivalent could experience different spindle forces on each side of the trivalent, in H. membranacea the sex trivalent aligns at the spindle equator with all of the autosomes, and then the sex chromosomes separate in anaphase I simultaneously with the autosomes. With this observation, H. membranacea can be used as a model system to study the balance of forces acting on a trivalent during meiosis I and analyze the functional importance of chromosome alignment in metaphase as a preparatory step for subsequent correct chromosome segregation.

Complete mitochondrial genomes of four species of praying mantises (Dictyoptera, Mantidae) with ribosomal second structure, evolutionary and phylogenetic analyses

Praying mantises are distributed all over the world. Though some Mantodea mitogenomes have been reported, an evolutionary genomic and phylogenetic analysis study lacks the latest taxonomic system. In the present study, four new mitogenomes were sequenced and annotated. Deroplatys truncate, D. lobate, Amorphoscelis chinensis and Macromantis sp. belong to Deroplatyidae, Amorphoscelidae and Photinaidae family, respectively. Our results indicated that the ATP8 gene may be lost in D. truncate and D. lobata mt genome, and four tRNA genes have not been found in D. truncate, D. lobata and Macromantis sp. A dN/dS pair analysis was conducted and it was found that all genes have evolved under purifying selection. Furthermore, we tested the phylogenetic relationships between the eight families of the Mantodea, including 35 species of praying Mantis. Based on the complete mitochondrial genome data, it was also suggested as sister to Deroplatyidae + Mantidae, Metallyticus sp., the only representative of Metallyticidae, is sister to the remaining mantises. Our results support the taxonomic system of Schwarz and Roy and are consistent with previous studies.

Mantidis Oötheca (mantis egg case) original species identification via morphological analysis and DNA barcoding

ETHNOPHARMACOLOGICAL RELEVANCE

Mantidis Oötheca (mantis egg case; sangpiaoxiao) is a medicine from an insect source, which has been widely used in Asian countries. However, misidentification due to a lack of information given variations in the medicinal portion of the ootheca and morphological similarities of the ootheca as an egg chamber.

AIM OF THE STUDY

Thus, this study aims to provide the first comprehensive data for discriminating authentic of Mantidis Oötheca. Here, we provide detailed ootheca morphology and their molecular information to accurately identify Mantidis Oötheca.

MATERIALS AND METHODS

Oothecae of Tenodera angustipennis (Saussure, 1869), Tenodera sinensis (Saussure, 1871), Hierodula patellifera Serville, 1839, and Hierodula sp. were used in the comparative morphological, principal component analysis, and DNA barcoding.

RESULTS

The morphological analyses revealed that the emergence area, outline, angle of distal end, width of air-filled layer, and weight are useful diagnostic characters. Using these quantitative and qualitative characteristics, we developed the effective identification key. Furthermore, our CO1 sequences from all individuals were monophyletic with high bootstrap values at genus and species levels. Moreover, morphological identification using our developed key among all studied individuals agreed with molecular identification results using CO1 barcoding data.

CONCLUSIONS

These multilateral approaches, including morphological, statistical, and DNA barcoding methods are highly reliable identification tools. Moreover, our diagnostic key characteristics and molecular barcoding should aid in the accurate identification, authentication, and quality control of Mantidis Oötheca medicinal materials.

The hindgut microbiota of praying mantids is highly variable and includes both prey-associated and host-specific microbes

Praying mantids are predators that consume a wide variety of insects. While the gut microbiome of carnivorous mammals is distinct from that of omnivores and herbivores, the role of the gut microbiome among predatory insects is relatively understudied. Praying mantids are the closest known relatives to termites and cockroaches, which are known for their diverse gut microbiota. However, little is known about the mantid gut microbiota or their importance to host health. In this work, we report the results of a 16S rRNA gene-based study of gut microbiome composition in adults and late-instar larvae of three mantid species. We found that the praying mantis gut microbiome exhibits substantial variation in bacterial diversity and community composition. The hindgut of praying mantids were often dominated by microbes that are present in low abundance or not found in the guts of their insect prey. Future studies will explore the role of these microbes in the digestion of the dietary substrates and/or the degradation of toxins produced by their insect prey.

Comparative Mitogenomic Analyses of Praying Mantises (Dictyoptera, Mantodea): Origin and Evolution of Unusual Intergenic Gaps

Praying mantises are a diverse group of predatory insects. Although some Mantodea mitogenomes have been reported, a comprehensive comparative and evolutionary genomic study is lacking for this group. In the present study, four new mitogenomes were sequenced, annotated, and compared to the previously published mitogenomes of other Mantodea species. Most Mantodea mitogenomes share a typical set of mitochondrial genes and a putative control region (CR). Additionally, and most intriguingly, another large non-coding region (LNC) was detected between trnM and ND2 in all six Paramantini mitogenomes examined. The main section in this common region of Paramantini may have initially originated from the corresponding control region for each species, whereas sequence differences between the LNCs and CRs and phylogenetic analyses indicate that LNC and CR are largely independently evolving. Namely, the LNC (the duplicated CR) may have subsequently degenerated during evolution. Furthermore, evidence suggests that special intergenic gaps have been introduced in some species through gene rearrangement and duplication. These gaps are actually the original abutting sequences of migrated or duplicated genes. Some gaps (G5 and G6) are homologous to the 5' and 3' surrounding regions of the duplicated gene in the original gene order, and another specific gap (G7) has tandem repeats. We analysed the phylogenetic relationships of fifteen Mantodea species using 37 concatenated mitochondrial genes and detected several synapomorphies unique to species in some clades.

[Identification of original species of Mantidis Oötheca (Sangpiaoxiao) based on DNA barcoding]

Both market research and literature reports both found that the ootheca of mantodea was all used as medicine. However, Chinese Pharmacopoeia only records the ootheca of three mantis species. The clinical use of ootheca unrecorded in Chinese Pharmacopoeia, will pose potential risks to drug safety. It's urgent to identify the origin of Mantidis Oötheca. The current researches about original animal in Mantidis Oötheca are based on morphology and unanimous. DNA barcoding fill gaps of the traditional morphological identification, which is widely used in animal classification studies. This study first use DNA barcoding to analyze genetic distance among different Mantidis Oötheca types, align COI sequences between mantis and Mantidis Oötheca and construct the phylogeny tree. The result confirmed that Tenodera sinensis and Hierodula patellifera were the origin insects of Tuanpiaoxiao and Heipiaoxiao, respectively, and Statilia maculate and Mantis religiosa were the origin insects of Changpiaoxiao.

Phylogeny of Dictyoptera: Dating the Origin of Cockroaches, Praying Mantises and Termites with Molecular Data and Controlled Fossil Evidence

Understanding the origin and diversification of organisms requires a good phylogenetic estimate of their age and diversification rates. This estimate can be difficult to obtain when samples are limited and fossil records are disputed, as in Dictyoptera. To choose among competing hypotheses of origin for dictyopteran suborders, we root a phylogenetic analysis (~800 taxa, 10 kbp) within a large selection of outgroups and calibrate datings with fossils attributed to lineages with clear synapomorphies. We find the following topology: (mantises, (other cockroaches, (Cryptocercidae, termites)). Our datings suggest that crown-Dictyoptera-and stem-mantises-would date back to the Late Carboniferous (~ 300 Mya), a result compatible with the oldest putative fossil of stem-dictyoptera. Crown-mantises, however, would be much more recent (~ 200 Mya; Triassic/Jurassic boundary). This pattern (i.e., old origin and more recent diversification) suggests a scenario of replacement in carnivory among polyneopterous insects. The most recent common ancestor of (cockroaches + termites) would date back to the Permian (~275 Mya), which contradicts the hypothesis of a Devonian origin of cockroaches. Stem-termites would date back to the Triassic/Jurassic boundary, which refutes a Triassic origin. We suggest directions in extant and extinct species sampling to sharpen this chronological framework and dictyopteran evolutionary studies.