Diplopod Species Research Articles

Toxic metals in Amazonian soil modify the bacterial community associated with Diplopoda

Toxic metal pollution in the Amazon is a serious problem that reduces the quality of water, soil, air, and consequently alters communities of fauna, flora, and microbiota, harming human health and well-being. Our aim was to determine the impact of toxic metals on the structure of the bacterial community associated with Diplopoda in the Amazon rainforest. Animals were kept in microcosms contaminated with cadmium (50 mg.kg−1), mercury (35 mg.kg−1) and no toxic metal (control). The intestinal and molting chamber microbiota were accessed by culture-dependent and culture-independent methods (16S metabarcoding). The cultivated strains were identified, and their functional traits evaluated: secretion of enzymes, growth at different pH, resistance to metals and antibiotics, and ability to reduce toxic effects of metals on plants. Our research described Brachyurodesmus albus, a new species of Diplopoda. We obtained 177 isolates distributed in 35 genera and 61 species of bacteria (Pseudomonadota, Bacillota, Bacteroidota and Actinomycetota) associated with the gut and molting chamber of B. albus. Metabarcoding data provided a more robust access to the bacterial community, resulting in 24 phyla, 561 genera and 6792 ASVs. The presence of metal Cd and Hg alters the composition and abundance of bacteria associated with B. albus (PERMANOVA p < 0.05). The microhabitat (gut and molting chamber) harbours bacterial communities that differ in composition and abundance (PERMANOVA p < 0.05). The presence of Cd and Hg alters important metabolic pathways related to the prokaryotic defense system; antimicrobial resistance genes, endocytosis and secretion system, estimated by PICRUSt. Bacteria selected with high resistance to Cd and Hg buffer the toxic effect of metals on tomato seedlings. This work describes B. albus and concludes that its diverse bacterial microbiota is altered by soil contamination by toxic metals, as well as being an important repository for prospecting strains to be applied in bioremediation programs.

Characterization of the complete mitochondrial genome of Spirobolus grahami (Diplopoda: Spirobolidae) with phylogenetic analysis

Diplopoda is one of the most diverse and important groups of soil arthropods, but little research has been done on their phylogenetic relationship and evolution. Here, we sequenced and annotated the complete mitochondrial genomes of Spirobolus grahami. The total mitogenome of S. grahami was typical circular, double-stranded molecules, with 14,875 bp in length, including 13 protein-coding genes, 22 tRNAs, two rRNAs, and one control region. Base composition analysis suggested that the mitochondrial sequences were biased toward A and T, with A + T content of 58.68%. The mitogenomes of S. grahami exhibited negative AT and positive GC skews. Most of the 13 PCGs had ATN as the start codon, except COX1 start with CGA, and most PCGs ended with the T stop codon. The dN/dS values for most PCGs were lower than 1, suggesting that purifying selection was likely the main driver of mitochondrial PCG evolution. Phylogenetic analyses based on 13 PCGs using BI and ML methods support the classification of genus Spirobolus and Tropostreptus. Glomeridesmus spelaeus is distantly related to the other Diplopoda species.

Evaluation of the consumption of agricultural and urban waste by the diplopod Trigoniulus corallinus as a strategy for formulating new combinations for the millicomposting process.

This study aimed to measure the consumption of different types of plant waste by the diplopod species Trigoniulus corallinus, in order to determine which would be the most suitable for the millicomposting process. To this end, a waste consumption experiment was carried out in the laboratory, using a completely randomized experimental design with 15 replicates and 13 organic residues from different sources. After 10days, the following parameters were evaluated: dry mass of the waste used to feed the diplopods, dry mass of the fecal pellets, and diplopod mortality. Significant differences were observed in the consumption rates of the diplopods in the different treatments, with the highest rates being observed for Mimosa caesalpiniifolia, with 44.49%, followed by Gliricidia sepium chips, with 38.24%. The highest values for pellet mass were obtained from the decomposition of Mimosa caesalpiniifolia litter (0.891g). The treatment with Syngonium auritum shavings showed 93% mortality after consumption, followed by the treatment with Heliconia psittacorum shavings, which showed 53%. Both species are ornamental and widely found in gardens and backyards. The diplopods have a preference for Mimosa caesalpiniifolia litter and Gliricidia sepium shavings. There is limited consumption of ornamental plant waste, with reports of toxicity to other organisms. Based on these results, a mixture of waste will be tested for millicomposting in urban farming areas that excludes toxic plants.

The Diplopoda from the middle course of Argeş river

23 species of Diplopoda are recorded from the poorly investigated region of the middle basin of the Argeş River, several species being recorded for the first time in this region while for other species like Rumaniulus mammosus it expands the known distribution.

Millipede Diversity and Distribution in the Sirumalai Hills (Eastern Ghats), Tamil Nadu, India

Millipedes are one of the significant terrestrial fauna in the forest ecosystem to decompose the plants' debris. Despite their environmental significance, records on millipede distribution are quite scarce and invalid in Tamil Nadu, India. The first investigation is an attempt to assess the population of millipedes at different elevation levels of Sirumallai Hills from July 2020 to June 2021. The number of millipedes was recorded using pitfall trapping and quadrant sampling. Millipede diversity and distribution in different elevations were evaluated with the help of Shannon’s and Simpson’s indexes and richness and evenness were estimated by standard methods. A total of 8 species of millipede belonging to the order Polydesmida, Sphaerotheriida and Spirobolida were recorded in lower, middle and higher elevations. Our results showed that Orthomorpha coarctata, Oxidus gracilis, Haphaphe haydeniana, Aulabolus newtoni and Trigoniulus corallinus species were in found all the elevations and most abundant in lower elevations. Arthosphaera magna, Arthosphaera dalyi and Arthosphaera distica species were abundant in middle elevations and scarce in upper and lower elevations. Diplopod species abundance and diversity were lesser in lower and higher elevations when compared to the middle elevation. Despite their richness similarities in all elevations, there were differences in the composition of the millipede species between the elevations.

Arthropod-based biotic integrity indices: A novel tool for evaluating the ecological condition of native forests in the Azores archipelago

Island ecosystems are experiencing a significant decline in biodiversity, with forest biodiversity being particularly affected by several biodiversity erosion drivers. This alarming situation highlights the urgent need for conservation managers to develop more accurate and efficient tools to assess and monitor the quality status of sites. To address this issue, our study focuses on the development of two biological integrity indices (IBI) that utilize arthropod communities as indicators to measure the quality of forest sites. In accordance with studies that showed stratification of species diversity, we developed an IBI for canopy stratum (IBI-Canopy) and an IBI for an intermediate stratum targeting the forest understory (IBI-SLAM). We calibrated both indices on seven parameters for comparison purpose with a previous developed epigean IBI. Percentages of endemic, native non-endemic and introduced species richness and abundance were included in both indices. Percentages of Diplopoda species richness and abundance were included in IBI-Canopy and percentages of Saprophagous species richness and abundance were included in IBI-SLAM. As expected species richness and abundance of endemic species were negatively related to disturbance and selected for both IBI. Surprisingly, species richness and abundance of native non-endemic species were positively related to disturbance. The study highlights the limitations of single measurements in detecting all types of pressure sources, and proposes a multi-measurement system to provide a more comprehensive understanding of the overall system conditions. Our efficient and accessible indices confirmed low preservation status in Flores Island compared to Terceira and Pico, consistent with prior empirical studies. Our analyses also showed that canopy detect disturbance earlier than intermediate understory stratum. Our methodology has successfully been developed and tailored to the unique arthropod communities found in the Azores forests. While it may not be suitable for random forest sites, it can serve as a valuable source of inspiration for the development of arthropod-based IBIs in other islands of the world for which standardized endemic and exotic species richness and abundance could be obtained. The study also showed that arthropod assemblages mimicked forest biodiversity stratification and this is reflected in differences expressed by the IBIs.

STRUKTUR KOMUNITAS DIPLOPODA TANAH PADA KETINGGIAN BERBEDA DI PERKEBUNAN TEH KABAWETAN BENGKULU

Soil diplopods are an important biotic component in agricultural land ecosystems. Its presence in the soil is an important in the decomposition process of soil organic matter, and plays a role in increasing soil fertility. This study aims to study the community structure of soil Diplopoda at different altitudes in the Bengkulu Kabawetan Tea Plantation. The location of the study used the stratified sampling method which is based on the altitude of 800 m, 900 m and 1000 m above sea level. Soil Diplopods were collected by using the 50x50 cm quadratic method and a 100 m line transect. Data analysis consisted of density, relative density, diversity index, and Morisita index. There were 4 types of soil Diplopods in the Bengkulu Kabawetan Tea Plantation, namely Arthrosphaera sp., Gyrodrepanum sp., Oxidus sp., and Trigoniulus sp. At an altitude of 900 m and 1000 m, 4 species of Diplopoda were found and at an altitude of 800 m consisted of 3 types of Diplopoda. The density of soil diplopods at the three study locations varied, with the highest density at an altitude of 1000 m followed by at an altitude of 800 m and at 900m. The diversity index at the three locations is low and moderate. The distribution of diplopods at the study site was random and uniform.

The Complete Mitochondrial Genome of Spirobolus bungii (Diplopoda, Spirobolidae): The First Sequence for the Genus Spirobolus.

Millipedes (Diplopoda) comprise one of the most important groups of large soil arthropods in terrestrial ecosystems; however, their phylogenetic relationships are poorly understood. Herein, the mitochondrial genome (mitogenome) of Spirobolus bungii was sequenced and annotated, which was 14,879 bp in size and included 37 typical mitochondrial genes (13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), and 22 transfer RNA genes (tRNAs)). Most of the 13 PCGs had ATN (AT/A/T/G) as the start codon except for COX1, which used CGA, and most PCGs ended with the T end codon. By comparing the gene arrangements of the mitogenomes among Diplopoda species, rearrangement occurred between and within orders. In contrast to Narceus annularus, the mitogenome genes of S. bungii had consistent orders but were transcribed in completely opposite directions, which was a novel finding in Spirobolidae. Moreover, the phylogenetic relationships within Diplopoda, which were based on the sequences of 13 PCGs, showed that S. bungii was clustered with N. annularus, followed by Abacion magmun. This indicated that there might be a close relationship between Callipodida and Spirobolida. These results could contribute to further studies on the genetics and evolutionary processes of S. bungii and other Diplopoda species.

Structure of the midgut epithelium in four diplopod species: histology, histochemistry and ultrastructure

Abstract The middle region of the digestive system of millipedes, the midgut, is responsible for all processes connected with digestion, but also takes part in homeostasis maintenance thanks to the ability to activate many mechanisms which neutralize changes occurring at different levels of the animal’s body. Numerous millipede species are treated as bioindicators of the natural environment and they are exposed to different stressors which originate from external environment. To obtain all data on the functioning of midgut of millipedes as the barrier against stressors, it is necessary to have a precise and general description of the midgut epithelium. Members from four millipede orders were selected for the studies: Polydesmus angustus (Polydesmida), Epibolus pulchripes (Spirobolida), Unciger transsilvanicus (Julida) and Glomeris tetrasticha (Glomerida). The structure and ultrastructure of their midgut epithelial cells (the digestive, secretory and regenerative cells) were documented using transmission electron microscopy and histochemical methods. The obtained results have been compared and discussed to previous ones, to present the general and structural organization of the midgut in Diplopoda. Our studies revealed that the ultrastructure of all cells which form the midgut epithelium in millipedes is general for all the species studied up to now and it resembles the cell ultrastructure observed in Chilopoda and Hexapoda, including the digestive, secretory and stem cells.

Evaluation of millicomposts from different vegetable residues and production systems in the lettuce seedling development

Millicomposting is a new, little known, and environmentally friendly biotechnology, which facilitates the biotransformation of plant residues into stable organic matter; this process is aided by the activity of diplopods, commonly known as millipedes, which act directly on the fragmentation of plant residues, thus accelerating the decomposition rates of various residues whose C/N ratios are out of reach for traditional composting. The final product of millicomposting is millipede humus, which has been called millicompost and can contribute to supply the growing demand for substrates used to produce vegetable seedlings in rural and urban environments. In this context, this study aimed to verify the efficiency of millicomposts obtained in two different production systems, located in different environments (Rio de Janeiro and Sao Paulo) with different diplopod species in the production of lettuce seedlings. Initially, a thorough characterization of the evaluated substrates was carried out, characterizing the physical, physical-chemical, and chemical properties. The performance of different substrates in the production of lettuce seedlings was evaluated by sowing crisp lettuce cultivar Grand Rapids in 200-cell expanded polystyrene trays. The seedlings were evaluated 30 days after sowing. Millicomposts produced in RJ and SP states have differences in their physical, physical-chemical, and chemical properties. Nevertheless, both produced lettuce seedlings with similar quality, whose phytotechnical parameters were superior to the commercial substrate. In this point of view, both millicomposts are efficient as a substrate in the production of lettuce seedlings and can be produced in rural and urban environments, meeting the current need for sustainable agricultural inputs.

Cyanogenic glycosides and plant-herbivore interactions

Cyanogenic glycosides are nitrogen containing secondary metabolites which offer plant defense mechanism against herbivores while recently various insects have developed ability to detoxify, sequester and synthesize these cyanogenic compounds. Dhurrin was the first identified and isolated CNGs from young leaves of sorghum, Sorghum vulgare. The presence of CNGs were confirmed in few species of Chilopods, Diplopods, Heteropterans, Coleopterans and Lepidopterans. Linamarin and Lotaustralin were the major CNGs distributed in Lepidopterans. They have developed an ability to de novo synthesize CNGs and detoxify them with the help of β-cyanoalanine synthase and rhodonase. This may be due to the course of insect evolution or the genes responsible for the synthesis of CNGs may get transferred from plants to insects. In future, the responsive genes in these arthropods should be silenced and expansion of transgenic cyanogenic plants may encouraged to ensure plant defense mechanism.

Complete mitochondrial genome of Glomeridesmus spelaeus (Diplopoda, Glomeridesmida), a troglobitic species from iron-ore caves in Eastern Amazon

We report the complete mitochondrial genome sequence of Glomeridesmus spelaeus, the first sequenced genome of the order Gomeridesmida. The genome is 14,825 pb in length and encodes 37 mitochondrial (13 PCGs, 2 rRNA genes, 22 tRNA) genes and contains a typical AT-rich region. The base composition of the mitogenome was A (40.1%), T (36.4%), C (15.8%), and G (7.6%), with an GC content of 23.5%. Our results indicated that G. spelaeus is only distantly related to the other Diplopoda species with available mitochondrial genomes in the public databases. As the broadest genetic characterization of a Glomeridesmida species available to date, the mitogenome of G. spelaeus will help understanding the evolution of such a little-known millipede group. Also, our data will be important for the characterization and conservation of the diverse invertebrate troglofauna of the Amazonian caves.

Heat tolerance and acclimation capacity in subterranean arthropods living under common and stable thermal conditions.

Cave‐dwelling ectotherms, which have evolved for millions of years under stable thermal conditions, could be expected to have adjusted their physiological limits to the narrow range of temperatures they experience and to be highly vulnerable to global warming. However, most of the few existing studies on thermal tolerance in subterranean invertebrates highlight that despite the fact that they show lower heat tolerance than most surface‐dwelling species, their upper thermal limits are generally not adjusted to ambient temperature. The question remains to what extent this pattern is common across subterranean invertebrates. We studied basal heat tolerance and its plasticity in four species of distant arthropod groups (Coleoptera, Diplopoda, and Collembola) with different evolutionary histories but under similar selection pressures, as they have been exposed to the same constant environmental conditions for a long time. Adults were exposed at different temperatures for 1 week to determine upper lethal temperatures. Then, individuals from previous sublethal treatments were transferred to a higher temperature to determine acclimation capacity. Upper lethal temperatures of three of the studied species were similar to those reported for other subterranean species (between 20 and 25°C) and widely exceeded the cave temperature (13–14°C). The diplopod species showed the highest long‐term heat tolerance detected so far for a troglobiont (i.e., obligate subterranean) species (median lethal temperature after 7 days exposure: 28°C) and a positive acclimation response. Our results agree with previous studies showing that heat tolerance in subterranean species is not determined by environmental conditions. Thus, subterranean species, even those living under similar climatic conditions, might be differently affected by global warming.

Quasi-experimental determination of a mass standard in the forest millipede &lt;em&gt;Centrobolus inscriptus&lt;/em&gt;

Sexual size dimorphism (SSD) in the diplopod species Centrobolus inscriptus has a positive correlation with body size. Intraspecific intersexual variation in mass was calculated twice in this species (males: 2.48 ± 0.57g; 2.00 ± 0.22g; females: 2.27 ± 0.28g; 2.61 ± 0.42g) and data sets tested for SSD. Males differed significantly from females in body mass (students t-test: t=9.38, d.f.=95, p<0.05). This was again found in the larger sample where males and females differed significantly from each other in mass (Wilcoxon matched pairs test: T= 554, n = 88, P = 0.00). When the two data sets were pooled and the mean’s compared, a difference was found (t=2.3162, n=273; p=0.020918). It was found males were lighter and have higher reproductive success through female preference for larger males when there was Size assortative mating behaviour. Conformity to the mass standard in sexual selection was suggested. Millipedes may influence concentrations of soil elements through sex‐specific difference.

Chilopoda and Diplopoda of semi natural flooded meadows in Matsalu, Estonia

In Matsalu National Park a flood is a natural disturbance which shapes ecosystems and communities. The impact of human activities (e.g. extensive mowing once a year or low stress grazing) on the habitat in this area is low. The disturbances are caused by natural conditions such as melting snow, precipitation and brackish sea water and the presence of flood is supported by flat relief. The aim of the current study was to describe the Chilopoda and Diplopoda assemblages of semi natural meadows and to find out the effect of habitat conditions on these invertebrates. On the 12 studied meadows we sampled and analysed soil invertebrates by using pitfall traps in the non-flooded and flooded areas of meadows. The individuals of 10 Chilopoda species and 15 Diplopoda species, which assemblages were more abundant and diverse in the non-flooded areas of meadows with trees and bushes nearby, were collected on semi natural meadows in Matsalu. Only a few species were represented in abundance on studied meadows including Leptoiulus proximus, L. cibdellus, Julus terrestris, J. scanicus. The species Pachymerium ferrugineum, Schendyla nemorensis, Julus terrestris, J. scanicus, Leptoiulus cibdellus, Xestoiulus laeticollis were also found in the areas flooded with brackish water. The activity density and species richness of Chilopoda and Diplopoda were significantly lower in the flooded areas of the meadow after flood water withdrawal compared to the non-flooded areas of the same meadows.

Myriapods (Arthropoda, Myriapoda) in the Pantanal of Poconé, Mato Grosso, Brazil

Abstract: The Brazilian Pantanal biome is one of the largest and most important floodplains in the world by virtue of its biodiversity and indispensable ecological services on local, regional, and global scales. Despite this importance, many gaps remain concerning its biodiversity as well as its generation and maintenance mechanisms. In view of expanding the information about its biological diversity, we compiled a list of Myriapoda (Arthropoda) species occurring in the Pantanal of Poconé, Mato Grosso, Brazil, based on the records from literature and on the specimens available in the zoological collections of Federal University of Mato Grosso -UFMT. A total of 33 Myriapoda species were recorded in the region. The Diplopoda species (20 spp.; 60.6%) are distributed 'between four orders: Polydesmida, represented by five families (Chelodesmidae, notably, with three species; Paradoxosomatidae and Pyrgodesmidae, with two species each; and Cyrtodesmidae and Fuhrmannodesmidae, with one species each, recently recorded in the region); Spirostreptida, represented by Spirostreptidae, with eight species; Spirobolida, with two species (one Rhinocricidae and one not identified); and Polyxenida. The Chilopoda (10 spp.; 30.3%) belong to three orders: Scolopendromorpha, with four species of the family Scolopendridae, two Scolopocryptopidae species, and one Cryptopidae species; Geophilomorpha, with the families Aphilodontidae and Schendylidae, with one species each; and Lithobiomorpha, with one Henicopidae species. Symphyla was represented by only two species (6.1%) of the family Scutigerellidae; and Pauropoda (3.0%) by a single species of Pauropodidae. The Myriapoda species richness, as well as the high number of new records in recent studies reinforce the importance of the northern region of the Pantanal biome as a diversity center with potential priority for measures aimed at the conservation of its many habitats.

Apheloria polychroma, a new species of millipede from the Cumberland Mountains (Polydesmida: Xystodesmidae).

Millipedes of the genus Apheloria Chamberlin, 1921 occur in temperate broadleaf forests throughout eastern North America and west of the Mississippi River in the Ozark and Ouachita Mountains. Chemically defended with toxins made up of cyanide and benzaldehyde, the genus is part of a community of xystodesmid millipedes that compose several Müllerian mimicry rings in the Appalachian Mountains. We describe a model species of these mimicry rings, Apheloria polychroma n. sp., one of the most variable in coloration of all species of Diplopoda with more than six color morphs, each associated with a separate mimicry ring.

Midgut of the diplopod Urostreptus atrobrunneus: structure, function, and redefinition of hepatic cells.

Diplopods are considered important macroarthropods the soil as part of its maintenance and balance. These animals usually do not occur in high densities, but population explosions caused by environmental disturbances, climate changes, and use of pesticides that eliminate possible competitors, have been reported. The millipede Urostreptus atrobrunneus Pierozzi and Fontanetti, 2006 have become a nuisance to humans in infestation sites in urban centers of the state of Sao Paulo, Brazil. As a contribution to the understanding of this potential pest, this study describes the histology, histochemistry, and ultrastructure of the U. atrobrunneus midgut, and presents the redefinition of hepatic cells somewhat controversial in the literature. The region of the midgut is characterized by the absence of a cuticular intima, and composed of a pseudostratified epithelium on a thick basal membrane, followed by a muscle layer, a layer of hepatic cells, lined by an external membrane. The morphology observed in U. atrobrunneus is similar to that reported for other species of diplopods. The hepatic cells have been previously described as randomly without forming a layer, however, the present results clearly demonstrate that these cells form a continuous layer over the whole midgut.

Chitin hoops obtained from Ommatoiulus sabulosus (Diplopoda, Julidae) used for bovine serum albumin adsorption

A new hoop shaped three dimensional chitin was obtained successfully from the body segment of a diplopod species (Ommatoiulus sabulosus) by following the procedure decolorization, demineralization and deproteinization. Purity of the hoop shaped three-dimensional chitin was proved by FT-IR analysis and chitinase digestive test. The important bands for α-chitin such as 1654.2, 1619.7 and 1552cm−1 were found after FT-IR analysis. And the chitinase digestive test revealed the purity of chitin (with digestion rate of 94.7%). SEM analysis showed that the chitin surface consisted of highly porous structure with nanofibers. Thermal stability of the hoop shaped chitin was recorded quite high (DTGmax=383°C). The nitrogen, carbon and hydrogen contents of the hoop shaped chitin were determined as 6.81%, 46.23% and 6.43% respectively. And also degree of acetylation (DA) of the chitin indicated the purity with 95.85%. Chitin hoops-BSA interaction was conducted at different pH, protein concentration and contact time. This new type of three-dimensional chitin obtained from the diplopod body segments can find more effective applications in further studies comparing to the conventional dust forms.

Three-dimensional chitin rings from body segments of a pet diplopod species: Characterization and protein interaction studies

Physicochemical characterization of new chitin isolates can provide valuable insights into designing of biomimetic materials. Chitin isolates with a definite three-dimensional (3D) structure can exhibit characteristics that distinguish them from other chitin specimens that are in form of powder or flakes without a definite and uniform shape. Herein, 3D chitin rings were produced from body segments of a diplopod (Archispirostreptus gigas) inhabiting tropical regions. This organism is cultured easily and can reach 38cm in length, which makes it a suitable source for isolation of chitin. The chitin rings were characterized via TGA, FT-IR, SEM and XRD analyses. Enzymatic digestion test with chitinase demonstrated that chitin isolates had high purity (digestion rate: 97.4%). The source organism had high chitin content; 21.02±2.23% on dry weight. Interactions of the chitin rings with bovine serum albumin (BSA) protein were studied under different conditions (pH: 4.0–8.0, chitin amount: 6–14mg, contact time: 30–360min, protein concentration: 0.2–1mg/mL). The highest BSA adsorption was observed at pH5.0 at 20°C. The adsorption equilibrium data exhibited a better fit to Langmuir adsorption and the pseudo-first order kinetic models. The findings presented here can be useful for further studies aiming to develop biocompatible and nontoxic biomaterials.