Reticulitermes Lucifugus Research Articles

Candidate target genes of the male-specific expressed Doublesex in the termite Reticulitermes speratus.

Eusocial insects such as termites, ants, bees, and wasps exhibit a reproductive division of labor. The developmental regulation of reproductive organ (ovaries and testes) is crucial for distinguishing between reproductive and sterile castes. The development of reproductive organ in insects is regulated by sex-determination pathways. The sex determination gene Doublesex (Dsx), encoding transcription factors, plays an important role in this pathway. Therefore, clarifying the function of Dsx in the developmental regulation of sexual traits is important to understand the social evolution of eusocial insects. However, no studies have reported the function of Dsx in hemimetabolous eusocial group termites. In this study, we searched for binding sites and candidate target genes of Dsx in species with available genome information as the first step in clarifying the function of Dsx in termites. First, we focused on the Reticulitermes speratus genome and identified 101 candidate target genes of Dsx. Using a similar method, we obtained 112, 39, and 76 candidate Dsx target genes in Reticulitermes lucifugus, Coptotermes formosanus, and Macrotermes natalensis, respectively. Second, we compared the candidate Dsx target genes between species and identified 37 common genes between R. speratus and R. lucifugus. These included several genes probably involved in spermatogenesis and longevity. However, only a few common target genes were identified between R. speratus and the other two species. Finally, Dsx dsRNA injection resulted in the differential expression of several target genes, including piwi-like protein and B-box type zinc finger protein ncl-1 in R. speratus. These results provide valuable resource data for future functional analyses of Dsx in termites.

Assessment of the insecticidal activity of five essential oils used against the subterranean termite Reticulitermes lucifugus (Rossi) (Blattodea, rhinotermitidae) in laboratory

Among Reticulitermes genus the most abundant species living in Italy is Reticulitermes lucifugus Rossi. This termite is very dangerous to wooden structures of artistic heritage and buildings. The traditional control of R. lucifugus is very difficult resulting in negatively impact on the environment, therefore the use of phytochemical, such as essential oils (EOs), could lead to an alternative to synthetic insecticides, with advantages in reducing environmental risks. In this work we investigated the insecticidal activity of EOs of Citrus bergamia Risso, Syzygium aromaticum L., Foeniculum vulgare Mill., Pelargonium odoratissimum L., and Origanum vulgare L. by inhalation against R. lucifugus workers. It is the first study to examine the efficacy of EOs on this termite species. Results showed that after 24 hours of treatment exposure, mortality occurred in all treatments and was dose-dependent, increasing when the treatment dose increased. At the lowest dose (2.5 μl/l), oregano, clove, and geranium EOs resulted in mortality of more than 80%. Oregano EO was the most active already at low doses, while fennel EO was the least effective. 24 hours after the treatment, the lowest DL50, obtained by the dose-response analysis, was detected for oregano EO (1.21 μl/l), followed by those of EOs of clove (1.28 μl/l), geranium (1.73 μl/l), fennel (2.20 μl/l), and bergamot (2.88 μl/l). This study highlighted the possibility of using these EOs in the termite control for the preservation of wooden structures.

THE RESISTANCE OF PINUS SYLVESTRIS L. WOOD MODYFIED WITH FURFURYL ALCOHOL FOR DESTRUCTION BY RETICULITERMES LUCIFUGUS VAR. SANTONENSIS (DE FEYTEAUD)

The aim of the research was to determine the changes in susceptibility of Scots pine (Pinus sylvestrisL.) wood to feeding bysubterranean termites Reticulitermes lucifugus var. santonensisconducted in accordance with the ASTM D 3345-08: 2009 Thesapwood after modification in furfuryl alcohol at concentration 50% with the addition citricacidat concentration 1%, naturalsapwood and heartwood experiment as a compulsory reference material were used for the tests.The blocks of Scots pine wood were used to create seasoned samples of 7% ± 1% moisture content.The blocks with dimensions of 25.4 x 25.4 x 6.4 mm were made from three trees. Each variant was represented by 5 blocks. All wood blocks were freeze-dried before starting the experiment in order to measure the dry weight. After 4 weeks of termite feeding visually rates of wooddestructionwere: 9 (light attack) for modified sapwood, 2.8 (heavy attack/failure)for natural sapwood and 8.2 (light attack/moderate attack)for natural heartwood.The loss of wood weight of blocks was: 0.01 gfor modified sapwood, 0.071 g for natural sapwood and 0.21 g for natural heartwood. The mortality of the termites in the case of modified sapwood was complete. The termite mortality in natural sapwood has been classified as slight, and in natural heartwood as slight to complete.

Wood feeding and social living: Draft genome of the subterranean termite Reticulitermes lucifugus (Blattodea; Termitoidae).

Termites (Insecta, Blattodea, Termitoidae) are a widespread and diverse group of eusocial insects known for their ability to digest wood matter. Herein, we report the draft genome of the subterranean termite Reticulitermes lucifugus, an economically important species and among the most studied taxa with respect to eusocial organization and mating system. The final assembly (~813 Mb) covered up to 88% of the estimated genome size and, in agreement with the Asexual Queen Succession Mating System, it was found completely homozygous. We predicted 16,349 highly supported gene models and 42% of repetitive DNA content. Transposable elements of R. lucifugus show similar evolutionary dynamics compared to that of other termites, with two main peaks of activity localized at 25% and 8% of Kimura divergence driven by DNA, LINE and SINE elements. Gene family turnover analyses identified multiple instances of gene duplication associated with R. lucifugus diversification, with significant lineage-specific gene family expansions related to development, perception and nutrient metabolism pathways. Finally, we analysed P450 and odourant receptor gene repertoires in detail, highlighting the large diversity and dynamical evolutionary history of these proteins in the R. lucifugus genome. This newly assembled genome will provide a valuable resource for further understanding the molecular basis of termites biology as well as for pest control.

Bio-Based Phase Change Materials for Wooden Building Applications

Solid wood can serve multifunctionality for energy savings in buildings. The study reveals the results of biodeterioration and degradation of solid Scots pine wood used to incorporate single or multicomponent fatty acid mixtures as bio-based phase change materials (BPCMs). The sapwood samples were impregnated with capric acid (CA), methyl palmitate (MP), lauryl alcohol (LA) and a mixture of coconut oil fatty acids and linoleic acid (CoFA-LA). The samples were tested against subterranean termites by an Italian species (Reticulitermes lucifugus), the wood boring beetle Hylotrupes bajulus and mold through a discoloration test. Tested against termites, the impregnated samples were significantly less susceptible to the attack than the controls, i.e., the tested BPCMs were resistant to R. lucifugus. The only test with MP terminated at the moment against H. bajulus showed positive results with no larvae surviving. The mold discoloration test revealed that the wood impregnated with CoFA-LA was identically susceptible to mold discoloration when compared to the control, nonimpregnated samples. This pioneer study verifies that solid wood employed for the encapsulation of BPCMs for building purposes can serve identically or somewhat better than similar wooden building elements regarding attacks of the above microorganisms and insects. Such multifunctional building elements will be tested further in a pilot scale building to characterize better the durability aspects of the new materials.

High Exploration Behavior of Termite Propagules Can Enhance Invasiveness

Social life is usually associated with enhanced propagule pressure, which increases the chance of introducing several individuals during a single introduction event. Social insects are therefore among the most successful invasive species, benefiting from rapid establishment and increased foundation success in new habitats. In termites, propagule pressure may also be increased by the development of reproductive individuals from a small group of foraging workers. This suggests that enhanced exploration activity may increase propagule pressure through an elevated chance of transporting isolated groups of foragers. Here, we analyzed the exploration behavior of three termite species of the Reticulitermes genus, comparing the invasive species Reticulitermes flavipes (testing both native and introduced populations) to the native species Reticulitermes grassei and Reticulitermes lucifugus. Different features representative of the exploration capacity were measured during 48 h, including: the number of tunnels, the length of tunnels, the number of foragers, and the interindividual distance of foragers in a straight line or through tunnels. Our results show that compared to the native Reticulitermes species, R. flavipes foragers from both populations dug more tunnels with a longer total length, and individuals were more spatially dispersed and covered a larger exploration zone. These findings suggest that the enhanced exploration ability of R. flavipes may have played a role in its invasion success, by increasing its propagule pressure through a higher chance of human-mediated transport. In addition, the absence of differences between the native and introduced populations of R. flavipes suggests that the exploration behaviors facilitating the worldwide invasion of this species originated in its native range.

Use of the proteomic tool MALDI-TOF MS in termite identification

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) has proved effective for the identification of many arthropods. A total of 432 termite specimens were collected in Mali, Cote d’Ivoire, Togo, Senegal, Switzerland and France. Morphologically, 22 species were identified, including Ancistrotermes cavithorax, Amitermes evuncifer, Cryptotermes brevis, Cubitermes orthognathus, Kalotermes flavicollis, Macrotermes bellicosus, Macrotermes herus, Macrotermes ivorensis, Macrotermes subhyalinus, Microcerotermes parvus, Microtermes sp., Odontotermes latericius, Procubitermes sjostedti, Promirotermes holmgreni, Reticulitermes grassei, Reticulitermes lucifugus, Reticulitermes santonensis, Trinervitermes geminatus, Trinervitermes occidentalis, Trinervitermes togoensis, Trinervitermes sp., Trinervitermes trinervoides and Trinervitermes trinervius. Analysis of MALDI-TOF MS spectra profiles from termites revealed that all were of high quality, with intra-species reproducibility and inter-species specificity. Blind testing of the spectra of 389 termites against our updated database with the spectra of 43 specimens of different termite species revealed that all were correctly identified with log score values (LSVs) ranging from 1.65 to 2.851, mean 2.290 ± 0.225, median 2.299, and 98.4% (383) had LSVs > 1.8. This study is the first on the use of MALDI-TOF for termite identification and shows its importance as a tool for arthropod taxonomy and reinforces the idea that MALDI-TOF MS is a promising tool in the field of entomology.

An interesting case of polystyrene consumption by <em>Reticulitermes lucifugus</em> (Blattodea: Neoisoptera, Rhinotermitidae)

A colony of Reticulitermes lucifugus from Apulia (SE Italian Peninsula) was recently observed to have partially consumed some polystyrene panels applied on a wall, and used like seat for termite nest. Further observations could allow to better understand if this colony is just able to physically consume and chew this plastic material, releasing it chemically intact after the passage throughout the termites’ digestive system, or if their microbiome could allow the insects to at least partially metabolize and degrade the ingested polystyrene fragments, as recently observed in a few other insects.

Decay, insect, and termite resistance of wood modified with epoxidized vegetable oils

Abstract Samples of Scots pine sapwood were treated with epoxidized linseed and soybean oils to improve decay, insect and termite resistance of wood. Non-epoxidized (raw) linseed and soybean oils were included as reference treatment in the study. In the epoxidation process, hydrogen peroxide was used to open double bounds, and acetic acid was added as a catalyst. Two retention levels, Ret A (80–140 kg m−3) and Ret B (170–270 kg m−3), two impregnation methods (full cell and empty cell) and emulsion technique were used. Samples treated with epoxidized oils had significantly lower mass losses than untreated samples while epoxidized oils showed higher mass losses than unepoxidized oils for Coniophora puteana and Trametes versicolor according to EN 113 for decay test. By adding boron, fungicidal properties were introduced to the treatment. All the vegetable oils showed 100% the mortality rate against larvae of Hylotrupes bajulus according to EN 47. Moreover, leached wood samples treated with oils also showed 100% larvae mortality. Additionally, termite testing based on EN 117 revealed 100% Reticulitermes lucifugus mortality for all leached oil treated samples.

Distribution of the termite Reticulitermes lucifugus (Isoptera) and the specifics of its invasion in Ukraine

Distribution of the termite Reticulitermes lucifugus (Isoptera) and the specifics of its invasion in Ukraine

Effects of starvation on survival, cannibalism, body mass, and intestinal protozoan profile in the subterranean termite Reticulitermes lucifugus

Scarcity or inadequate nutrition can affect biological and behavioural aspects of subterranean termites and their intestinal protozoan profile. The aim of this study was to investigate changes in survival, cannibalism, body mass, and protist community structure of Reticulitermes lucifugus Rossi subspecies “Sicily” following starvation to provide basic knowledge for the development of more specific studies on a possible survival strategy under stressful conditions. In nature, this termite consumes many food sources and its feeding activity is continuous during the year. In a 35-day laboratory experiment, groups of 50 termites (worker/soldier ratio 49:1) were subjected to two diets, starvation (no source of cellulose offered to the termites) and filter-paper feeding (as a control), kept for 35 days with 7-day intervals of inspection, and compared with termites freshly collected from a field colony on May 2017. Under starvation, termite survival decreased to 0% after 35 days for both workers and soldiers, whereas in the fed group (filter-paper diet) it was 83% for workers and 66% for soldiers. Cannibalism was on average 84% on dead workers, 1.7% on survivor workers, and 100% on dead soldiers. The body mass of workers decreased from 3.5 mg/worker (first day of the test) to 2.05 mg/worker (last day of the test). The community structure and abundance of the intestinal protozoa of workers changed in response to starvation. Starvation caused the loss of four, six, and two protist species after 7, 14, and 28 days, respectively, with only one species persisting after 28 days. In most inspection dates, results were significantly different from those of filter-paper-fed and field-collected groups.

Molecular Identity of Holomastigotes (Spirotrichonymphea, Parabasalia) with Descriptions of Holomastigotes flavipes n. sp. and Holomastigotes tibialis n. sp.

Holomastigotes is a protist genus (Parabasalia: Spirotrichonymphea) that resides in the hindguts of "lower" termites. It can be distinguished from other parabasalids by spiral flagellar bands that run along the entire length of the cell, an anterior nucleus, a reduced or absent axostyle, the presence of spherical vesicles inside the cells, and the absence of ingested wood particles. Eight species have been described based on their morphology so far, although no molecular data were available prior to this study. We determined the 18S rRNA gene sequences of Holomastigotes from the hindguts of Hodotermopsis sjostedti, Reticulitermes flavipes, Reticulitermes lucifugus, and Reticulitermes tibialis. Phylogenetic analyses placed all sequences in an exclusive and well-supported clade with the type species, Holomastigotes elongatum from R.lucifugus. However, the phylogenetic position of Holomastigotes within the Spirotrichonymphea was not resolved. We describe two new species, Holomastigotes flavipes n. sp. and Holomastigotes tibialis n. sp., inhabiting the hindguts of R.flavipes and R.tibialis, respectively.

New Species of Spirotrichonympha from Reticulitermes and the Relationships Among Genera in Spirotrichonymphea (Parabasalia).

Spirotrichonymphea is a class of hypermastigote parabasalids defined by their spiral rows of many flagella. They are obligate hindgut symbionts of lower termites. Despite more than 100yr of morphological and ultrastructural study, the group remains poorly characterised by molecular data and the phylogenetic positions and taxonomic validity of most genera remain in question. The genus Spirotrichonympha has been reported to inhabit several termite genera, including Reticulitermes, Coptotermes, and Hodotermopsis. The type species for this genus, Spirotrichonympha flagellata, was described from Reticulitermes lucifugus but no molecular data are yet available for this species. In this study, three new Spirotrichonympha species are described from three species of Reticulitermes. Their molecular phylogenetic position indicates that the genus is not monophyletic, as Spirotrichonympha species from Coptotermes, Paraneotermes, and Hodotermopsis branch separately. In contrast, the genus Holomastigotoides is monophyletic, as demonstrated using new sequences from Holomastigotoides species. The presence of Holomastigotoides in Prorhinotermes and the distinct phylogenetic positions of Spirotrichonympha from Reticulitermes and Coptotermes are consistent with a previously proposed symbiont fauna replacement in the ancestor of Reticulitermes.

Evolution of the asexual queen succession system and its underlying mechanisms in termites.

One major advantage of sexual reproduction over asexual reproduction is its promotion of genetic variation, although it reduces the genetic contribution to offspring. Queens of social insects double their contribution to the gene pool, while overuse of asexual reproduction may reduce the ability of the colony to adapt to environmental stress because of the loss of genetic diversity. Recent studies have revealed that queens of some termite species can solve this tradeoff by using parthenogenesis to produce the next generation of queens and sexual reproduction to produce other colony members. This reproductive system, known as asexual queen succession (AQS), has been identified in the subterranean termites Reticulitermes speratus, Reticulitermes virginicus and Reticulitermes lucifugus and in the Neotropical higher termites Embiratermes neotenicus and Cavitermes tuberosus The studies presented here have uncovered the unusual modes of reproduction in termites and have aimed to identify their underlying mechanisms. The study of AQS, the mixed use of sexual and asexual reproduction, is of fundamental importance as it may provide a key to solve the evolutionary paradox of sex.

Susceptibility of hornbeam and Scots pine woods to destruction by the subterranean termite Reticulitermes lucifugus ROSSI, 1792 (Blattodea: Isoptera)

Abstract The article presents the results of tests of the degree of damage to Scots pine (Pinus sylvestris) and hornbeam (Carpinus betulus) woods by the termite Reticulitermes lucifugus. Both wood species are classified as “susceptible to destruction by termites” in the EN 350-2:2000 standard. The procedures described in the ASTM D 3345-08 standard (2009) were applied in the experiments. During laboratory coercion tests, wood samples from these two species were damaged to a degree between light attack and moderate attack with penetration. Recent Scots pine sapwood was damaged to a heavy degree. The results can be associated with the much higher density of hornbeam wood as compared to Scots pine sapwood. The mortality rate of the termites in the test containers with both wood species was similar and low, no greater than 10%. In the light of the results, the classification of the susceptibility of native wood species to termite feeding, as stated in the EN 350-2:2000 standard, appears to be oversimplified.

Polyamidoamines (PAAs) functionalized with siloxanes as wood preservatives against fungi and insects

Abstract A novel treatment based on polyamidoamines (PAAs) for the preservation of wood against fungi and insects with a broad protection functionality, low effective concentration, and low environmental impact has been developed. PAAs were synthesized by nucleophile addition of ethanolamine (EtA) and/or 3-aminopropyltriethoxysilane (APTES) to N,N′-methylene-bisacrylamide (MBA). The molar ratios in the tested formulation were: I) MBA:EtA=1:1; II) MBA:APTES=1:1; III) MBA:EtA:APTES=1:0.5:0.5. These formulations, characterized by ESI-MS, NMR, FT-IR, were tested against: (a) the wood decay fungi (Coniophora puteana, Coriolus versicolor, and Poria placenta); (b) the subterranean termite Reticulitermes lucifugus, and the drywood termite Kalotermes flavicollis; (c) the woodborer Stegobium paniceum. Tests in combination with leaching showed that formulation II and III can be utilized as fungal wood preservatives for use classes 2–3 (EN 335:2013). In addition, all PAAs formulations were equally effective in preserving wood against the subterranean termite, and formulation II was most effective against drywood termite. On the other hand, the formulation I showed good efficacy against S. paniceum.

Temporal variations in symbiotic hindgut protist community of the subterranean termite Reticulitermes lucifugus Rossi in Sicily

The dynamics of symbiotic protist communities of Reticulitermes lucifugus “Sicily” were investigated to assess the effects of seasonal environmental conditions and the termite’s feeding activity. In worker and soldier castes, the total protist population (total abundance), individual species abundances, and species proportions in their hindguts were examined monthly from December 2012 to February 2014. The main protist species taken into account were Dinenympha fimbriata Kirby, D. gracilis Leidy, Pyrsonympha flagellata Gras., Spirotrichonympha flagellata Grassi u. Foa, Holomastigotes elongatum Grassi u. Foa, and Trichonympha agilis Leidy, while others were not specifically identified, but were counted together. Seasonal comparisons between worker and soldier castes were made. Further, monthly data of workers were examined. We always found the presence of symbiontic protists in worker and soldier hindguts, therefore we hypothesize that termites fed without periods of interruption. In both castes the total protist population and species abundance showed variable trends with the highest values in summer. Workers were found to have significantly larger populations of protists and abundances of individual species than soldiers. Similar protist species were observed in both castes and in all periods, except for H. elongatum which was sometimes absent in soldiers. In hindguts of workers and soldiers the proportions of the protist species often showed a significant variation across seasons except for S. flagellata and T. agilis. In both castes we always detected the highest percentage of Dinenympha spp. with respect to the other species. Elements that might influence these aspects are discussed.

The susceptibility of neolithic waterlogged beech wood (Fagus sylvatica L.) to destruction by Reticulitermes lucifugus Rossi

The article presents the results of a test on the resistance of Neolithic waterlogged beech wood (Fagus sylvatica L.) to destruction by sReticulitermes lucifugus Rossi. Methodology consistent with the AS TM D 3345-08 Standard was applied in the experiment. In the coercion test, the modern beech wood was destroyed at an intermediate stage between light att ack and moderate attack with penetration, whereas the pine sapwood was heavily d amaged. Under the same conditions, the waterlogged beech wood was seriousl y damaged or completely destroyed by the termites. However, unlike the modern pine and beech wood, all the termites died after feeding on the waterlogged b eech wood. In spite of the complete destruction of the waterlogged beech wood i n the coercion test, it seems that under natural conditions where there is a poss ible choice between different wood species, the infestation by termites of waterlo gged wood uncovered in archaeological work does not necessarily happen. Wo od containing few nutritional substances and substantial lignin, as w ell as having a high moisture content facilitating the development of parasitic mic roorganisms, will deter termites.

The gut microbiota of the wood-feeding termite Reticulitermes lucifugus (Isoptera; Rhinotermitidae)

Termite gut is host to a complex microbial community consisting of prokaryotes, and in some cases flagellates, responsible for the degradation of lignocellulosic material. Here we report data concerning the analysis of the gut microbiota of Reticulitermes lucifugus (Rossi), a lower termite species that lives in underground environments and is widespread in Italy, where it causes damage to wood structures of historical and artistic monuments. A 16S rRNA gene clone library revealed that the R. lucifugus gut is colonized by members of five phyla in the domain Bacteria: Firmicutes (49 % of clones), Proteobacteria (24 %), Spirochaetes (14 %), the candidatus TG1 phylum (12 %), and Bacteroidetes (1 %). A collection of cellulolytic aerobic bacteria was isolated from the gut of R. lucifugus by enrichment cultures on different cellulose and lignocellulose substrates. Results showed that the largest amount of culturable cellulolytic bacteria of R. lucifugus belongs to Firmicutes in the genera Bacillus and Paenibacillus (67 %). These isolates are also able to grow on xylan and show the largest clear zone diameter in the Congo red test. Reticulitermes lucifugus hosts a diverse community of bacteria and could be considered an acceptable source of hydrolytic enzymes for biotechnological applications.

Mildew fungi found in termites (Reticulitermes lucifugus) and their nests

This paper presents the results of observation of mould growth in laboratory colonies of termites. It also attempts to determine the species of mould fungi present in the research laboratory and the main colonies and their entomopathogenic for the termites. The following four species were found in test termite colonies: <em>Trichoderme viride</em>, <em>Mucor</em> <em>himeralis</em>, <em>Rhizopus</em> <em>nigricans</em>, <em>Aspergillus</em> sp., <em>Aspergillus</em> <em>flavus</em>, <em>Alternaria</em> sp., <em>Penicylium</em> <em>verucosum</em> and <em>Fusarium</em> sp. were recognisable in test colonies with domestic and exotic wood. Morphological observations of the fungi were carried out using a microscope with a 40x magnification. The growth of mould fungi in test containers caused death of whole termite colonies.