Internal Armature of the Hindgut of Pericapritermes nitobei (Shiraki)

The internal armature of the hindgut of Pericapritermes nitobei was examined under a light microscope. Termites were obtained from Iriomote Island, Okinawa Prefecture, Japan, identified based on the typological characters of soldiers and 12S (mitochondrial) ribosomal RNA sequencing, and dissected to examine hindgut morphology. The hindgut of P. nitobei could be separated into four parts, P1-P4, and P1-P3 had cuticular spines on the inner surface. P1 bore small triangular spines. P2 formed an enteric valve, composed of six finger-shaped enteric pads with triangular spines, and six marginal regions with small dot-like spines. P3 bore three different types of spines: relatively large star-shaped spines; thorn-like small spines, and long curved spines with brush-like tips.

Fig Pollinating Wasp Transfers Nematodes into Figs of Ficus racemosa in Sumatra, Indonesia

The fruits (figs) of fig trees (Ficus spp, known as ‘bak ara’ in Aceh), are the source of food for many species of faunas in the forest, including birds, monkeys, orangutans, etc.  Pollination within the figs totally depends on female fig wasps that belong to family Agaonidae. Fig trees and their pollinating wasps rely on each other to survive.  Female fig wasps are known to transport nematodes into receptive figs when the wasps enter the figs to lay  eggs.  An investigation on the nematodes carried by female pollinating wasps Ceratosolen fusciceps Mayr into figs of Ficus racemosa was conducted in Sumatra, Indonesia. The figs on the trees were regularly sampled to determine the presence of nematodes and infer their ecology. The Baermann funnel method was employed to extract the nematodes from the figs.  Eight species of nematodes were recorded from the figs, two of which are still unidentified.  The species found were (1) Teratodiplogaster fignewmani, (2) Teratodiplogaster sp., (3) Parasitodiplogaster sp., (4) Schistonchus sp1., (5) Schistonchus sp2., (6) Mononchoides sp., (7) and (8) two undescribed Diplogastridae species (‘umbrella-like’ species 1 and species 2).  This is the most diverse fig nematode community recorded. The highest nematode populations were routinely found in D-phase figs, when the new generations of wasps were about to emerge.   Details of the ecology of each nematode species are likely to differ, but as a group they did not seem to significantly affect seed and wasp development in F. racemosa fig

Evidence of hermaphroditism and sex ratio distortion in the fungal feeding nematode Bursaphelenchus okinawaensis

Nematodes have many different reproductive strategies along with their divergent life-histories; the ability of hermaphrodite to self- and cross-fertilize is useful for genetic manipulation. Here, we demonstrate the hermaphroditism of the fungal feeding nematode Bursaphelenchus okinawaensis, which was formerly described as a parthenogenetic nematode, and we show its other unique sexual characteristics. To determine that it is hermaphroditic, we performed the following experiments: 1) observation of the pronuclear and chromosome behavior during oogenesis and early embryogenesis; 2) observation of spermatogenesis during the fourth larval stage; 3) investigation of sperm utilization; and 4) investigation of phenotypic segregation after cross-mating using an chemically-induced visible mutant. We then investigated the mating preferences and spermatid size difference between males and hermaphrodites. B. okinawaensis males successfully mated only with sperm-depleted old hermaphrodites, and the spermatid sizes of males were almost the same as those of hermaphrodites. Moreover, the sex ratio of cross-fertilized progeny was highly skewed toward hermaphrodites. B. okinawaensis is phylogenetically distant from established model nematodes such as C. elegans and is more closely related to some economically relevant parasitic nematodes. This newly discovered hermaphroditic nematode has great potential for evolutionary and parasitological research

First report of the nematode Leidynema appendiculata from Periplaneta fuliginosa

The smokybrown cockroach Periplaneta fuliginosa has spread all over the world, and is now one of the most undesired inva- sive alien pests in Japan. Because cockroaches are generally infected by thelastomatid nematodes, they are being distributed around the world with their parasitic nematodes. Nothing is known about parasitic nematode species in P. fuliginosa differences, or similarity of the parasite’s population structures between the different countries of the host cockroaches. Here we investi- gated the P. fuliginosa invasive to Japan and found that 100% of individuals were infected with one nematode species. According to the morphology and the sequence of the D2/D3 expansion segment of the 28S ribosomal RNA gene, we identified the para- site as Leidynema appendiculata. This nematode reproduced by haplodiploidy and its developmental timing under various con- ditions is quite divergent. Their population in the hindgut of P. fuliginosa was controlled with a few adult females and a male. This is the first report of the thelastomatid nematode isolated from the smokybrown cockroach, and is the basis for our future research examining the origin, distribution route and immigration history of the cockroach and the impact of L. appendiculata on native Japanese cockroach species

Reverse taxonomy for elucidating diversity of insect-associated nematodes: a case study with termites

BACKGROUND: The molecular operational taxonomic unit(MOTU)has recently been applied to microbial and microscopic animal biodiversity surveys. However, in many cases, some of the MOTUs cannot be definitively tied to any of the taxonomic groups in current databases. To surmount these limitations, the concept of "reverse taxonomy" has been proposed, i.e. to primarily list the MOTUs with morphological information, and then identify and/or describe them at genus/species level using subsamples or by re-isolating the target organisms. Nevertheless, the application of "reverse taxonomy" has not been sufficiently evaluated. Therefore, the practical applicability of "reverse taxonomy" is tested using termite-associated nematodes as a model system for phoretic/parasitic organisms which have high habitat specificity and a potential handle (their termite host species) for re-isolation attempts. METHODOLOGY: Forty-eight species (from 298 colonies) of termites collected from the American tropics and subtropics were examined for their nematode associates using the reverse taxonomy method and culturing attempts (morphological identification and further sequencing efforts). The survey yielded 51 sequence types (= MOTUs) belonging to 19 tentatively identified genera. Within these, four were identified based on molecular data with preliminary morphological observation, and an additional seven were identified or characterized from successful culturing, leaving eight genera unidentified. CONCLUSIONS: That 1/3 of the genera were not successfully identified suggests deficiencies in the depth of available sequences in the database and biological characters, i.e. usually isolated as phoretic/parasitic stages which are not available for morphological identification, and too many undiscovered lineages of nematodes. Although there still is the issue of culturability of nematodes, culturing attempts could help to make reverse taxonomy methods more effective. However, expansion of the database, i.e., production of more DNA barcodes tied to biological information by finding and characterizing additional new and known lineages, is necessary for analyzing functional diversity.Natsumi Kanzaki, Robin M. Giblin-Davis, Rudolf H. Scheffrahn, Hisatomo Taki, Alejandro Esquivel, Kerrie A. Davies and E. Allen Herr

The developmental and structural uniqueness of the embryo of the extremophile viviparous nematode, Tokorhabditis tufae

Viviparity, a reproductive form that supplies nutrients to the embryo during gestation, has repeatedly and independently occurred in multiple lineages of animals. During the convergent evolution of viviparity, various modifications of development, structure, and physiology emerged. A new species of nematode, Tokorhabditis tufae, was discovered in the alkaline, hypersaline, and arsenic-rich environment of Mono lake. Its reproductive form is viviparity because it is obligately live-bearing and the embryo increases in size during development. However, the magnitude of the increase in size and nutrient provisioning are unclear. We measured egg and embryo sizes at three developmental stages in T. tufae. Eggs and embryos of T. tufae at the threefold stage were respectively 2.6- and 3.6-fold larger than at the single-cell stage. We then obtained T. tufae embryos at the single-cell, lima bean, and threefold developmental stages and investigated the egg hatching frequency at three different concentrations of egg salt buffer. Removal of embryos from the uterus halted embryonic development at the single-cell and lima bean stages in T. tufae irrespective of the solution used for incubation, indicating the provision of nutrients within the uterus. Ultrastructural and permeability evaluation showed that the permeability barrier did not form during embryonic development, resulting in increased molecular permeability. This high permeability caused by the absence of the permeability barrier likely enables supply of nutrients from the mother. The structural and physiological modifications in T. tufae are like those in other viviparous animals. We conclude that T. tufae is a viviparous rather than an ovoviviparous nematode. T. tufae will facilitate investigation of the evolution of viviparity in animals

\u3ci\u3eFicotylus laselvae\u3c/i\u3e n. sp. (Tylenchomorpha: Anguinidae) associated with \u3ci\u3eFicus colubrinae\u3c/i\u3e in Costa Rica

Ficotylus laselvae n. sp. was recovered from under the bracts of figs (syconia) of Ficus colubrinae from La Selva, Costa Rica, during a survey of nematode rainforest biodiversity and is described herein. This is only the second report of an association between the nematode suborder Tylenchina and the sycones of figs. Previous reports of most nematode associates of the sycones of figs have been from the lumen and involved transmission by female fig wasp pollinators (Agaonidae) during pollination/oviposition (e.g., Schistonchus and Parasitodiplogaster spp.). The association between F. laselvae n. sp. and Ficus colubrinae may involve an invertebrate host, but none was recovered from dissections of the bracts during this study. It is also possible that this is a rainforest understory nematode that feeds ectoparasitically in protected areas on the aerial parts of F. colubrinae. Molecular analysis using near-full-length sequences of the small subunit (SSU) rRNA and D2-D3 expansion segments of the large subunit (LSU) rRNA genes of Ficotylus laselvae n. sp. suggests that it is a member of the suborder Tylenchina (infraorder: Tylenchomorpha; family: Anguinidae) and that the closest sequenced species is F. congestae from the lumen of sycones of Ficus congesta from Queensland, Australia. Although both nematode species are associated with figs, they are morphologically divergent, suggesting that the different micro-niches that they fill provide different selective pressures for evolution of differing morphological characters or they represent different life history morphotypes of a dicyclic genus