Food habits of 3 myrmecophilous bug species on myrmecophytic Macaranga (Malpighiales: Euphorbiaceae) vary from herbivory to predation.

Myrmecophytes have mutualistic relationships with symbiotic ants. Although myrmecophytic Macaranga (Malpighiales: Euphorbiaceae) species are well protected by aggressive Crematogaster (Hymenoptera: Formicidae) ants, some bug species occur on the myrmecophytes. To clarify the associations of these bugs with the plants and the ants, we studied the food habits of 3 bug species, Pilophorus lambirensis Nakatani et Komatsu, 2013 (Hemiptera: Miridae: Phylinae), Phylinae sp. 1, and Arbela sp. 1 (Hemiptera: Nabidae). We conducted field observations in a Bornean rainforest. First, we located these bugs and studied their behavioral responses to the ants on Macaranga species; we then conducted stable isotope analyses. All bugs avoided direct contact with ants, but they occurred only on trees with active ants. Pilophorus lambirensis and Phylinae sp. 1 were most commonly observed on the apical parts of host trees, whereas Arbela sp. 1 was mainly in areas distant from the apical parts where ants were sparse. The stable isotope ratios indicated that Phylinae sp. 1 fed on food bodies, which are nutrient-rich spherical bodies produced by Macaranga trees on the apical parts for ants. Although the main diet of the other 2 species remains unclear, nitrogen isotopic signatures demonstrated that P. lambirensis is herbivorous, whereas Arbela sp. 1 is carnivorous. However, the distant location from ants and its isotopic signatures indicated that Arbela sp. 1 rarely fed on the ants. At least 2 mirid bug species might obtain enemy-free space in addition to the food provided by the myrmecophytes.

Comparison of Genetic Structure between Endangered and Common Butterflies, Ypthima multistriata and Y. argus (Lepidoptera; Nymphalidae), Inhabiting Japan.

Genetic structures of two closely related butterflies, Ypthima multistriata and Y. argus, inhabiting Japan were compared based on the mitochondrial cytochrome c oxidase subunit I (COI) sequences. The former species is classified as a vulnerable species and exhibits a characteristic pattern of voltinism: univoltine and bivoltine populations are distributed in a scattered manner. The latter species is common and has a normal geographical pattern of voltinism: the number of annual generations is correlated with latitude. Our genetic analyses of these two species yielded contrasting results: a spatial analysis of molecular variance (SAMOVA) and FST between each pair of populations revealed a locally fragmented genetic structure for Y. multistriata, compared to three distinct geographic groups of Y. argus within which range-wide gene flow occurs. Although Y. argus is a common species, only the southernmost populations in Japan had higher genetic diversity, while the other populations had the same or lower levels of genetic diversity, compared to Y. multistriata. These results indicate that: 1) the degree of fragmentation of Y. multistriata populations was higher; however, markedly lower genetic diversity was not found, and 2) although Y. argus is a common species, its populations may not be genetically robust. In addition, AMOVA revealed a relationship between voltinism and genetic variation in Y. multistriata. This result suggests a phylogenetic constraint of voltinism in this butterfly.

Evolutionary diversification of Japanese Stomaphis aphids (Aphididae, Lachninae) in relation to their host plant use and ant association.

Phytophagous insects are among the most diverse of the earth's organisms, and their diversification patterns and the driving forces behind these have attracted considerable research interest. Host shifting to closely related plant species is thought to play an important role in phytophagous insect diversification, but the extent to which other interactions such as mutualistic associations affect diversification is not yet known. In this study, we reconstructed the molecular phylogeny of Japanese Stomaphis aphids and determined whether host shifting or mutualistic association with different ant species could explain diversification in this aphid genus. We analyzed 12 species of Stomaphis and grouped them into ten well-supported DNA lineages. Species in each lineage used a single or a few host plant species, but were mutualistically associated with many ant species of the genus Lasius. This result suggests that Stomaphis evolutionarily diversified primarily through host plant shifts. Interestingly, the reconstructed phylogeny suggests that Stomaphis host shifts occasionally occurred between very distantly related host plant taxa (spanning up to five plant orders). The dependence of Stomaphis on long-lasting Lasius ant colonies situated in temperate deciduous forests where Lasius is the dominant ant genus may have led the aphids to shift to distantly related but spatially adjacent host tree species.

[SIGNIFICANCE OF INTRADUCTAL CARCINOMA OF THE PROSTATE IN POST-OPERATIVE BIOCHEMICAL RECURRENCE].

(Objective) We investigated the prognostic significance of intraductal carcinoma of the prostate (IDC-P) in radical prostatectomy specimens. (Materials and methods) We evaluated 441 patients treated with radical prostatectomy and analyzed data on IDC-P, lymph node metastases, Gleason score, seminal vesicle invasion, extraprostatic extension, surgical margin, total cancer volume, and zonal origin of dominant cancer focus in radical prostatectomy specimens. The median follow-up was 50 months (range 6-164 months). (Results) We identified IDC-P in 112 cases (25.4%). The five-year biochemical progression-free survival rate in patients with IDC-P was significantly lower than for those without IDC-P (35.8% vs 69.6%; p<0.0001). In a univariate analysis, IDC-P (p<0.0001), lymph node metastases (p=0.0022), Gleason score (p<0.0001), seminal vesicle invasion (p<0.0001), extraprostatic extension (p<0.0001), surgical margin (p<0.0001) and total cancer volume (p<0.0001) were significantly associated with the biochemical progression-free survival. In a multivariate analysis, Gleason score (p<0.0001), IDC-P (p=0.0002), seminal vesicle invasion (p=0.0011), extraprostatic extension (p=0.0012), surgical margin (p=0.0019) and lymph node metastases (p=0.0402) were significantly associated with biochemical progression-free survival. (Conclusions) The presence of IDC-P is an independent factor of biochemical recurrence in prostate cancer patients treated with radical prostatectomy. We therefore recommend that the presence of IDC-P in radical prostatectomy specimens be reported.

Host-ant specificity of endangered large blue butterflies (Phengaris spp., Lepidoptera: Lycaenidae) in Japan.

Large blue butterflies, Phengaris (Maculinea), are an important focus of endangered-species conservation in Eurasia. Later-instar Phengaris caterpillars live in Myrmica ant nests and exploit the ant colony's resources, and they are specialized to specific host-ant species. For example, local extinction of P. arion in the U. K. is thought to have been due to the replacement of its host-ant species with a less-suitable congener, as a result of changes in habitat. In Japan, Myrmica kotokui hosts P. teleius and P. arionides caterpillars. We recently showed, however, that the morphological species M. kotokui actually comprises four genetic clades. Therefore, to determine to which group of ants the hosts of these two Japanese Phengaris species belong, we used mitochondrial COI-barcoding of M. kotokui specimens from colonies in the habitats of P. teleius and P. arionides to identify the ant clade actually parasitized by the caterpillars of each species. We found that these two butterfly species parasitize different ant clades within M. kotokui.

Congruence of microsatellite and mitochondrial DNA variation in acrobat ants (Crematogaster subgenus Decacrema, Formicidae: Myrmicinae) inhabiting Macaranga (Euphorbiaceae) myrmecophytes.

A previously reported mitochondrial DNA (mtDNA) phylogeny of Crematogaster (subgenus Decacrema) ants inhabiting Macaranga myrmecophytes indicated that the partners diversified synchronously and their specific association has been maintained for 20 million years. However, the mtDNA clades did not exactly match morphological species, probably owing to introgressive hybridization among younger species. In this study, we determined the congruence between nuclear simple sequence repeat (SSR, also called microsatellite) genotyping and mtDNA phylogeny to confirm the suitability of the mtDNA phylogeny for inferring the evolutionary history of Decacrema ants. Analyses of ant samples from Lambir Hills National park, northeastern Borneo, showed overall congruence between the SSR and mtDNA groupings, indicating that mtDNA markers are useful for delimiting species, at least at the local level. We also found overall high host-plant specificity of the SSR genotypes of Decacrema ants, consistent with the specificity based on the mtDNA phylogeny. Further, we detected cryptic genetic assemblages exhibiting high specificity toward particular plant species within a single mtDNA clade. This finding, which may be evidence for rapid ecological and genetic differentiation following a host shift, is a new insight into the previously suggested long-term codiversification of Decacrema ants and Macaranga plants.

An ancient tripartite symbiosis of plants, ants and scale insects.

In the Asian tropics, a conspicuous radiation of Macaranga plants is inhabited by obligately associated Crematogaster ants tending Coccus (Coccidae) scale insects, forming a tripartite symbiosis. Recent phylogenetic studies have shown that the plants and the ants have been codiversifying over the past 16-20 million years (Myr). The prevalence of coccoids in ant-plant mutualisms suggest that they play an important role in the evolution of ant-plant symbioses. To determine whether the scale insects were involved in the evolutionary origin of the mutualism between Macaranga and Crematogaster, we constructed a cytochrome oxidase I (COI) gene phylogeny of the scale insects collected from myrmecophytic Macaranga and estimated their time of origin based on a COI molecular clock. The minimum age of the associated Coccus was estimated to be half that of the ants, at 7-9Myr, suggesting that they were latecomers in the evolutionary history of the symbiosis. Crematogaster mitochondrial DNA (mtDNA) lineages did not exhibit specificity towards Coccus mtDNA lineages, and the latter was not found to be specific towards Macaranga taxa, suggesting that patterns of associations in the scale insects are dictated by opportunity rather than by specialized adaptations to host plant traits.