Multiple Factors Maintaining High Species-Specificity in Macaranga-Crematogaster (Hymenoptera: Formicidae) Myrmecophytism: Higher Mortality in Mismatched Ant-Seedling Pairs

Myrmecophytism, a type of mutualistic symbiosis, occurs between certain species of Macaranga trees and Crematogaster ants in the tropics of Southeast Asia. Several recent studies have revealed that myrmecophytism in Macaranga-Crematogaster involves a highly species-specific partnership, but there is less specificity at the beginning of the symbiosis when ant foundress queens settle into host seedlings. However, how 'mis-matched' species combinations of ants and plants are selected against in the field has not yet been investigated. We therefore experimentally swapped foundress queens among three sympatric species of myrmecophytic Macaranga and subsequently examined growth and survival of the ants and recipient plants. Our results suggest that severe mortality occurs among ants and seedlings of unmatched pairs throughout multiple processes, such as initial worker production, early colony growth after initial worker appearance, and defense by ants against herbivores. This contributes to the maintenance of high species-specificity in Macaranga-Crematogaster myrmecophytism.ArticleSOCIOBIOLOGY. 55(3):883-898 (2010)journal articl

Phylogeography of the Coccus scale insects inhabiting myrmecophytic Macaranga plants in Southeast Asia

Comparative historical biogeography of multiple symbionts occurring on a common host taxa can shed light on the processes of symbiont diversification. Myrmecophytic Macaranga plants are associated with the obligate mutualistic symbionts: Crematogaster (subgenus Decacrema) ants and Coccus scale insects. We conduct phylogeographic analyses based on mitochondrial cytochrome oxidase I (COI) from 253 scale insects collected from 15 locations in Borneo, Malaya and Sumatra, to investigate the historical biogeography of the scales, and then to draw comparisons with that of the symbiotic, but independently dispersing, Decacrema ants which are not specific to different Coccus lineages. Despite the different mode of ancient diversification, reconstruction of ancestral area and age estimation on the Coccus phylogeny showed that the scales repeatedly migrated between Borneo and Malaya from Pliocene to Pleistocene, which is consistent with the Decacrema ants. Just as with the ants, the highest number of lineages in the scale insects was found in northern northwest Borneo, suggesting that these regions were rainforest refugia during cool dry phases of the Pleistocene. Overall, general congruence between the Plio-Pleistocene diversification histories of the symbiotic scales and ants suggests that they experienced a common history of extinction/migration despite their independent mode of dispersal and host-colonization.ArticlePopulation ecology. 52(1):137-146 (2010)journal articl

Emotion-reacting fashion design: intelligent garment and accessory recognizing facial expressions

Although mental disorders have emerged as serious social challenges, social stigma, including prejudice and misunderstanding, hinder suitable treatment for the patients. It is crucial to monitor our internal psychological and emotional states to avoid the unconscious progression of mental disorders. This research aims to achieve emotion-reacting garments and accessories, based on a passive and continuous emotion recognition system in real time. First, this study proposes a systematic design for emotion-reacting garments and accessories, which employs emotion estimation based on facial expressions. Next, emotion-reacting fashion design is discussed for intelligent garments and accessories that interact with our bodies and mind. To achieve this system, a functionally extended collar made of transparent polycarbonate material is designed for integration with the digital camera modules. In addition, this study discusses how to create a physical stimulus on emotion-reacting garments and accessories. The intelligent garments and accessories using RGB-LEDs create visual effects that reflect emotions. In terms of audio effects, emotion-related keywords are employed to select the music played in intelligent garments. Finally, prototypes reacting to emotions are show

Suzaku Observations of the Centaurus Cluster: Absence of Bulk Motions in the Intracluster Medium

The Centaurus cluster (z=0.0104) was observed with the X-ray Imaging Spectrometer (XIS) onboard the Suzaku X-ray satellite in three pointings, one centered on the cluster core and the other two offset by +-8' in declination. To search for possible bulk motions of the intracluster medium, the central energy of He-like Fe-K line (at a rest-frame energy of 6.7 keV) was examined to look for a positional dependence. Over spatial scales of 50 kpc to 140 kpc around the cluster core, the central line energy was found to be constant within the calibration error of 15 eV. The 90% upper limit on the line-of-sight velocity difference is |Delta_v|< 1400 km/s, giving a tighter constraint than previous measurements. The significant velocity gradients inferred from a previous Chandra study were not detected between two pairs of rectangular regions near the cluster core. These results suggest that the bulk velocity does not largely exceed the thermal velocity of the gas in the central region of the Centaurus cluster. The mean redshift of the intracluster medium was determined to be 0.0097, in agreement with the optical redshift of the cluster within the calibration uncertainty. Implications of the present results for the estimation of the cluster mass are briefly discussed.Comment: 9 pages, 4 figures. Accepted for publication in PASJ. Version with high-quality color figures at http://cosmic.riken.jp/ota/publications/index.htm

The efficacy of incretin therapy in patients with type 2 diabetes undergoing hemodialysis

BACKGROUND: Although incretin therapy is clinically available in patients with type 2 diabetes undergoing hemodialysis, no study has yet examined whether incretin therapy is capable of maintaining glycemic control in this group of patients when switched from insulin therapy. In this study, we examined the efficacy of incretin therapy in patients with insulin-treated type 2 diabetes undergoing hemodialysis. METHODS: Ten type 2 diabetic patients undergoing hemodialysis received daily 0.3 mg liraglutide, 50 mg vildagliptin, and 6.25 mg alogliptin switched from insulin therapy on both the day of hemodialysis and the non-hemodialysis day. Blood glucose level was monitored by continuous glucose monitoring. After blood glucose control by insulin, patients were treated with three types of incretin therapy in a randomized crossover manner, with continuous glucose monitoring performed for each treatment. RESULTS: During treatment with incretin therapies, severe hyperglycemia and ketosis were not observed in any patients. Maximum blood glucose and mean blood glucose on the day of hemodialysis were significantly lower after treatment with liraglutide compared with treatment with alogliptin (p < 0.05), but not with vildagliptin. The standard deviation value, a marker of glucose fluctuation, on the non-hemodialysis day was significantly lower after treatment with liraglutide compared with treatment with insulin and alogliptin (p < 0.05), but not with vildagliptin. Furthermore, the duration of hyperglycemia was significantly shorter after treatment with liraglutide on both the hemodialysis and non-hemodialysis days compared with treatment with alogliptin (p < 0.05), but not with vildagliptin. CONCLUSIONS: The data presented here suggest that patients with type 2 diabetes undergoing hemodialysis and insulin therapy could be treated with incretin therapy in some cases