This study clarified the effects of host tree size on the numbers of epiphyte species and individuals on a tree, based on observation of 122 species and 2,162 individuals of epiphytes on 430 target trees in a Bornean primary lowland dipterocarp forest. We analyzed relationships of the diameter at breast height (DBH) of target host trees with the probability of epiphyte presence, number of epiphyte species on each target tree (species richness), number of epiphyte individuals on each target host tree (abundance), and cumulative number of epiphyte species. The probability of epiphyte presence was estimated by a generalized linear model (GLM) with a logistic distribution to be higher than 50 % on trees with DBH>40 cm. A GLM with a quasi-Poisson distribution showed that both species richness and epiphyte abundance increased exponentially with DBH. The most rapid increase was found for trees with DBH>40 cm. Also, about half of all epiphyte species recorded in this study were only found on trees with DBH>60 cm. These results suggest that in lowland tropical rainforests in the Southeast Asian tropics, large trees play an important role in maintaining the species diversity of epiphyte assemblages by providing them with habitats. Meanwhile, several epiphyte species were found only trees with DBH ≤ 40 cm, suggesting that the small trees also provide essential habitats with such epiphyte species. Primary forests with various sizes of trees are necessary for conservation of the epiphyte assemblages.

Colony composition and behavioral characteristics of the myrmicine ant, Aphaenogaster rugulosa, a species endemic to Yonagunijima Island, were investigated. Colonies nested in rotten woods fallen on the forest floor. All queenright colonies (N＝42) were monogynous with one dealate queen. The average colony size in worker number was 140.5±SD 94.9. Under laboratory conditions, workers and larvae fed on both fresh and dried insect preys. The workers used a kind of tool to transport diluted sugar water to the nest chamber. They dropped pine needles and trashes into the diluted sugar water and then transported the food-soaked materials back into the nest chamber, where nest members then sucked on the materials inside the nest chamber. Trophic eggs were laid by the workers, the majority of which were given to the larvae. The queens also fed on trophic eggs as well as insect preys. The workers under an orphan condition laid reproductive eggs that grew up to be males.

A new Rafflesia population was found in Naha Jaley, Sarawak, in 2012. This study aimed to identify this Rafflesia species and investigate its bud growth. First, we described the flower characteristics and compared them with Rafflesia keithii and R. tuan-mudae, which are candidate species for the flower. Also, we investigated the phylogenetic position of this Rafflesia within Rafflesiaceae using DNA analysis. To estimate bud growth curve, we observed bud development from April 2013 to November 2013 in the field. Based on morphological comparisons and phylogenetic analysis, we confirmed the newly discovered population of the Rafflesia at Naha Jaley was R. tuan-mudae, which is the new locality of the species at the most Eastern side of the known distribution for this species. The results indicated that absolute growth rate was greater in larger buds. We also estimated that it took a year to bloom from the initial bud stage. The mortality in one of our sites was very high, with more than 80 % of buds dead prior to flower opening. This flower would be vulnerable to extinction due to their extraordinary characteristics and anthropogenetic effects. Finally, we discussed how Rafflesia populations in Naha Jaley can be conserved both in-situ and ex-situ.

Longitudinal and geographic variations in the green moisture content and basic density of bamboo culm were evaluated by using linear mixed-effect models for three bamboo species (Bambusa vulgaris Schrad. ex J.C., Bambusa maculata Widjaja, and Gigantochloa atter (Hassk) Kurz ex Munro) naturally grown in four locations in Lombok Island, Indonesia. The mean green moisture contents and basic densities were 74.2 % and 0.69 g cm^－3 for B. vulgaris, 78.5 % and 0.65 g cm^－3 for B. maculata, and 80.3 % and 0.65 g cm^－3 for G. atter, respectively. No significant differences in green moisture content and basic density were found among the species. A significant negative correlation between basic density and green moisture content was found in all three species. Based on the results of model selections for longitudinal variations, the green moisture content decreased with an increase in the culm height in all three species, and basic density tended to increase from the base to the top of the culm. Relatively large geographical variation was found in the green moisture content and basic density of G. atter, although the main reasons for variation of these properties were individual culm in three species.