The phylogeny of Colocasiomyia (Drosophilidae) is analysed using data for 70 morphological characters, many of which are re‐evaluated from or added to those used previously, for an expanded taxon sample of 24 Colocasiomyia ingroup species. A special focus is put on three species, of which two have remained unresolved for their relationships to other Colocasiomyia species, and the other is a newly discovered species. The analysis results in a single, most parsimonious cladogram, in which a clade comprising the three focal species is recognized along with other clades recovered for the known species groups of Colocasiomyia. Based on this, a new species group—the gigantea group—is established, including Colocasiomyia gigantea (Okada), C. rhaphidophorae Gao & Toda, n.sp. and C. scindapsae Fartyal & Toda, n.sp. These species of the gigantea group breed on inflorescences/infructescences of the subfamily Monsteroideae (Araceae) exceptionally among Colocasiomyia species, most of which use plants of the subfamily Aroideae as their hosts. Colocasiomyia gigantea uses Epipremnum pinnatum (L.) Engler, C. rhaphidophorae uses Rhaphidophora hookeri Schott and C. scindapsae uses Scindapsus coriaceus Engler as their hosts. The host plants of the gigantea group are epiphytes and differ in the structure of spadix and the fruiting process from those of the Aroideae. To understand how the species of the gigantea group adapt to properties of their host plants, their reproductive ecology—most intensively that of C. gigantea—is investigated. The lifecycle of C. gigantea is characterized by its relatively slow embryonic development (taking approximately 6 days), the very long duration of the full‐grown first instar within the egg capsule (approximately three months) until dehiscence of host infructescence, and its relatively fast larval and pupal development (taking approximately 11 or 12 days). Some morphological adaptations and the reproductive strategy in terms of ‘egg size vs. number’ trade‐off are discussed in relation to their reproductive habits and peculiar lifecycles.

Pine wilt disease (PWD) constitutes a serious threat to pine forests. Since development depends on temperature and drought, there is a concern that future climate change could lead to the spread of PWD infections. We evaluated the risk of PWD in 21 susceptible Pinus species on a global scale. The MB index, which represents the sum of the difference between the mean monthly temperature and 15 when the mean monthly temperatures exceeds 15°C, was used to determine current and future regions vulnerable to PWD (MB ≥ 22). For future climate conditions, we compared the difference in PWD risks among four different representative concentration pathways (RCPs 2.6, 4.5, 6.0, and 8.5) and two time periods (2050s and 2070s). We also evaluated the impact of climate change on habitat suitability for each Pinus species using species distribution models. The findings were then integrated and the potential risk of PWD spread under climate change was discussed. Within the natural Pinus distribution area, southern parts of North America, Europe, and Asia were categorized as vulnerable regions (MB ≥ 22; 16% of the total Pinus distribution area). Representative provinces in which PWD has been reported at least once overlapped with the vulnerable regions. All RCP scenarios showed expansion of vulnerable regions in northern parts of Europe, Asia, and North America under future climate conditions. By the 2070s, under RCP 8.5, an estimated increase in the area of vulnerable regions to approximately 50% of the total Pinus distribution area was revealed. In addition, the habitat conditions of a large portion of the Pinus distribution areas in Europe and Asia were deemed unsuitable by the 2070s under RCP 8.5. Approximately 40% of these regions overlapped with regions deemed vulnerable to PWD, suggesting that Pinus forests in these areas are at risk of serious damage due to habitat shifts and spread of PWD.

Two taxonomically undescribed Colocasiomyia species were discovered from inflorescences of Alocasia macrorrhizos in Kota Kinabalu City, Sabah, Borneo, Malaysia. The aims of this study were to investigate the reproductive ecology of the flies and the plant, ascertain the importance of the flies as pollinators and examine the intimate association between flowering events and life history of the flies. We conducted sampling, observations and field pollination experiments. The flies were attracted by the odour of female-phase inflorescences in the early morning on the first day of anthesis. They fed, mated and oviposited in the inflorescences for 1 day. On the second day, the flies, covered with pollen grains, left the male-phase inflorescences for the next female-phase inflorescences. The immature forms of both fly species hatched, developed and pupated within the infructescences without damaging the fruits, and developed adults emerged when the mature infructescences dehisced. The flowering events and fly behaviours were well synchronized. In field pollination experiments, inflorescences bagged with a fine mesh (insect exclusion) produced almost no fruits, whereas those bagged with a coarse mesh (bee exclusion) produced as many fruits as the open-pollinated controls. These results indicate that these flies are the most efficient and specialised pollinators for their host, A. macrorrhizos. These flies, in return, depend on A. macrorrhizos for food and habitat through most of their life cycle. This study provides a deeper insight into the less recognised, highly intimate pollination mutualism between Araceae plants and Colocasiomyia flies.

Rapid expansion of exotic bamboos has lowered species diversity in Japan's ecosystems by hampering native plant growth. The invasive potential of bamboo, facilitated by global warming, may also affect other countries with developing bamboo industries. We examined past (1975–1980) and recent (2012) distributions of major exotic bamboos (Phyllostachys edulis and P. bambusoides) in areas adjacent to 145 weather stations in central and northern Japan. Bamboo stands have been established at 17 sites along the latitudinal and altitudinal distributional limit during the last three decades. Ecological niche modeling indicated that temperature had a strong influence on bamboo distribution. Using mean annual temperature and sun radiation data, we reproduced bamboo distribution (accuracy = 0.93 and AUC (area under the receiver operating characteristic curve) = 0.92). These results infer that exotic bamboo distribution has shifted northward and upslope, in association with recent climate warming. Then, we simulated future climate data and projected the climate change impact on the potential habitat distribution of invasive bamboos under different temperature increases (i.e., 1.5°C, 2.0°C, 3.0°C, and 4.0°C) relative to the preindustrial period. Potential habitats in central and northern Japan were estimated to increase from 35% under the current climate (1980–2000) to 46%–48%, 51%–54%, 61%–67%, and 77%–83% under 1.5°C, 2.0°C, 3.0°C, and 4.0°C warming levels, respectively. These infer that the risk areas can increase by 1.3 times even under a 1.5°C scenario and expand by 2.3 times under a 4.0°C scenario. For sustainable ecosystem management, both mitigation and adaptation are necessary: bamboo planting must be carefully monitored in predicted potential habitats, which covers most of Japan.