Volcanic eruptions can have significant impacts on plant and animal communities. Thus, it is important to understand the recovery process following these eruptions, particularly on isolated islands, in order to assist with biodiversity management and conservation. We studied relationships between vegetation structure and avian species composition on Miyakejima Island, Japan, where a volcanic eruption in 2000 destroyed almost half of the vegetated land. Bird species and nine vegetation variables were surveyed at 24 sampling sites from 2011 to 2014. The results showed that avian species composition mainly varied along two vegetation variables, namely plant species richness and total basal area of all tree species. Bird species were classified into four groups, that is, grassland species, widely distributed species, developing-forest species, and developed-forest species. Developed-forest species were only recorded at the sites where vegetation height was more than 10 m. The relationship between developed-forest bird abundance and vegetation height was similar to that between total basal area of all tree species and vegetation height. The restoration of mature evergreen forest is essential to conserve avian diversity on the island, and natural seed dispersal by birds plays an important role in supporting forest restoration after a major disturbance.

Large quantities of anthropogenic nitrogen (N) in the marine environment are detrimental for coastal ecosystems and understanding the magnitude and distribution of this N opens paths to remediation. One area of concern is Cocos Lagoon, in the south of Guam, Northern Mariana Islands, which hosts a diversity of corals including Acropora species listed in the Endangered Species Act. Degradation of Guam's coral reefs may be influenced by untreated sewage effluent. To gain insight into the spatial extent of human N pollution, we deployed 50 macroalgal thalli (Padina sp.) as bio-indicators in a grid pattern over the entire lagoon for one week and then measured the stable N isotopes of bio-available N (δ¹⁵N). We observed relatively low δ¹⁵N values (∼1–2‰) in the shallow areas in the east suggesting coastal currents bringing in fixed N from the open ocean or local N₂ fixation. The comparatively high δ¹⁵N values (∼6‰) in the deeper channel of the lagoon suggest sewage as a major source of N. The distribution of δ¹⁵N values was not determined by the distance to N sources, such as river outlets or the tourist resort on Cocos Island but by the bathymetry, which affects the residence time and influx of oceanic water.

The genetic population structure and demographic history of the whale shark Rhincodon typus, including 28 samples around Japan, the northernmost limit of distribution of the species, were examined based on partial sequences of the mitochondrial control region. Neighbor-joining tree and the minimum spanning network of haplotypes showed no clear phylogeographic structure. The pairwise Φ_ST values between each of the nine localities in the Indo-Pacific and the locality in the Atlantic were very high and significant, indicating the existence of genetic differentiation between the Indo-Pacific and the Atlantic. The existence of some level of genetic differentiation was also suggested between the Indian and the eastern Pacific, because the Φ_ST values were significant (though before Bonferroni correction) when comparing the Gulf of California in the eastern Pacific with three of the six localities in the Indian Ocean. In the Pacific Ocean, none of the Φ_ST values among the three localities (the Philippines and Taiwan, Japan, and Gulf of California) were significant, which indicates that migrations occur between the eastern and the western North Pacific as well as between north and south in the western North Pacific. The mismatch distributions and Bayesian skyline plots suggested that the Indo-Pacific and the Atlantic populations have different demographic history; population expansion had occurred in the Indo-Pacific while secondary contact among differentiated lineages was indicated in the Atlantic. Global distribution of effective population size (Ne) of the whale shark was estimated to be 63% in the Indo-Pacific and 37% in the Atlantic.

The vocal repertoire of males of Cornufer vitianus from the lowland mangrove forests of Viwa Island, off the coast of Viti Levu, Fiji is described. All calls were placed into two categories: those with a high fundamental frequency, and those with a low fundamental frequency. Within each category, there is relatively high call variation. Individual males are capable of producing both the low- and high-frequency calls; some males produce predominantly the high-frequency call, others are low-frequency callers, and others alternate between the two forms. C. vitianus is among the most sexually size dimorphic amphibians known. Females were conspicuously and significantly larger than males, and we found the ratio of the mean female-to-male snout–vent lengths of 2.22. Extreme sexual size dimorphism (SSD) is a trait rare among anurans as a whole, yet is most often seen among species of the genera Cornufer and Platymantis of the western Pacific. A hypothesis is put forward relating call variability and SSD in C. vitianus.

The present study examined the helminth fauna of marsupial frogs (Gastrotheca spp.). Forty-one individuals of six species of the genus Gastrotheca (G. excubitor, G. griswoldi, G. marsupiata, G. monticola, G. peruana, and G. stictopleura) from the Peruvian Andean highlands were analyzed for parasites. Eleven species of nematodes were found: Rhabdias cff. elegans, Oswaldocruzia proencai, Aplectana hylambatis, A. membranosa, A. vellardi, Cosmocerca brasiliensis, C. cruzi, C. parva, Cosmocercoides lilloi, Parapharyngodon sp., and Oxyascaris sp. All the recorded nematode species are generalists with a direct life cycle that can colonize hosts through cutaneous infection, often through contact with soil, suggesting that the terrestrial habitat of the hosts is the main factor responsible for the observed infection patterns. All these nematode species represent new parasite records for the host species studied.

European honey bees (Apis mellifera) were first introduced to the Hawaiian Islands in the late 1800s, and are now ubiquitous across the state in both managed and feral colonies. Though they play an important role in pollination services for native plants and agricultural crops, the competitive impacts they may have on native bees are not well understood. We assessed bee interactions on the preferred floral resources of Hylaeus anthracinus at the Ka Iwi State Scenic Shoreline on O‘ahu, including Heliotropium foertherianum, Scaevola taccada, and Myoporum sandwicense. Bee visitation frequency and duration were documented and analyzed in one-hour increments from 08:00–13:00 totaling 90 hours of video recordings of the focal plants. Honey bee visitation frequency to H. foertherianum peaked at 11:00, and corresponded with a significant reduction in H. anthracinus visitation that resulted in a bimodal activity distribution for H. anthracinus. Feeding duration of H. anthracinus was significantly reduced when visiting H. foertherianum flowers following a honey bee, but unchanged when visiting after conspecifics. Honey bee feeding duration was unaltered by the species of the previous visitor, indicating that deterrence of H. anthracinus to flowers may not be the result of nectar exploitation. S. taccada and M. sandwicense received low overall bee visitation, prohibiting further analyses. We conclude that the presence of honey bees on a preferred foraging resource results in a temporal niche partitioning of H. anthracinus indicative of interference competition, possibly the result of interspecific chemical cues. Future honey bee management considerations are discussed.

Since floras of oceanic islands are distinct from those of the closest continents, islands can serve as useful systems for understanding the evolution of host specificity during speciation of parasitic plants. Orobanche boninsimae (Orobanchaceae) is a holoparasitic plant species endemic to the isolated Bonin (Ogasawara) Islands; previous observations suggested several possible host species for O. boninsimae. In this study we sought to provide more definitive identification of O. boninsimae host plants through DNA analyses of host plant roots. We investigated nine populations of O. boninsimae from Chichijima and Hahajima Islands and determined their hosts by DNA barcoding of the chloroplast trnH-psbA region. We determined that three endemic woody species, Ochrosia nakaiana (Apocynaceae), Melicope grisea (Rutaceae), and Melicope nishimurae (Rutaceae), and one exotic tree, Bischofia javanica (Phyllanthaceae), were host species of O. boninsimae. These three families are newly recorded as hosts for the genus Orobanche, suggesting that O. boninsimae might have developed these unique host specificities in the islands. In addition, we established that O. boninsimae parasitizes completely different species between the islands, even though all available host species of O. boninsimae execpt for M. nishimurae were commonly distributed throughout these islands. This result suggests that intraspecific differentiation for host preference and possibly cryptic speciation has occurred between isolated islands.