Sesbania tomentosa (Fabaceae) is an endemic flowering plant primarily adapted to coastal strand and dry lowland habitat in the Hawaiian Islands. Previous studies have attempted to delineate distinct taxa from among the extant populations. In the most recent treatment of Hawaiian Fabaceae, however, S. tomentosa was recognized as a single polymorphic species with two forms. To readdress issues of taxonomy, the present study utilized microsatellite marker variation and DNA sequencing to discriminate Hawaiian Sesbania populations. While there was no DNA sequence variation among species for ITS or TRPT gene regions, microsatellite analysis found a highly differentiated population structure at the nine loci sampled. Bayesian genetic clustering assignments and associated private alleles occurred in a distinct phylogeographic pattern. As a result, three distinct genetic groups were identified corresponding to islands of origin: populations from Nihoa, Kaua‘i, and O‘ahu (group 1), populations from Maui, Kaho‘olawe, and Moloka‘i (group 2), and populations from Hawai‘i Island (group 3). The extremely varied yet randomly overlapping morphologies among the populations suggest widespread convergent evolution has occurred and precludes any subspecific taxonomic designations. We interpret the high levels of genetic marker and morphologic differentiation exhibited by Hawaiian Sesbania to be a product of the plant’s reproductive ecology and its influence in sub-structuring populations on a small geographic scale. Efforts toward preservation of the wide range of distinctive appearing morphotypes should continue, facilitated by the natural tendency of the plant to maintain a more or less fixed state of certain traits within populations.

The species of Eleotris from Indonesia are reviewed and compared to the known species described from the area. Nine species are recognized including three new species in the ‘melanosoma’ neuromast pattern group. These are described using genetic and morpho-meristic approaches. The new species differ by a high percentage of genetic divergence in partial COI gene (652 bp) and by several characters including the number of pectoral fin rays, the number of scales in lateral, predorsal, forward and zigzag series. The main characteristics of the other known species in the area in the ‘melanosoma’ group, Eleotris melanosoma Bleeker, 1853 and Eleotris macrolepis (Bleeker, 1875), both belonging to this group, are given for comparison. A key for Eleotris species from Indonesia is provided.

Previous studies have documented 836 species of marine macroalgae from Viet Nam. In the present study, marine algal samples were collected along the coast of south central Viet Nam. Morphological observations revealed three new records for the South China Sea, including Zellera tawallina and Grateloupia huangiae (Rhodophyta), and Dictyota grossedentata (Phaeophyceae). The results of morphological observations were supported by phylogenetic analyses. Therefore, the seaweed flora of Viet Nam now comprises 838 marine macroalgal species including 418 Rhodophyta, 149 Phaeophyceae, 183 Chlorophyta, and 88 Cyanobacteria.

Drosophila suzukii (Diptera: Drosophilidae) is a significant pest of wild and cultivated soft-skinned fruits. D. suzukii was first detected outside of its native range in 1983 on Mauna Ka‘ala in Wai‘anae, Hawai‘i, and has since spread throughout North America, South America, and Europe. While D. suzukii is not considered a crop pest in Hawai‘i, little data is available on the distribution of the species on a landscape scale on the archipelago. In this study, we document the distribution and abundance of D. suzukii and characterize its host use of ‘ōhelo (Vaccinium reticulatum) across an altitude gradient on the eastern slope of Mauna Loa, Hawai‘i. In total we collected 2,503 D. suzukii across 14 field sites over a four-month period in 2016. Endemic ‘ōhelo is a host for D. suzukii as we detected adult emergence across field sites with up to 1.88 flies per 1 mL of berries. Our preliminary population data shows that D. suzukii abundance is greater at higher altitudes and in forested habitats on Mauna Loa. Given the population abundance of D. suzukii and their ability to use at least one of the three endemic Vaccinium in Hawai‘i as a host, further research on host–use interactions with native and non-native insects is warranted.

The investigation of sex bias and pseudohermaphroditism is a relatively unexplored area of research in the Neostromboidae. Here, we inform on these phenomena in a population of Gibberulus dekkersi Maxwell, Hernandez Duran, Rowell & Rymer, 2021 on Green Island, Great Barrier Reef. We collected 598 individuals, and noted the size of the cluster in which it occurred. Each individual was placed ventral side up and the body of the animal observed at the time of righting. Sex was determined by the presence or absence of a verge. During this sexing process, females were inspected for the presence of external male sexual organs to indicate the presence or absence of pseudohermaphroditism. We found that, overall, the population was not sexually biased towards one sex. However, we did find that individual clusters within the population showed significant sex bias, with different clusters favouring either males or females. Smaller clusters had a structural sex-ratio bias in favour of females. No evidence for pseudohermaphroditism was recorded, which indicates that the marine pollutant tributyltin (TBT) may not be present or at harmful levels in the surrounding environment. This study adds information from an unstudied Queensland taxon to the growing evidence on sex bias, clustering effects and pseudohermaphroditism within the Neostromboidae.

This paper considers whether Huxley's modification of the Wallace line represents a regional boundary affecting distribution in myxomycetes, using patterns of species composition from the territories of Borneo, Palawan, and the remainder of the Philippine archipelago. With a total of 30 species of myxomycetes belonging to 16 genera (taxonomic diversity index, TDI = 1.88), Borneo recorded the highest taxonomic diversity compared to Palawan with 56 species (TDI = 2.67) and the oceanic Philippines with 159 species (TDI = 4.18). Based on species composition, Borneo is more similar to Palawan (coefficient of community, CC = 0.395) than it is to the oceanic Philippines (0.254). However, Palawan is more similar to oceanic Philippines (0.502) than it is to Borneo. This suggests that Borneo and Palawan have a certain affinity in terms of species composition of myxomycetes, but Palawan still seems to have a higher community similarity to the remainder of the Philippine archipelago when compared to Borneo. Therefore, in terms of species composition alone, myxomycetes do not appear to concur with the biogeographic region delineated by Huxley's line.

I studied population densities of forest bird communities in the Mariana Islands of Saipan, Aguiguan and Sarigan in order to evaluate hypotheses concerning seasonal shifts in populations, habitat effects on densities, inter-island differences in densities, social group size and underlying reasons for community structuring. With the exception of one species, I found no evidence to support the hypothesis that seasonal shifts occur in populations. Hence, this island system differs in this regard from mainland tropical forests. I also found, contrary to theory, no evidence that the presence of altered habitat permits populations to be greater than they would be in their absence, as disturbed habitat had far lower densities of most species than native forest. Furthermore, I found no support for the hypothesis that social group size differs seasonally as a consequence of differential breeding activity, which is again contrary to findings for mainland tropical forests. A high density of nectar resources on two islands appeared responsible for high population densities of the Micronesian Myzomela on them. Inter-island density comparisons showed strong evidence for there being unfilled niches on Sarigan, thereby making the island a favorable site for species translocations. Examination of the prehistoric composition of Marianas forest bird communities indicated that they once resembled in density structure those of the comparatively pristine Palau Islands. Removing ecologically similar but now absent species from the original Mariana communities likely resulted in reduced competition for resources in ways that increased niche breadth and, thus, populations. The wholesale loss of species in the Marianas has led to communities in which three ecologically versatile species now account for the vast majority of individuals in the community.

Axis deer (Axis axis) are invasive species that threaten native ecosystems and agriculture on Maui Island. To mitigate negative effects, it is necessary to understand current abundance, population trajectory, and how to most effectively reduce the population. Our objectives were to examine the population history of Maui axis deer, estimate observed population growth, and use species-specific demographic parameters in a VORTEX population viability analysis to examine removal scenarios that would most effectively reduce the population. Only nine deer were introduced in 1959, but recent estimates of >10,000 deer suggest population growth rates (r) ranging between 0.147 and 0.160 even though >11,200 have been removed by hunters and resource managers. In VORTEX simulations, we evaluated an initial population size of 6,000 females and 4,000 males, reflecting the probable 3F:2M sex ratio, with annual removal rates of 10%, 20%, and 30% over a 10-year period. A removal rate of 10% resulted in a positive growth rate of 0.103 ± 0.001. A 20% removal rate resulted in only a slightly negative growth, while a 30% removal rate resulted in –0.130 ± 0.004. By increasing the ratio of females removed to 4F:1M in the 30% harvest scenario, the decline nearly doubled, resulting in –0.223 ± 0.004. Effectively reducing axis deer will most likely require an annual removal of approximately 20–30% of the population and with a greater proportion of females to increase the population decline. Selective removal of males may not only be inefficient, but also counterproductive to population reduction goals.