Tropical drylands are among the most threatened ecosystems worldwide, and fewer than 10% of tropical dry forests in Hawai‘i remain intact. Terrestrial arthropods comprise most of the endemic fauna on many islands, including Hawai‘i, where they provide ecosystem services such as pollination, decomposition, and a reliable prey base for predators. The objective of our study was to measure understory arthropod diversity and relative abundances in two common habitat types within dryland Hawai‘i—a non-native grassland, dominated by Cenchrus setaceus (fountain grass) with few native shrubs, and a native woodland, dominated by Metrosideros polymorpha (‘ōhi‘a). We used generalized additive models to examine patterns of understory arthropod dynamics measured monthly or bimonthly in relation to the two habitat types and local climatic variables. We found that temperature and habitat type were significant predictors of the abundance of certain arthropod families and orders. A greater abundance of spiders was in the woodland than grassland habitat, and more beetles and ants (particularly the Argentine ant, Linepithema humile) were in the grassland than woodland habitat. Temperature significantly predicted overall family-level richness and diversity of arthropods as well as Araneae, Heteroptera, Hymenoptera, and Lepidoptera abundance. Precipitation significantly predicted Heteroptera abundance. Significant positive associations were found among some arthropod groups, including several arachnid groups and families of Hemiptera. Documentation of insect and other arthropod community dynamics improves our understanding of ecological community function, supporting management of island communities comprised of both native and non-native species.

The Northern kelp crab (Pugettia producta) is a common omnivore that inhabits bull kelp (Nereocystis luetkeana) beds in the Salish Sea (Washington, USA). Rising ocean temperatures associated with ongoing environmental changes have the potential to alter organismal physiology and consequently change their feeding strategies, especially in organisms with high feeding flexibility such as omnivores. In this study, we performed feeding trials with P. producta at ambient and elevated temperatures to determine if elevated temperatures characteristic of short-term heat waves induce changes in feeding rate or preferred food type. We offered crabs N. luetkeana blades, Lacuna vincta snails, or a combination of both as food options in choice and no-choice feeding trials. Our results showed that elevated temperatures did not change crab feeding rates or their preference for algal tissue versus animal tissue. When offered the two food options in choice feeding trials, crabs consistently chose to incorporate both into their diet, demonstrating that they are opportunistic consumers across a range of temperatures. The feeding behaviors of grazers and omnivores in kelp beds are impactful in shaping the habitat around them. Thus, studies such as this are essential to improving our understanding of how elevated temperatures may affect trophic interactions among kelp forest inhabitants and ecosystems. Further work to investigate the effects of elevated temperatures on P. producta feeding, including how diet may shift across ontogeny, is needed to understand and accurately predict how elevated temperatures will affect future trophic interactions within Salish Sea bull kelp ecosystems.

Hibiscus rosa-sinensis L. (Malvaceae) is the tropics' most iconic flower, prominent in art, fashion, decoration and medicine. However, it has never been found growing in the wild and its origins are perplexing. Carl Linnaeus named Hibiscus rosa-sinensis in 1753, basing his description on plants with bright red, double flowers in cultivation in India, Sri Lanka and Indonesia. Its postulated origins have included China, southeast and south Asia, Indian Ocean islands, East Africa and the Americas. In 1769, Joseph Banks and Daniel Solander made collections of a red, double-flowered hibiscus growing in gardens in the Society Islands, eastern Polynesia. Polynesians refer to this hibiscus as kaute or cognate names; it was long considered a pre-European introduction to the South Pacific islands from Asia and to be conspecific with H. rosa-sinensis. Recent linguistic and botanical studies have shown kaute to be a critically endangered new species, H. kaute L.A.J. Thomson & Butaud. In pre-European times, Polynesians domesticated H. kaute and apparently took it westwards across the South Pacific Ocean, in traditional canoes sailing over distances of more than 5,000 km, demonstrating its importance in Polynesian culture and medicine. The related spectacular, variegated Hibiscus cooperi J.J. Veitch was described from cultivation in Britain in 1863. In 2020 H. cooperi was shown to be native to Erromango Island, Vanuatu. Molecular and leaf morphological data reveal that Hibiscus × rosa-sinensis is a pre-historic hybrid between H. kaute and H. cooperi; two species whose natural ranges are separated by more than 4,000 km of Pacific Ocean. This cross produces hybrid offspring with an array of petal colours and floral forms but with generally uniform foliage intermediate between the parental species. As a nothospecies (hybrid species), its correct scientific name is to be rendered as Hibiscus × rosa-sinensis.

Zooplankton are key ecosystem components in the pelagic food web. These organisms move vertically to avoid visual predators (i.e., fish) that prey on them; such movement is known as diel vertical migration (DVM). This study aims to elucidate the dynamics of the daily vertical migration of zooplankton and to determine the factors that govern their migration behavior in an understudied Philippine Lake in Lake Wood (Mindanao Island) from March to April 2019. Zooplankton and several environmental parameters were sampled in the deepest part of the lake at specific depths (1 m, 15 m, 30 m, 50 m, and 70 m) during noon and midnight. Adult females of Thermocyclops crassus displayed typical diel vertical migration patterns accompanied by large migration amplitudes. The food-rich epilimnion supports the abundance of T. crassus during the night and rather dwells in the hypolimnion during the day to evade visual predators. The study underscores the intricate interplay among predation pressure, temperature, water transparency, and total dissolved solids, collectively shaping the observed vertical migration behavior of adult female T. crassus. These perspectives provide a deeper understanding of how these organisms navigate the intricate challenges posed by their environment, offering insights into their strategies for survival and thriving within the ecosystem.

Birds often prey on agricultural pests, potentially making them effective pest management agents; thus, changes in bird populations may have impacts on plant health. Using an exclosure treatment, we test whether birds reduce herbivore damage and increase crop yield on the island of Luta in the Mariana Island chain. We focused on Luta because the nearby island of Guåhan has experienced widespread bird loss due to an invasive snake, and thus, this experiment simulating bird loss could provide an indication of potential cascading impacts to agriculture on Guåhan. We planted two crops—eggplant and long bean—within bird exclosure and control treatments at three working farms, and measured herbivore damage, crop yield, and spider web abundance in the presence and absence of birds. The influence of birds varied among crops and farms. Herbivore damage did not differ between treatments in long bean, but damage was greater for eggplant in the absence of birds at one farm (“Farm 3”). Yield of eggplant did not differ between treatments, but yield and weight of long bean was lower in the absence of birds at Farm 1. Spider webs were 270% greater in the absence of birds at Farm 1, whereas spider webs were more abundant in the presence of birds at the other two farms. These results suggest that birds may control pest populations, but the effects vary depending on the crop and environmental context.

The Pacific silverstripe halfbeak, Hyporhamphus naos is one of the most commercially important fish species in Mazatlán Bay, north-western Mexico. Irrespective of its relatively small size, it is highly appreciated in the local gastronomy. Every year between April and May adults congregate to spawn in Mazatlán Bay; however, information about their parasite fauna is lacking. This study reports on the metazoan parasite fauna of H. naos. Thirty individuals were sampled during the 2022 fishing season. Nine parasite taxa were collected, including five species of ectoparasites, that is, the monogeneans Axinoides sp. and Kuhnia sp., the copepods Ergasilus sp. and Lepeophtheirus sp., and the isopod Mothocya gilli Bruce, 1986, and four endoparasites, the nematode Philometra sp., and three metacercariae including the heterophyid Opisthometra planicollis (Rudolphi, 1819), the strigeid Cardiocephaloides medioconiger (Dubois and Pérez-Vigueras, 1949), and the cyathocotylid Mesostephanus microbursa Caballero, Grocott and Zerecero, 1953. Parasites were identified using morphology, or a combination of morphology and DNA sequences. This study includes new host records for all metazoan parasites collected, except for Philometra sp. which has been previously documented infecting the gonads of H. naos. Philometra sp. was the species with the lowest prevalence (<10%), whereas O. planicollis and C. medioconiger reached the highest prevalence values with 63.3% and 50%, respectively. We discuss the factors that potentially determine the infection parameters of the metazoan parasites in the area, and the potential zoonotic importance of the cyathocotylid M. microbursa.

The origin of soils on Niue Island, an uplifted South Pacific former atoll, has long been a subject of debate because the soils are highly radioactive. A new assessment of proposed sources shows that content in the soils of major elements such as Fe and Al rules out erosion of the carbonate buildup or pristine aragonite coral. Subaerial volcanic ash has been previously argued to be a major source and according to a newly employed diagnostic ratio of Fe₂O₃/Al₂O₃ it is confirmed as a definite minor contributor. Fe₂O₃/Al₂O₃ ratios offer evidence that the most likely major soil precursor is pumice rafted periodically from neighboring seamounts or from the volcanically active Tongan Trench. Pumice raftings likely contributed to the soil formation of other uplifted atolls having configurations similar to Niue Island.