Mosquito surveillance is essential for the early detection of species incursions and preventing vector-borne disease outbreaks. A variety of traps and attractants (lures), including those that generate CO2, are used in mosquito surveillance. In this study, we measured the CO2 production rate and longevity of three yeast-generated CO2 recipes and evaluated the performance of Biogents (BG) Sentinel traps baited with BG-Lure, yeast-generated CO2, or combined BG-Lure and yeast-generated CO2 for mosquito detection. The recipe containing the highest sugar (500 g) produced significantly larger CO2 volumes and sustained release for longer than other recipes. Traps baited with yeast-generated CO2 captured greater numbers of mosquitoes than those baited with BG-Lure alone or with the combined treatment. Although BG Sentinel traps baited with BG-Lure are currently the primary mosquito surveillance tools at Hawai‘i’s ports of entry, our findings suggest that more effective attractants than BG-Lure may be available and warrant consideration for use in Hawai‘i.
In this study, the complete mitochondrial genome of a longnose conger, Rhynchoconger ectenurus, collected from the East China Sea, was obtained using high-throughput sequencing technology. The sequence composition and structural characteristics were comprehensively depicted, and the phylogenetic implications with related species were also analyzed. The entire length of the mitochondrial DNA molecule was 17,717 bp in size, with a higher AT proportion (57.10%) and an obvious anti-G bias (15.87%). Unexpectedly, a novel gene arrangement was detected in the region from ND6 to tRNA-Pro (P), which was quite different from typical vertebrate mitogenomes. ND6 and its flanking tRNA-Glu (E) are displaced to a position between tRNA-Thr (T) and tRNA-Pro (P), where a duplicated control region emerged upstream of ND6. Tandem duplication and random loss model appears to be the most suitable explanation for this gene rearrangement event. Phylogenetic analysis using concatenated nucleotide sequences of protein-coding genes with the maximum-likelihood method confirmed a close relationship with Conger japonicus. Further, species with the same reorganized gene order grouped together, indicating a possible convergent evolution in the mitogenome of these fishes. The results of this research enriched the mitochondrial genome database of Congridae species and provided new insights into the mitochondrial gene order characters in phylogenetic implications of bony fishes.
Polynesian rats (Rattus exulans) are perhaps the fourth most widespread detrimental species of invasive commensal rodent on the planet. Here, we review their biology, impacts, and management in Pacific Islands. Their temperate to tropical distribution resulted from accompanying ancestral Polynesian settlers during their migration 700-4,000 yr ago. This invasive species is unique for several reasons: (a) R. exulans do not hybridize with any other species; consequently; (b) they have been used as a proxy to test hypotheses about the prehistoric movement and colonization of people throughout the Pacific islands; and (c) they have recognized value among some Pacific Island peoples. Nonetheless, introductions of R. exulans are associated with extinctions of some plants and animals prehistorically, and still have detrimental effects on native species, agriculture, human health, and infrastructure. There is great interest in reducing R. exulans populations and eradicating them from many islands to recover native and endemic plants and animals and to reduce harmful effects to humans. However, the behavior and ecology of this species present some challenges for managers in that they are considered more difficult to eradicate than more widespread invasive rat species.
While invasive species can facilitate the establishment of other invasive species and exacerbate negative impacts on native ecosystems, they may alternatively control other invasive species, producing a net benefit for native species. In Gu & aring;han (also known as Guam), the invasive brown treesnake, Boiga irregularis, is most famous for its role in the decline of native birds. However, the snake also reduced numbers of nonnative seed predators such as rats (Rattus spp.) and mice whether, in Gu & aring;han, the snake has indirectly benefitted trees by reducing seed predation by nonnative rodents. We placed trays of seeds from six forest tree species at multiple forest sites in the islands of Gu & aring;han, which has snakes, and Saipan, which has no established population of snakes and approximately five times as many rats. Surprisingly, no significant differences in seed removal were detected between islands, except for one nonnative species, pap & aring;ya (Carica papaya), which was removed in higher proportions from trays in Saipan. Overall, seed removal was low-less than half of the seeds of all species on both islands were removed from our trays, indicating that these tree species may not suffer from high rodent predation rates. Our results did not show indirect benefits of snakes for native forest tree species via reduced seed predation, at least in the species we tested. Thus, we did not find evidence of beneficial cascading effects from one invasive species controlling another.
Invasive yellowjackets of the genus Vespula have established thriving populations across several Pacific islands, in some cases profoundly disrupting ecosyspredatory habits, and extended active season allow them to deplete carbohydrate and protein resources, compete with native fauna, and impact pollination networks. The lack of natural enemies can result in extreme colony density and forager abundance in some habitats. We synthesize current knowledge on their biology, diet, ecological impacts, pathogens, and distribution across the Pacific Basin, with emphasis on their effects on native arthropods, plants, and pollinators. Economic consequences include damages to apiculture, horticulture, outdoor recreation, and human health. Management strategies, including nest destruction, toxic baiting, and experimental biological control, remain largely localized and limited in scale. We highlight gaps in distributional data, especially for French Polynesia, and stress the importance of biosecurity, targeted control in sensitive habitats, and emerging approaches such as biocontrol and genetic technologies. Addressing these knowledge gaps and integrating adaptive management will be essential to mitigate the ecological and economic impacts of these formidable invaders on Pacific island ecosystems.
The green sea turtle (Chelonia mydas) is listed as an endangered species in Mexico and presents significant conservation challenges due to its changing migratory patterns throughout its life stages and the thousands of kilometers it travels between its birthplace and foraging grounds. To understand the natal origins of green sea turtle populations of the Baja California peninsula, samples were collected over two years from two populations at opposite sides in the Baja California peninsula, with one located in the middle of the Gulf of California (Bahia de Los & Aacute;ngeles [BLA]) and the other on the Pacific Western coast (Complejo Lagunar Ojo de Liebre [CLOL]), both located in Mexico. The mitochondrial DNA control region was sequenced and compared with potential source populations in the Pacific Ocean. The mixed-stock analysis indicated that both Baja California populations originate from nesting sites in the Eastern Pacific, primarily from the Revillagigedo Islands and the coast of Michoac & aacute;n. Statistical analysis was used to evaluate the contribution of turtles originating from the Revillagigedo Islands and the coast of Michoac & aacute;n to both sites, which found that statistically both Revillagigedo and Michoac & aacute;n contribute the same number of individuals to the BLA and CLOL zones (Bayes Factor <1.9 for both populations [1.59 and 1.14, respectively]).
In Hawai'i, the survival of Hawaiian waterbirds heavily depends on intensive management efforts. Unfortunately, their population is at risk due to the threat of small Indian mongooses (Urva auropunctata), which have been preying on the nests and chicks of native waterbirds in wetland habitats. To betred cameras to observe mongoose predation events on three endangered Hawaiian waterbird species: the Hawaiian coot (Fulica alai), Hawaiian common gallinule (Gallinula galeata sandvicensis), and Hawaiian stilt (Himantopus mexicanus knudseni). The study found that mongooses depredated 133 eggs from 34 Hawaiian waterbird nests, which included seven coot, 10 gallinule, and 17 stilt nests, during 62 nest visits. On the initial mongoose visit, an average of 1.4, 3.3, and 2.5 eggs were depredated in coot, gallinule, and stilt nests, respectively. The researchers also observed that mongoose predation events followed a bimodal pattern throughout the day, with a 25.8% higher frequency of predation events in the afternoon. In addition, mongooses tended to prey on Hawaiian waterbird nests during the later stages of development. Seasonally, mongoose predation events were significantly more frequent during the dry season (n = 22), relative to the proportion of waterbird nests available, compared with the wet season (n = 12). Predation events are most frequent during the hotter dry season and in the afternoons when swapping of co-incubating parents on the nest is more likely. Conservation managers for waterbird species in Hawai'i should prioritize predator control efforts to mitigate the impact of small Indian mongooses.
Members of the octocoral family Primnoidae are widely distributed in the deep sea around the world but rarely reported in the tropical western Pacific. Based on the examination of 30 primnoid specimens collected from seamounts in the tropical western Pacific, we identified 5 genera and 13 species based on the morphological and phylogenetic analyses. These include two new species of Callogorgia Gray, 1858, six new species and one known species of 1908, one new and one known species of Candidella Bayer, 1954, and a known species transferred to the new genus Paracandidella gen. nov. The ten new speC. paralyra sp. nov., Paracalyptrophora robusta sp. nov., P. elegans sp. nov., and Candidella curva sp. nov. Compared with the mitochondrial marker mtMutS, the nuclear marker 28S rDNA is more effective for discriminating primnoid species but still limited in discerning certain genera and species. This study reveals a high species diversity of Primnoidae in the tropical western Pacific, and it is helpful for understanding the deep-sea biodiversity and conservation in the tropical western Pacific Ocean.
We assessed the effects of insularity, sexual size dimorphism, and habitat use in an isolated population of Clark's Spiny Lizard, Sceloporus clarkii. We captured 120 individuals from Isabel Island National Park, of which 69 were females and 51 were males. First, we compared snout-vent length between island and mainland populations of S. clarkii; second, we compared five morphological traits between sexes within the isolated population. Finally, we assessed the relationship between morphological traits and habitat use (diameter of perch and perch height) from the island population. We observed that the insular population of S. clarkii exhibited a dwarfed form compared to the mainland population. Within the island population, we observed differences in body length: females were 10% shorter than males, with smaller heads (exhibiting allometry in females and isometry in males). Females and males used similar diameters of perch and perch heights. Surprisingly, we did not observe relationships between morphological traits and habitat use in either sex.
Oceanic islands harbor a set of unique plant taxa due to their geographical isolation that promotes rapid evolution. The fern Adenophorus tripinnatifidus Gaudich. is endemic to the Hawaiian Islands and restricted to mesic and wet forests at upper elevations. Morphologically, it is highly variable, and previous genetic studies have identified unique alleles restricted to certain populations. The present study was conducted to investigate the population genetic structure of A. tripinnatifidus using genomic data. We collected plant samples from three of the main Hawaiian Islands: Kaua'i, Maui, and Moloka'i. ddRADseq libraries were prepared, and sequences were analyzed using STRUCTURE and DAPC. Both STRUCTURE and DAPC supported the presence of two genetic groups, the Kaua'i population and the Maui and Moloka'i populations. We detected no admixture between these groups, which may indicate that individuals were exclusive to either group. The observed genetic differentiation may suggest divergence among A. tripinnatifidus populations. However, the absence of samples from O'ahu and Hawai'i introduces limitations, as intermediate populations could provide further insights into gene flow and differentiation. We discuss alternative explanations for the observed patterns, including ecological adaptations. These findings suggest that geographic isolation between island groups may be driving genetic differentiation with potential implications for the conservation and management of endemic Hawaiian ferns.
Introduced rats can have detrimental impacts on forest regeneration, with consequences for other trophic levels. Rats frequently consume or damage fruit, seeds, and seedlings, disrupting ecosystem processes that provide food and habitat for bird populations. These impacts are exacerbated on oceanic islands where plants and animals have evolved without mammalian herbivores and seed predators, leaving many native species at risk of extinction due to invasive species and other stressors. The goal of this study was to evaluate the relationship between rodent management in the Alaka`i Wilderness Preserve on Kaua`i Island, Hawai`i (USA), and three variables: fruiting density, seed rain, and seedling emergence that influence forest regeneration processes. This area is one of the last remaining refuges for Kaua`i's native forest birds, most of which are threatened or endangered. Seed traps and seedling emergence plots were set in areas with and without rodent control, and seed rain, fruiting density, and seedling emergence were monitored within these plots from February to June 2023. We found no difference in seed rain, seedling emergence, or fruiting density inside and outside of areas of rodent control for common plant species in the subcanopy. These findings potentially suggest that in the Alaka`i Wilderness Preserve, either current levels of rodent management actions have not significantly influenced forest regeneration processes for these plant species, or alternatively, current levels of predation of plants by rodents are not substantial enough to impact forest regeneration processes.
In August of 2023, we conducted the first survey of rat lungworm (Angiostrongylus cantonensis) in wild rats (Rattus spp.) from the island of Kaua'i since 1964. Our objectives were to capture and obtain specimens of wild rats from Kaua'i, to confirm infection status of A. cantonensis, and to obtain detailed infection-level data where possible. In addition, we intend to standardize survey protocols for measuring infection levels in Hawai'i, allowing for more appropriate comparisons between locations and over time. A total of fourteen rats (11 R. exulans, 3 R. rattus) were trapped, 50% of which had adult A. cantonensis worms, and 36% exhibited lung granulation. Here we discuss the relevance of these findings and suggest further surveillance is necessary to better understand the status of rat lungworm throughout the Hawaiian Islands.
Herbarium databases can play a crucial role in the study of botany, ecology, and biogeography. With 22,717 specimens, the Nadeaud botanical database of the herbarium of French Polynesia represents a significant resource for the study and preservation of the unique and diverse flora of French Polynesia. This study aims to describe the taxonomic and geographic distributions as well as the ecology of native and endemic vascular plants included in the database. We focused our analysis on native angiosperms representing more than 14,000 specimens, 416 endemic taxa, and 190 non-endemic native taxa. First, the distribution of native angiosperms and the rate of endemism for French Polynesia, for each archipelago and for 60 islands were characterized. The environmental variables associated with each specimen were extracted, which enabled us to document the ecology of the various taxa present in the different archipelagos and islands. We found high rates of endemism in the high-elevation islands, such as the Marquesas and the Society archipelagos, compared to low-lying atolls of the Tuamotu. Environmental correlates enabled us to group them according to their archipelago and/or island endemism, revealing the relevance of the variables chosen for the biogeographical study. The limited geographical distribution of some endemic taxa underlines their vulnerability in relation to certain threatened ecosystems within islands. The taxonomic and geographical distribution of native angiosperms highlights the disparate distribution of taxa among the French Polynesia. This study is an important step toward a better planning of projects related to the preservation of the flora of French Polynesia.
Macrobenthos play a crucial role in monitoring marine ecosystems, as their species composition and community structure are significantly affected by pollution and human activities. Bottom trawling was carried out in October 2022 and March 2023 to collect samples of macrobenthos. A total of twelve macrobenthic samples were collected, and the community composition, species diversity index (H ', J ', D), and ecological status index (AMBI, M-AMBI) were analyzed to determine the seasonal changes, community structure, and ecological status. A total of 94 macrobenthic species were identified, reflecting the biodiversity of the area. This diversity was attributed to the unique topography creating local eddies and upwellings and to effective conservation measures such as fishing restrictions, pollution control, and artificial reef construction. The dominant species included Turritella bacillum and Murex trapa in both seasons, with Oratosquilla oratoria and Bufonaria rana also dominating in autumn. The biodiversity indices were slightly greater in autumn, indicating better community stability. The H ' index revealed moderate disturbance in spring and light disturbance in autumn, whereas the AMBI index suggested no significant disturbance. The M-AMBI index indicated that most stations had good or high ecological statuses. This study revealed good ecological quality in the Nanji Islands, largely due to effective conservation measures and unique environmental conditions.
No previous paleo-parasitological research has been conducted at archaeological sites on New Guinea, in contrast to that of elsewhere in Oceania, where multiple Melanesian and Polynesian archipelagos have recently been investigated. Here we examine samples from four archaeological sites in the New Guinea Highlands, comprising three rock-shelters (Yuku, Kiowa, and Manim) and one open site (Wanelek), encompassing time periods from the Last Glacial Maximum to the Late Holocene. Five helminth parasite taxa were identified, almost all in Late Holocene layers: Toxocara canis, Dipylidium caninum, Hymenolepis sp., Taenia sp., and an unknown trematode, some of which could have had adverse effects on people and their domestic animals. Results suggest the presence of introduced dogs and pigs at Yuku, Wanelek, and Manim, which, when considering site formation processes, suggests dispersal to the Highlands within the last c. 4,000 yr. These are the first pre-European contact records of helminth parasites for Sahul.
Anoplolepis gracilipes (yellow crazy ant), among the world's most damaging invasive ants and likely native to Southeast Asia, occurs in similar to 90% of countries and territories in the tropical Pacific islands region. Several characteristics contribute to their socioeconomic and environmental impacts, which primarily affect people's well-being, agriculture and biodiversity. Unpredictable, sometimes repeated, population outbreaks are often observed. They use formic acid for defense, and when in large numbers this enables them to overwhelm prey and competitors. Competition is the major population regulator among ants, and high abundance enables yellow crazy ant populations to dominate other ants. Their abundance is compounded by monopolization of carbohydrate resources, often through mutualisms with honeydew-producing insects. Tolerant of diverse habitats, the ants are likely to increase in latitudinal distribution with climate change. The best management option, preventing their arrival, is possible in only a few locations in the region. Where they are already present, the arrival of new populations should be avoided. Biosecurity efforts should also focus on reducing domestic spread among islands and preventing the arrival of new mutualists. Eradication of yellow crazy ants requires toxicants with potential nontarget impacts and often fails or is prohibitively expensive. Long-term monitoring and effective biosecurity are essential to ensure the ant's continued absence after eradication. The recent interest in genomic approaches to invasive ant control shows promise, as does the use of viruses and other microorganisms. However, these tools are far from operational. We outline recommendations to improve the management of yellow crazy ants in the region.
