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Open Access Publications from the University of California
Cover page of The Magnitude of Global Marine Species Diversity

The Magnitude of Global Marine Species Diversity


The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be discovered.

Cover page of Increased Oceanic Microplastic Debris Enchances Oviposition in an Endemic Pelagic Insect

Increased Oceanic Microplastic Debris Enchances Oviposition in an Endemic Pelagic Insect


Plastic pollution in the form of small particles (diameter less than 5 mm)—termed ‘microplastic’— has been observed in many parts of the world ocean. They are known to interact with biota on the individual level, e.g. through ingestion, but their population-level impacts are largely unknown. One potential mechanism for microplastic-induced alteration of pelagic ecosystems is through the introduction of hard-substrate habitat to ecosystems where it is naturally rare. Here, we show that microplastic concentrations in the North Pacific Subtropical Gyre (NPSG) have increased by two orders of magnitude in the past four decades, and that this increase has released the pelagic insect Halobates sericeus from substrate limitation for oviposition. High concentrations of microplastic in the NPSG resulted in a positive correlation between H. sericeus and microplastic, and an overall increase in H. sericeus egg densities. Predation on H. sericeus eggs and recent hatchlings may facilitate the transfer of energy between pelagic and substrate-associated assemblages. The dynamics of hard-substrate-associated organisms may be important to understanding the ecological impacts of oceanic microplastic pollution.

Cover page of Life on the High Seas - the Bug Darwin Never Saw

Life on the High Seas - the Bug Darwin Never Saw


Among millions of insect species known in the world only five species of Halobates (Heteroptera: Gerridae) are able to live in the high seas. The general public is probably not aware that there are insects living on the open ocean and even most marine scientists have never seen a live or preserved specimen with their own eyes. The genus Halobates was first collected during a Russian oceanographic expedition around the world between 1815 and 1818.

Cover page of Occurrence and Density of <em>Halobates micans (Hemiptera: Gerridae) in the Eastern South Indian Ocean</em>

Occurrence and Density of Halobates micans (Hemiptera: Gerridae) in the Eastern South Indian Ocean


Two species of ocean skaters, Halobates germanus and Halobates micans, live in the tropical and subtropicalwaters of the Indian Ocean. From December 1992 to December 1993, Halobates was intensively sampledin the easternmost region of the South Indian Ocean (13–18.5°S, 114–121E°), from which there have been a small number of records of Halobates. No H. germanus was caught, but a total of 1190 H. micans were collected, with densities estimated at 13 900–28 100 individuals/km2. This suggests that H. micans lives in the study area at high densities comparable to those in the Atlantic and the Pacific Oceans. We also discuss the possible effects of ocean currents and winds on the geographic distributions of the two Halobates speciesin the eastern South Indian Ocean.

Cover page of Aquatic Heteroptera (Insecta: Gerromorpha and Nepomorpha) from Xishuangbanna, Yunnan, China

Aquatic Heteroptera (Insecta: Gerromorpha and Nepomorpha) from Xishuangbanna, Yunnan, China


Eighty five species of aquatic and semi-aquatic Heteroptera belonging to 14 families are reported from Xishuangbanna and nearby counties in Yunnan. Collecting locations and habitats are given. Ten species (Hydrometra jaczewskii, H. longicapitis, H. orientalis, Amemboa (Amemboa) sexualis, A. (A.) lyra, Metrocoris ciliatus, Pleciobates pacholatkoi, Ptilomera burmana, Rhyacobates anderseni, Ventidus pulai) are new records for China. In addition, Nine new species (Timasius yunanensis, Ranatra lansburyi, R. sterea, Micronecta (Micronecta) erythra, M. (M.) janssoni, M. (M.) lobata, M. (M.) ornitheia, M. (Unguinecta) melanochroa, Anisops pseudostali) based on material collected during this study, have been described and published elsewhere.

Cover page of The Marine Insect <em>Halobates </em>(Heteroptera: Gerridae): Biology, Adaptations, Distribution, and Phylogeny

The Marine Insect Halobates (Heteroptera: Gerridae): Biology, Adaptations, Distribution, and Phylogeny


Among the million or so insect species known, only a few thousand are found in marine habitats. The genus Halobatesis almost exclusively marine and is unique in having the only known species to live in the open ocean. Of the 46 Halobatesspecies described, only five are completelyoceanic in habitat, with the majority of species living in coastal areas associated with mangroves or other marine plants. This review presents a brief historical account of the genus and providesinformation on various aspects of its life history, ecology, special adaptations, distribution, and biogeography. Distribution maps of the five oceanic species as well as several of the more widely distributed coastal species have been updated. The phylogeny and evolution of Halobatesbased on morphology and recent molecular data are also discussed. A key to all known species of Halobatesand related genera and a checklist of all species and their distributions are included as appendices.

Cover page of Marine Insects of Guam: Heteroptera and Diptera

Marine Insects of Guam: Heteroptera and Diptera


A list of marine Heteroptera and Diptera currently known from Guam is given. Some notes on biology and distribution are alsoincluded.

Cover page of Mitochondrial DNA sequence variation and phylogeography of oceanic insects (Hemiptera: Gerridae: <em>Halobates</em> spp.)

Mitochondrial DNA sequence variation and phylogeography of oceanic insects (Hemiptera: Gerridae: Halobates spp.)


Relatively few insects have invaded the marine environment, and only five species of sea skaters, Halobates Eschscholtz (Hemiptera: Gerridae), have successfully colonized the surface of the open ocean. All five species occur in the Pacific Ocean, H. germanus White also occurs in the Indian Ocean, whereas H. micans Eschscholtz is the only species found in the Atlantic Ocean. We sequenced a 780 bp long region of the mitochondrial cytochrome oxidase subunit I gene (COI) for a total of 66 specimens of the five oceanic Halobates species. Our purpose was to investigate the genetic variation within species and estimate the amount of gene flow betweenpopulations. We defined 27 haplotypes for H. micans and found that haplotype lineages from each of the major oceans occupied by this species are significantly different, having sequences containing five to seven unique base substitutions. We conclude that gene flow between populations of H. micans inhabiting the Atlantic, Pacific, and Indian Ocean is limited and hypothesize that these populations have been separated for 1 to 3 million years. Similarly, there may be limited gene flow between H. germanus populations found in the Pacific and Indian Ocean and between H. sericeus populations inhabiting thenorthern and southern parts of the Pacific Ocean. Finally, we discuss our findings in relation to recent hypotheses about the influence of oceanic diffusion on the distribution and population structure of oceanic Halobates spp.

Sex Attractant in the Marine Insect Trochopus plumbeus (Heteroptera: Veliidae): a Preliminary Report


We present evidence of sex-attracting substances, produced by males of the marine insect Trochous plumbeus. This small veliid is widely distributed in the Caribbean. Large numbers were found in the mangrove areas of several islands in the Bahamas. Field assays using live insects and extracts demonstrated that females were highly attracted to males and male extracts, but not the opposite. Gas chromatography-mass spectrometry analyses of extracts from both males and females revealed the presence of a series of aldehydes and long-chain aliphatic acids that are insoluble in water, some of which could possibly act as surface-dispersible semiochemicals.