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As a dispersive lineage expands its distribution across a heterogeneous landscape, it leaves behind allopatric populations with varying degrees of geographic isolation that often differentiate rapidly. In the case of oceanic islands, even narrowly separated populations often differentiate, which seems contrary to the highly dispersive nature of the founding lineage. This pattern of highly dispersive lineages differentiating across narrow sea barriers has perplexed biologists for more than a century. We used two reduced-representation genomic datasets to examine the diversification of a recent, rapid geographic radiation, the white-eyes (Aves: Zosterops) of the Solomon Islands. We incorporated methods that targeted phylogenetic structure, population structure, and explicit tests for gene flow. Both datasets showed evidence of gene flow among species, but not involving the closely spaced islands in the New Georgia Group. Instead, gene flow has occurred among the larger islands in the archipelago, including those recently connected by land bridges as well as those isolated by large expanses of deep ocean. Populations separated by shallow seas, and connected by land bridges during glacial cycles, ranged from no differentiation to both phenotypic and genomic differentiation. These complex patterns of gene flow and divergence support a model of rapid geographic radiation in which lineages differentially evolve dispersal disparity and phenotypic differences.

Malawimonadida is a deep-level (arguably "kingdom-scale") lineage of eukaryotes whose phylogenetic affinities are uncertain but of great evolutionary interest, as the group is suspected to branch close to the root of the tree of eukaryotes. Part of the difficulty in placing Malawimonadida phylogenetically is its tiny circumscription: at present, it comprises only two described and one cultured but undescribed species, all of them are freshwater suspension-feeding nanoflagellates. In this study, we cultivated and characterised Imasa heleensis gen. nov., sp. nov. (Imasidae fam. nov.), the first marine malawimonad to be described. Light and electron microscopy observations show that Imasa is largely similar to other malawimonads, but more frequently adheres to the substrate, often by means of a pliable posterior extension. Phylogenetic analyses based on two ribosomal RNA genes and four translated protein-coding genes using three different taxon sets place Imasa as sister to the three freshwater malawimonad strains with strong support. Imasa's mitochondrial genome is circular-mapping and shows a similar gene complement to other known malawimonads. We conclude that Imasa represents an important expansion of the range of taxa available for future evolutionary study.

We reconstruct the phylogeny of imperial pigeons (genus Ducula) using mitochondrial and nuclear sequence data. We evaluate the most likely biogeographic scenario for the evolution of this group that colonized many islands of the Pacific Ocean. The divergence time analysis suggests that the basal divergences within Ducula occurred more recently than in the fruit doves (genus Ptilinopus), a group that is also well diversified in Oceania. The imperial pigeons colonized the Melanesian region several times independently, and the diversification within this region led to several species in sympatry, in particular in the Bismarck archipelago. Central Polynesia was also colonized several times, first by a lineage during the Miocene that led to the large D. latrans, sister to the New Caledonian endemic D. goliath, then more recently by the widespread D. pacifica, during the Pleistocene. The phylogenetic pattern obtained with the extant Ducula species showed that the Eastern Polynesian endemics do not form a monophyletic group, with the Pacific Imperial Pigeon D. pacifica sister species with good support to the Polynesian Imperial Pigeon D. aurorae. However, the impact of recent anthropic extinctions has been important for the imperial pigeons, more than for the smaller fruit doves, suggesting that several Ducula lineages might be missing today.

Anthropogenic habitat changes and the introduction of pigs, dogs, cats and rats have caused acatastrophic decline in the terrestrial biodiversity of Pacific archipelagos. At present, economicglobalization and an increased demand for timber are promoting industrial logging and plantationexpansion. Commercial logging can be sustainable but in practice it more often leads to landdegradation, especially on small flat islands. On large and mountainous islands, however, moremodest impacts can be expected as the narrowly endemic species tend to inhabit montane forestswhere logging is difficult. In this study we use ornithological data collected at different elevationsto assess the extent to which the avifauna of Makira, a large mountainous island in Melanesia, willbe affected by deforestation of the lowlands, most of which are under timber concessions. Our datasuggest that a majority of the endemic bird species use lowland forest to some extent and that thismay even apply to species hitherto associated with montane forest. If current commercial forestryprogrammes are continued, the forest habitat may be disturbed or lost over large parts of Makira,potentially undermining the natural resource base for the local subsistence economy, exacerbatingclimate change and threatening the integrity of one of the most important areas for biodiversityconservation on earth. Our study highlights the importance of understanding the habitat require-ments of endemic species and the urgency of establishing and effectively managing community-based protected areas in suitable lowland forests of the Pacific.Keywords: biodiversity, forestry, Galathea 3 expedition, montane fauna, Pacific Islands, SolomonIslands

Changes in mating signals among populations contribute to species formation. Often these signals involve a suite of display traits of different sensory modalities ("multimodal signals"); however, few studies have tested the consequences of multimodal signal divergence with most focusing on only a single divergent signal or suite of signals of the same sensory modality. Populations of the chestnut-bellied flycatcher Monarcha castaneiventris vary in song and plumage color across the Solomon Islands. Using taxidermic mount presentation and song playback experiments, we tested for the relative roles of divergent song and color in homotypic ("same type") recognition between one pair of recently diverged sister taxa (the nominate chestnut-bellied M. c. castaneiventris and the white-capped M. c. richardsii forms). We found that both plumage and song type influenced the intensity of aggressive response by territory-owners, with plumage color playing a stronger role. These results indicate that differences in plumage and song are used in homotypic recognition, suggesting the importance of multimodal signal divergence in the evolution of premating reproductive isolation.

Fruit traits that selectively deter vertebrate seed predators without affecting high-quality seed dispersers are said to exhibit directed deterrence. Directed deterrence has been criticized as being unlikely in natural systems, but has rarely been explicitly tested. We evaluated the potential for directed deterrence to explain the double-layered viscous fruit morphology and fruiting phenology of Terminalia impediens, a common canopy tree endemic to New Guinea. The large fleshy fruits of this tree are consumed and dispersed by cassowaries (Casuarius spp.) and are consumed and killed by palm cockatoos (Probosciger aterrimus). Fruit flesh in this tree species appears to function as a deterrent to seed predation by palm cockatoos; the fruits of T. impediens fall to the ground before ripening, and are avoided by palm cockatoos until after the flesh has rotted off the hard nut. We found that palm cockatoos are able to prey upon seeds from fruits without flesh on the forest floor more efficiently than they can consume seeds from unripe fruit still on the trees. Further, through foraging preference tests, we found that palm cockatoos largely ignore seeds within ripe fruit on the ground, but readily eat the seeds when the fruit flesh has been removed. Cassowaries consume the fruit whole, when ripe, and defecate seeds in piles away from parent trees, where seed predation rates are lower. These results challenge the prevailing view that fleshy fruits evolved in tight synchrony with high-quality seed dispersers and add support to the non-exclusive hypothesis that aspects of fruit fleshiness may also have evolved as a response to seed predation.

— We report new observational and specimen data on the avifauna of Kolombangara, Western Province, Solomon Islands. These data, collected from 3–9 October 1974 and 13–21 May 2004, and supplemented with more recent observations, represent the first comprehensive survey of this globally significant island since 1927. All encounters of montane species are reported along with select species accounts for notable lower-elevation species. Numerous observations presented here suggest avifauna even more unique than previously reported. For example, we confirm a probable resident form of Peregrine Falcon (Falco peregrinus) and report the first observations and collected materials for a Blue-faced Parrotfinch (Erythrura trichroa) from Kolombangara. We observed all of the island's high-elevation endemics and found their relative abundances and patterns of occurrence to be consistent with those of an intact montane avifauna. Our findings suggest that despite large-scale modification of lowland habitat, montan...

We describe the rules of primary flight-feather replacement for Pelagic Cormorants (Phalacrocorax pelagicus), and contrast the completeness of primary replacement in individuals from Asia and North America. In adult Pelagic Cormorants primary replacement is stepwise, with multiple waves of molt, each initiated at the innermost primary (P1), proceeding simultaneously toward the tip of the wing. Shugart and Rohwer's (1996) ontogenetic model for generating and maintaining stepwise primary replacement depended upon incomplete molts. In each new episode of molt, waves of primary replacement were thought to be initiated at P1 and at each arrested wave that had failed to replace all old feathers in the preceding molt. Because most adult Pelagic Cormorants from North America completely replace their primaries but maintain stepwise primary molts, the latter assumption must be relaxed. In contrast to the present-day situation in North America, Pelagic Cormorants from northeastern Asia have incomplete molts of their primaries, and may be forced to skip breeding in some years to clear their wings of overworn primaries. Young birds from Asia start the replacement of their juvenile primaries later than North American birds and replace more feathers simultaneously. Implicancias de la Muda Primaria Completa e Incompleta en la Historia de Vida de Phalacrocorax pelagicus Resumen. Describimos las reglas de reemplazo de plumas primarias para Phalacrocorax pelagicus y contrastamos la totalización del reemplazo de primarias entre individuos de Asia y América del Norte. En individuos adultos, el reemplazo de primarias ocurre en varias etapas, con múltiples secuencias de muda cada una iniciada en la primaria más interna (P1), procediendo simultáneamente hacia la punta del ala. El modelo ontogenético de Shugart y Rohwer (1996) para la generación y mantenimiento del reemplazo en etapas de las plumas primarias depende de mudas incompletas. Se pensaba que en cada nuevo episodio de muda las secuencias de reemplazo de primarias eran iniciadas en P1 y en cada punto de interrupción de la muda precedente que hubiera impedido el reemplazo de todas las plumas viejas. Debido a que la mayoría de los individuos adultos de P. pelagicus de Norteamérica reeemplazan completamente sus primarias pero aún lo hacen en etapas, la última suposición debe ser re-evaluada. En contraste con la situación actual en Norteamérica, individuos del noreste de Asia tienen mudas incompletas de sus primarias y pueden verse forzados a no reproducirse en algunos años para despojarse de la presencia de primarias desgastadas. Las aves juveniles de Asia comienzan el reemplazo de sus primarias más tarde y reemplazan más plumas simultáneamente que las aves de Norteamérica.

We provide the first comprehensive description of a bird community from a lowland rainforest site on a major island in the Solomon Islands. During two dry season visits (July 1997, June 1998) to the lower Garanga River valley on the island of Isabel, we recorded 65 resident and 6 migrant species of birds. We document relative abundances, habitat preferences, and foraging guilds for the members of the bird community. The Garanga River site sustains all but 11 of the 76 species of landbirds known from Isabel. Of those 11 species, four are small-island or beach specialists, three are montane, and four are of unknown status. Habitat heterogeneity, maintained largely by river dynamics, is a major contributor to avian diversity at the site. The avifauna is dominated by nonpasserines, especially parrots, pigeons, kingfishers, and hawks. The flightless rail Nesoclopeus woodfordi, previously regarded as rare and threatened with extinction, was common. We recorded Ixobrychus flavicollis, Falco severus, and Eudynamys scolopacea for the first time on Isabel. We also documented occurrence in the lowlands of Micropsitta finschii, Collocalia spodiopygia, Coracina caledonica, and Pachycephala pectoralis, four species previously thought to be confined to upper elevations on Isabel. The depauperate understory avifauna of the Garanga River site may be anthropogenic and could belie what otherwise seems to be an intact avifauna.

We examine the validity of Phalacrocorax [Stictocarbo] kenyoni, which was described by Siegel-Causey (1991) from the Aleutian Islands using midden remains and existing skeletal specimens. We emphasize a morphometric evaluation of the taxon using 224 skeletal specimens of North Pacific cormorants, but we also evaluate the qualitative characters originally used to characterize P. kenyoni. Principal components and discriminant function analyses of 14 skeletal characters failed to support the validity of the species. Similarly, all seven of the character states that Seigel-Causey described as unique to P. kenyoni also were found in P. pelagicus and P. urile. Thus, the three type specimens of P. kenyoni appear to be P. pelagicus. Although we could not confirm the validity of P. kenyoni, our morphometric analyses revealed that P. pelagicus individuals from the central Aleutians are smaller than those from surrounding populations.

Biologists have long used islands as natural laboratories for understanding the diversification of life. A conclusion from these studies — notably those of Ernst Mayr — is that life on far-flung archipelagos accumulates from a simple one-way flow of colonists from continents to islands. Filardi and Moyle set out to test this assumption by estimating the relationships of a pan-Pacific bird group, the monarch flycatchers that feature in Mayr's work, through space and time. Their molecular phylogenetic data show that the traditional idea of the islands as stepping stones, with species colonizing Australasia by island-hopping their way across the oceans, does not fit the facts. Instead, the diversity of life across the major Pacific archipelagos is the product of a single radiation involving colonization from islands to continents as well as vice versa. Oceanic islands have long served as natural laboratories for understanding the diversification of life1,2,3,4. In particular, the many thousands of islands spanning the tropical Pacific support an unparalleled array of terrestrial communities whose patterns of diversity contributed fundamental insights to the development of classical speciation and biogeographic theory4,5,6,7,8. Much of this work is founded on an assumption derived from traditional taxonomic approaches, namely that faunas on these widely separated archipelagos stem from a simple one-way, downstream flow of colonists from continents to islands2,4. Here we show, with the use of molecular phylogenetic data from one of the original bird families used to justify this assumption, that a diverse array of endemic island genera and species are the product of a single radiation that diversified across all major Pacific archipelagos in a non-stepping-stone fashion, and recently recolonized continental areas. The geographic scope and lineage-specific approach of this study reveal evolutionary patterns long obscured by traditional taxonomic surveys and indicate that widely dispersed archipelagos can be sources of biological diversity.

Systematic relationships among monarch flycatchers (genus Monarcha) are poorly understood despite dramatic patterns of morphological differentiation that have long attracted the attention of evolutionary biologists. With sequence data from the mitochondrial ND2 gene and Control Region, we produced a phylogenetic hypothesis for evolutionary relationships within Monarcha and among the biogeographically complex Solomon Island endemics. Outgroup analyses contradicted monophyly of the genus by imbedding a representative of the genus Clytorhynchus within one of two major clades recovered within Monarcha. These two monarch clades generally correspond with ecological and morphological distinctions, suggesting the genus may warrant revision pending the inclusion of taxa currently allied with Clytorhynchus (e.g., Neolalage spp.). Maximum likelihood reconstructions support monophyletic groupings of the two endemic Solomon Island monarch radiations, however, two currently recognized superspecies (Monarcha manadensis and M. melanopsis) were polyphyletic and paraphyletic, respectively. Interestingly, molecular and morphological differentiation were strikingly decoupled among several Solomon Island endemics and between migratory and non-migratory forms of Monarcha trivirgatus in eastern Australia, suggesting morphological evolution has masked the true history of speciation in these groups. This initial phylogeny provides a novel platform for ongoing exploration of the history underlying dramatic patterns of geographic variation among tropical Pacific flycatchers.