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Islands are separated by natural barriers that prevent gene flow between terrestrial populations and promote allopatric diversification. Birds in the South Pacific are an excellent model to explore the interplay between isolation and gene flow due to the region’s numerous archipelagos and well-characterized avian communities. The wattled honeyeater complex (Foulehaio spp.) comprises three allopatric species that are widespread and common across Fiji, Tonga, Samoa, and Wallis and Futuna. Here, we explored patterns of diversification within and among these lineages using genomic and morphometric data. We found support for three clades of Foulehaio corresponding to three recognized species. Within F. carunculatus, population genetic analyses identified nine major lineages, most of which were composed of sub-lineages that aligned nearly perfectly to individual island populations. Despite genetic structure and great geographic distance between populations, we found low levels of gene flow between populations in adjacent archipelagos. Additionally, body size of F. carunculatus varied randomly with respect to evolutionary history (as Ernst Mayr predicted), but correlated negatively with island size, consistent with the island rule. Our findings support a hypothesis that widespread taxa can show population structure between immediately adjacent islands, and likely represent many independent lineages loosely connected by gene flow.

Native forests increasingly have been reduced to remnant fragments on many Pacific islands. Island and continental ecosystems differ in a number of ways that may increase conservation value of such forest fragments on islands. However, few studies have examined performance of tree populations in Polynesian forest fragments. We tested potential conservation value of the largest contiguous patch of lowland lava flow forest on Tutuila, American Samoa, by determining uniqueness, potential vulnerability, and possible viability of the tree community therein. We recorded 1,186 trees ≥ 10 cm dbh (diameter at breast height) from 37 species in 12 transects (each 10 m wide) running from edge to edge across the forest, as well as 1,332 seedlings and 991 saplings within 62 miniplots (each 25 m2). Locations within the forest of all 462 trees ≥ 30 cm dbh, of the 10 most dominant species, were then plotted. The most dominant tree species was Pometia pinnata. Similarity indices between the study site and other pr...

Pteropids are large, highly mobile bats that are distributed widely across islands of the Pacific and Indian Oceans, southern Asia, and Australia. Dispersal behaviors and colonization patterns of pteropid species among oceanic islands are poorly known. In the southern Pacific, Pteropus samoensis and P. tonganus have partially overlapping ranges, existing in sympatry on the Samoan and Fijian archipelagos. These species exhibit differences in morphology and roosting behavior, with P. samoensis being smaller and tending to roost solitarily or in small groups. Here, we use genetic data to explore whether these species also exhibit differences with regard to patterns of population genetic structure within and between these archipelagos. Phylogenetic analyses of mitochondrial DNA are consistent with earlier morphological recognition of different subspecies of P. samoensis on the Samoan vs. Fijian archipelagos. Patterns of mtDNA haplotype sharing suggest that P. tonganus experiences restricted gene flow between,...

Small mammals were surveyed along an elevational transect on Mount Isarog (summit at 1,966 m) in southeastern Luzon, Philippines. Removal trapping was conducted at six sites ranging from remnant dipterocarp forest (475 m) to mossy forest (1,750 m). A total of 255 small mammals was captured in 9,001 trap nights. Species captured were one shrew ( Crocidura grayi ) and seven rodents ( Apomys musculus, Apomys cf. microdon, Archboldomys luzonensis, Batomys sp., Chrotomys gonzalesi, Rattus everetti , and Rhynchomys isarogensis ). Five species are nocturnal, one diurnal, and two have variable diel activity. On the basis of trap success with two kinds of bait, analysis of stomach contents, and captive feeding trials, we recognize four trophic groups: omnivorous (three species), insectivorous (two species), granivorous-frugivorous (one species), and vermivorous (two species). Species richness and relative abundance followed predicted patterns of increase with elevation. Four species endemic to Mount Isarog were found only at high elevations.

Background Differences among species and among years in reproductive seasonality (the tendency for clusters of events to fall at approximately the same point in each year) and synchrony (amount of clustering of events within a year) have been intensively studied in bats, but are difficult to assess. Here, we use randomization methods with circular statistics to test for synchrony and seasonality of reproduction in three species of nectarivorous megachiropteran bats on Negros Island in the central Philippines. Results In Rousettus amplexicaudatus, estimated dates of birth were both highly synchronous and highly seasonal. In Macroglossus minimus, estimated births were seasonal and significantly clustered within years, but within each year births occurred over a broad period, indicating a low level of synchrony. In Eonycteris spelaea, estimated births were also seasonal and had statistically significant synchrony, with birth periods within years intermediate in synchrony between R. amplexicaudatus and M. minimus. All three species had a similar seasonal pattern, with two birth periods in each year, centered on March or April and August or September. In one species, R. amplexicaudatus, primigravid females (in their first pregnancy) produced their young in June and July, a birth period significantly different in timing from the two birth periods of older adult females. This more conservative pattern of young females may allow higher survival of parents and offspring at cost of a lost reproductive opportunity. There was weak evidence that in some years primigravid females of M. minimus might differ in timing from older adults. There were few significant differences in reproductive timing among different years, and those differences were generally less than two weeks, even during a severe drought in the severe el Niño of 1983. Conclusion The results suggest that these species follow an obligately seasonal pattern of reproductive timing with very little phenotypic plasticity. The resampling methods were sensitive to differences in timing of under two weeks, in some cases, suggesting that these are useful methods for analyses of seasonality in wild populations of bats.

Background Differences among species and among years in reproductive seasonality (the tendency for clusters of events to fall at approximately the same point in each year) and synchrony (amount of clustering of events within a year) have been intensively studied in bats, but are difficult to assess. Here, we use randomization methods with circular statistics to test for synchrony and seasonality of reproduction in three species of nectarivorous megachiropteran bats on Negros Island in the central Philippines.

A number of bats are known to use modified leaves or 'tents' as daytime roosting sites. This behaviour has been reported for 14 species of phyllostomids in the genera Artibeus, Ectophylla, Mesophylla, Uroderma, and Vampyressa (Brooke 1987, Timm 1987), and two species in the pteropodid genus Cynopterus (Goodwin 1979, Phillips 1924, Sandhu 1984). Here we report tentroosting by the Oriental house bat, Scotophilus kuhlii Leach (= S. temminckii (Horsfield)), in the Philippines. This is the first record of such behaviour for a vespertilionid. On the evening of 20 May 1987, on the campus of Ateneo de Manila University, Quezon City, Luzon Island (140 38' N, 1210 3' E; elev. 50 m) we observed several large microchiropterans emerging from the crown of a fan palm, Livistona rotundifolia (Lam.) Mart. The palm was about 12 m in height, and had approximately 35 mature fronds. It was located at the edge of a grassy lawn at the top of a fairly steep slope. Surrounding vegetation consisted of shrubs and small trees. The crown was in the open and conspicuously higher than most of the surrounding vegetation or buildings. Subsequent examination of the crown with binoculars during the day revealed that many of the older fronds had been modified to form tents (Figure 1). A number of microchiropteran bats were observed roosting under two of the modified fronds. Several other fronds may also have sheltered bats, but were too tightly folded for visual confirmation. Three tents were clearly unoccupied. Fifteen to twenty Scotophilus kuhlii were flushed from one of the

Trapping and netting of small mammals on a land-bridge island (Leyte) and on an oceanic island (Negros) revealed similar patterns of elevational change in abundance and species richness. Fruit bats (Pteropodidae) reached their greatest local densities in agricultural areas, and were least abundant in montane mossy forest. The fruit bats found to be common in agri-cultural areas are widespread in Southeast Asia: in contrast, species that were most common in forested areas are Philippine endemics. Fruit bat abundance was greater on the oceanic island than on the land-bridge island. Trappable small mammals (families Soricidae and Muridae) showed no change in species richness with increasing elevation, but did show a gradual increase in overall abundance. Even though the oceanic island was depauperate of non-volant mammal species, it had the higher abundance of non-volant mammal individuals; however, this may have been due primarily to differences associated with the elevation of sampling sites. Murid rodents at the higher elevations on Leyte tend to be those that are members of the old endemic group of Philippine murids, and those at lower elevations tend to be members of more recently arrived groups. Most non-volant small mammals at all elevations on the oceanic Negros, and in agri-cultural areas on Leyte, are non-native species.