Variation in developmental arrest among male orangutans: a comparison between a Sumatran and a Bornean population
Dunkel LP, Arora N, van Noordwijk MA, Atmoko SS, Putra AP, Krützen M, van Schaik CP
Frontiers in Zoology 2013, 10:12 (19 March 2013)
The presence of two sexually active male morphs with different reproductive tactics in a single species is rare among mammals. The most striking case of bimaturism among primates is exhibited by the orangutan (Pongo spp), in which one adult morph, the unflanged male, irreversibly develops into another one, the flanged form, but may remain arrested in the unflanged state for many years. However, it has been suggested that such arrest is less common among Bornean orangutans (Pongo pygmaeus) compared to Sumatrans (Pongo abelii). To investigate this possible inter-specific difference we compared both the number of developing males and the ratios of the two male morphs at two long-term study sites, Suaq Balimbing on Sumatra and Tuanan on Borneo.
First, we observed a significantly greater number of flanged than unflanged males per month in the Tuanan study area, whereas the opposite pattern held at Suaq. Second, the same contrast held for the total number of identified individuals over the study, with more flanged than unflanged males at Tuanan and the opposite at Suaq. These differences were mainly due to transient males. For Tuanan, the identification results were confirmed by detailed genetic analyses. Finally, we recorded a higher proportion of unflanged males that became flanged during any given year at Tuanan than at Suaq.
These results show that developmental arrest is far more common at Suaq than at Tuanan. Preliminary comparisons suggest that this is a general contrast between the island taxa of orangutans and should help efforts to identify the function and proximate control of developmental arrest in orangutan males.
Inger Winkelmann, Paula F. Campos, Jan Strugnell, Yves Cherel, Peter J. Smith, Tsunemi Kubodera, Louise Allcock, Marie-Louise Kampmann, Hannes Schroeder, Angel Guerra, Mark Norman, Julian Finn, Debra Ingrao, Malcolm Clarke, and M. Thomas P. Gilbert
Mitochondrial genome diversity and population structure of the giant squid Architeuthis: genetics sheds new light on one of the most enigmatic marine species
Proc. R. Soc. B May 22, 2013 280 1759 20130273; doi:10.1098/rspb.2013.0273 1471-2954
Despite its charismatic appeal to both scientists and the general public, remarkably little is known about the giant squid Architeuthis, one of the largest of the invertebrates. Although specimens of Architeuthis are becoming more readily available owing to the advancement of deep-sea fishing techniques, considerable controversy exists with regard to topics as varied as their taxonomy, biology and even behaviour. In this study, we have characterized the mitochondrial genome (mitogenome) diversity of 43 Architeuthis samples collected from across the range of the species, in order to use genetic information to provide new and otherwise difficult to obtain insights into the life of this animal. The results show no detectable phylogenetic structure at the mitochondrial level and, furthermore, that the level of nucleotide diversity is exceptionally low. These observations are consistent with the hypotheses that there is only one global species of giant squid, Architeuthis dux (Steenstrup, 1857), and that it is highly vagile, possibly dispersing through both a drifting paralarval stage and migration of larger individuals. Demographic history analyses of the genetic data suggest that there has been a recent population expansion or selective sweep, which may explain the low level of genetic diversity.
Judith Brown, Paul Brickle, Beth E. Scott, Investigating the movements and behaviour of Patagonian toothfish (Dissostichus eleginoides Smitt, 1898) around the Falkland Islands using satellite linked archival tags, Journal of Experimental Marine Biology and Ecology, Volume 443, May 2013, Pages 65-74, ISSN 0022-0981, 10.1016/j.jembe.2013.02.029.
Knowledge of the seasonal movements of Patagonian toothfish is an essential component for understanding their ecology and fisheries management. As only one demersal longline vessel participates in this fishery in Falkland’s waters, over a vast slope area, the use of conventional tags to provide data on migration or stock assessment is not viable. In contrast, archival pop-up tags have enabled the examination of toothfish movements without having to recapture tagged individuals with reasonably high success rates. Patagonian toothfish (n = 30, > 127 cm LT) were tagged with pop-up satellite tags between 19/09/2007 and 7/07/2010 in the South Atlantic close to the Falkland Islands. The data from 16 tags that successfully released and uploaded data (plus one recaptured fish) revealed strong site fidelity, with eleven toothfish moving less than 50 km from their release position over a 6 month period. Furthermore, depth data inferred three behavioural patterns showing seasonal bathymetric movements, foraging and spawning activities. Coinciding with the reported spawning months of July–August, spawning movements were recorded with fish moving repeatedly into shallower waters of 900–1200 m. Foraging behaviours were also evident with differences in the scale of foraging movement related to fish size, possibly linked to a shift in diet with size. Fish were found to move deeper during December and these are potentially post-spawning movements allowing the fish to take advantage of different prey availability.
Armstrong, J. B., Bond, M. H. (2013), Phenotype flexibility in wild fish: Dolly Varden regulate assimilative capacity to capitalize on annual pulsed subsidies. Journal of Animal Ecology. doi: 10.1111/1365-2656.12066
1. Large digestive organs increase rates of energy gain when food is plentiful but are costly to maintain and increase rates of energy loss when food is scarce. The physiological adaptations to this trade-off differ depending on the scale and predictability of variation in food abundance.
2. Currently, there is little understanding of how animals balance trade-offs between the cost and capacity of the digestive system in response to resource pulses: rare, ephemeral periods of resource superabundance. We investigated the physiological and behavioural tactics of the fish Dolly Varden (Salvelinus malma) that rear in watersheds with low in situ productivity, but experience annual resource pulses from the spawning migrations of Pacific salmon. The eggs of Pacific salmon provide high-energy food for Dolly Varden.
3. Dolly Varden sampled 6 weeks prior to the resource pulse exhibited atrophy of the stomach, pyloric caeca, intestine and liver. Throughout the portion of the growing season prior to the resource pulse, fish exhibited empty stomachs, low indices of energy condition and muscle isotope signatures reflecting the previous resource pulse.
4. During the resource pulse, Dolly Varden exhibited large digestive machinery, gorged on salmon eggs and rapidly stored energy in fat reserves, somatic growth and gonad development. Dolly Varden appeared to achieve nearly their entire annual energy surplus during the ∼5-week period when sockeye salmon spawn.
5. Digestive flexibility provides Dolly Varden the energy efficiency required to survive and reproduce when resource abundance is concentrated into an annual pulse that is predictable, yet highly ephemeral. Although fish are known to incur extremely variable energy budgets, our study is one of the first to document digestive flexibility in wild fish. Our study emphasizes that fish can rely heavily on rare, high-magnitude foraging opportunities. Human actions that attenuate spikes in food abundance may have stronger than anticipated effects on consumer energy budgets.
Clauss, M., Dittmann, M. T., Müller, D. W. H., Meloro, C. and Codron, D. (2013), Bergmann′s rule in mammals: a cross-species interspecific pattern. Oikos. doi: 10.1111/j.1600-0706.2013.00463.x
Although Bergmann’s rule – stating that among closely related species, the bigger ones will inhabit the colder climates/higher latitudes – was formulated for inter-specific comparisons, most analyses that tested this pattern in mammals were on an intra-specific level. To date, no large-scale taxonomy-driven cross-species evaluation of the pattern predicted by Bergmann exists. Here we show, in a dataset comprising 3561 mammal species from 26 orders, that while there is no significant correlation between latitude and body mass using conventional methods, this correlation is highly significant when the phylogenetic structure of the dataset is accounted for, thus supporting Bergmann’s claim that the rule only applies to closely related species. Analyses of different subsets indicate that the Bergmann’s rule is evident across a variety of latitude ranges. In many taxonomic subsets, when analysed alone, there is no significant correlation between body mass and latitude. In combination with both the significant relationship in the overall dataset and with results of intra-specific analyses from the literature, this suggests that Bergmann’s rule describes a fundamental principle within mammals, but that its expression has been modified by a variety of factors during mammalian diversification yet to be resolved.
How Stressed are Birds in an Urbanizing Landscape? Relationships Between the Physiology of Birds and Three Levels of Habitat Alteration
Carlos A. Chávez-Zichinelli, Ian Macgregor-Fors, Javier Quesada, Patricia Talamás Rohana, Marta C. Romano, Ricardo Valdéz, and Jorge E. Schondube
The Condor 2013 115 (1), 84-92
In this study we measured two physiological traits (levels of corticosterone and immunoglobulin) in two species of landbirds, the Canyon Towhee (Melozone fusca) and Inca Dove (Columbina inca), occupying three degrees of human alteration of a subtropical mountain landscape: forest edges, croplands, and urban sites. We found that both physiological variables differed by species and habitat condition. In both species, corticosterone concentration was significantly higher in croplands. But immunoglobulin concentration behaved differently, in C. inca being highest at urban sites, where in M. fusca it was lowest. Contrary to expectation, we only found one strong significant relationship between both physiological variables: M. fusca in urban areas. Our results suggest that 30% of the towhees captured in urban areas are under chronic stress. Results for body condition support this hypothesis, as the condition of towhees in urban areas was poorer, suggesting physiological vulnerability. Although we expected the density of both species to be high in urban areas because of the amount and predictability of resources, we found a significantly lower density of M. fusca in urban areas, suggesting that the habitat variables influencing the physiological condition of M. fusca affected its population density. In summary, our results suggest that a substantial proportion of Canyon Towhees in the urban area studied have physiological limitations, while the Inca Dove seems to have an appropriate physiological response despite low values for body condition in urban areas.
A Spatial Analysis of Factors Affecting Nesting Success of Shorebirds in the Canadian Prairies
Mary E. Garvey, Erica Nol, David W. Howerter, and Llwellyn M. Armstrong
The Condor 2013 115 (1), 58-66
Conversion of natural grassland to cropland has been postulated as a cause for population declines among grassland birds. We evaluated nest-site habitat characteristics and landscape composition for three species of prairie-breeding shorebirds nesting across the agricultural landscape of prairie Canada. Nests of the Upland Sandpiper (Bartramia longicauda) and Willet (Tringa semipalmata) were found disproportionately in natural grazed (57%) or natural idled (21%) patches, whereas Marbled Godwit (Limosa fedoa) nests were in habitats in proportion to their availability on the landscape. We examined multiple landscape variables (proportions of crop, natural idled, natural grazed, and wetland habitats, edge density, and patch area) across a broad geographic scale, using relatively large samples of nests, and found no strong relationships. Neither nest-site habitat characteristics nor landscape-level effects influenced daily survival rates of Upland Sandpiper or Willet nests. Variation in landscape composition at three different spatial scales (200, 600, and 2000 m) also did not influence daily nest-survival rates. To adequately inform land-use management programs aimed at shorebird conservation, further research should examine site-selection patterns and characteristics of nest sites that maximize survival of chicks and adults during subsequent stages in reproduction.
Breeding Performance of the Grasshopper Buzzard (Butastur rufipennis) in a Natural and A Human-Modified West African Savanna
Ralph Buij, Kim Kortekaas, Roderick R. D. Van Krimpen, Rien Van Wijk, Saskia Van Der Zanden, Hans H. De Iongh, Ignas M. A. Heitkönig, Geert R. De Snoo, and Jan Komdeur
The Condor 2013 115 (1), 47-57
Few studies have examined raptor reproduction in response to land-use change in sub-Saharan Africa, hampering conservation efforts to address regional declines. To further our understanding of mechanisms underlying the dramatic declines of West African raptors, we examined the relationship between environmental conditions, nest density, and measures of reproduction in the Grasshopper Buzzard (Butastur rufipennis). Analyses were based on 244 nest sites divided between transformed and natural habitat in northern Cameroon. At the landscape scale, nest density increased with the density of preferred nest trees. Nests were more widely spaced in transformed than in natural habitat. Dispersion was adjusted to differences in availability of small mammals, which was negatively associated with distance to nearest neighbor, and in the area under cultivation, which was positively associated with distance to nearest neighbor. Productivity was positively associated with rainfall, canopy shielding the nest, availability of grasshoppers, and the nest’s visibility from ground level; canopy shielding, grass cover, rainfall, and distance to nearest neighbor were positively associated with nest success. In natural habitat, losses of eggs and nestlings to natural predators were greater than in transformed habitats, while losses through human predation were small. Productivity and nest success were unaffected by land use because of the opposing effects of greater predation pressure, closer spacing of nests, and more food in natural habitat than in transformed habitat. Thus transformed habitat may provide adequate breeding habitat for the Grasshopper Buzzard, but declining rainfall and intensifying anthropogenic land use are likely to affect future reproductive output.
Genetic Structure of the Common Eider in the Western Aleutian Islands Prior to Fox Eradication
Sarah A. Sonsthagen, Sandra L. Talbot, Robert E. Wilson, Margaret R. Petersen, Jeffrey C. Williams, G. Vernon Byrd, and Kevin G. McCracken
The Condor 2013 115 (1), 28-39
Since the late 18th century bird populations residing in the Aleutian Archipelago have been greatly reduced by introduced arctic foxes (Alopex lagopus). We analyzed data from microsatellite, nuclear intron, and mitochondrial (mtDNA) loci to examine the spatial genetic structure, demography, and gene flow among four Aleutian Island populations of the Common Eider (Somateria mollissima) much reduced by introduced foxes. In mtDNA, we found high levels of genetic structure within and between island groups (ΦST = 0.643), but we found no population subdivision in microsatellites or nuclear introns. Differences in genetic structure between the mitochondrial and nuclear genomes are consistent with the Common Eider’s breeding and winter biology, as females are highly philopatric and males disperse. Nevertheless, significant differences between islands in the mtDNA of males and marginal significance (P = 0.07) in the Z-linked locus Smo 1 suggest that males may also have some level of fidelity to island groups. Severe reduction of populations by the fox, coupled with females‘ high philopatry, may have left the genetic signature of a bottleneck effect, resulting in the high levels of genetic differentiation observed in mtDNA (ΦST = 0.460–0.807) between islands only 440 km apart. Reestablishment of the Common Eider following the fox’s eradication was likely through recruitment from within the islands and bolstered by dispersal from neighboring islands, as suggested by the lack of genetic structure and asymmetry in gene flow between Attu and the other Near Islands.
Multi-Scale Habitat Selection of the Endangered Hawaiian Goose
Christina R. Leopold and Steven C. Hess
The Condor 2013 115 (1), 17-27
After a severe population reduction during the mid-20th century, the endangered Hawaiian Goose (Branta sandvicensis), or Nēnē, has only recently re-established its seasonal movement patterns on Hawai‘i Island. Little is currently understood about its movements and habitat use during the nonbreeding season. The objectives of this research were to identify habitats preferred by two subpopulations of the Nēnē and how preferences shift seasonally at both meso-and fine scales. From 2009 to 2011, ten Nēnē ganders were outfitted with 40-to 45-g satellite transmitters with GPS capability. We used binary logistic regression to compare habitat use versus availability and an information-theoretic approach for model selection. Meso-scale habitat modeling revealed that Nēnē preferred exotic grass and human-modified landscapes during the breeding and molting seasons and native subalpine shrubland during the nonbreeding season. Fine-scale habitat modeling further indicated preference for exotic grass, bunch grass, and absence of trees. Proximity to water was important during molt, suggesting that the presence of water may provide escape from introduced mammalian predators while Nēnē are flightless. Finescale species-composition data added relatively little to understanding of Nēnē habitat preferences modeled at the meso scale, suggesting that the meso-scale is appropriate for management planning. Habitat selection during our study was consistent with historical records, although dissimilar from more recent studies of other subpopulations. Nēnē make pronounced seasonal movements between existing reserves and use distinct habitat types; understanding annual patterns has implications for the protection and restoration of important seasonal habitats.
Sap Consumption by the White-Fronted Woodpecker and its Role in Avian Assemblage Structure in Dry Forests
M. Gabriela Núñez Montellano, Pedro G. Blendinger, and Leandro Macchi
The Condor 2013 115 (1), 93-101
The White-fronted Woodpecker (Melanerpes cactorum) drills holes in branches and trunks to feed on sap flows, providing an energy-rich food resource for other birds. Here we describe ecological and behavioral traits of the White-fronted Woodpecker related to its sap-feeding habits in the semiarid Chaco of Argentina and explore the structure of the avian assemblage in relation to the sap resource. Sap consumption by the White-fronted Woodpecker and other sap-feeding species was strongly seasonal and positively associated with periods of resource scarcity. The White-fronted Woodpecker actively defended the sap wells from smaller birds. Specialist and facultative nectarivores that assimilate sucrose at a high rate represented an important proportion of sap-feeding birds. In this system of woodpecker, sap, and other sap-feeding species, each species‘ consumption depends on its physiological and behavioral characteristics as well as on the availability of other food in the surrounding environment.
Post-Fledging Dispersal Timing and Natal Range Size of Two Songbird Species in an Urbanizing Landscape
Ian J. Ausprey and Amanda D. Rodewald
The Condor 2013 115 (1), 102-114
Little is known about juvenile birds‘ movements during the post-fledging stage of development, especially in urbanizing landscapes where novel ecological factors such as invasive plants and altered densities of conspecifics might influence fledglings‘ use of space. In 2008 and 2009 we used radio telemetry to track movements of fledgling Northern Cardinals (Cardinalis cardinalis; n = 45) and Acadian Flycatchers (Empidonax virescens; n = 31) in a network of riparian forests embedded within a rural-to-urban gradient of landscapes in central Ohio. A subset of 20 cardinals and 11 flycatchers survived sufficiently long for subsequent analyses of their movement. Natal ranges of juvenile cardinals decreased in size with proximity to fragment edge, and fledglings moved less from nests surrounded by extensive cover of the Amur honeysuckle (Lonicera maackii). Conversely, the size of natal ranges of juvenile flycatchers was positively related to honeysuckle cover. During the study period, 70% of the cardinals dispersed from natal sites at an average of 47 ± 2 days after fledging. Dispersal patterns of individual cardinals varied; birds dispersed locally within their natal forest fragment or made extended movements into the surrounding landscape matrix. In our study area the density of cardinals increased with urbanization, and fledglings tended to disperse later from sites of high densities of conspecifics. Collectively, our results suggest that while novel ecological factors associated with urbanization may influence fledglings‘ movements, patterns are likely species-specific.
Songbird use of Floodplain and Upland Forests Along the Upper Mississippi River Corridor During Spring Migration
Eileen M. Kirsch, Patricia J. Heglund, Brian R. Gray, and Patrick Mckann
The Condor 2013 115 (1), 115-130
The Upper Mississippi River is thought to provide important stopover habitat for migrating landbirds because of its north-south orientation and floodplain forests. The river flows through the Driftless Area of southwestern Wisconsin and southeastern Minnesota where forests are plentiful, yet forests of the floodplain and Driftless Area uplands differ greatly in landscape setting, tree species composition, and topography. We compared landbird assemblages in these upland and floodplain forests over three springs, 2005–2007, using line-transect surveys at randomly selected areas in and within 16 km of the floodplain. We found more species of both transient and locally breeding migrants per survey in floodplain than in upland forest. Detections of transient neotropical migrants did not differ statistically by habitat. Detections of locally breeding neotropical and temperate-zone migrants and transient temperate-zone migrants were greater in floodplain than in upland forest. Between floodplain and upland forest, assemblages of locally breeding species, including neotropical and temperate-zone migrants (of which some individuals were in transit), differed substantially, but assemblages of transients (including both neotropical and temperate-zone migrants) did not differ as much. Only two species of transient migrants had clear affinities for floodplain forest, and none had an affinity for upland forest, whereas most locally breeding migrants had an affinity for either upland or floodplain forest. Within each spring, however, detections of transient neotropical migrants shifted from being greater in floodplain to greater in upland forests. This intraseasonal shift may be related to the phenology of certain tree species.
Species Limits and Clinal Variation in a Widespread High Andean Furnariid: The Buff-Breasted Earthcreeper (Upucerthia validirostris)
Juan I. Areta and Mark Pearman
The Condor 2013 115 (1), 131-142
The Buff-breasted Earthcreeper (Upucerthia validirostris) is endemic to western Argentina, and the Plain-breasted Earthcreeper (U. jelskii, including subspecies saturata in the north and pallida in the south), ranges from northern Peru to northwestern Argentina. They have been considered subspecies, as constituents of a superspecies, and as different species. From north to south, a morphocline, involving an increase of rustiness of the plumage and of 15% in bill length, 10% in wing length, and 20% in tail length, links jelskii to validirostris. The cline linking jelskii and pallida is gradual, over 1800 km; that between pallida and validirostris is steep, over 80 km. The northernmost record of validirostris is from the northern Calchaquies Valley, Salta, northwestern Argentina, a valley surrounded by mountains of up to 6300 m above sea level through which the lowest pass is at over 4900 m, forming a barrier between validirostris and the southernmost record of pallida to the north. The song, continuous song, duet, and call of validirostris are structurally indistinguishable from those of jelskiilpallida and from the single available recorded song of saturata. In all playback experiments, validirostris answered by approaching and vocalizing to voices of validirostris and jelskii /pallida and vice versa. Treatment of validirostris as a single species is warranted, and three subspecies can be tentatively recognized: southern validirostris (large, rufescent birds with buff bellies restricted to Argentina), central and northern jelskii (small, pale birds ranging from northwestern Argentina to central Peru), and northern saturata (small, dark, and brownish birds in northern central Peru).