In vitro regeneration of apomictic bluestem grasses

Explants from immature inflorescences of four genotypes of Old World bluestem grasses, (Bothriochloa spp.), produced callus tissue on Linsmaier and Skoog (RM) and 1/2 Murashige and Skoog (1/2 MS) media containing high levels of growth regulators. Callus masses were composed of two distinct tissue types, one a compact, white, embryogenic portion (E calli), the other soft, translucent, gelatinous and nonembryogenic (NE calli). When transferred to medium with a reduced level of 2,4-D, and/or supplemented with zeatin, E callus underwent further organization culminating in shoot production. Light and scanning electron microscopy confirmed the embryogenic pathway of differentiation. Genotype significantly affected callus induction frequency and the number of plants regenerated. The RM medium induced more explants to initiate callus compared to the 1/2 MS medium. Age of the inflorescence explant, as indicated by size, was critical for callus induction. Inflorescences with racemes 8 mm in length were superior to older ones. Five-hundred-twenty-two plantlets were regenerated and grown to maturity.     

Social networks based on frequency of roost cohabitation do not reflect association rates of Myotis lucifugus within their roosts

Bats are a group of mammals well known for forming dynamic social groups. Studies of bat social structures are often based upon the frequency at which bats occupy the same roosts because observing bats directly is not always possible. However, it is not always clear how closely bats occupying the same roost associate with each other, obscuring whether associations result from social relationships or factors such as shared preferences for roosts. Our goal was to determine if bats cohabitating buildings were also found together inside roosts by using anti‐collision technology for PIT tags, which enables simultaneous detection of multiple tags. We PIT‐tagged 293 female little brown myotis (Myotis lucifugus) and installed antennas within two buildings used as maternity roosts in Yellowstone National Park. Antennas were positioned at roost entryways to generate cohabitation networks and along regions of attic ceilings in each building to generate intraroost networks based on proximity of bats to each other. We found that intraroost and cohabitation networks of buildings were significantly correlated, with the same bats tending to be linked in both networks, but that bats cohabitating the same building often roosted apart, leading to differing assessments of social structure. Cohabitation rates implied that bats associate with a greater number of their roost‐mates than was supported by observations within the roost. This caused social networks built upon roost cohabitation rates to be denser, smaller in diameter, and contain nodes with higher average degree centrality. These results show that roost cohabitation does not reflect preference for roost‐mates in little brown myotis, as is often inferred from similar studies, and that social network analyses based on cohabitation may provide misleading results.     

Isolation and characterization of polymorphic microsatellite loci for the study of paternity and population structure in the little penguin Eudyptula minor

We isolated and characterized eight novel microsatellite loci in the little penguin Eudyptula minor, using nonradioactive polymerase chain reaction‐based techniques to screen GA and GAAA repeats from enriched genomic DNA libraries. All eight loci were polymorphic and seven were variable in our main study population (mean H_E = 0.613, mean N_A = 7.14). Cross‐amplification using a microsatellite primer developed in Spheniscus demersus (African penguin) yielded one additional polymorphic locus. This locus combined with six of the little penguin loci is suitable for paternity assignment in little penguins (exclusion probability for seven unlinked loci = 0.993).     

西藏昌都发现白鹭

<正>2013年9月至2014年6月,笔者在西藏昌都市八宿县、贡觉县、芒康县和昌都县先后观察并拍摄到白鹭(Egretta garzetta),为西藏首次发现。2013年9月29日,在八宿县然乌镇政府后方的湖边(29°30′17.28″N,96°45′25.44″E,海拔3 934 m),观察到2只白鹭成鸟,其体形纤瘦,全身羽毛白色,头部无羽冠,肩、背和前胸的蓑状羽也消失,呈冬羽特征;虹膜为黄色;眼先黄绿;嘴黑色,但嘴裂处及下嘴基部显淡黄色;胫与跗跖部黑色,趾黄绿色。2014年5月至6月,     

Arctic warming: nonlinear impacts of sea‐ice and glacier melt on seabird foraging

Arctic climate change has profound impacts on the cryosphere, notably via shrinking sea‐ice cover and retreating glaciers, and it is essential to evaluate and forecast the ecological consequences of such changes. We studied zooplankton‐feeding little auks (Alle alle), a key sentinel species of the Arctic, at their northernmost breeding site in Franz‐Josef Land (80°N), Russian Arctic. We tested the hypothesis that little auks still benefit from pristine arctic environmental conditions in this remote area. To this end, we analysed remote sensing data on sea‐ice and coastal glacier dynamics collected in our study area across 1979–2013. Further, we recorded little auk foraging behaviour using miniature electronic tags attached to the birds in the summer of 2013, and compared it with similar data collected at three localities across the Atlantic Arctic. We also compared current and historical data on Franz‐Josef Land little auk diet, morphometrics and chick growth curves. Our analyses reveal that summer sea‐ice retreated markedly during the last decade, leaving the Franz‐Josef Land archipelago virtually sea‐ice free each summer since 2005. This had a profound impact on little auk foraging, which lost their sea‐ice‐associated prey. Concomitantly, large coastal glaciers retreated rapidly, releasing large volumes of melt water. Zooplankton is stunned by cold and osmotic shock at the boundary between glacier melt and coastal waters, creating new foraging hotspots for little auks. Birds therefore switched from foraging at distant ice‐edge localities, to highly profitable feeding at glacier melt‐water fronts within <5 km of their breeding site. Through this behavioural plasticity, little auks maintained their chick growth rates, but showed a 4% decrease in adult body mass. Our study demonstrates that arctic cryosphere changes may have antagonistic ecological consequences on coastal trophic flow. Such nonlinear responses complicate modelling exercises of current and future polar ecosystem dynamics.