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71.
Persistence of genetic variation in recolonized Tsuga canadensis (Eastern hemlock) populations following historic forest clearance
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Candice Y. Lumibao Marissa Gaskill Kelsey Flood Jason S. McLachlan 《Plant Species Biology》2016,31(1):73-79
The recovery of genetic variation in newly recolonized populations is an important concern in forest conservation genetics. We examined the potential recovery of genetic diversity and changes to genetic structure in populations of the wind‐pollinated species Tsuga canadensis that naturally regenerated following the extensive 19th century regional forest clearance for agriculture in west‐central Massachusetts. We genotyped 264 individuals across six microsatellite loci and compared levels and patterns of genetic variation between primary forests (forests that were logged but never cleared) and secondary forests (stands that were recolonized following agricultural abandonment). We found no significant reductions in genetic diversity in secondary forests (AR = 5.450; HS = 0.718) compared to primary forests (AR = 5.742; HS = 0.730). Moreover, the population genetic differentiation was also not significantly reduced in secondary compared to primary forests, with no significant genetic structure observed among all populations. These results suggest rapid genetic recovery of T. canadensis populations in recolonized forests compared with other late‐successional temperate tree species. 相似文献
72.
Highly social ants, bees and wasps employ sophisticated recognition systems to identify colony members and deny foreign individuals access to their nest. For ants, cuticular hydrocarbons serve as the labels used to ascertain nest membership. Social parasites, however, are capable of breaking the recognition code so that they can thrive unopposed within the colonies of their hosts. Here we examine the influence of the socially parasitic slave-making ant, Polyergus breviceps on the nestmate recognition system of its slaves, Formica altipetens. We compared the chemical, genetic, and behavioral characteristics of colonies of enslaved and free-living F. altipetens. We found that enslaved Formica colonies were more genetically and chemically diverse than their free-living counterparts. These differences are likely caused by the hallmark of slave-making ant ecology: seasonal raids in which pupa are stolen from several adjacent host colonies. The different social environments of enslaved and free-living Formica appear to affect their recognition behaviors: enslaved Formica workers were less aggressive towards non-nestmates than were free-living Formica. Our findings indicate that parasitism by P. breviceps dramatically alters both the chemical and genetic context in which their kidnapped hosts develop, leading to changes in how they recognize nestmates. 相似文献
73.
Candice A. Myers Tim Slack Corby K. Martin Stephanie T. Broyles Steven B. Heymsfield 《PloS one》2016,11(2)
Objective
To examine change in county-level adult obesity prevalence between 2004 and 2009 and identify associated community characteristics.Methods
Change in county-level adult (≥20 years) obesity prevalence was calculated for a 5-year period (2004–2009). Community measures of economic, healthcare, recreational, food environment, population structure, and education contexts were also calculated. Regression analysis was used to assess community characteristics associated (p<0.01) with change in adult obesity prevalence.Results
Mean±SD change in obesity prevalence was 5.1±2.4%. Obesity prevalence decreased in 1.4% (n = 44) and increased in 98% (n = 3,060) of counties from 2004–2009. Results showed that both baseline levels and increases in physically inactive adults were associated with greater increases in obesity prevalence, while baseline levels of and increases in physician density and grocery store/supercenter density were related to smaller increases in obesity rates. Baseline levels of the Hispanic population share were negatively linked to changing obesity levels, while places with greater Hispanic population growth saw greater increases in obesity.Conclusions
Most counties in the U.S. experienced increases in adult obesity prevalence from 2004 to 2009. Findings suggest that community-based interventions targeting adult obesity need to incorporate a range of community factors, such as levels of physical inactivity, access to physicians, availability of food outlets, and ethnic/racial population composition. 相似文献74.
ABSTRACT: Malaria affects large parts of the developing world and is responsible for almost 800,000 deaths annually. As climates change, concerns have arisen as to how this vector-borne disease will be impacted by changing rainfall patterns and warming temperatures. Despite the importance and controversy surrounding the impact of climate change on the potential spread of this disease, little information exists on the tolerances of several of the vector species themselves. METHODS: Using a ramping protocol (to assess critical thermal limits - CT) and plunge protocol (to assess lethal temperature limits - LT) information on the thermal tolerance of two of Africa's important malaria vectors, Anopheles arabiensis and Anopheles funestus was collected. The effects of age, thermal acclimation treatment, sex and strain (laboratory versus wild adults) were investigated for CT determinations for each species. The effects of age and sex for adults and life stage (larvae, pupae, adults) were investigated for LT determinations. RESULTS: In both species, females are more tolerant to low and high temperatures than males; larvae and pupae have higher upper lethal limits than do adults. Thermal acclimation of adults has large effects in some instances but small effects in others. Younger adults tend to be more tolerant of temperature changes than older age groups. Long-standing laboratory colonies are sufficiently similar in thermal tolerance to field-collected animals to provide reasonable surrogates when making inferences about wild population responses. Differences between these two vectors in their thermal tolerances, especially in larvae and pupae, are plausibly a consequence of different habitat utilization. CONCLUSIONS: Limited plasticity is characteristic of the adults of these vector species relative to others examined to date, suggesting limited scope for within-generation change in thermal tolerance. These findings and the greater tolerance of females to thermal extremes may have significant implications for future malaria transmission, especially in areas of current seasonal transmission and in areas on the boundaries of current vector distribution. 相似文献
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Vernica A. Segarra Clara Primus Graciela A. Unguez Ashanti Edwards Candice Etson Sonia C. Flores Catherine Fry Ashley N. Guillory Susan L. Ingram Mark Lawson Richard McGee Stephanie Paxson Laura Phelan Kirsta Suggs Leticia R. Vega Elizabeth Vuong J. Christopher Havran Alfredo Leon Michael D. Burton J. Luis Lujan Marina Ramirez-Alvarado 《Molecular biology of the cell》2020,31(23):2495
Scientific societies aiming to foster inclusion of scientists from underrepresented (UR) backgrounds among their membership often delegate primary responsibility for this goal to a diversity-focused committee. The National Science Foundation has funded the creation of the Alliance to Catalyze Change for Equity in STEM Success (ACCESS), a meta-organization bringing together representatives from several such STEM society committees to serve as a hub for a growing community of practice. Our goal is to coordinate efforts to advance inclusive practices by sharing experiences and making synergistic discoveries about what works. ACCESS has analyzed the approaches by which member societies have sought to ensure inclusivity through selection of annual meeting speakers. Here we discuss how inclusive speaker selection fosters better scientific environments for all and identify challenges and promising practices for societies striving to maximize inclusivity of speakers in their scientific programming. 相似文献
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The Laurentian Great Lakes have been subject to numerous introductions of nonindigenous species, including two recent benthic
fish invaders, Eurasian ruffe (Gymnocephalus cernuus) and round gobies (Neogobius melanostomus), as well as the benthic bivalve, zebra mussel (Dreissena polymorpha). These three exotic species, or “exotic triad,” may impact nearshore benthic communities due to their locally high abundances
and expanding distributions. Laboratory experiments were conducted to determine (1) whether ruffe and gobies may compete for
habitat and invertebrate food in benthic environments, and (2) if zebra mussels can alter those competitive relationships
by serving as an alternate food source for gobies. In laboratory mesocosms, both gobies and ruffe preferred cobble and macrophyte
areas to open sand either when alone or in sympatry. In a 9-week goby–ruffe competition experiment simulating an invasion
scenario with a limited food base, gobies grew faster than did ruffe, suggesting that gobies may be competitively superior
at low resource levels. When zebra mussels were added in a short-term experiment, the presence or absence of mussels did not
affect goby or ruffe growth, as few zebra mussels were consumed. This finding, along with other laboratory evidence, suggests
that gobies may prefer soft-bodied invertebrate prey over zebra mussels. Studies of interactions among the “exotic triad”,
combined with continued surveillance, may help Great Lakes fisheries managers to predict future population sizes and distributions
of these invasive fish, evaluate their impacts on native food webs, and direct possible control measures to appropriate species. 相似文献
80.
Ge Zhang Jonas Bacelis Candice Lengyel Kari Teramo Mikko Hallman ?yvind Helgeland Stefan Johansson Ronny Myhre Verena Sengpiel P?l Rasmus Nj?lstad Bo Jacobsson Louis Muglia 《PLoS medicine》2015,12(8)