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201.
We studied a guild of desert winter annual plants that differ in long-term variation in per capita reproductive success (lb, the product of per capita survival from germination to reproduction, l, times per capita reproduction of survivors, b) to relate individual function to population and community dynamics. We hypothesized that variation in lb should be related to species' positions along a trade-off between relative growth rate (RGR) and photosynthetic water-use efficiency (WUE) because lb is a species-specific function of growing-season precipitation. We found that demographically variable species have greater RGR and greater leaf carbon isotope discrimination (Delta, a proxy inversely related to WUE). We examined leaf nitrogen and photosynthetic characteristics and found that, in this system, variation in Delta is a function of photosynthetic demand rather than stomatal regulation of water loss. The physiological characteristics that result in low Delta in some species may confer greater photosynthetic performance during the reliably moist but low temperature periods that immediately follow winter rainfall in the Sonoran Desert or alternatively during cool periods of the day or early growing season. Conversely, while species with high Delta and high RGR exhibit low leaf N, they have high biomass allocation to canopy leaf area display. Such trait associations may allow for greater performance during the infrequent conditions where high soil moisture persists into warmer conditions, resulting in high demographic variance. Alternatively, high variance could arise from specialization to warm periods of the day or season. Population dynamic buffering via stress tolerance (low RGR and Delta) correlates negatively with buffering via seed banks, as predicted by bet-hedging theory. By merging analyses of population dynamics with functional trait relationships, we develop a deeper understanding of the physiological, ecological, and evolutionary mechanisms involved in population and community dynamics. 相似文献
202.
Greg W. Rouse Nerida G. Wilson Shana K. Goffredi Shannon B. Johnson Tracey Smart Chad Widmer Craig M. Young Robert C. Vrijenhoek 《Marine Biology》2009,156(3):395-405
We report observations on spawning and early development in bone-eating worms of the genus Osedax. Individual females of Osedax rubiplumus were observed at 1820 m depth freely spawning hundreds of oocytes, and females of an undescribed species, Osedax “orange collar”, were observed spawning in laboratory aquaria. Cytological and molecular analysis of the spawned oocytes
of two Osedax species revealed no evidence for the bacterial endosymbionts that the female worms require for their nutrition, suggesting
that the bacteria must be acquired later from the environment, as they are in other siboglinids. Individual O. “orange collar” females released an average of 335 (±130) eggs per day, but the number of oocytes spawned per day varied
greatly, suggesting that not all the females spawned daily. Fertilization rates of the spawned oocytes varied from 0 to 100%,
though most females showed nearly 100% fertilization rates. Oocytes spawned in the laboratory at 4–6°C were negatively buoyant.
If fertilized, these oocytes extruded polar bodies and then after at least four hours cleaved unequally. Subsequent cleavages
occurred in a spiral pattern at roughly 2-h intervals, resulting in free-swimming trochophore larvae after 24 h. These lecithotrophic
trochophores swam for 9–16 days before settling with several hooked chaetae, similar to those of dwarf Osedax males. The larval life span of the Osedax species studied in the laboratory appears to be shorter than in closely related Vestimentifera. Osedax rubiplumus, on the other hand, has much larger oocytes and so may have greater dispersal potential than these other Osedax species. The high fecundity and apparently continuous reproduction of Osedax boneworms permits the opportunistic exploitation of sunken vertebrate bones.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
203.
Rochelle Constantine Debbie Steel Judy Allen Megan Anderson Olive Andrews C. Scott Baker Peta Beeman Daniel Burns Jean-Benoît Charrassin Simon Childerhouse Michael Double Paul Ensor Trish Franklin Wally Franklin Nick Gales Claire Garrigue Nadine Gibbs Peter Harrison Nan Hauser Amanda Hutsel Curt Jenner Micheline-Nicole Jenner Greg Kaufman Anne Macie David Mattila Carlos Olavarría Adrian Oosterman David Paton Michael Poole Jooke Robbins Natalie Schmitt Peter Stevick Alden Tagarino Kirsten Thompson Juney Ward 《Marine Biology》2014,161(5):1087-1093
Understanding the dynamics of population recovery is particularly complex when an organism has multiple, remote breeding and feeding grounds separated by one of the longest known migration routes. This study reports on the most comprehensive assessment of humpback whale (Megaptera novaeangliae) movements between remote Antarctic waters south of New Zealand and east Australia (EA), and the migratory corridors and breeding grounds of Australia and Oceania. A total of 112 individual whales were identified; 57 from microsatellites and 61 by fluke with 23 % (n = 26) matched to sites outside Antarctica. Despite large datasets from other southern regions being included in the comparison, the whales were predominantly linked to EA (n = 24). Only two matches to the Oceania catalogues directly north was surprising; therefore the primary feeding grounds of these endangered whales still remain unknown. The confirmation of the Balleny Islands as an important feeding ground for EA whales could provide an insight into reasons behind the rapid recovery of this population. Determining the feeding grounds of Oceania’s whales may explain whether prey energetics or migration length are limiting factors to their recovery and will allow an understanding of future ecosystem changes in these whales. 相似文献
204.
Behavioral genomics of honeybee foraging and nest defense 总被引:9,自引:1,他引:8
Hunt GJ Amdam GV Schlipalius D Emore C Sardesai N Williams CE Rueppell O Guzmán-Novoa E Arechavaleta-Velasco M Chandra S Fondrk MK Beye M Page RE 《Die Naturwissenschaften》2007,94(4):247-267
The honeybee has been the most important insect species for study of social behavior. The recently released draft genomic
sequence for the bee will accelerate honeybee behavioral genetics. Although we lack sufficient tools to manipulate this genome
easily, quantitative trait loci (QTLs) that influence natural variation in behavior have been identified and tested for their
effects on correlated behavioral traits. We review what is known about the genetics and physiology of two behavioral traits
in honeybees, foraging specialization (pollen versus nectar), and defensive behavior, and present evidence that map-based
cloning of genes is more feasible in the bee than in other metazoans. We also present bioinformatic analyses of candidate
genes within QTL confidence intervals (CIs). The high recombination rate of the bee made it possible to narrow the search
to regions containing only 17–61 predicted peptides for each QTL, although CIs covered large genetic distances. Knowledge
of correlated behavioral traits, comparative bioinformatics, and expression assays facilitated evaluation of candidate genes.
An overrepresentation of genes involved in ovarian development and insulin-like signaling components within pollen foraging
QTL regions suggests that an ancestral reproductive gene network was co-opted during the evolution of foraging specialization.
The major QTL influencing defensive/aggressive behavior contains orthologs of genes involved in central nervous system activity
and neurogenesis. Candidates at the other two defensive-behavior QTLs include modulators of sensory signaling (Am5HT
7
serotonin receptor, AmArr4 arrestin, and GABA-B-R1 receptor). These studies are the first step in linking natural variation in honeybee social behavior
to the identification of underlying genes. 相似文献
205.
Associations between Water Physicochemistry and Prymnesium parvum Presence,Abundance, and Toxicity in West Texas Reservoirs 下载免费PDF全文
Matthew M. VanLandeghem Mukhtar Farooqi Greg M. Southard Reynaldo Patiño 《Journal of the American Water Resources Association》2015,51(2):471-486
Toxic blooms of golden alga (Prymnesium parvum) have caused substantial ecological and economic harm in freshwater and marine systems throughout the world. In North America, toxic blooms have impacted freshwater systems including large reservoirs. Management of water chemistry is one proposed option for golden alga control in these systems. The main objective of this study was to assess physicochemical characteristics of water that influence golden alga presence, abundance, and toxicity in the Upper Colorado River basin (UCR) in Texas. The UCR contains reservoirs that have experienced repeated blooms and other reservoirs where golden alga is present but has not been toxic. We quantified golden alga abundance (hemocytometer counts), ichthyotoxicity (bioassay), and water chemistry (surface grab samples) at three impacted reservoirs on the Colorado River; two reference reservoirs on the Concho River; and three sites at the confluence of these rivers. Sampling occurred monthly from January 2010 to July 2011. Impacted sites were characterized by higher specific conductance, calcium and magnesium hardness, and fluoride than reference and confluence sites. At impacted sites, golden alga abundance and toxicity were positively associated with salinity‐related variables and blooms peaked at ~10°C and generally did not occur above 20°C. Overall, these findings suggest management of land and water use to reduce hardness or salinity could produce unfavorable conditions for golden alga. 相似文献