Now showing items 1-20 of 125

    • Photoprotection by carotenoid pigments in the copepod Diaptomus nevadensis 

      Hairston, Nelson G., Jr. (National Academy of Sciences, 1976-03)
      Individuals of the copepod Diaptomus nevadensis that contain high concentrations of carotenoids survive significantly better in natural intensities of visible light than less pigmented copepods. Vertical migration and ...
    • The timing of copepod diapause as an evolutionarily stable strategy 

      Hairston, Nelson G., Jr.; Munns, Wayne R. (University of Chicago, 1984-06)
      Diaptomus sanguineus, a small freshwater copepod, avoids periods of intense fish predation by producing diapausing eggs. We developed a computer simulation of the copepod's life history and used it to compete populations ...
    • Fish size, visual resolution, and prey selectivity 

      Li, Kao T.; Wetterer, James K.; Hairston, Nelson G., Jr. (Ecological Society of America, 1985-12)
      Planktivorous bluegill sunfish (Lepomis macrochirus) are known to consume large prey preferentially. Disagreement exists in the literature over whether this size-selectivity reflects optimal foraging behavior by the fish ...
    • Rapid evolution of a life-history trait 

      Hairston, Nelson G., Jr.; Walton, W. E. (National Academy of Sciences, 1986-07)
      The copepod Diaptomus sanguineus begins diapause in permanent ponds in late March as an adaptation to avoid summer fish predation. During a study of copepod populations in two Rhode Island ponds, a severe drought dried one ...
    • Partial photoperiodic control of diapause in three populations of the freshwater copepod Diaptomus sanguineus 

      Hairston, Nelson G., Jr.; Olds, Emily J. (University of Chicago Press, 1986-08)
      Populations of the freshwater calanoid copepod Diaptomus sanguineus inhabiting three Rhode Island ponds switch from making subitaneous (immediately hatching) to diapausing eggs on different dates. From results of previous ...
    • Sulfur and carbon isotopes as tracers of salt-marsh organic matter flow 

      Peterson, B.J.; Howarth, R. W.; Garritt, R.H. (Wiley, 1986-08-01)
      Stable isotopes of sulfur and carbon were used to trace the dominant flows of organic matter from producers to macroconsumers in Great Sippewissett Salt Marsh on Cape Cod. Spartina alterniflora and sulfur-oxidizing bacteria ...
    • A field test for the cues of diapause in a freshwater copepod 

      Hairston, Nelson G., Jr.; Dillon, Theresa A.; De Stasio, Bart T. (Ecological Society of America, 1990-12)
      The freshwater calanoid copepod Diaptomus sanguineus switches each year in spring from making eggs that hatch immediately to making diapausing eggs that rest in lake sediments for an extended period. In lakes and ponds ...
    • A cytogenetic analysis of reproduction in common shrews (Sorex araneus) from a karyotypic hybrid zone 

      Searle, J.B. (Mendelian Society of Lund, 1990-12)
      Sixteen pregnant female common shrews were collected near Oxford (U.K.) from a hybrid zone between two karyotypic races which differ by Robertsonian rearrangements. Some females were homozygotes and others were ‘simple’ ...
    • Inputs of sediment and carbon to an estuarine ecosystem: Influence of land use 

      Howarth, R. W.; Fruci, J.R.; Sherman, D.M. (Wiley, 1991-02-01)
      Estuaries and coastal marine ecosystems receive large inputs of nutrients, organic carbon, and sediments from non—point—source runoff from terrestrial ecosystems. In the tidal, freshwater Hudson River estuary, such inputs ...
    • Growth-related constraints on diet selection by sunfish 

      Walton, William E.; Hairston, Nelson G., Jr.; Wetterer, James K. (Ecological Society of America, 1992-04)
      Diet selectivity by the planktivorous bluegill sunfish (Lepomis macrochirus) is correlated with the fishes' visual resolution. Poor visual capabilities are thought to impose a constraint on the ability of small sunfish to ...
    • Cause-effect relationships in energy flow, trophic structure, and interspecific interactions 

      Hairston, Nelson G., Jr.; Hairston, Nelson G., Sr. (University of Chicago, 1993-09)
      Measurements of the efficiency of energy transfer between trophic levels are consis- tent with the hypothesis that it is trophic structure that controls the fraction of energy consumed at each trophic level, rather than ...
    • Role of overlapping generations in maintaining genetic variation in a fluctuating environment 

      Ellner, Stephen; Hairston, Nelson G., Jr. (University of Chicago, 1994-03)
      Population genetics theory suggests that temporally fluctuating selection on pheno- types can act to maintain genetic variance only under very restrictive conditions. However, this conclusion is based on models with discrete ...
    • The interaction of photoperiod and temperature in diapause timing: a copepod example 

      Hairston, Nelson G., Jr.; Kearns, C. M. (University of Chicago Press, 1995-08)
      In many organisms, photoperiod and temperature are thought to be the most significant token cues for seasonally timed life history events, including diapause in arthropods. A common pattern in many species of terrestrial ...
    • Age and survivorship of diapausing eggs in a sediment egg bank 

      Hairston, Nelson G., Jr.; Van Brunt, Robert A.; Kearns, Colleen M.; Engstrom, Daniel R. (Ecological Society of America, 1995-09)
      We determined the densities of diapausing eggs of the copepod Diaptomnus sanguineas in sediments from two small freshwater lakes in Rhode Island. Sediment cores, sliced at 1-cm intervals, showed that egg densities ranged ...
    • Phenotypic variation in a zooplankton egg bank 

      Hairston, Nelson G., Jr.; Kearns, Colleen M.; Ellner, Stephen P. (Ecological Society of America, 1996-12)
      Dormant propagule pools may store potentially significant genetic variation that can influence the rate and direction of microevolution via directional selection, tem- porally fluctuating selection, and evolution of trait ...
    • The hypothetical Old-Northern chromosome race of Sorex araneus found in the Ural Mts 

      Polyakov, A.V.; Borodin, P.M.; Luká?ová, L.; Searle, J.B.; Zima, J. (Finnish Zoological and Botanical Publishing Board, 1997)
      Chromosomes of two populations of the common shrew, Sorex araneus L. (Mammalia, Insectivora, Soricidae), from the northern Ural Mts. were investigated. In both sites, homozygous, all-metacentric autosomal complements were ...
    • Does food web complexity eliminate trophic-level dynamics? 

      Hairston, Nelson G., Jr.; Hairston, Nelson G., Sr. (University of Chicago, 1997-05)
    • The Benefits of Induced Defenses Against Herbivores 

      Karban, Richard; Agrawal, Anurag A.; Mangel, Marc (Ecological Society of America, 1997-07-01)
      Previous explanations for the evolution of induced resistance of plants to herbivory emphasized arguments based on saving costs when allocations to defense were not needed; these models met with limited empirical support. ...
    • Human alteration of the global nitrogen cycle: Causes and consequences 

      Vitousek, P.M.; Aber, J.; Bayley, S. E.; Howarth, R. W.; Likens, G. E.; Matson, P. A.; Schindler, D. W.; Schlesinger, W. H.; Tilman, G. D. (Wiley, 1997-08-01)
      Nitrogen is a key element controlling the species composition, diversity, dynamics, and functioning of many terrestrial, freshwater, and marine ecosystems. Many of the original plant species living in these ecosystems are ...