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Full-Text Articles in Population Biology

Communication For Mate Selection In Anurans: Dominant Frequency Versus Snout-Vent-Length, Shari Jean Kunert Dec 2010

Communication For Mate Selection In Anurans: Dominant Frequency Versus Snout-Vent-Length, Shari Jean Kunert

Department of Environmental Studies: Undergraduate Student Theses

No abstract provided.


Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville Nov 2010

Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville

School of Biological Sciences: Dissertations, Theses, and Student Research

Two ecological risks associated with the use of transgenic crops include the effects of transgene products on non-target organisms and the effects of a transgene after it moves from crops into a wild plant population. In work presented here, we specifically investigate the ecological risks of virus-resistant transgenic squash. We observed pollinator behavior to determine if pollinators are affected by nontarget effects of the virus-resistant transgene. We found that pollinator behavior did differ between conventional and virus-resistant transgenic squash due to pleiotropic effects of the transgene. This difference in pollinator behavior can affect plant mating patterns, thereby affecting crop-wild hybridization …


Alfred Russel Wallace, Geographer, Charles H. Smith Jan 2010

Alfred Russel Wallace, Geographer, Charles H. Smith

DLPS Faculty Publications

Among the great explorers and thinkers who advanced geography in the nineteenth century and helped it evolve into the subject that exists today is a man who is not always connected with the field, Alfred Russel Wallace (1823–1913). Most commonly recognized as ‘the other man’ in the history of the discovery of the principle of natural selection, Wallace’s commitment to the study of landscape and its physical, biological, and human elements was lifelong, and resulted in a wide range of contributions to biogeography, physical geography, human geography, and ethnography. In this year of the double anniversaries of Charles Darwin’s birth …


Assessing Genetic Differentiation Among Populations Of The Invasive Plant Impatiens Glandulifera In Maine, Jordan R. Schoonover Jan 2010

Assessing Genetic Differentiation Among Populations Of The Invasive Plant Impatiens Glandulifera In Maine, Jordan R. Schoonover

Honors Theses

The annual herbaceous plant Impatiens glandulifera Royle is native to the Himalayas and is a significant invasive species in Europe. In the past century, it was introduced to the United States, where it has become established in 12 states. This study evaluated genetic differentiation among four Maine populations, to address a theory that posits hybridization of distinct lineages as a trigger for invasiveness. Regions of microsatellite repeats were evaluated at two polymorphic loci for 41 plants sampled from the four populations. A striking finding was that the observed heterozygosity was substantially higher than the heterozygosity expected from random combination of …


Genetic Variation For Susceptibility To Storm-Induced Stem Breakage In Solidago Altissima: The Role Of Stem Height And Morphology, M. Wise, W. Abrahamson Dec 2009

Genetic Variation For Susceptibility To Storm-Induced Stem Breakage In Solidago Altissima: The Role Of Stem Height And Morphology, M. Wise, W. Abrahamson

Warren G. Abrahamson, II

While storms can have obvious ecological impacts on plants, plants’ potential to respond evolutionarily to selection for increased resistance to storm damage has received little study. We took advantage of a thunderstorm with strong wind and hail to examine genetic variation for resistance to stem breakage in the herbaceous perennial Solidago altissima. The storm broke the apex of nearly 10% of 1883 marked ramets in a common-garden plot containing 26 genets of S. altissima. Plant genets varied 20-fold in resistance to breakage. Stem height was strongly correlated with resistance to breakage, with taller stems being significantly more susceptible. A stem’s …


Spatiotemporal Variation Of Fruit Digestible-Nutrient Production In Florida's Uplands, J. Layne, W. Abrahamson Dec 2009

Spatiotemporal Variation Of Fruit Digestible-Nutrient Production In Florida's Uplands, J. Layne, W. Abrahamson

Warren G. Abrahamson, II

We examined annual total digestible nutrient (TDN) production by fruits of eight species (Quercus chapmanii, Q. geminata, Q. inopina, Q. laevis, Q. myrtifolia, Carya floridana, Sabal etonia, Serenoa repens) that account for the major proportion of TDN production by fruits and seeds in Florida’s xeric upland associations (southern ridge sandhill, sand pine scrub, scrubby flatwoods). Mean annual fruit TDN of all species combined over a 27-year span in sandhill and scrub and 24 years in scrubby flatwoods was highest (45.4 kg/ha) in sandhill, intermediate in scrubby flatwoods (28.8 kg/ha), and lowest in scrub (14.2 kg/ha). Sandhill fruit TDN production was …


Ducking As The Means Of Resistance In "Candy-Cane" Stems Of Goldenrod: Straightened Stems Lose Their Edge, M. J. Wise, W. G. Abrahamson, J. A. Cole Dec 2009

Ducking As The Means Of Resistance In "Candy-Cane" Stems Of Goldenrod: Straightened Stems Lose Their Edge, M. J. Wise, W. G. Abrahamson, J. A. Cole

Warren G. Abrahamson, II

Herbivores are among the most pervasive selective forces acting on plants, and the number of plant chemicals that presumably evolved for defense against herbivory is immense. In contrast, biologists are only beginning to appreciate the important roles that architectural traits can play in antiherbivore defense. One putative architectural-resistance trait is the nodding stem apex of some goldenrods (Solidago ; Asteraceae). Individuals of S. altissima genets that undergo temporary nodding in the late spring (i.e., “candy-cane ramets) have been shown to be more resistant than individuals of erect-stemmed genets to certain apex-attacking” herbivores. We tested the hypothesis that the greater resistance …


Nutrition As A Facilitator Of Host-Race Formation: The Role Of Food Quality In The Shift Of A Stem-Boring Beetle To A Gall Host, C. P. Blair, R. V. Schlanger, S. E. Diamond, W. G. Abrahamson Dec 2009

Nutrition As A Facilitator Of Host-Race Formation: The Role Of Food Quality In The Shift Of A Stem-Boring Beetle To A Gall Host, C. P. Blair, R. V. Schlanger, S. E. Diamond, W. G. Abrahamson

Warren G. Abrahamson, II

1. The importance of host-race formation to herbivorous insect diversity depends on the likelihood that successful populations can be established on a new plant host. A previously unexplored ecological aid to success on a novel host is better nutritional quality. The role of nutrition was examined in the shift of the stem-boring beetle Mordellistena convicta to fly-induced galls on goldenrod and the establishment there of a genetically distinct gall host race. 2. First, larvae of the host race inhabiting stems of Solidago gigantea were transplanted into stems and galls of greenhouse-grown S. gigantea plants. At the end of larval development, …