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Articles 1 - 11 of 11

Full-Text Articles in Biology

Modeling Interactions Of Browsing Predation, Infaunal Activity And Recruitment In Marine Soft-Sediment Habitats, Sara M. Lindsay, David S. Wethey, Sarah A. Woodin Oct 1996

Modeling Interactions Of Browsing Predation, Infaunal Activity And Recruitment In Marine Soft-Sediment Habitats, Sara M. Lindsay, David S. Wethey, Sarah A. Woodin

Faculty Publications

In marine soft-sediment habitats, the sediment surface is altered by activities of sediment dwellers (infauna). Such biogenic disturbance can influence recruitment success if settling larvae and juveniles avoid disturbed sites or if juveniles die as a result of disturbance after settling. Because infauna commonly lose exposed body parts to browsing predators and disturb less sediment as a result, we developed a simulation model to examine the interactions between browsing predation, infaunal adult activity, and recruitment. Sediment disturbance in the model was based on data for the polychaete Abarenicola pacifica. We simulated the activity of two general types of predators: prey …


Pelage Coloration In Oldfield Mice (Peromyscus Polionotus): Antipredator Adaptation?, Mark C. Belk, Michael H. Smith Aug 1996

Pelage Coloration In Oldfield Mice (Peromyscus Polionotus): Antipredator Adaptation?, Mark C. Belk, Michael H. Smith

Faculty Publications

Reflectance spectra (in full light and moonlight) of dorsal pelage of 469 adult oldfield mice (Peromyscus polionotus) comprising nine regional samples were compared to reflectance spectra of corresponding surface and subsurface soil samples to test for a selective effect of predation on color of pelage. Mice were slightly more reddish in hue, generally had more chroma, and were less reflective than soil at all locations. Color of pelage within locations was not significantly correlated with color of soil. Among all locations, brightness of pelage and soil were significantly positively correlated. Among mainland locations, there was a significant positive …


Morphometry Of Juvenile And Subadult Loligo Pealei And L. Plei From The Northern Gulf Of Mexico, Guillermo Sánchez, Harriet M. Perry, Christine B. Trigg, Michael Vecchione, Clyde Roper, Patricia M. Biesot Jul 1996

Morphometry Of Juvenile And Subadult Loligo Pealei And L. Plei From The Northern Gulf Of Mexico, Guillermo Sánchez, Harriet M. Perry, Christine B. Trigg, Michael Vecchione, Clyde Roper, Patricia M. Biesot

Faculty Publications

Two species of Loligo are abundant in northern Gulf waters: the long-finned squid, Loligo pealei. and the arrow squid, Loligo plei. Variability within species and similarities between the species often hamper accurate identification. The two species more closely resemble each other in areas of sympatry. and there is overlap in almost all of the diagnostic characters. Small specimens of Loligo are not easily identified. and there are few studies detailing their morphometry. Because of the taxonomic uncertainties associated with the identification of juveniles and subadults of L. pealei and L. plei, the species were differentiated by isoelectric …


Abundant Protein-Containing Particles In The Sea, Richard A. Long, Farooq Azam Jun 1996

Abundant Protein-Containing Particles In The Sea, Richard A. Long, Farooq Azam

Faculty Publications

The interaction of bacteria with particulate organic matter has implications for organic matter cycling and bacterial ecology in the ocean. Until recently, the focus has been on 'classical' particles visible by unaided eye (marine snow) or light microscopy. Recent discoveries of several new types of abundant particles, from sub-micrometer to sub-marine snow, are changing our ideas of the physical and chemical nature of the particle field with which pelagic bacteria interact. Previous workers have discovered polysaccharide-containing (Alcian Blue stainable) transparent exopolymer particles (TEP) ranging from 3 to 100s of micrometers. Looking for additional components of the sub-marine snow particle field, …


Settlement And Early Post-Settlement Survival Of Sessile Marine Invertebrates On Topographically Complex Surfaces: The Importance Of Refuge Dimensions And Adult Morphology, Linda J. Walters, David S. Wethey Jun 1996

Settlement And Early Post-Settlement Survival Of Sessile Marine Invertebrates On Topographically Complex Surfaces: The Importance Of Refuge Dimensions And Adult Morphology, Linda J. Walters, David S. Wethey

Faculty Publications

We predicted that both refuge dimension and growth form would influence settlement and short-term post-settlement success (≤7 d) of sessile marine invertebrates that live attached to hard substrata in low energy environments. Individuals with unlimited attachment to the substrata should rapidly be protected by their growth form, thus decreasing their need to settle in refuges and limiting the length of time any locations on heterogeneous substrata act as refuges. Alternatively, organisms with limited attachment to the substrata should remain susceptible to the causes of mortality for a longer time, and as a result should settle in high quality refuges (sites …


Effects Of High-Molecular-Weight Dissolved Organic Matter On Nitrogen Dynamics In The Mississippi River Plume, Wayne S. Gardner, Ronald Benner, Rainer M.W. Amon, James B. Cotner Jr., Joann F. Cavaletto, Jeffrey R. Johnson Mar 1996

Effects Of High-Molecular-Weight Dissolved Organic Matter On Nitrogen Dynamics In The Mississippi River Plume, Wayne S. Gardner, Ronald Benner, Rainer M.W. Amon, James B. Cotner Jr., Joann F. Cavaletto, Jeffrey R. Johnson

Faculty Publications

The dynamics of N and its interactions with labile dissolved organic C (DOC), bacteria, and phytoplankton were studied to determine potential effects of dissolved organic matter (DOM) and light on N dynamics in surface waters of the Mississippi River (USA) plume in the Gulf of Mexico. Bacterial uptake of added labeled N compounds ( 15NH4+ or 15N-labeled dissolved free amino acids. DFAA) was stimulated more by high-molecular-weight (HMW, >l kDa) DOM than by low-molecular-weight (LMW, < l kDa) DOM. An index that inversely indicated the presence of labile DOC was defined as the fraction of assimilated Amino acid-15N that was Recovered as 15N -Ammonium (ANRA), following the additions of high-levels (4 µM) of 15N -DFAA. …


Infection And Fungal Development Of Tubakia Dryina On Sweet Gum (Liquidambar Styraciflua), Josephine Taylor, Shane Clark Jan 1996

Infection And Fungal Development Of Tubakia Dryina On Sweet Gum (Liquidambar Styraciflua), Josephine Taylor, Shane Clark

Faculty Publications

Infection and fungal development of Tubakia dryina were investigated on leaves of sweet gum using a combination of microscopic techniques. Conidia of T. dryina adhered to the leaf surface and formed septate germ tubes. Germ tubes terminated in small appressoria that formed directly over epidermal cells. Intra- and intercellular hyphae ramified extensively throughout the leaf tissue. Host cells associated with the infection site became necrotic and collapsed, resulting in macroscopic disease symptoms.


Adaptations Facilitating Facultative Oophagy In The Gray Rat Snake, Elaphe Obsoleta Spiloides [Abstract], Stephen J. Mullin Jan 1996

Adaptations Facilitating Facultative Oophagy In The Gray Rat Snake, Elaphe Obsoleta Spiloides [Abstract], Stephen J. Mullin

Faculty Publications

No abstract provided.


Dietary Overview Of Hemidactylus Turcicus With Possible Implications Of Food Partitioning, Daniel Saenz Jan 1996

Dietary Overview Of Hemidactylus Turcicus With Possible Implications Of Food Partitioning, Daniel Saenz

Faculty Publications

A stomach content analysis was conducted on Hemidactylus turcicus, the Mediterranean gecko, from 19 April 1990 to 15 October 1990, on the campus of Stephen F. Austin State University, Nacogdoches, Texas. Geckos (N = 167) were placed into four size groups based on snout-vent-length (5 29 mm, 30-39 mm, 40-49 mm, and z 50 mm) and three microhabitat groups based on perch height (those occupying perch sites < 1.52 m, 2 1.52 m to 5 3.05 m, and > 3.05 m). Stomach contents were analyzed and sex, size, and microhabitat groups were compared using Schoener's percent overlap index. Volumetrically, the most important prey items taken were Orthoptera, Lepidoptera, and Isopoda. Geckos of …


The Arabidopsis Homeotic Genes Apetala3 And Pistillata Are Sufficient To Provide The B Class Organ Identity Function, Beth A. Krizek, Elliot M. Meyerowitz Jan 1996

The Arabidopsis Homeotic Genes Apetala3 And Pistillata Are Sufficient To Provide The B Class Organ Identity Function, Beth A. Krizek, Elliot M. Meyerowitz

Faculty Publications

The class B organ identity genes, APETALA3 and PISTILLATA, are required to specify petal and stamen identity in the Arabidopsis flower. We show here that the activities of these two genes are sufficient to specify petals and stamens in flowers, in combination with the class A and C genes, respectively. Flowers of plants constitutively expressing both PISTILLATA and APETALA3 under the control of the 35S promoter from cauliflower mosaic virus consist of two outer whorls of petals and inner whorls of stamens. These plants also exhibit vegetative phenotypes that are not present in either of the singly (APETALA3 …


Intraspecific Life History Variation In Sceloporus Undulatus: A Factor Analysis, Geoffrey R. Smith, John W. Rowe, R. E. Ballinger Jan 1996

Intraspecific Life History Variation In Sceloporus Undulatus: A Factor Analysis, Geoffrey R. Smith, John W. Rowe, R. E. Ballinger

Faculty Publications

No abstract provided.