Life Sciences Commons^™

A Review Of Shellfish Restoration As A Tool For Coastal Water Quality Management., Michael A. Rice

Michael A Rice

In many areas, coastal residents and others oppose establishment of bivalve molluscan aquaculture projects on the basis of perceived negative environmental impacts. Often overlooked are positive environmental impacts of shellfish aquaculture that can potentially mitigate the impacts of other anthropogenic activities. Filter feeding by populations of bivalve mollusks is reviewed with respect to their ability to act as an estuarine filter, increase clarity of coastal waters and facilitate the removal of nitrogen and other nutrients from eutrophic coastal waters. Most species of cultured bivalve mollusks clear particles from waters at rates of 1 to 4 L/h, and populations of shellfish …

Yponomeuta Evonymellus Outbreaks In Southern Finland: Spatial Synchrony But Different Local Magnitudes, Brian J. Wilsey, Conchita Alonso, Timo Vuorisalo, Tuija Honkanen

Brian J. Wilsey

Defoliations of Prunus padus by Yponomeuta evonymellus were monitored in two areas in southern Finland. During a long-term study (1980–1995) in the area with high peak defoliations, P. padus trees recorded two defoliation peaks, leading to complete defoliation of many trees. The negative relationship between pupal mass and current year tree defoliation during the peak years suggested shortage of food affected reproductive potential of Y. evonymellus. Furthermore, no delayed induced resistance was observed in these populations. Interannual correlations in degrees of defoliation experienced by individual trees were low, i.e. high defoliation in one year did not predict the degree of …

Effects Of Willows (Salix Brachycarpa) On Populations Of Salicylate-Mineralizing Microorganisms In Alpine Soils, Steven K. Schmidt, David A. Lipson, Ted K. Raab

Ted K. Raab

We used the substrate-induced growth-response (SIGR) method to quantify salicylate-mineralizing microbes and total microbial biomass in soils from under willows (Salix brachycarpa) and in surrounding meadows dominated by the sedge Kobresia myosuroides. Willows had a strong effect on the biomass of salicylate-mineralizing microbes in both years of this study. There were always higher biomass levels of salicylate mineralizers in soils from under Salix (4.6–10.1 ug C/ g) than under Kobresia (0.23–0.76 ug/ g). In contrast, total microbial biomass was not significantly different under these plant species in 1996 and was only higher under Salix on one date in 1997. These …

Precise, Highly Female-Biased Sex Ratios In A Social Spider, Leticia Avilés, John Mccormack, Asher Cutter, Todd Bukowski

John E. McCormack

It has been recognized for some time that the risk of producing maleless clutches should select for a lower than binomial variance in the sex ratio of organisms with female–biased sex ratios, small clutches and breeding groups containing the clutch of a single female. However, to date, precise sex ratios have only been reported for organisms with haplodiploid sex determination, a system which allows direct control of the sex of individual offspring. In contrast, under heterogametic sex determination chance is expected to play a crucial role in determining the sex composition of any one family, in particular when males are …

An Outline Of A Theory Of The Constructional Constraints Governing Early Organismic Evolution, Winfried S. Peters, Bernd Herkner

Winfried S. Peters

This paper has no abstract; this is the first paragraph. The origin of life is one of the most fascinating biological enigmas (Dyson 1985, de Duve 1991). A multitude of hypotheses is available, ranging from the classical "primordial broth" (Haldane 1929) to the "genetic takeover" (Cairns-Smith 1982). Most of these models center on biochemical, metabolic, or genetic aspects. To our knowledge a comprehensive investigation into the mechanical constraints governing the early development of organismic constructions is not available to date. Attempting to close this gap, we here present an outline of a theory of the transformation of constructions in early …

The Male-Male Tandem: A Novel Form Of Mate Guarding In Perithemis Tenera, Paul V. Switzer, Jaime K. Schultz

Paul V. Switzer

No abstract provided.

Proximate Constraints On Intruder Detection In The Dragonfly Perithemis Tenera (Odonata: Libellulidae): Effects Of Angle Of Approach And Background, Paul V. Switzer, Perri K. Eason

Paul V. Switzer

The implications of insects’ vision for territorial defense have been relatively little studied in the field. In the dragonfly Perithemis tenera Say we investigated whether either the angle at which an intruder was viewed by a territorial resident or the background against which it was viewed affected the detection of that intruder. Residents detected intruders at a greater distance if the intruders were directly in front of them; they also detected more intruders in front of them than from other angles. Intruders viewed against distant vegetation were detected more readily than were intruders against near vegetation. Residents detected more intruders …

Protein-Coding Genes As Molecular Markers For Ecologically Distinct Populations: The Case Of Two Bacillus Species, T. Palys, E. Berger, I. Mitrica, L. Nakamura, Frederick Cohan

Frederick M. Cohan

No abstract provided.

Toward An Ecosystem Approach To Remediation In The Great Basin, Ted K. Raab

Ted K. Raab

We consider the web of interactions among geologic materials, soils, plants, and animals to ask, "If mining or other extractive energy technologies occur in desert regions, what do we need to know to return the land to productivity?" The Great Basin represents a formidable challenge in this regard, as winters in these cold deserts and seasonal lack of moisture during parts of the year severely constrain the growing season for vegetation. Due to the nature of current or proposed mining activities in this region, we have chosen to concentrate on two potential pollutants: the trace element selenium (Se) and nitrate …

Size Selectivity Of Crappie Angling, Leandro E. Miranda, Brian S. Dorr

Brian S Dorr

Abstract.—Over 6,000 black crappies Pomoxis nigromaculatus and white crappies P. annularis were tagged in five lakes and reservoirs to quantify size selectivity of angling. Total length of fish tagged ranged from 20.0 to 39.8 cm; fish caught by anglers ranged from 20.0 to 38.8 cm. Return rates were low at lengths near 20 cm, increased gradually to a peak between 26 and 32 cm, and decreased for longer fish. This pattern was consistent among the five lakes and reservoirs and did not differ between species. Observed size-selective exploitation resulted in the lopsided removal of intermediate age-classes, thereby simulating a reversed …

Biodiversity And Ecosystem Functioning: Importance Of Species Evenness In An Old Field, Brian J. Wilsey, Catherine Potvin

Brian J. Wilsey

Changes in land use, habitat fragmentation, nutrient enrichment, and environmental stress often lead to reduced plant diversity in ecosystems. However, it remains controversial whether these reductions in diversity will affect energy flow and nutrient cycling. Diversity has two components: species richness, or the number of plant species in a given area, and species evenness, or how well distributed abundance or biomass is among species within a community. We experimentally varied species evenness and the identity of the dominant plant species in an old field of Quebec to test whether plant productivity would increase with increasing levels of evenness, and whether …

Effects Of Resource Availability On Carbon Allocation And Developmental Instability In Cloned Birch Seedlings, Brian J. Wilsey, Janne H. Lappalainen, Jocelyn Martel, Kyösti Lempa, Vladimir Ossipov

Brian J. Wilsey

Abundant nitrogen improves seedling growth and establishment. Vigorous growth brings about changes in rates and patterns of plant development and changes in the relationship between primary and secondary metabolism, which may make seedlings more susceptible to herbivores and pathogens than are slow-growing seedlings. We studied how nitrogen fertilization and manual defoliation of source leaves affect growth, carbon allocation, and developmental instability in cloned seedlings of white birch (Betula pubescens Ehrh.). Biomass was higher, whereas concentrations of most classes of phenolic compounds were lower in the nitrogen-rich environment. Interestingly, fertilization did not change the concentrations of cell wall–bound proanthocyanidins, which represent …

The Baldwin Effect: An Archeology, David Depew

David J Depew

Abstract: “The Baldwin effect” stands for a wide variety of ways in which learn ing can be conceived as guiding adap tive evolution ary change. An analysis of the history of this notion reveals that it does not reliably refer either to a theory-neutral empirical phenomenon or to a single theoretical hypothesis. On the contrary, articulations of the general idea depend on distinctive, but in commensurable, theoretical backgrounds. In reconstructing the conceptual history of the Baldwin effect I hope to support contemporary explorations of idea by encouraging the articulation of new theoretical frameworks in which it might make sense. I …

Keeping And First Breeding Record Of Bourret’S Box Turtle Cuora Galbinifrons Bourreti, Obst And Reimann, 1994, With Comments On Its Conservation Status, Edgar Lehr, Joachim Fiebig

Edgar Lehr

A group of Bourret's box turtles were obtained from the animal trade in central Vietnam in 1993. Although eggs were recorded in captivity since 1994, successful breeding was first achieved in 1998. Three clutches each containing one egg were laid between March and June 1998 and one clutch of two eggs was laid in 1999. The eggs had an average length of 55.4 mm and an average width of 30.0 mm. At a temperature of 24-30 °C the eggs hatched after an incubation period of 85-117 days. One hatchling incubated constantly under 27.5 °C left the egg after 97 days …

The Tadpole Of The Central American Toad Bufo Luetkenii Boulenger, Edgar Lehr, Gunther Kohler, James Mccranie

Edgar Lehr

No abstract provided.

Use Of Thermal Water By The Andean Toad Bufo Spinulosus, Edgar Lehr, Emilio Fuentes, Gunther Kohler

Edgar Lehr

Tadpoles of the Andean toad Bufo spinulosus were found in warm water of a thermal spring in central Peru (Banos, 3460 m elev., Departamento Hmlnuco, Provincia Dos de Mayo). Adjacent water bodies of similar size but without connections to the thermal spring did not contain tadpoles. Water temperatures of the thermal and non-thermal water were measured and compared. 33,4 °C was the highest water temperature where a tadpole of Bufo spinulosus was observed.

A New Species Of Phrynopus From Peru (Amphibia, Anura, Leptodactylidae), Edgar Lehr, Gunther Kohler, Elias Ponce

Edgar Lehr

A new species of leptodactylid frog, Phrynopus horstpauli, is described from the eastern Andean slopes of central Peru (Departamento de Huanuco, Provincia de Ambo, Distrito de Conchamarca) between 3030 and 3430 m elevation. The new species is assigned to the Phrynopus Peruanus group. Phrynopus horstpauli occurs sympatrically with Gastrotheca Griswoldi and another undescribed species of Phrynopus.

Barriers To Genetic Exchange Between Bacterial Species: Streptococcus Pneumoniae Transformation, J. Majewski, P. Zawadzki, P. Pickerill, Frederick M. Cohan, C. W. Dowson

Frederick M. Cohan

No abstract provided.

Temperature-Dependent Parental Investment In The Giant Waterbug Belostoma Flumineum (Heteroptera: Belostomatidae), Scott Kight

Scott Kight