Biology Commons^™

Tactical Adjustment Of Signaling Leads To Increased Mating Success And Survival, Laura Sullivan-Beckers, Eileen A. Hebets

Eileen Hebets Publications

Most sexually reproducing animals overcome the challenge of searching for and attracting mates by utilizing signals that are broadcast through a spatially and temporally varying environment. A diverse suite of behavioral solutions exist for overcoming such environmental variability, including the adjustment of signaling behavior based upon receiver feedback. Few studies have directly examined the relationship between such tactical signaling adjustments and proxies of male fitness; the few that have, failed to find a relationship. Using the wolf spider, Schizocosa rovneri, we set out to first quantify among-male variation in the form and degree of responsiveness to female feedback. Following …

Plasticity In Female Mate Choosiness: A Result Of Variation In Perceived Predation Risk And The Interaction Of Female Age And Male Density, Ashley Atwell

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

In many species, female mate choices can be a strong source of sexual selection. Females often prefer a certain male phenotype, and this can be due to benefits females gain from mating with preferred males. However, such benefits can sometimes be outweighed by the cost of searching for a preferred male. These costs and benefits often change concomitantly with changes in environmental (e.g., predator abundance and conspecific density) and internal factors (e.g., female age). Thus, female mate choosiness (the degree to which preferences for certain males are expressed) should often be plastic. Plasticity in female mate choosiness may be complicated …

Autism As The Early Closure Of A Neuroplastic Critical Period Normally Seen In Adolescence, Julia Marie Berger, Troy T. Rohn, Julia Thom Oxford

Biology Faculty Publications and Presentations

The most severe cases of autism are diagnosed by extreme social dysfunction and other behavioral abnormalities. A number of genetic studies have been conducted to correlate behavioral phenotypes to genetic dysfunctions, but no “autism gene” has yet been discovered. In addition, environmental factors have been found to influence the development of autistic traits with high probability. This review will examine the role of a shortened period of neuroplasticity as a unifying feature of the autistic phenotype. The neuroplastic period of interest normally extends into adolescence, allowing for neural integration and the development of language and social skills. Early closure of …

Cellular And Population Plasticity Of Helper Cd4(+) T Cell Responses, G Magombedze, P B. Reddy, S Eda, V V. Ganusov

Faculty Publications and Other Works -- General Biology

Vertebrates are constantly exposed to pathogens, and the adaptive immunity has most likely evolved to control and clear such infectious agents. CD4(+) T cells are the major players in the adaptive immune response to pathogens. Following recognition of pathogen-derived antigens naïve CD4(+) T cells differentiate into effectors which then control pathogen replication either directly by killing pathogen-infected cells or by assisting with generation of cytotoxic T lymphocytes (CTLs) or pathogen-specific antibodies. Pathogen-specific effector CD4(+) T cells are highly heterogeneous in terms of cytokines they produce. Three major subtypes of effector CD4(+) T cells have been identified: T-helper 1 (Th1) cells …

The Pea Aphid Uses A Version Of The Terminal System During Oviparous, But Not Viviparous, Development, Ryan D. Bickel, Hillary C. Cleveland, Joanna Barkas, Caitlin C. Jeschke, Amelie A. Raz, David L. Stern, Gregory K. Davis

Biology Faculty Research and Scholarship

Background: In most species of aphid, female nymphs develop into either sexual or asexual adults depending on the length of the photoperiod to which their mothers were exposed. The progeny of these sexual and asexual females, in turn, develop in dramatically different ways. The fertilized oocytes of sexual females begin embryogenesis after being deposited on leaves (oviparous development) while the oocytes of asexual females complete embryogenesis within the mother (viviparous development). Compared with oviparous development, viviparous development involves a smaller transient oocyte surrounded by fewer somatic epithelial cells and a smaller early embryo that comprises fewer cells. To investigate …

Potential And Realized Nutrient Resorption In Serpentine And Non-Serpentine Chaparral Shrubs And Trees, Rebecca E. Drenovsky, Catherine E. Koehler, Kathryn Skelly, James H. Richards

Biology

Low-nutrient adapted species have numerous mechanisms that aid in nutrient conservation. Hypothetically, species adapted to nutrient-poor soils should have tighter internal nutrient recycling, as evidenced by greater resorption. However, literature results are mixed. We suggest methodological factors may limit our understanding of this process. We hypothesized that plants adapted to serpentine soils would be more proficient in resorbing N and P than plants adapted to non-serpentine soils, although there would be differences among functional groups within each soil type. For six growing seasons, we sampled senescent leaf tissue from the dominant and co-dominant shrubs and trees found in serpentine and …

Reconstitution Of The Olfactory Epithelium Following Injury In Apoe-Deficient Mice, Britto P. Nathan, Salina Gairhe, Ikemefuna Nwosu, Stephen Clark, Robert G. Struble

Britto P. Nathan

ApoE, a protein component of lipoproteins, is extensively expressed in the primary olfactory pathway. Because apoE has been shown to play a vital role in nerve repair and remodeling, we hypothesized that apoE expression will increase in the injured olfactory epithelium (OE), and that apoE deficiency in apoE knockout (KO) mice will lead to delayed/incomplete reconstitution of the OE following injury. To directly test this hypothesis, we compared OE regeneration in wild-type (WT) and KO mice following injury induced by intranasal irrigation of Triton X-100. OE was collected at 0, 3, 7, 21, 42, and 56 days post lesion. The …

Reconstitution Of The Olfactory Epithelium Following Injury In Apoe-Deficient Mice, Britto P. Nathan, Salina Gairhe, Ikemefuna Nwosu, Stephen Clark, Robert G. Struble

Faculty Research & Creative Activity

ApoE, a protein component of lipoproteins, is extensively expressed in the primary olfactory pathway. Because apoE has been shown to play a vital role in nerve repair and remodeling, we hypothesized that apoE expression will increase in the injured olfactory epithelium (OE), and that apoE deficiency in apoE knockout (KO) mice will lead to delayed/incomplete reconstitution of the OE following injury. To directly test this hypothesis, we compared OE regeneration in wild-type (WT) and KO mice following injury induced by intranasal irrigation of Triton X-100. OE was collected at 0, 3, 7, 21, 42, and 56 days post lesion. The …

Reconstitution Of The Olfactory Epithelium Following Injury In Apoe-Deficient Mice, Britto Nathan, Salina Gairhe, Ikemefuna Nwosu, Stephen Clark, Robert Struble

Faculty Research & Creative Activity

ApoE, a protein component of lipoproteins, is extensively expressed in the primary olfactory pathway. Because apoE has been shown to play a vital role in nerve repair and remodeling, we hypothesized that apoE expression will increase in the injured olfactory epithelium (OE), and that apoE deficiency in apoE knockout (KO) mice will lead to delayed/incomplete reconstitution of the OE following injury. To directly test this hypothesis, we compared OE regeneration in wild-type (WT) and KO mice following injury induced by intranasal irrigation of Triton X-100. OE was collected at 0, 3, 7, 21, 42, and 56 days post lesion. The …

Locomotion In Response To Shifting Climate Zones: Not So Fast, Martin E. Feder, Theodore Garland Jr., James H. Marden, Anthony J. Zera

School of Biological Sciences: Faculty Publications

Although a species’ locomotor capacity is suggestive of its ability to escape global climate change, such a suggestion is not necessarily straightforward. Species vary substantially in locomotor capacity, both ontogenetically and within/among populations, and much of this variation has a genetic basis. Accordingly, locomotor capacity can and does evolve rapidly, as selection experiments demonstrate. Importantly, even though this evolution of locomotor capacity may be rapid enough to escape changing climate, genetic correlations among traits (often due to pleiotropy) are such that successful or rapid dispersers are often limited in colonization or reproductive ability, which may be viewed as a trade-off. …

Time Constraints Mediate Predator-Induced Plasticity In Immune Function, Condition, And Life History, Robby Stoks, Marjan De Block, Stefanie Slos, Wendy Van Doorslaer, Jens Rolff

Dartmouth Scholarship

The simultaneous presence of predators and a limited time for development imposes a conflict: accelerating growth under time constraints comes at the cost of higher predation risk mediated by increased foraging. The few studies that have addressed this trade-off have dealt only with life history traits such as age and size at maturity. Physiological traits have largely been ignored in studies assessing the impact of environmental stressors, and it is largely unknown whether they respond independently of life history traits. Here, we studied the simultaneous effects of time constraints, i.e., as imposed by seasonality, and predation risk on immune defense, …

Proliferation Zones In The Salmon Telencephalon And Evidence For Environmental Influence On Proliferation Rate, Sean C. Lema, Mark J. Hodges, Michael P. Marchetti, Gabrielle A. Nevitt

Biological Sciences

Cell proliferation occurs in the brain of fish throughout life. This mitotic activity contributes new neurons to some brain subdivisions, suggesting potential for plasticity in neural development. Recently we found that the telencephalon in salmonids (salmon, trout) is significantly reduced in fish reared in hatcheries compared to wild fish, and that these differences resulted in part from rearing conditions. Here, we describe localized areas of cell proliferation in the telencephalon of juvenile coho salmon (Oncorhynchus kisutch) and begin to explore whether mitotic activity in these areas is sensitive to environmental conditions. Using the 5-bromo-2'-deoxyuridine (BrdU) cell birthdating technique, …

Social Interactions Of Lythrypnus Dalli And Their Effects On Aggression, Neuropeptides, Steroid Metabolism, And Sex-Typical Morphology, Michael Paul Black

Biology Dissertations

Social interactions can have profound effects on the behavior, physiology, and overall fitness of an individual. An example of this in Lythrypnus dalli is the removal of a male from a social group resulting in a dominant female fish changing sex. The dominant female's transformation involves a suite of changes including brain, behavior, morphology, and physiology. Following the social trigger (male removal), sex-changing individuals' morphology, steroid levels, and changes in the behavior were quantified in the field and compared to results found previously in the laboratory. There were lower rates of aggressive and courtship behavior in the field, but the …

Evolution And Plasticity Of Photosynthetic Thermal Tolerance, Specific Leaf Area And Leaf Size: Congeneric Species From Desert And Coastal Environments, Charles A. Knight, David D. Ackerly

Biological Sciences

• We examined whether increased high temperature photosynthetic thermal tolerance (PT), reduced specific leaf area (SLA) and reduced leaf size represent correlated and convergent adaptations for recently diverged Encelia, Salvia, Atriplex and Eriogonumcongeneric species pairs from contrasting thermal and water environments (the Mojave Desert and coastal California). We also studied whether variation in PT is associated with inducible small heat shock protein expression (sHsp).

• Traits were measured in a common environment (CE) and in the field to partition effects of phenotypic plasticity and genetic divergence.

• We found little evidence for convergent adaptation of PT (CE measurements). Field …

An Ecological And Evolutionary Analysis Of Photosynthetic Thermotolerance Using The Temperature-Dependent Increase In Fluorescence, Charles A. Knight, David D. Ackerly

Biological Sciences

The hypothesis that species inhabiting warmer regions have greater photosynthetic tolerance of high temperatures was tested using the temperature-dependent increase in fluorescence (T-F_o). Congeneric species pairs of Atriplex, Salvia, Encelia, and Eriogonum with desert versus coastal distributions were studied in a common environment and in the field. In addition, 21 species with contrasting microclimate distributions were studied at a field site in a northern California chaparral community. The average July maximum temperature within the current distributions of species was quantified using a geographic information system. Four parameters (T_crit, T_S20, …