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Biology

Reproduction

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Full-Text Articles in Life Sciences

The Impact Of The Social Environment On Reproductive Plasticity: The Role Of Male Harassment And Larval Competition In Callosobruchus Maculatus, Elisabeth Bacon Apr 2019

The Impact Of The Social Environment On Reproductive Plasticity: The Role Of Male Harassment And Larval Competition In Callosobruchus Maculatus, Elisabeth Bacon

Senior Theses

Effects of the social environment on reproductive behavior are widespread. How the social environment promotes or inhibits behavioral plasticity is less known. I examined the role of male harassment and larval competition on reproductive behaviors in Callosobruchus maculatus. For experiment one, I manipulated male harassment level during female oviposition. I measured oviposition substrate preference, clutch size, egg size, and the trade-off between egg and clutch size. For experiment two, I investigated the effect of the social environment during larval development inside the bean. Groups consisted of a control and sex-ratio-based competition treatments. I recorded the mating behavior of all emerged ...


Characterization Of Vitellogenesis In The Bonnethead Shark Sphyrna Tiburo, Adrien Kathleen Mowle Jan 2018

Characterization Of Vitellogenesis In The Bonnethead Shark Sphyrna Tiburo, Adrien Kathleen Mowle

UNF Graduate Theses and Dissertations

Vitellogenin (Vtg) is a precursor to yolk-proteins produced in the liver of many invertebrates and non-mammalian vertebrates; its synthesis is stimulated by the hormone estradiol (E2). This study is the first to characterize vitellogenin synthesis in a placental viviparous elasmobranch, the yolk-sac placental bonnethead shark, Sphyrna tiburo. This study focused on determining where and when Vtg is produced, as well as what hormonal factors regulate Vtg production. The liver was confirmed as the site of Vtg production via immunohistochemistry. Immunoreactivity was also observed within granulosa cells of ovarian follicles; further experimentation is needed to determine if this is indicative of ...


Synchronization Of Reproduction In Deertoe Mussel (Truncilla Truncata), Kendell R. Loyd Dec 2017

Synchronization Of Reproduction In Deertoe Mussel (Truncilla Truncata), Kendell R. Loyd

MSU Graduate Theses

Freshwater mussels, Order Unionoida, are diverse and widespread in North America but have suffered general decline and many extinctions in recent decades. The reproductive biology of Unionoida is complex and may be vulnerable to human impacts. Male mussels release aggregates of sperm called spermatozeugmata that drift downstream. Females obtain spermatozeugmata from the water and brood the fertilized eggs internally during development. Many aspects of general reproductive biology are poorly understood, including the mechanisms that coordinate spawning and the route by which sperm meet eggs in the female. The present study focuses on reproduction in the Deertoe (Truncilla truncata), which spawns ...


Characterizing The Developmental And Reproductive Toxicities Of Cannabidiol And Δ9-Tetrahydrocannabinol, Dennis Ray Carty Jan 2017

Characterizing The Developmental And Reproductive Toxicities Of Cannabidiol And Δ9-Tetrahydrocannabinol, Dennis Ray Carty

Electronic Theses and Dissertations

Medical marijuana is legal in twenty-nine of the United States and an additional nineteen states have passed legislation for cannabidiol (CBD) treatment of drug-resistant epilepsy, such as Dravet Syndrome (DS) which is diagnosed in children as young as two months. While CBD has shown anecdotal and recently clinical trial efficacy in reducing seizure frequency in DS patients, little is known about the potential adverse side-effects on child physiology, brain development, adult disease, or subsequent generations. Moreover, CBD is rarely administered without including low concentrations of Δ9-tetrahydrocannabinol (THC). The goal of this project is to characterize the relative morphological, behavioral, reproductive ...


Stable Isotopes And The Ecology And Physiology Of Reptiles, Andrew M. Durso May 2016

Stable Isotopes And The Ecology And Physiology Of Reptiles, Andrew M. Durso

All Graduate Theses and Dissertations

Animals trade-off limited resources among competing demands. Trade-offs are difficult to quantify because it is challenging to measure investment into disparate physiological systems using a common scale. Additionally, biologists desire methods to more precisely measure energy status in wild animals. I used stable isotopes to help solve both of these problems. I examined natural spatial and temporal variation in stable isotope signatures of wild lizards and found significant variation. In the lab, I was able to demonstrate the utility of nitrogen stable isotope ratios of uric acid pellets for measuring nutritional stress. By tracing labeled amino acids through the bodies ...


Mechanisms Of Transgenerational Centromere Inheritance, Evan Michael Smoak Jan 2016

Mechanisms Of Transgenerational Centromere Inheritance, Evan Michael Smoak

Publicly Accessible Penn Dissertations

Centromeres control genetic inheritance by directing chromosome segregation, but centromeres in most species are not genetically encoded. Instead, centromeres are specified epigenetically by the presence of Centromere Protein A (CENP-A), a histone H3 variant which replaces canonical histone H3 in centromeric nucleosomes. This dissertation describes underlying mechanisms governing CENP-A nucleosome transmission and epigenetic centromere inheritance during the cell cycle. In the first part of this dissertation, I discuss the role of the CENP-A nucleosome binding protein CENP-C in stabilizing CENP-A nucleosomes at the centromere. Our work demonstrates that CENP-C both reshapes the histone core of the nucleosome, and that CENP-C ...


Macgillivray's Seaside Sparrow (Ammodramus Maritimus Macgillivraii) Breeding Biology & Population Density At Tom Yawkey Wildlife Center, Yianni P. Laskaris Jan 2016

Macgillivray's Seaside Sparrow (Ammodramus Maritimus Macgillivraii) Breeding Biology & Population Density At Tom Yawkey Wildlife Center, Yianni P. Laskaris

Electronic Theses and Dissertations

MacGillivray's Seaside Sparrow (Ammodramus maritimus macgillivraii) is a coastal marsh species sensitive to habitat alteration and threatened by coastal wetland loss. Data on seaside sparrow distribution, breeding success, and critical habitats are lacking in South Carolina. To better understand the demographics and incubation behavior of the species, I monitored breeding success, densities, song output, and presence of predators at three 7-hectare plots at the densest known population in the state. I also placed temperature data-loggers in a subset of nests to discern any links between incubation behavior and nest fate. Densities varied from a low of 5 birds/ha ...


Asian Carp Reproductive Ecology Along The Upper Mississippi River Invasion Front, Carlos Antonio Camacho Jan 2016

Asian Carp Reproductive Ecology Along The Upper Mississippi River Invasion Front, Carlos Antonio Camacho

Graduate Theses and Dissertations

Introduced in the 1960s and 1970s, Grass Carp (Ctenopharyngodon idella), Silver Carp (Hypophthalmichthys molitrix), and Bighead Carp (H. nobilis), collectively called Asian Carp in the US, have invaded the Mississippi River Basin and are expanding their range, threatening ecosystem integrity. Impounded sections on the Upper Mississippi River associated with lock and dams may be poor habitats for reproduction and recruitment due to their lentic flow characteristics and perceived lack of adequate spawning habitat. However, tributaries connected to the impounded sections possess several requirements needed for successful spawning and observations of adults are becoming more prevalent. Unfortunately, little is known regarding ...


The Reproductive Ecology Of The Timber Rattlesnake, Crotalus Horridus, In Northwestern Arkansas: Interactions Between Environment, Steroid Hormones, And Life History, Craig Michael Lind May 2015

The Reproductive Ecology Of The Timber Rattlesnake, Crotalus Horridus, In Northwestern Arkansas: Interactions Between Environment, Steroid Hormones, And Life History, Craig Michael Lind

Theses and Dissertations

In this dissertation I examined the relationship between individual energetic status, hormone production, and life history trait expression in field-active Timber Rattlesnakes, Crotalus horridus. In chapter one I reviewed what is known regarding these relationships in snakes and defined major research goals. In chapter two I described the seasonal profile of testosterone (T) and corticosterone (CORT) in relation to the breeding season and to individual energetic status in males. Results showed that the seasonal pattern of T production in C. horridus was different than other pit viper species with similar mating patterns. Testosterone was elevated in the months leading up ...


Maximum Entropy Modeling Of Indiana Bat (Myotis Sodalis) Maternity Roost Habitat, Joseph Robert Lemen Jan 2015

Maximum Entropy Modeling Of Indiana Bat (Myotis Sodalis) Maternity Roost Habitat, Joseph Robert Lemen

MSU Graduate Theses

Since 1967, the Indiana bat (Myotis sodalis) has been on the U.S. Endangered Species list due to disruption of hibernating bats in caves, summer habitat degradation, and more recently, the onset of White-nose Syndrome. The purpose of this study is to evaluate landscape variables associated with Indiana bat maternity roost trees in an attempt to better understand what factors play a role in their distribution in north central Missouri. I tracked reproductive female Indiana bats to 20 different primary and secondary roost trees; these are roosts that had multiple bats visit them on multiple occasions. GPS location data for ...


Direct Benefits Of Ejaculate-Derived Compounds On Female Reproduction And Immunity In The Field Cricket, Gryllus Texensis, Amy Marie Worthington Jan 2015

Direct Benefits Of Ejaculate-Derived Compounds On Female Reproduction And Immunity In The Field Cricket, Gryllus Texensis, Amy Marie Worthington

Graduate Theses and Dissertations

Sex consumes energy and drastically increases rates of disease, yet many female animals mate more than is necessary to ensure reproductive success. Surprisingly, this trend exists even in species in which the only resource that females receive from mating is the ejaculate itself. In this dissertation, I use the Texas field cricket, Gryllus texensis, to investigate how high mating rates enhance female fecundity and immune response, resulting in increased lifetime fitness. Using laboratory experiments, I examine the effect that mating multiple times and with multiple males has on female fecundity and survival. My results demonstrate that although the risks associated ...


Parasite Infection Mediates Trait Tradeoffs In Fundulus Heteroclitus, Sarah Dunn Jan 2015

Parasite Infection Mediates Trait Tradeoffs In Fundulus Heteroclitus, Sarah Dunn

University Honors Program Theses

To be successful, an animal must eat, grow, and reproduce. With limited resources, there are tradeoffs between these critical life history parameters but the direction of the tradeoffs is largely unknown in a changing environment. To determine whether environmental context affects life-history tradeoffs, I surveyed and quantified investment into reproduction, growth, and a proxy for immunity (parasitism), in the mummichog, Fundulus heteroclitus, a common inhabitant of salt marshes in Georgia. Three salt marsh sites along coastal Georgia (Shellman Bluff, Skidaway Island, and Tybee Island) were selected using a proxy for anthropogenic disturbance (impervious surface), which also fell along a gradient ...


The Reproductive Biology Of The Finetooth Shark, Carcharhinus Isodon, In The Northwest Atlantic Ocean, Amanda Brown Jan 2015

The Reproductive Biology Of The Finetooth Shark, Carcharhinus Isodon, In The Northwest Atlantic Ocean, Amanda Brown

UNF Graduate Theses and Dissertations

Shark fisheries are a multimillion dollar industry in the United States and have significant contributions both recreationally and commercially. In order to maintain this industry, fisheries must be properly managed. An understanding of life history and reproduction is crucial in order to adequately manage shark fisheries. The finetooth shark, Carcharhinus isodon, is a member of the small coastal shark (SCS) fishery complex. It is found in Atlantic waters from South Carolina to Florida and throughout the Gulf of Mexico. This species has recently come under increased fishing pressure and has previously been overfished. New data is needed in order to ...


Reproduction And Nesting In Teleost Fish, With A Focus On Reproduction In Centrarchids And Specific Analysis Of Nesting In Lepomis Megalotis, Rebecca Irene Allee May 2014

Reproduction And Nesting In Teleost Fish, With A Focus On Reproduction In Centrarchids And Specific Analysis Of Nesting In Lepomis Megalotis, Rebecca Irene Allee

Undergraduate Honors Thesis Collection

Fish represent the most diverse and oldest living class of vertebrates, making up approximately 48% of all known members of the subphylum Vertebrata (Bolis, et al. 2001). They are able to live in a wide variety of habitats, from salt water to fresh water and from cold polar seas to areas of intense pressure in the depths of the ocean (Moyle and Cech 1996). Because of this overwhelming diversity, the evolution and ecology of fishes has been a dynamic field of study (Moyle and Cech 1996). Researchers have generally divided fish into three distinct groups: jawless fishes (Class Agnatha), cartilaginous ...


Life History Tradeoffs And The Costs Of Reproduction In Arizona Bark Scorpions (Centruroides Sculpturatus), Michael Marie Webber May 2014

Life History Tradeoffs And The Costs Of Reproduction In Arizona Bark Scorpions (Centruroides Sculpturatus), Michael Marie Webber

UNLV Theses, Dissertations, Professional Papers, and Capstones

Tradeoffs in life history evolution result from conflicts in the time and energy that can be simultaneously invested in activities such as growth, reproduction, and survival. Reproduction is an energetically costly activity for organisms, and is known to elicit alterations in the daily activity patterns of individuals. I investigated reproductive tradeoffs in the Arizona Bark Scorpion,Centruroides sculpturatus. To better understand the nature of tradeoffs in this species, I examined the influence of reproductive state on the predatory efficiency and thermal preference of reproductive females. Further, I examined the influence of reproductive activities (i.e. gestation) on the ability of ...


How Male Attractiveness Mediates The Effect Of An Immune Challenge On Reproductive Traits And Sickness Behavior In The Texas Field Cricket (Gryllus Texensis), Melissa Shari Corona Telemeco Jan 2014

How Male Attractiveness Mediates The Effect Of An Immune Challenge On Reproductive Traits And Sickness Behavior In The Texas Field Cricket (Gryllus Texensis), Melissa Shari Corona Telemeco

Graduate Theses and Dissertations

Trade offs between life-history traits are well studied; however, most studies examine only two life-history traits at a time. For instance, in invertebrates, there is much evidence for the trade-off between reproduction and immunity but no studies that consider how investment in attractiveness might mediate this trade-off. In this study, I test two hypotheses. First, attractive male crickets (Gryllus texensis) have acquired larger resource pools than unattractive males and can invest more in all life-history traits. Attractive males should therefore have better body condition and show a less pronounced trade-off than unattractive males. Second, that attractive and unattractive males start ...


Seasonality Of Conceptions Under Varying Conditions In A Rhesus Macaque Breeding Colony, Ryan Disney Patrick Dunk Aug 2013

Seasonality Of Conceptions Under Varying Conditions In A Rhesus Macaque Breeding Colony, Ryan Disney Patrick Dunk

Theses and Dissertations

Rhesus macaques (Macaca mulatta) are well documented as seasonal breeders. Despite this, little is known about what factors influence seasonal reproduction in rhesus. It has been proposed that rhesus are "relaxed income breeders" (Brockman and van Schaik, 2005), which means they respond to changes in photoperiod but endogenous cues can allow deviations from photoperiod-timed seasonality. This study presents the results of a natural experiment on the influence of different housing conditions (featuring different levels of environmental exposure) on the seasonal pattern of reproduction in rhesus. Once the number of attempts was controlled for, rhesus did not exhibit a seasonal distribution ...


Impact Of Self-Fertilization On Fecundity, The Timing Of First Reproduction, And Population Genetic Structure: Is A Mate Worth The Wait?, Serena Caplins Jun 2013

Impact Of Self-Fertilization On Fecundity, The Timing Of First Reproduction, And Population Genetic Structure: Is A Mate Worth The Wait?, Serena Caplins

Theses and Dissertations

Organisms capable of self-fertilization typically exhibit two evolutionary syndromes uniting high inbreeding depression with low levels of selfing, or low inbreeding depression and high levels of selfing. This study tests for inbreeding depression in an apparent self-compatible, hermaphroditic marine nemertean worm, Prosorhochmus americanus. Fecundity and timing to first reproduction were assessed in isolated and paired worms. Isolated worms produced significantly more offspring than paired worms and did not show inbreeding avoidance. The selfing rate of natural populations was evaluated using species-specific microsatellites and is consistent with preferential selfing (mean: 0.801), though some outcrossing appears to take place. Population genetic ...


Effects Of Environmental Variables On The Reproduction Of Quagga Mussels (Dreissena Rostriformis Bugensis) In Lake Mead, Nv/Az, Richard Steven Ianniello May 2013

Effects Of Environmental Variables On The Reproduction Of Quagga Mussels (Dreissena Rostriformis Bugensis) In Lake Mead, Nv/Az, Richard Steven Ianniello

UNLV Theses, Dissertations, Professional Papers, and Capstones

In 2007, quagga mussels (Dreissena rostriformis bugensis) were found in Lake Mead and have spread downstream on the Colorado River and to other lakes and reservoirs in the Southwestern United States. The quagga mussel's extremely quick colonization of Lake Mead and annual veliger abundance trends provide evidence that the quagga mussels in the Southwest have different reproductive behavior than in previous habitats. This study is one of the first to specifically examine quagga mussel reproduction in the Southwest and examines how quagga mussel reproduction varies at sites known to have different temperatures and other environmental variables resulting from the ...


A Comprehensive Research Framework For Geographic Parthenogenesis In Whiptail Lizards (Genus Aspidoscelis), Adam Leland Jan 2013

A Comprehensive Research Framework For Geographic Parthenogenesis In Whiptail Lizards (Genus Aspidoscelis), Adam Leland

UNLV Theses, Dissertations, Professional Papers, and Capstones

One of the most compelling topics in biology has been the ubiquity of sexual reproduction in living organisms. Because the ecological and evolutionary advantages of sex are well founded, those organisms that reproduce asexually remain enigmatic. Parthenogenesis, the clonal reproduction of an all-female species without the need for males, is a relatively common form of asexual reproduction in vertebrates, and has been subject of numerous academic investigations. Many parthenogenic organisms also share aspects of their geographic distributions, such as inhabiting higher latitudes, higher altitudes, islands or island-like habitats, xeric environments, and marginal, disturbed or ecotonal habitats relative to their sexual ...


Benzo[A]Pyrene Effects On Fundulus Heteroclitus Reproductive Endpoints, Frank Booc Jan 2013

Benzo[A]Pyrene Effects On Fundulus Heteroclitus Reproductive Endpoints, Frank Booc

Electronic Theses and Dissertations

Benzo[a]pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) that modulates aromatase enzyme function and, thus, potentially interrupts normal reproductive function. The aim of this study was to use a fish model, Fundulus heteroclitus, to assess whether BaP exposure adversely impacted reproduction. Adult fish were exposed to waterborne BaP concentrations of (0, 1 or 10 μg/L) for 28 days. Males and females were combined for the second half of the exposure (days 14-28) in order to quantitate egg production and fertilization success. Egg fertilization and subsequent hatching success of F1 embryos was significantly decreased by 10 μg/L ...


Assessing The Link Between Coastal Development And The Quality Of Fish Habitat In Mangrove Tidal Tributaries, Justin Micheal Krebs Jan 2012

Assessing The Link Between Coastal Development And The Quality Of Fish Habitat In Mangrove Tidal Tributaries, Justin Micheal Krebs

Graduate Theses and Dissertations

To assess the potential influence of coastal development on the quality of estuarine habitat for nekton, we characterized land use and the intensity of land development surrounding small tidal tributaries of Tampa Bay. Based on this characterization, we classified tributaries as undeveloped, industrial, urban or man-made (i.e., mosquito-control ditches). Over one-third (37%) of tributaries were determined to be heavily developed, while fewer than one-third (28%) remain relatively undeveloped. We then examined the nekton community from eleven tributaries in watersheds representing the defined land-use classes. Whereas mean nekton density and species richness were both independent of land use, nekton-community structure ...


Mitochondrial Dna Inheritance In Bivalves: A Comparative Study Involving The Unique System Of Doubly Uniparental Inheritance, Sarah Heishman May 2011

Mitochondrial Dna Inheritance In Bivalves: A Comparative Study Involving The Unique System Of Doubly Uniparental Inheritance, Sarah Heishman

Honors Theses

A comparative study of Doubly Uniparental Inheritance (DUI) in the bivalve mollusks Mytilus edulis and Geukensia demissa has yielded unanticipated results. Around the world, it has been reported that members of the taxonomic family Mytilidae (along with the families of Unionidae and Veneridae) consistently exhibit DUI. However, the hard-to-place Geukensia demissa, which is a member of this family, has had varying reports of its DUI status. Most reports involving G. demissa vary with the location in which it is being studied, which prompts more questions than it answers. Due to many months of unsuccessful DNA purification attempts, sequencing and an ...


Reproductive Tactics Of Aphidophagous Lady Beetles: Comparison Of A Native Species And An Invasive Species That Is Displacing It, Yukie Kajita Dec 2008

Reproductive Tactics Of Aphidophagous Lady Beetles: Comparison Of A Native Species And An Invasive Species That Is Displacing It, Yukie Kajita

All Graduate Theses and Dissertations

Coccinella septempunctata L. (Coleoptera: Coccinellidae) has been introduced to North America in recent decades, raising concerns of adverse impacts on native lady beetles, including the congeneric C. transversoguttata richardsoni (Brown). The central focus of my dissertation is to understand the importance of reproduction, in particular, in promoting invasion of C. septempunctata and its replacement of native lady beetles in alfalfa fields of western North America. Studies were conducted to compare reproductive tactics of the invasive C. septempunctata and the native C. transversoguttata, by addressing: 1) maximum rate of reproduction of overwintered lady beetles, 2) population dynamics of the invasive and ...


Temperature-Dependent Sex Determination In Manouria Emys Emys, The Asian Forest Tortoise, Sherri Ann Emer May 2007

Temperature-Dependent Sex Determination In Manouria Emys Emys, The Asian Forest Tortoise, Sherri Ann Emer

Biology Theses

Captive husbandry programs in zoos have documented nesting behavior and have successfully hatched Manouria emys emys, but data on sex determining mechanisms and sex ratios are absent. A total of 30 M. e. emys eggs were artificially incubated at five different temperatures in constant humidity. Mean incubator temperatures were 24.99°C, 25.06°C, 27.18°C, 28.00°C, and 30.79°C. Incubation duration ranged from 60 days to 92 days, and hatching success was 50%. Sex determined by histology and laparoscopy resulted in male differentiation at low temperatures (24.99°C, 27.18°C) and female ...


Ubiquitin-Mediated Proteolysis During Gametogenis In Chlamydomonas Reinhardtii, Hall Thomas Mcgee Jan 1997

Ubiquitin-Mediated Proteolysis During Gametogenis In Chlamydomonas Reinhardtii, Hall Thomas Mcgee

Honors Theses

Scientists in the field of cell biology have focused considerable attention on a unicellular species of green algae known as Chlamydomonas reinhardtii. This organism is relatively common in bodies of fresh water and some types of soil, but most of the attention is due to its value as a model for biochemical studies. This laboratory has undertaken a broad study of the species including exploration into a special class of proteins, called heat shock proteins, and certain biochemical processes of the organism. The work herein described is a part of this latter study, and also a preliminary step in a ...


Relationships Of Epidermal Morphology And Breeding Behaviors In Pebble Nest-Building Minnows (Pisces: Cyprinidae), William R. Mcguire Feb 1993

Relationships Of Epidermal Morphology And Breeding Behaviors In Pebble Nest-Building Minnows (Pisces: Cyprinidae), William R. Mcguire

Master's Theses

Abstrad The objective of this study was to determine if epidermal morphology corresponds with reproductive behavior in cyprinid fishes. Representative species of nest-building fishes (Nocomds leptocephalus, Semotilus atromeculatus, exoglossum maxillingua) and non nest-building fishes (Campostoma anomaulm and Clinostomus funduloides) were studied. Light and scanning electron microscopy were used to examine epidermal morphology and keratin distribution of skins from the snout, cheek, mandible, anterior dorso-lateral trunk, and caudal peduncle of breeding males of nest-building species and were compared to those in non nest-building cyprinid species. Previous frame-by-frame analysis of video tapes of reproductive activities of each species and literature accounts were ...


Reproductive Strategies Of Northern Goshawks And Cooper's Hawks In North-Central New Mexico, Patricia L. Kennedy May 1991

Reproductive Strategies Of Northern Goshawks And Cooper's Hawks In North-Central New Mexico, Patricia L. Kennedy

All Graduate Theses and Dissertations

I assumed that the reproductive strategies of the two Accipiter species investigated in this study, the northern Goshawk (A. gentilis) and the Cooper's hawk (A. cooperii), would be similar to the strategies of other monogamous raptors with sex role partitioning. Any differences in the species' reproductive strategies, particularly hunting strategies, were expected to be a function of their size differences. Contrary to predictions, results indicated that, in north-central New Mexico during brood rearing, both species had similar hunting strategies and utilized similar prey species. These results also indicated that the reproductive strategies of the Cooper's hawk were not ...


The Effects Of Photoperiod And Melatonin Injections On The Reproductive System Of The Male Mongolian Gerbil (Meriones Unguiculatus), Luis Jose Cova Marchan Jan 1984

The Effects Of Photoperiod And Melatonin Injections On The Reproductive System Of The Male Mongolian Gerbil (Meriones Unguiculatus), Luis Jose Cova Marchan

Master's Theses

This work was undertaken to study the effects of photoperiod and melatonin on fertility in male Mongolian gerbils (Meriones unguiculatus). Four groups of fifteen animals each, were placed in different photoperiods (ambient, ranging from 14L:10D to 11.3L:12.3D; 24L:10D; 14L:10D; and 1L:23D). After 35 days, three gerbils from each photoperiod condition were sacrificed and the testes, epididymides, seminal vesicles, prostate, kidneys, adrenals, thymus and hypophysis were weighed. The testes and epididymides were placed in Bouin's fixative and used for histological studies. Also, two males from each photoperiod condition were paired individually with a ...


The Effects Of Photoperiod And Melatonin Injections On The Reproductive System Of Male Mice, Mus Musculus, Icr Strain, Margaret Ann Shugart Aug 1980

The Effects Of Photoperiod And Melatonin Injections On The Reproductive System Of Male Mice, Mus Musculus, Icr Strain, Margaret Ann Shugart

Master's Theses

The reproductive effects of long (24L:OD), natural (14L:lOD), and short (1L:23D) photoperiods were studied in the male mouse, Mus musculus, ICR strain. One third of the mice in each photoperiodic regimen were sacrificed after 45 days. Half of the remaining mice in each regimen received daily melatonin (5-methoxy-N-acetyl tryptamine) injections for 45 additional days. Body weights, testicular and accessory sex organ weights were measured and microscopic examinations of the testes were made. Plasma testosterone levels were determined using radioimmunoassay. Other organ (pituitary, kidney, adrenal, thymus, thyroid) weights were also obtained.