Browsing by Subject "courtship"
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Item Captive and Wild Observations of the Courtship and Spawning Behavior of Guadalupe Bass Micropterus treculii(2013-12-06) Enriquez, Edward JamesThe Guadalupe Bass Micropterus treculii is native to the Texas Hill Country of central Texas. It is distributed across portions of the Brazos, Colorado, Guadalupe and San Antonio River basins. The Guadalupe Bass is threatened by hybridization with non-native smallmouth bass Micropterus dolomieu. Because pure bred Guadalupe Bass are increasingly harder to find in areas where Smallmouth Bass have become established, Texas Parks and Wildlife Department developed a captive spawning program for Guadalupe Bass for supplemental stocking to counter the influence of hybridization. To determine potential mechanisms influencing hybridization in Guadalupe Bass populations, objectives were: (1) characterize nesting habitat and behavior, (2) compare courtship behaviors in native and hatchery environments, and (3) identify behaviors potentially influencing genetic diversity in offspring of hatchery fish. Initial field studies included snorkeling and visual surveys conducted during September and November in 2012 in Gorman Creek, South Llano River, Pedernales River, and the Guadalupe River; no active nests or reproductive adult Guadalupe Bass were observed. During February through May of 2013, visual surveys were repeated at the four field sites. In addition courtship and spawning behavior of Guadalupe Bass were recorded at A.E. Wood Hatchery. In both hatchery and natural environments, previously undocumented reproductive behaviors were observed. Breeding color patterns of males and females became more differentiated, aggressive behavior of males included opercular flaring and jaw locking, and individual males courted multiple females simultaneously and syntopically at nest sites. Only 50% of the available nesting mats were used because of the monopolization of females and nest sites by a few males. Frequencies were significantly different for several male and female behaviors when comparing hatchery to natural environments. The prototypical courting and spawning sequence of the Guadalupe Bass were visually represented in kinematic diagrams. Although behavioral sequences were similar in hatchery and natural sites, certain transition probabilities differed. Potential mechanisms for hybridization were: similar color pattern changes in males and females of both species, female preference in both species for larger males, similar use of nesting habitat in both species, similar reproductive behavioral repertoire, and the monopolization of nesting sites and females by males.Item Fitting It All Together: How Courtship- and Mating-Responsive Genes Affect Drosophila melanogaster Male Behavior(2011-10-21) Ellis, Lisa LynnBehavior is a complex process resulting from the integration of genetic and environmental information. Thus, the genetically tractable Drosophila melanogaster was utilized to better understand the interplay between these factors since Drosophila males and females exhibit sex-specific courtship behaviors that are innate yet modifiable. These sex-specific behaviors, as well as sexually dimorphic development, are regulated, in part, by the somatic sex-determination hierarchy. Since reproductive behaviors rely on the rapid integration of multiple sensory cues, it is likely that the perception and integration of such cues and mating-induced physiological changes are mediated in part by changes in gene expression. Therefore, it was hypothesized that assaying gene expression changes in response to courtship or mating in Drosophila males would uncover new targets of the sex-determination hierarchy and other behaviorally important loci. We took a novel approach to find these behaviorally-responsive loci by utilizing microarray technology to assess courtship- or mating-induced gene expression changes in Drosophila male whole bodies or heads. Mutations in candidate loci were tested for effects on reproductive behaviors and present the first data showing that egghead (egh) and female-specific independent of transformer (fit) affect male reproductive behavior. egh is up regulated in male heads 20 min after courting and is required post-developmentally in a subset of neurons for robust male courtship behavior. fit, a fat body-expressed sex-determination hierarchy target gene, is up regulated in male whole bodies after 5 min of courtship. fit is also up regulated in male heads after 20 min of courtship or 2 hrs after mating. Mutations in fit result in male-male courtship; more specifically, fit mutants direct courtship towards males and also elicit courtship from wild-type males. By analyzing fit's role in courtship behavior, we also shed light on the role the fat body plays in modulating behavior. These studies provide the first pieces of evidence that gene expression changes occur in Drosophila males performing reproductive behaviors. This novel approach identified behaviorally important loci that are expressed in the nervous system and the fat body, indicating that both tissues modulate behavior. Also identified were sex-determination hierarchy target genes and it is likely that further analysis of the remaining candidates will reveal more members of this genetic cascade.Item The Effects of Genetic and Environmental Factors on the Reproductive Behaviors of Drosophila melanogaster(2014-12-18) Saleem, SehreshThe behavioral responses to varying environmental conditions and social interactions are multifaceted and require the coordination of complex neural circuits. Behaviors in animals are continuously affected by varying factors including, but not limited to, environment, genetic makeup, physiological state, or experience. Understanding the fundamental interactions between genotype, environment and phenotype is essential in understanding how evolutionary pressures shape behavior. In this dissertation, I used D. melanogaster to investigate various environmental and genetic components regulating the adult male and female mating behaviors. I explored the genetic components regulating different mating behaviors in adults by investigating the role of p24 proteins in male and female mating behaviors. p24 proteins comprise a family of type-I transmembrane proteins of ~24kDa that are present in yeast and plants as well as metazoans ranging from Drosophila to humans. These proteins are most commonly localized to the endoplasmic reticulum (ER)-Golgi interface and are incorporated in anterograde and retrograde transport vesicles. Drosophila melanogaster expresses nine p24 genes, grouped into four subfamilies. Based upon our mRNA and protein expression data, Drosophila p24 family members are expressed in a variety of tissues. To identify biological functions for particular Drosophila p24 proteins, we used RNA interference (RNAi) to reduce p24 expression. Ubiquitous reduction of most p24 genes resulted in complete or partial lethality during development. Reducing p24 levels in adults caused defects in female fecundity (egg laying) and reduced male fertility. We showed that reduced female fecundity is related to decreased neural p24 expression. These results provide the first genetic analysis of all p24 family members in a multi-cellular animal and indicate vital roles for Drosophila p24s in development and reproduction, implicating neural expression of p24s in the regulation of female behavior. Reproductive behaviors are also modified by social and environmental factors. Particularly, optimizing behavioral strategies that increase mating success are important, and prior sexual experiences as well as the current social environment can potentially affect an animal?s strategy for obtaining mates. Therefore, I investigated two separate scenarios, one where adult males were placed in a male-dense environment and their mating behaviors were quantified post male-male social interaction, and another scenario where the postmating behaviors of males were evaluated after achieving a successful sexual experience. Males reared in male-dense environments increased their mating durations with females, but do not affect the egg laying behavior or fecundity of the females. I found that although majority of the females remated with males within 24 hrs of the first mating, the prior social experience of the male did not influence the female remating latency. Males exposed to other males during early adulthood also did not have a competitive advantage against males raised in isolation. On the other hand, males with prior sexual experience changed their courtship dance and out competed sexually na?ve males in the same mating arena. Females also preferred sexually experienced males by employing their auditory abilities to listen to the male?s modified courtship dance and responded positively by mating with them. Our findings have helped highlight the different behavioral responses shown by flies towards various environmental conditions.Item The relationship between cheliped color and body size in female Callinectes sapidus and its role in reproductive behavior(Texas A&M University, 2004-11-15) Williams, Kirsten LaureneMany species use color during courtship displays, with the more colorful individuals often selected as potential mates. Female blue crabs, Callinectes sapidus, display prominent red markings on their chelipeds, which is absent in males. I tested the hypothesis that females use this sexual dimorphism as an effective signal to potential mates. Body size was positively correlated with size of the colorful pattern on the crusher dactyl. Digital imaging techniques were used to examine and quantify a pattern of coloration in the female blue crab. Morphometric measurements were made using digital images of the carapace and chelae of crabs collected along the Gulf of Mexico coast in Galveston, Texas. Color complexity was examined on digital images of the chelae using Adobe? Photoshop? and Image J. Specific wavelengths were selected and their presence within the attribute quantified and evaluated. To determine whether male blue crabs prefer more colorful females, males were given a choice between females of different female coloration. Males displayed more often and directed more courtship displays towards the more colorful females. I hypothesize that male blue crabs use cheliped coloration as a visual cue for mate selection.