+publisher:"Texas A&M University" +contributor:("DeWitt, Thomas J.")

Texas A&M University

1. Ginter, Carly C. Comparative Analysis of the Morphology and Materials Properties of Pinniped Vibrissae.

Degree: MS, Wildlife and Fisheries Sciences, 2012, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10491

► Vibrissae (whiskers) are important components of the mammalian tactile sensory system, and primarily function as detectors of environmental vibrotactile cues. Pinnipeds possess the largest and… (more)

▼ Vibrissae (whiskers) are important components of the mammalian tactile sensory system, and primarily function as detectors of environmental vibrotactile cues. Pinnipeds possess the largest and most highly innervated vibrissae among mammals and their vibrissae demonstrate a diversity of shapes and likely mechanical properties. These two characteristics are important for vibrotactile sensory perception. Vibrissae of most phocid seals exhibit a beaded morphology with repeated sequences of crests and troughs along their length. I comparatively characterized differences in vibrissae morphologies among phocid species with a beaded profile, phocid species with a smooth profile, and otariids with a smooth profile using traditional and geometric morphometric methods to test the hypothesis that vibrissal morphologies are species-specific manipulations of a common pattern. The traditional and geometric morphometric datasets were subsequently combined by mathematically scaling each to true rank, followed by a single eigendecomposition. Quadratic discriminant function analysis demonstrated that 79.3, 97.8 and 100% of individuals could be correctly classified to taxon based on vibrissal shape variables in the traditional, geometric and combined morphometric analyses, respectively. At least three separate morphologies were identified since phocids with beaded vibrissae, phocids with smooth vibrissae, and otariids each occupied distinct morphospace in the geometric morphometric and combined data analyses. Another important characteristic that influences the transduction of vibrotactile information to the mechanoreceptors in the follicle-sinus complex is the materials properties of the vibrissae. Vibrissae were modeled as cantilever beams and flexural stiffness (EI) was measured to test the hypotheses that the shape of beaded vibrissae reduces flexural stiffness and that vibrissae are anisotropic (orientations differ in EI). Species were significantly different and smooth vibrissae were generally stiffer than beaded vibrissae. Beaded vibrissae decrease vibrations in flow, which, combined with lower flexural stiffness values, may enhance detection of small changes in flow from swimming prey. The anterior plane of the vibrissae is likely the most biologically significant in tracking hydrodynamic trails but had lower flexural stiffness values than the dorsoventral orientation. There is likely a complex interaction between shape and mechanical properties in pinniped vibrissae but the ecological and functional implications are currently unknown. Advisors/Committee Members: Marshall, Christopher D. (advisor), DeWitt, Thomas J. (committee member), Ingole, Sudeep (committee member).

Subjects/Keywords: whiskers; seals; sea lions; morphology; flexural stiffness

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APA (6^th Edition):

Ginter, C. C. (2012). Comparative Analysis of the Morphology and Materials Properties of Pinniped Vibrissae. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10491

Chicago Manual of Style (16^th Edition):

Ginter, Carly C. “Comparative Analysis of the Morphology and Materials Properties of Pinniped Vibrissae.” 2012. Masters Thesis, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10491.

MLA Handbook (7^th Edition):

Ginter, Carly C. “Comparative Analysis of the Morphology and Materials Properties of Pinniped Vibrissae.” 2012. Web. 18 Apr 2021.

Vancouver:

Ginter CC. Comparative Analysis of the Morphology and Materials Properties of Pinniped Vibrissae. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10491.

Council of Science Editors:

Ginter CC. Comparative Analysis of the Morphology and Materials Properties of Pinniped Vibrissae. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10491

Texas A&M University

2. Pease, Allison Ann. Patterns in Functional Structure and Diversity of Stream Fish Assemblages Related to Environmental Factors at Multiple Scales.

Degree: PhD, Wildlife and Fisheries Sciences, 2011, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8588

► The distribution and abundance of stream fishes are influenced by many factors operating at multiple scales. Understanding how environmental variables influence the structure of stream… (more)

▼ The distribution and abundance of stream fishes are influenced by many factors operating at multiple scales. Understanding how environmental variables influence the structure of stream fish assemblages is important for habitat assessment, stream restoration, and for predicting responses to environmental change. An emerging view in community ecology is that a focus on the functional structure of species assemblages in relation to environmental gradients may reveal more general patterns applicable across geographic regions. In this study, I used functional traits related to the trophic ecology, habitat use, and life-history strategies of fishes to examine the influences of environmental factors on stream fish assemblages. The research was carried out in two large regions: the Río Grijalva basin in southern Mexico and the Brazos and Trinity basins in Central Texas. In both regions, relationships between functional structure of stream fish assemblages and environmental factors at local, landscape, and regional scales were examined. Environmental characteristics at all three scales influenced the functional attributes of assemblages studied here. At the local reach scale, stream size, substrate characteristics, the availability of riffle and pool habitats, and abundance of in-stream cover structures were related to the functional trait composition of fish assemblages in the Río Grijalva Basin and in Central Texas streams. Landscape features most strongly related to functional structure in both regions were the extent of forested area in the watershed and the amount of land developed for urban and agricultural uses. At the regional scale, broad physiographic differences between ecoregions had a large influence on the taxonomic and functional composition of stream fish assemblages in Central Texas. Along the broad-scale longitudinal fluvial gradient of the Grijalva region, pronounced changes in the species composition, functional trait diversity, and trophic structure of fish assemblages were observed. Advisors/Committee Members: Winemiller, Kirk O. (advisor), Rosenthal, Gil G. (committee member), Mateos, Mariana (committee member), DeWitt, Thomas J. (committee member).

Subjects/Keywords: stream fish assemblages; Rio Grijalva; Central Texas; trophic ecology; functional traits; community structure

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APA (6^th Edition):

Pease, A. A. (2011). Patterns in Functional Structure and Diversity of Stream Fish Assemblages Related to Environmental Factors at Multiple Scales. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8588

Chicago Manual of Style (16^th Edition):

Pease, Allison Ann. “Patterns in Functional Structure and Diversity of Stream Fish Assemblages Related to Environmental Factors at Multiple Scales.” 2011. Doctoral Dissertation, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8588.

MLA Handbook (7^th Edition):

Pease, Allison Ann. “Patterns in Functional Structure and Diversity of Stream Fish Assemblages Related to Environmental Factors at Multiple Scales.” 2011. Web. 18 Apr 2021.

Vancouver:

Pease AA. Patterns in Functional Structure and Diversity of Stream Fish Assemblages Related to Environmental Factors at Multiple Scales. [Internet] [Doctoral dissertation]. Texas A&M University; 2011. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8588.

Council of Science Editors:

Pease AA. Patterns in Functional Structure and Diversity of Stream Fish Assemblages Related to Environmental Factors at Multiple Scales. [Doctoral Dissertation]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8588

Texas A&M University

3. Dickey, Aaron. Host-Associated Differentiation in an Insect Community.

Degree: PhD, Entomology, 2011, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8695

► Host-Associated Differentiation (HAD) is the formation of genetically divergent hostassociated lineages maintained by ecological isolation. HAD is potentially an important route to ecological speciation in… (more)

▼ Host-Associated Differentiation (HAD) is the formation of genetically divergent hostassociated lineages maintained by ecological isolation. HAD is potentially an important route to ecological speciation in parasites including many insects. While HAD case studies are accumulating, there is a dearth of negative results in the literature making it difficult to know how common the phenomenon really is or whether there are specific traits of parasites which promote HAD. To address these two problems, studies are needed which both publish negative results (i.e., parasites not showing HAD) and test for HAD in multiple parasite species on the same pair of host species (i.e., control for host plant effects). In this study, HAD was tested in three species of herbivorous insects and one parasitoid species on the same two host tree species: pecan and water hickory. The insects were selected based on the presence or absence of two traits, parthenogenesis and endophagy. A test for HAD was considered “positive” when population substructure was explained by host-association. To test for the presence of HAD, insects were sampled sympatrically to eliminate geographical isolation as a confounding factor, sampling was replicated spatially to assure that HAD persisted, and multiple loci were sampled from each individual. Genetic data was analyzed using cluster analyses. HAD was found in both pecan leaf phylloxera and yellow pecan aphid but not in pecan bud moth or in the parasitoid of the yellow pecan aphid, Aphelinus perpallidus. Interestingly, both taxa showing HAD are parthenogenetic and both taxa not showing HAD reproduce sexually. Species showing HAD were tested for the presence of a pre-mating reproductive isolating mechanism (RIM) which could be maintaining HAD despite the potential for gene flow. Selection against migrants to the alternative host was tested in yellow pecan aphid using a no-choice fitness experiment. The overall contribution of this RIM to total isolation was positive and ranged from 0.614 to 0.850. The RIM of “habitat preference” was tested in pecan leaf phylloxera using a dual-choice preference experiment. In this species, preference was only detected for phylloxera originating from water hickory suggesting that host discrimination ability may be a less important factor promoting differentiation in phylloxera. Advisors/Committee Members: Medina, Raul F. (advisor), Eubanks, Micky D. (committee member), Harris, Marvin K. (committee member), DeWitt, Thomas J. (committee member).

Subjects/Keywords: Parthenogenesis; Endophagy; Aphids; Carya, Solidago, Genetic Differentiation; Amplified Fragment Length Polymorphisms; Host-Parasite Interactions; Reciprocal Transplant; Host Plant Discrimination; Sequential Radiation

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APA (6^th Edition):

Dickey, A. (2011). Host-Associated Differentiation in an Insect Community. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8695

Chicago Manual of Style (16^th Edition):

Dickey, Aaron. “Host-Associated Differentiation in an Insect Community.” 2011. Doctoral Dissertation, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8695.

MLA Handbook (7^th Edition):

Dickey, Aaron. “Host-Associated Differentiation in an Insect Community.” 2011. Web. 18 Apr 2021.

Vancouver:

Dickey A. Host-Associated Differentiation in an Insect Community. [Internet] [Doctoral dissertation]. Texas A&M University; 2011. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8695.

Council of Science Editors:

Dickey A. Host-Associated Differentiation in an Insect Community. [Doctoral Dissertation]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8695

Texas A&M University

4. Davis, Kaycee Marie. Digital Analysis of Eye Pigmentation of Hereford, Hereford x Bos indicus or Hereford x Bos taurus Cattle.

Degree: MS, Animal Breeding, 2013, Texas A&M University

URL: http://hdl.handle.net/1969.1/151943

► Ocular neoplasia in cattle with white faces contributes to large production losses. It occurs less frequently in cattle with pigmented eyelids. Corneoscleral pigmentation (irregular extension… (more)

▼ Ocular neoplasia in cattle with white faces contributes to large production losses. It occurs less frequently in cattle with pigmented eyelids. Corneoscleral pigmentation (irregular extension of color from the iris into the sclera) is related to eyelid pigmentation and possibly ocular neoplasia. The objectives of this study were to evaluate eyelid and corneoscleral pigmentation using digital images and objective quantification of pixel intensities (the color of eyelid and corneoscleral regions within the image) to obtain a proportion of eyelid and corneoscleral pigment. Hereford, Hereford × Bos indicus and Hereford × Bos taurus animals were included in the study (n = 1083). Upper and lower eyelid pigment proportions and corneoscleral pigment proportions were determined independently. Fixed effects included breed type, age categories and sex of the animal. Lesion presence (1) or absence (0) was obtained by visual appraisal and was assumed binomially distributed. Left eyelid pigmentation proportions (averaged for upper and lower eyelids) for Hereford (0.67 ± 0.021) were significantly lower than Bos indicus (0.94 ± 0.011) or Bos taurus (0.92 ± 0.011) crosses. Right eyelid pigmentation proportions (averaged for upper and lower eyelids) differed (P < 0.05) for Hereford (0.68 ± 0.022), Bos indicus (0.94 ± 0.011) and Bos taurus (0.90 ± 0.011). Corneoscleral pigmentation proportions (averaged for left and right eyes) differed for each of the three breed types, Hereford (0.05 ± 0.034), Bos indicus (0.32 ± 0.018) and Bos taurus (0.40 ± 0.016). Mature animals (0.34 ± 0.017) had a significantly greater proportion of corneoscleral pigment than did the calves and yearlings (0.17 ± 0.018). Proportion of lesion presence for Hereford (0.07 ± 0.022) was significantly more than Bos indicus (0.01 ± 0.005) or Bos taurus (0.01 ± 0.003). By age category, mature animals (0.06 ± 0.011) had significantly greater presence of lesions than did the calves and yearlings (0.01 ± 0.002). There were strong positive correlations for upper and lower eyelid, between left and right eyelids and between eyelid and corneoscleral pigmentation. Crossbreeding with Bos taurus or Bos indicus animals increase pigmentation and possibly inhibit incidence of ocular neoplasia. Advisors/Committee Members: Riley, David G. (advisor), DeWitt, Thomas J. (committee member), Herring, Andy D. (committee member), Hale, Dan S. (committee member).

Subjects/Keywords: Hereford; cancer eye; eyelid pigmentation

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APA (6^th Edition):

Davis, K. M. (2013). Digital Analysis of Eye Pigmentation of Hereford, Hereford x Bos indicus or Hereford x Bos taurus Cattle. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/151943

Chicago Manual of Style (16^th Edition):

Davis, Kaycee Marie. “Digital Analysis of Eye Pigmentation of Hereford, Hereford x Bos indicus or Hereford x Bos taurus Cattle.” 2013. Masters Thesis, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/151943.

MLA Handbook (7^th Edition):

Davis, Kaycee Marie. “Digital Analysis of Eye Pigmentation of Hereford, Hereford x Bos indicus or Hereford x Bos taurus Cattle.” 2013. Web. 18 Apr 2021.

Vancouver:

Davis KM. Digital Analysis of Eye Pigmentation of Hereford, Hereford x Bos indicus or Hereford x Bos taurus Cattle. [Internet] [Masters thesis]. Texas A&M University; 2013. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/151943.

Council of Science Editors:

Davis KM. Digital Analysis of Eye Pigmentation of Hereford, Hereford x Bos indicus or Hereford x Bos taurus Cattle. [Masters Thesis]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/151943

Texas A&M University

5. Carlson, Keely Britt. Developmental Simulation of the Adult Cranial Morphology of Australopithecus sediba.

Degree: PhD, Anthropology, 2014, Texas A&M University

URL: http://hdl.handle.net/1969.1/153581

► The present study involves the developmental simulation of the adult cranial morphology of the newly discovered species, Australopithecus sediba. Au. sediba has been the focus… (more)

▼ The present study involves the developmental simulation of the adult cranial morphology of the newly discovered species, Australopithecus sediba. Au. sediba has been the focus of considerable discussion and debate in paleoanthropology, following its announcement as a new species in 2010. The unique mosaic morphology of the Malapa hominins - with features aligning them to both earlier species of australopith as well as later Homo - has led some to hypothesize that Au. sediba represents the best candidate ancestor to the genus Homo. To date, only a single, relatively complete cranium has been recovered from the Malapa fossil site, belonging to the type specimen designated MH1. While its second molars are erupted and in occlusion, the third molars remain in the crypt, indicating the juvenile status of MH1. Some commentators have suggested that, because MH1 was a juvenile, its morphology may have changed substantially as it progressed towards adulthood. Further, these changes may have been significant enough to alter current interpretations of its morphological affinities, including traits thought to align Au. sediba with the genus Homo. As such, understanding the degree and nature of change to be expected to occur between second and third molar eruption is of crucial importance. The present study has addressed this problem using 3D geometric morphometric techniques for the developmental simulation of the MH1 fossil cranium. Landmark-based developmental vectors were acquired from three extant hominoid species, including chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla), and modern humans (H. sapiens). Vectors were separated by sex to control for the influence of secondary sexual characteristics and applied to the reconstructed MH1 cranium. Six virtual adult crania were generated in total, a male and female from each of the three extant hominoid species used in simulation. In order to understand the morphological affinities of these generated adults in a broader comparative context, multivariate tests were carried out using a sample of non-robust hominin crania. The results indicate that the majority of morphological changes expected to occur between second and third molar eruption are related to puberty. Results acquired from principal components analysis (PCA) and Procrustes distance matrix analysis indicate that all simulated adult crania of Au. sediba show greater similarities to one another than to other hominin species. All simulated Au. sediba adults consistently clustered together with the original juvenile cranium in PCA, separate from other hominin taxa. Results acquired from distance matrices also indicate that variation within the sample of simulated adult Au. sediba crania does not exceed that of other extant hominoid species, regardless of the developmental vector applied. Therefore, the results of this study provide empirical support for a separate, species-level diagnosis for Au. sediba, and further indicate the need to account for sexual dimorphism in morphometric studies of developmental… Advisors/Committee Members: de Ruiter, Darryl J (advisor), Wright, Lori (committee member), Carlson, David (committee member), DeWitt, Thomas J (committee member).

Subjects/Keywords: Australopithecus sediba; geometric morphometrics; developmental simulation

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APA (6^th Edition):

Carlson, K. B. (2014). Developmental Simulation of the Adult Cranial Morphology of Australopithecus sediba. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/153581

Chicago Manual of Style (16^th Edition):

Carlson, Keely Britt. “Developmental Simulation of the Adult Cranial Morphology of Australopithecus sediba.” 2014. Doctoral Dissertation, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/153581.

MLA Handbook (7^th Edition):

Carlson, Keely Britt. “Developmental Simulation of the Adult Cranial Morphology of Australopithecus sediba.” 2014. Web. 18 Apr 2021.

Vancouver:

Carlson KB. Developmental Simulation of the Adult Cranial Morphology of Australopithecus sediba. [Internet] [Doctoral dissertation]. Texas A&M University; 2014. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/153581.

Council of Science Editors:

Carlson KB. Developmental Simulation of the Adult Cranial Morphology of Australopithecus sediba. [Doctoral Dissertation]. Texas A&M University; 2014. Available from: http://hdl.handle.net/1969.1/153581

6. Case, Janelle Elaine. The feeding biomechanics of juvenile red snapper (Lutjanus campechanus) from the northwestern Gulf of Mexico.

Degree: MS, Wildlife and Fisheries Sciences, 2009, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-1386

► Juvenile red snapper are attracted to structure and settle onto low profile reefs, which serve as nursery grounds. Little is known about their life history… (more)

▼ Juvenile red snapper are attracted to structure and settle onto low profile reefs, which serve as nursery grounds. Little is known about their life history during this time. However, recent studies from a shell bank in the NW Gulf of Mexico have shown higher growth rates for juveniles located on mud habitats adjacent to low profile reefs, perhaps due to varied prey availability and abundance. To further investigate the habitat needs of juvenile red snapper, individuals were collected from a low profile shell ridge (on-ridge) and adjacent mud areas (off-ridge) on Freeport Rocks, TX, and divided into three size classes (≤3.9 cm SL, 4.0-5.9 cm SL, ≥6 cm SL). Feeding morphology and kinematics were characterized and compared among size classes and between the two habitats. A dynamic jaw lever model was used to make predictions about feeding mechanics, and kinematic profiles obtained from high-speed videos of prey capture events validated the model’s predictive ability. Model output suggested an ontogenetic shift in feeding morphology from a juvenile feeding mode (more suction) to an adult feeding mode (more biting). Stomach contents revealed a concomitant shift in prey composition that coincided with the ontogenetic shift in feeding mode. The model also predicted that on-ridge juveniles would have faster jaw closing velocities compared to off-ridge juveniles, which had slower, stronger jaws. Analysis of prey capture events indicated that on-ridge juveniles demonstrated greater velocities and larger displacements of the jaws than off-ridge juveniles. Shape analysis was used to further investigate habitat effects on morphology. Off-ridge juveniles differed from on-ridge in possessing a deeper head and body. Results from model simulations, kinematic profiles, personal observations, and shape analysis all complement the conclusion that on-ridge juveniles exhibited more suction feeding behavior, whereas off-ridge juveniles used more biting behavior. Stomach contents demonstrated an early switch to piscivory in off-ridge juveniles compared to on-ridge juveniles, which may account for higher off-ridge growth rates. Habitat disparity, perhaps available prey composition, generated variations in juvenile feeding mechanics and consequently feeding behavior. This disparity may ultimately affect the growth rates and recruitment success of juvenile red snapper from different habitats. Advisors/Committee Members: Marshall, Christopher D. (advisor), DeWitt, Thomas J. (committee member), Rooker, Jay R. (committee member).

Subjects/Keywords: biomechanics; red snapper

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APA (6^th Edition):

Case, J. E. (2009). The feeding biomechanics of juvenile red snapper (Lutjanus campechanus) from the northwestern Gulf of Mexico. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1386

Chicago Manual of Style (16^th Edition):

Case, Janelle Elaine. “The feeding biomechanics of juvenile red snapper (Lutjanus campechanus) from the northwestern Gulf of Mexico.” 2009. Masters Thesis, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-1386.

MLA Handbook (7^th Edition):

Case, Janelle Elaine. “The feeding biomechanics of juvenile red snapper (Lutjanus campechanus) from the northwestern Gulf of Mexico.” 2009. Web. 18 Apr 2021.

Vancouver:

Case JE. The feeding biomechanics of juvenile red snapper (Lutjanus campechanus) from the northwestern Gulf of Mexico. [Internet] [Masters thesis]. Texas A&M University; 2009. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1386.

Council of Science Editors:

Case JE. The feeding biomechanics of juvenile red snapper (Lutjanus campechanus) from the northwestern Gulf of Mexico. [Masters Thesis]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1386

7. Harrison, Kyle Edward. Ecological Factors Explaining Genetic Differentiation in Aphidomorpha Associated with Pecan and Water Hickory Trees.

Degree: PhD, Entomology, 2017, Texas A&M University

URL: http://hdl.handle.net/1969.1/161395

► Host-associated differentiation (HAD) is a form of ecologically mediated host-race formation between parasite populations. Since HAD can ultimately lead to speciation, it has been proposed… (more)

Subjects/Keywords: Host-associated differentiation (HAD); Aphidomorpha; Carya illinoinensis; Carya aquatica; reproductive isolation; population genetic structuring; immigrant inviability; sympatry; allochrony; gall-making; asexual reproduction; host fidelity; host-shifting

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APA (6^th Edition):

Harrison, K. E. (2017). Ecological Factors Explaining Genetic Differentiation in Aphidomorpha Associated with Pecan and Water Hickory Trees. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/161395

Chicago Manual of Style (16^th Edition):

Harrison, Kyle Edward. “Ecological Factors Explaining Genetic Differentiation in Aphidomorpha Associated with Pecan and Water Hickory Trees.” 2017. Doctoral Dissertation, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/161395.

MLA Handbook (7^th Edition):

Harrison, Kyle Edward. “Ecological Factors Explaining Genetic Differentiation in Aphidomorpha Associated with Pecan and Water Hickory Trees.” 2017. Web. 18 Apr 2021.

Vancouver:

Harrison KE. Ecological Factors Explaining Genetic Differentiation in Aphidomorpha Associated with Pecan and Water Hickory Trees. [Internet] [Doctoral dissertation]. Texas A&M University; 2017. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/161395.

Council of Science Editors:

Harrison KE. Ecological Factors Explaining Genetic Differentiation in Aphidomorpha Associated with Pecan and Water Hickory Trees. [Doctoral Dissertation]. Texas A&M University; 2017. Available from: http://hdl.handle.net/1969.1/161395

Texas A&M University

8. Guzman, Alejandra. Bite performance and feeding kinematics in loggerhead turtles (Caretta caretta) within the context of longline fishery interactions.

Degree: MS, Wildlife and Fisheries Sciences, 2009, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2844

► Feeding biomechanics and foraging behavior are likely contributors to loggerhead sea turtle (Caretta caretta) bycatch in the pelagic longline fishery. To investigate these contributions, loggerhead… (more)

▼ Feeding biomechanics and foraging behavior are likely contributors to loggerhead sea turtle (Caretta caretta) bycatch in the pelagic longline fishery. To investigate these contributions, loggerhead bite performance was measured in several size classes of captive-reared juveniles, captive sub-adults and adults, as well as wild loggerheads. A kinematic study was conducted to investigate loggerhead interactions with modified longline hooks. Kinematic and behavioral variables were assessed in relation to five longline hooks to determine if loggerhead feeding behavior is modulated relative to hook type, size, and offset. The bite force study demonstrated that mean maximum post-hatchling bite force was 2.5N and mass was the best predictor of post-hatchling bite force. Mean maximum bite force of juveniles with mean straight carapace length (SCL) of 12, 31, 44, and 65 cm were 27, 152, 343, and 374 N, respectively. Sub-adult and adult mean maximum bite force was 575 N. Maximum bite force had a positive linear relationship with all head and body morphometrics (P<0.001). Carapace width was the best predictor of bite force throughout ontogeny. The kinematic study demonstrated no differences between hook treatments in all kinematic variables analyzed. The results of this study suggest loggerhead feeding behavior may be stereotypical. Only 33% of all interactions resulted in “hooking” events. “Hooking” was lowest in 16 gage circle hooks with no offset and the 18 gage circle hooks with 10°offset which may be indicative of a lower possibility of the turtle drowning. “Hooking” was highest in the 16 gage circle hooks with 10°offset. The proportion of turtles “hooked” in the mouth was significantly greater than those “hooked” in the throat (P=0.001). Sixteen gage circle hooks with 10° offset had the highest percentage of throat “hooking”, and the 18 gage circle hooks without offset resulted in the lowest percentage of throat hooking. When interacting with J hooks with a 25° offset (9 gage), turtles mostly oriented their head away from the hook offset; however, when interacting with the 16 and 18 gage circle hooks with 10° offset, turtles mostly oriented their heads toward the hook offset. These data suggest that turtles may distinguish between small and large offsets, and may modulate their feeding behavior accordingly. Alternatively, turtles may be detecting hook size or hook shape. A more thorough characterization of loggerhead bite performance and feeding kinematics will be useful when developing or modifying longline fishery gear aimed at reducing loggerhead bycatch. Advisors/Committee Members: Marshall, Christopher D. (advisor), DeWitt, Thomas J. (committee member), Landry, Andre M. (committee member).

Subjects/Keywords: sea turtles; longline; bite force; feeding kinematics

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APA (6^th Edition):

Guzman, A. (2009). Bite performance and feeding kinematics in loggerhead turtles (Caretta caretta) within the context of longline fishery interactions. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2844

Chicago Manual of Style (16^th Edition):

Guzman, Alejandra. “Bite performance and feeding kinematics in loggerhead turtles (Caretta caretta) within the context of longline fishery interactions.” 2009. Masters Thesis, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2844.

MLA Handbook (7^th Edition):

Guzman, Alejandra. “Bite performance and feeding kinematics in loggerhead turtles (Caretta caretta) within the context of longline fishery interactions.” 2009. Web. 18 Apr 2021.

Vancouver:

Guzman A. Bite performance and feeding kinematics in loggerhead turtles (Caretta caretta) within the context of longline fishery interactions. [Internet] [Masters thesis]. Texas A&M University; 2009. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2844.

Council of Science Editors:

Guzman A. Bite performance and feeding kinematics in loggerhead turtles (Caretta caretta) within the context of longline fishery interactions. [Masters Thesis]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2844

Texas A&M University

9. Ruehl, Clifton Benjamin. Resource variation and the evolution of phenotypic plasticity in fishes.

Degree: MS, Wildlife and Fisheries Sciences, 2004, Texas A&M University

URL: http://hdl.handle.net/1969.1/486

► Resource variation and species interactions require organisms to respond behaviorally, physiologically, and morphologically within and among generations to compensate for spatial and temporal environmental variation.… (more)

▼ Resource variation and species interactions require organisms to respond behaviorally, physiologically, and morphologically within and among generations to compensate for spatial and temporal environmental variation. One successful evolutionary strategy to mitigate environmental variation is phenotypic plasticity: the production of alternative phenotypes in response to environmental variation. Phenotypic plasticity yields multiple characters that may enable organisms to better optimize phenotypic responses across environmental gradients. In this thesis, I trace the development of thought on phenotypic plasticity and present two empirical studies that implicate phenotypic plasticity in producing morphological variation in response to resource variation. The first empirical study addresses trophic plasticity, population divergence, and the effect of fine-scale environmental variation in western mosquitofish (Gambusia affinis). Offspring from two populations were fed either attached or unattached food items offered in three orientations: (1) water surface, (2) mid-water, (3) benthic, and (4) a daily rotation of the former three (fine-grained variation). Attached food induced wide heads, blunt snouts and rounded pectoral fins relative to morphology in the unattached treatment. Mid-water feeding induced elongated heads and deeper mid-bodies relative to benthic and surface feeding induced morphologies. The rotating treatment produced intermediate morphologies. Population divergence seemed related to both trophic and predation ecology. Ecomorphological consequences of induced morphologies and the need for inclusion of greater ecological complexity in studies of plasticity are discussed. The second study examines induced morphological plasticity and performance in red drum (Sciaenops ocellatus). I fed hatchery fish either hard or soft food for two months. Performance trials were designed to measure their ability to manipulate and consume hard food items. External morphology and the mass of pharyngeal crushing muscles were assessed for variation among treatments. A hard food diet induced deeper bodies and larger heads, more massive pharyngeal muscles, and initially more efficient consumption of hard food than fish receiving soft food. The observed morphological variation is in accordance with variation among species. Determining evolutionary mechanisms operating within red drum populations should eventually aid in developing and optimizing conservation efforts and ease the transition from hatchery facilities to estuaries. Advisors/Committee Members: DeWitt, Thomas J. (advisor), Pinckney, James L. (committee member), Winemiller, Kirk O. (committee member).

Subjects/Keywords: resource polymorphism; trophic plasticity; ecomorphology; foraging ecology; geometric morphometrics; population differentiation; induced morphology; fine grained resource variation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ruehl, C. B. (2004). Resource variation and the evolution of phenotypic plasticity in fishes. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/486

Chicago Manual of Style (16^th Edition):

Ruehl, Clifton Benjamin. “Resource variation and the evolution of phenotypic plasticity in fishes.” 2004. Masters Thesis, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/486.

MLA Handbook (7^th Edition):

Ruehl, Clifton Benjamin. “Resource variation and the evolution of phenotypic plasticity in fishes.” 2004. Web. 18 Apr 2021.

Vancouver:

Ruehl CB. Resource variation and the evolution of phenotypic plasticity in fishes. [Internet] [Masters thesis]. Texas A&M University; 2004. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/486.

Council of Science Editors:

Ruehl CB. Resource variation and the evolution of phenotypic plasticity in fishes. [Masters Thesis]. Texas A&M University; 2004. Available from: http://hdl.handle.net/1969.1/486

Texas A&M University

10. Garza, Mark Isaac. Predator induced defenses in prey with diverse predators.

Degree: MS, Wildlife and Fisheries Sciences, 2006, Texas A&M University

URL: http://hdl.handle.net/1969.1/3309

► Phenotypic plasticity is an environmentally based change in phenotype and can be adaptive. Often, the change in an organism's phenotype is induced by the presence… (more)

▼ Phenotypic plasticity is an environmentally based change in phenotype and can be adaptive. Often, the change in an organism's phenotype is induced by the presence of a predator and serves as a defense against that predator. Defensive phenotypes are induced in freshwater physid snails in response to both crayfish and molluscivorous fish. Alternative morphologies are produced depending on which of these two predators snails are raised with, thus protecting them from each of these predators' unique mode of predation. Snails and other mollusks have been shown to produce thicker, differently shaped shells when found with predators relative to those found without predators. This production of thicker, differently shaped shells offers better protection against predators because of increased predator resistance. The first study in this thesis explores costs and limits to plasticity using the snailfish- crayfish system. I exposed juvenile physid snails (using a family structure) to either early or late shifts in predation regimes to assess whether developmental flexibility is equally possible early and late in development. Physid snails were observed to produce alternative defensive morphologies when raised in the presence of each of the two predators. All families responded similarly to the environment in which they were raised. Morphology was found to be heritable, but plasticity itself was not heritable. Morphology was found to become less flexible as snails progressed along their respective developmental pathways. In the second study, I raised physid snails with and without shell-crushing sunfish and examined the differences in shell thickness, shell mass, shell size and shell microstructural properties between the two treatment groups. Shells of snails raised with predators were found to be larger, thicker and more massive than those raised without predators, but differences in microstructure were found to be insignificant. I conclude that the observed shell thickening is accomplished by the snails' depositing more of the same material into their shells and not by producing a more complex shell composition. Advisors/Committee Members: DeWitt, Thomas J. (advisor), Coganto, Anthony I. (committee member), Fitzgerald, Lee (committee member).

Subjects/Keywords: inducible defenses; shell morphology; Physa; Lepomis microlophus; morphometrics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Garza, M. I. (2006). Predator induced defenses in prey with diverse predators. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/3309

Chicago Manual of Style (16^th Edition):

Garza, Mark Isaac. “Predator induced defenses in prey with diverse predators.” 2006. Masters Thesis, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/3309.

MLA Handbook (7^th Edition):

Garza, Mark Isaac. “Predator induced defenses in prey with diverse predators.” 2006. Web. 18 Apr 2021.

Vancouver:

Garza MI. Predator induced defenses in prey with diverse predators. [Internet] [Masters thesis]. Texas A&M University; 2006. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/3309.

Council of Science Editors:

Garza MI. Predator induced defenses in prey with diverse predators. [Masters Thesis]. Texas A&M University; 2006. Available from: http://hdl.handle.net/1969.1/3309

Texas A&M University

11. Papadopoulos, Anthony. An ecophysiological framework for the morphological evolution of bluegill sunfish.

Degree: PhD, Wildlife and Fisheries Sciences, 2009, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-1393

► Body shape affects the capacity and efficiency of swimming in fishes, and places constraints on foraging and reproductive performance. Hence, fitness components, such as aerobic… (more)

▼ Body shape affects the capacity and efficiency of swimming in fishes, and places constraints on foraging and reproductive performance. Hence, fitness components, such as aerobic swimming capacity and efficiency, can be determined from analysis of swimming energetics using active respirometry. In particular, body shape adaptations, such as streamlining, aim at reducing hydrodynamic drag (resistance), thereby increasing swimming efficiency in the presence of water flow, which is a principal contributor to resistance for fish inhabiting rivers. For two populations of bluegill sunfish, one from the Brazos River and the other from Moelman’s Slough (a Brazos River oxbow lake), the metabolic transport rate (MTR) was determined to evaluate differences in swimming efficiency. The standard cost of swimming (SCOS) was also determined to evaluate differences in swimming capacity, which represents the overall capacity of the skeletal muscles to generate mechanical power to overcome hydrodynamic resistance. The MTR and the SCOS describe holistic swimming performance, where the MTR specifies the hydrodynamic response due to swimming, and the SCOS specifies the physiologic response due to swimming. The differences in swimming performance are mainly attributed to factors affecting hydrodynamic resistance and could be predicted by morphology; because body shape, like water flow, is also a principal contributor to resistance. Multivariate body shape, from generalized Procrustes analysis, was used to assess the influence of multiple shape traits on swimming costs. This measure of shape related to swimming performance using partial least-squares analysis showed the two bluegill populations to be significantly different. The results were as follows: the shallow-bodied condition in bluegills was highly correlated with efficient swimming and low swimming capacities; whereas, deep-bodied bluegills were highly correlated with inefficient swimming and high swimming capacities. This is an empirical case of divergent natural selection. For convergence, however, the position of the caudal peduncle is consistent with optimal swimming speed (Um), which depends on standard metabolic rate (SMR), or metabolic maintenance. Bluegills with erect caudal peduncles have a high range of swimming speeds without suffering much cost of swimming ability compared to bluegills with prone caudal peduncles. The adaptive physiological response to high Um is due to a low SCOS because swimming efficiency is low and metabolic maintenance is high. In other words, bluegills that are inefficient swimmers and require a high energy intake cannot survive unless they gain the ability to increase their foraging capacity by thrust or metabolic power reduction. This is perhaps one of the most remarkable adaptive physiological responses due to the joint effects of shape and SMR. Advisors/Committee Members: DeWitt, Thomas J. (advisor), Neill, William H. (committee member), Olszewski, Thomas D. (committee member), Roelke, Daniel L. (committee member).

Subjects/Keywords: standard metabolic rate; swimming efficiency; morphology; adaptation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Papadopoulos, A. (2009). An ecophysiological framework for the morphological evolution of bluegill sunfish. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1393

Chicago Manual of Style (16^th Edition):

Papadopoulos, Anthony. “An ecophysiological framework for the morphological evolution of bluegill sunfish.” 2009. Doctoral Dissertation, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-1393.

MLA Handbook (7^th Edition):

Papadopoulos, Anthony. “An ecophysiological framework for the morphological evolution of bluegill sunfish.” 2009. Web. 18 Apr 2021.

Vancouver:

Papadopoulos A. An ecophysiological framework for the morphological evolution of bluegill sunfish. [Internet] [Doctoral dissertation]. Texas A&M University; 2009. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1393.

Council of Science Editors:

Papadopoulos A. An ecophysiological framework for the morphological evolution of bluegill sunfish. [Doctoral Dissertation]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1393

Texas A&M University

12. Partridge, Charlyn G. The Effect of Environmental Contaminants on Mating Dynamics and Population Viability in a Sex-Role-Reversed Pipefish.

Degree: PhD, Zoology, 2010, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7324

► Understanding how anthropogenic activity impacts the health and viability of wildlife populations is one of the most important tasks of environmental biology. A key concern… (more)

▼ Understanding how anthropogenic activity impacts the health and viability of wildlife populations is one of the most important tasks of environmental biology. A key concern related to bi-products of human activity is the accumulation of environmental pollutants within aquatic environments. Pollutants such as endocrine disruptors and heavy metals have the potential to impact both human and wildlife populations in contaminated areas. While much research has focused on how these compounds impact natural selection processes, such as viability and reproduction, their effect on sexual selection processes is not as clear. The goal of this dissertation was to address how environmental contaminants impact sexual selection processes in a sex-role reversed pipefish and evaluate how these effects may impact long-term population viability. Here we show that short periods of exposure to environmentally relevant concentrations of a synthetic estrogen result in male pipefish with female-like secondary sexual traits. While these males are capable of reproduction, exposed males are discriminated against by females in mate choice tests. In natural populations, this type of discrimination could reduce male mating opportunities, potentially reducing their reproductive success. In an additional component of this dissertation, it was discovered that pipefish populations around Mobile Bay, specifically Weeks Bay, are currently being exposed to significantly elevated levels of mercury. These populations are genetically distinct from coastal populations but moderate levels of gene flow occur among sites, and gene flow between contaminated and non-contaminated population may be influencing how environmental contaminants are impacting genetic diversity and population viability. In the case of endocrine disruptors, migration between contaminated and non-contaminated sites may negatively impact population viability. Morphological traits induced with exposure to contaminants may be maintained for extended periods of time, therefore, the effect the exposed phenotype has on mating dynamics and sexual selection could be carried to non-contaminated sites if exposed individuals move to new populations. On the other hand, immigration of individuals from non-contaminated sites into contaminated areas may help maintain genetic diversity within exposed populations. In conclusion, the work presented in this dissertation shows that the presence of environmental toxins can significantly impact sexual selection processes, which in turn can have profound effects on the viability and future evolutionary trajectory of populations. Future work in this area should not only address how these toxins impact individual fitness, but should also address how population structure may be influencing the severity of these compounds on natural populations. Advisors/Committee Members: Jones, Adam G. (advisor), Rosenthal, Gil (committee member), MacKenzie, Duncan (committee member), DeWitt, Thomas J. (committee member).

Subjects/Keywords: pipefish; endocrine disruptors; EE2; mating dynamics; population structure

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Partridge, C. G. (2010). The Effect of Environmental Contaminants on Mating Dynamics and Population Viability in a Sex-Role-Reversed Pipefish. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7324

Chicago Manual of Style (16^th Edition):

Partridge, Charlyn G. “The Effect of Environmental Contaminants on Mating Dynamics and Population Viability in a Sex-Role-Reversed Pipefish.” 2010. Doctoral Dissertation, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7324.

MLA Handbook (7^th Edition):

Partridge, Charlyn G. “The Effect of Environmental Contaminants on Mating Dynamics and Population Viability in a Sex-Role-Reversed Pipefish.” 2010. Web. 18 Apr 2021.

Vancouver:

Partridge CG. The Effect of Environmental Contaminants on Mating Dynamics and Population Viability in a Sex-Role-Reversed Pipefish. [Internet] [Doctoral dissertation]. Texas A&M University; 2010. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7324.

Council of Science Editors:

Partridge CG. The Effect of Environmental Contaminants on Mating Dynamics and Population Viability in a Sex-Role-Reversed Pipefish. [Doctoral Dissertation]. Texas A&M University; 2010. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7324

Texas A&M University

13. Magorokosho, Cosmos. Genetic diversity and performance of maize varieties from Zimbabwe, Zambia and Malawi.

Degree: PhD, Plant Breeding, 2007, Texas A&M University

URL: http://hdl.handle.net/1969.1/4669

► Large scale and planned introduction of maize (Zea mays) in southern Africa was accomplished during the last 100 years. Since then, smallholder farmers and breeders… (more)

▼ Large scale and planned introduction of maize (Zea mays) in southern Africa was accomplished during the last 100 years. Since then, smallholder farmers and breeders have been selecting varieties best adapted to their specific growing conditions. Six studies were conducted to generate information on the current levels of genetic diversity and agronomic performance of both farmer-developed and commercially-bred maize varieties in Zimbabwe, Zambia and Malawi to help in the identification of sources of new alleles for improving yield, especially under the main abiotic stresses that prevail in the region. In the first study, 267 maize landraces were collected from smallholder farmers in different agro-ecological zones of the three countries for conservation and further studies. Passport data and information on why smallholder farmers continue to grow landraces despite the advent of modern varieties were also collected along with the landraces. The second study revealed considerable variation for phenological, morphological and agronomic characters, and inter-relationships among the landraces and their commercial counterparts. A core sample representing most of the diversity in the whole collection of landraces was selected for further detailed analyses. The third study revealed high levels of molecular diversity between landraces originating from different growing environments and between landraces and commercially-bred varieties. The Simple Sequence Repeat (SSR) data also showed that the genetic diversity introduced from the original gene pool from the USA about 100 years ago is still found in both the descendant landraces and commercially-bred varieties. The fourth study showed that in general, commercially-bred varieties outyielded landraces under both abiotic stress and nonstress conditions with some notable exceptions. Landraces were more stable across environments than improved varieties. The most promising landraces for pre-breeding and further investigation were also identified. The clustering patterns formed based on agronomic data were different from SSR markers, but in general the genotype groupings were consistent across the two methods of measuring diversity. In the fifth study, the more recently-bred maize varieties in Zimbabwe showed consistent improvement over older cultivars in grain yield. The apparent yearly rate of yield increase due to genetic improvement was positive under optimum growing conditions, low soil nitrogen levels and drought stress. The sixth study revealed that in general, genetic diversity in Zimbabwean maize has neither significantly decreased nor increased over time, and that the temporal changes observed in this study were more qualitative than quantitative. The results from the six studies confirm the origin of maize in southern Africa and reveals that considerable genetic variation exists in the region which could be used to broaden the sources of diversity for maize improvement under the current agro-ecological conditions in southern Africa. Advisors/Committee Members: Betran, Javier (advisor), DeWitt, Thomas J (committee member), Rooney, William L (committee member), Smith, Wayne C (committee member).

Subjects/Keywords: Maize; Diversity; Africa

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Magorokosho, C. (2007). Genetic diversity and performance of maize varieties from Zimbabwe, Zambia and Malawi. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/4669

Chicago Manual of Style (16^th Edition):

Magorokosho, Cosmos. “Genetic diversity and performance of maize varieties from Zimbabwe, Zambia and Malawi.” 2007. Doctoral Dissertation, Texas A&M University. Accessed April 18, 2021. http://hdl.handle.net/1969.1/4669.

MLA Handbook (7^th Edition):

Magorokosho, Cosmos. “Genetic diversity and performance of maize varieties from Zimbabwe, Zambia and Malawi.” 2007. Web. 18 Apr 2021.

Vancouver:

Magorokosho C. Genetic diversity and performance of maize varieties from Zimbabwe, Zambia and Malawi. [Internet] [Doctoral dissertation]. Texas A&M University; 2007. [cited 2021 Apr 18]. Available from: http://hdl.handle.net/1969.1/4669.

Council of Science Editors:

Magorokosho C. Genetic diversity and performance of maize varieties from Zimbabwe, Zambia and Malawi. [Doctoral Dissertation]. Texas A&M University; 2007. Available from: http://hdl.handle.net/1969.1/4669

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