Biology Commons^™

The Ecology And Life History Of The Mexican Tetra, Astyanax Mexicanus, (Teleostei: Characidae) In The Lower Rio Grande Valley, Texas, Mario Estrada

Theses and Dissertations - UTB/UTPA

The Mexican tetra has been found to migrate from shallow waters in the spring and summer months into deeper waters during the winter months when temperatures are too cold for their survival. This fish is omnivorous with insect material being the major source of food. Its food types include green algae, nematoceran larvae, hemipterans, coleopterans, hymenopterans, dipterans, ostracods, fish eggs and amphipods. Furthermore, size classes showed that the Mexican tetras reached their largest size at the River site and smaller sizes at the Bridge and Gate sites and apparently breed year round. They are capable of producing from 300 to …

The Ecology And Vocalisations Of Banded Ground-Cuckoo Neomorphus Radiolosus, Bernabé López-Lanús, Karl S. Berg, Ralf Strewe, Paul G. W. Salaman

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

El Cuco-Hormiguero Franjeado Neomorphus radiolosus es un ave rara, con problemas de conservación y cuya información sobre comportamiento y biología es deficiente. Cualquier dato adicional en este aspecto representa un instrumento importante para su conservación. Presentamos nuevos datos sobre su compartamiento en base a individuos observados en la Estación Biológica Jatun Sacha Bilsa, Esmeraldas, Ecuador, y la Reserva El Pangan, Nariño, Colombia.

Current Status Of Northern Beardless-Tyrannulet And Tropical Parula In Bentsen-Rio Grande Valley State Park And Santa Ana National Wildlife Refuge, Southern Texas, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

There are no published records of Northern Beardless-Tyrannulet (Camptostoma imberbe) and Tropical Parula (Parilla pitiayumi) nesting in the Lower Rio Grande Valley of Texas since the late 1940s. In this 1996- 1998 study, both species were confirmed nesting at Santa Ana National Wildlife Refuge, and Northern Beardless-Tyrannulet was also confirmed at Bentsen Rio Grande Valley State Park. Most Northern Beardless-Tyrannulet nests were between clumps of ball-moss (Tillandsia recurvata) in cedar elm (Ulmus crassifolia) trees, and nests were active from 21 March-23 September. Only fe. males build nests or incubate. Two-three young fledged per successful nest, but three nests were abandoned …

Changes In The Breeding Bird Community Of Subtropical Evergreen Forest In The Lower Rio Grande Valley Of Texas, 1970s-1990s, Timothy Brush, Alberto Cantu

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Breeding-bird censuses conducted in 1994-1996 at the Santa Ana National Wildlife, southern Texas were compared to those done on the same site in 1973-1978. The study site was described as subtropical evergreen forest in the 1970s, but is now thorn-forest with remnant evergreen forest. Canopy cover was incomplete and lower and trees were smaller and more densely packed in 1994-1996 than in 1973-1978. Seven bird species typical of thorn-forest and thorn-scrub, which were not present in 1973-1978, made up 20% of the breeding bird community in 1994-1996. Species tolerant of thorn-forest and thorn-scrub made up 76.0% of the breeding bird …

The Brood-Rearing Habitat, Brood Home Range, And Fecundity Of The Snowy Plover (Charadrius Alexandrinus) In Coastal Southern Texas, Jeffery R. Rupert

Theses and Dissertations - UTB/UTPA

Habitat fragmentation has been shown to have negative effects on avian communities. I looked at the effects of corridor width and vegetation characteristics on nesting densities and breeding success of birds in the Lower Rio Grande Valley. There were definite trends in this study of increasing species richness and nesting densities with increasing corridor widths. Multiple regression revealed little correlation between tree density, diameter at breast height, tree height, canopy cover and ground cover with nesting density or nesting success. However, factors such as parasitism by the Bronzed Cowbird (Molothrus aeneus) and predation were much greater in narrower corridors. This …

Homology Among The Autosomal Chromosomes Of Boophilus Annulatus (Say) And B. Microplus (Canestrini), Bonnie S. Gunn

Theses and Dissertations - UTB/UTPA

Autosomes of Boophilus annulatus and B. microplus were compared using C- and G-bands to establish the degree of homology. Karyotypes of both species consisted of 20 autosomes and an XX:XO sex determination system with the X being the largest chromosome. All chromosomes of B. annulatus were acrocentric with heterochromatin limited to centromeric regions. The B. microplus karyotype was acrocentric with one band of noncentromeric heterochromatin occurring in three chromosome pairs. Interspecific comparisons indicated seven pairs of G-band homologous autosomes and three G-band homologous pairs when added interstitial heterochromatin was considered. The number three chromosome of both species showed variation in …

The Biological Flora Of Coastal Dunes And Wetlands. Sesuvium Portulacastrum (L.) L., Robert I. Lonard, Frank W. Judd

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Sesuvium portulacastrum (L.) L. (sea purslane, cenicilla) is a pantropical, perennial, trailing herb (Aizoaceae) with pink-purple or occasionally white flowers that grows on coastal beaches of five continents and many islands. Herein we present a review of the biology of S. portulacastrum. It is an important pioneer species on sandy beaches in the subtropics and tropics, where its stoloniferous, mat-forming growth habit promotes embryonic dune formation in belts parallel to the shoreline. Colonies act as barriers to intercept and hold water and wind transported sand. Sesuvium portulacastrum's success as a colonizing species is related, in large part, to its …

Red-Breasted Mergansers, Mergus Serrator, Nesting In Southern Texas, Jeffery R. Rupert, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

No abstract provided.

Feeding And Nesting Ecology Of The Great Kiskadee, Pitangus Sulphuratus Texanus (Passeriformes: Tyrannidae) In The Lower Rio Grande Valley, Texas, Robert Luis Gorena

Theses and Dissertations - UTB/UTPA

The foraging and nesting ecology of the Great Kiskadee was studied in the Lower Rio Grande Valley, Texas during 1994 and 1995. Adult kiskadees were found to be omnivorous, feeding mainly on fleshy fruits, fish, and dragonflies, and capturing animal prey mainly by surface gleaning into water or hawking prey out of midair. Nests are constructed mainly during March and April and are built at heights between 6 and 10 meters apparently without preference to tree species. Of 29 nests observed, 66% (19) were active during at least part of the breeding season. Nestlings are fed a diet very similar …

Effect Of Myristicin, A Constituent Of Parsley, On Levels Of Glutathione And Glutathione S-Transferase In Mice Tissues, Maria Theresa Tijerina

Theses and Dissertations - UTB/UTPA

Glutathione (GSH) and related enzymes interact as a ubiquitous and efficient detoxification system in biological organisms. Several naturally occurring, as well as synthetic compounds, are known to increase the levels of glutathione/glutathione S-transferases (GST). One of the natural compounds includes myristicin, which is a constituent of parsley leaf oil as well as other natural foods. The extent to which the levels of the GSH/GST system can be induced appears to be dependent on the specific tissue type and the amount of myristicin administered. Our results show that increased amounts of myristicin exhibited beneficial effects within a certain range for each …

Cell Wall Degrading Enzymes Produced By The Phytopathogenic Fungus Phymatotrichum Omnivorum, Jacobo Ortega

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The extracellular plant cell wall degrading enzymes of Phymatotrichum omnivorum and the effect of different carbon sources on the production of these enzymes were investigated. Cellobiohydrolase, endoglucanase and xylanase activities were detected in fluids collected from cultures containing sodium carboxymethyl cellulose (CMC) or xylan as carbon sources and enzyme inducers. The highest activities of cellobiohydrolase and xylanase were measured in fluids collected from cultures containing xylan. Results of this study indicate that P. omnivorum constitutively produces small amounts of endoglucanase.

Abundance And Diversity Of Aquatic Birds On Two South Texas Oxbow Lakes., Diane Teter, David L. Mcneely

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Avian use of two oxbow lakes located in urban surroundings of south Texas was studied for one year. Both abundance and diversity of aquatic birds were notably reduced in the more intensely developed area. Possible factors resulting in these differences are reviewed.

Effects Of Competition And Predation On Prothonotary Warblers And House Wrens Nesting In Eastern Iowa, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

In a fragmented midwestern floodplain forest, a small Prothonotary Warbler (Protonotaria citrea) population experienced high competition with House Wrens (Troglodytes aedon) and mammalian nest predation in 1988-89. Despite the provision of 3 types of nest boxes and higher water levels, Prothonotary Warblers did not nest successfully and decreased in the fragmented forest in 1990-91. House Wrens used >90% of the nest boxes in both years. Wren territories doubled within the nestbox area, while remaining constant on an unmanipulated area. In contrast, a larger warbler population had high nesting success during 1990-91 in a relatively unfragmented, wetter forest tract. Such forests, …

New And Interesting Records Of Birds From A Dry Forest Reserve In South-West Ecuador, Karl S. Berg

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

La reserva forestal Cerro Blanco es una de las pocas áreas protegidas con más de 200 ha de bosque seco sobre el oeste ecuatoriano. Aunque existen listas de registros de aves en la reserva, con frecuencia no se conocen las fechas ni localidades en que fueron tomados. De otro lado, esta información no incluye observaciones de algunas de las partes de más difícil acceso en la reserva, ni muestra con precisión las diferentes altitudes, los tipos de bosques o las estaciones. Una información más amplia será cada vez más importante para la conservación y manejo de la vida silvestre de …

Biological Inventory, Natural History, And Human Impact Of Palo Alto National Battlefield, Norman L. Richard, Alfred T. Richardson

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

During 1993 a floral and fauna inventory was conducted on the Palo Alto National Battlefield Historic Site . Vegetational associations were mapped, and the impacts of agriculture and ranching were assessed. Attention was given to identifying endangered, threatened, or candidate species present within the site boundaries, and also species which may have been extirpated. An attempt has been made to envision where historic roadways were located and how the 1846 landscape may have appeared.

Biology Of The Palo Alto Battlefield Site: A Summary, Norman L. Richard, Alfred Richardson

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

No abstract provided.

The Genus Urochloa (Poaceae: Paniceae) In Texas, Including One Previously Unreported Species For The State, J. K. Wipff, Robert I. Lonard, Stanley D. Jones, Stephan L. Hatch

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Urochloa is represented in Texas by three species, U. mosambicensis, U. panicoides, and U. reptans. Urochloa mosambicensis is being reported new for Texas. Urochloa panicoides has recently been reported in the state and is listed in the Federal Noxious Weed Act. Urochloa reptans has been recognized in Texas and the U. S. as Panicum reptans or, more recently, Brachiaria reptans. A key to distinguish related genera, a key to the species of Urochloa in Texas, species descriptions, and their distribution in Texas are provided.

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Urochloa está representada en Texas por tres especies, U. mosambicensis, U. panicoides y U. reptans. …

Development Of Mass-Rearing Techniques For Aphelinus Asychis Walker For Use In A Biological Control Program Against Russian Wheat Aphid, Robin Lynn Whitaker-Deerberg

Theses and Dissertations - UTB/UTPA

Mass-rearing techniques were developed for the parasitoid Aphelinus asychis Walker (Hymenoptera:Aphelinidae) for use in a biological control program against the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera:Aphididae). Daily ovipositional activity, host-feeding behavior, effects of population density in the rearing cages and effects of cold storage on mummies were determined.

Daily ovipositional activity peaked at day 5 after emergence of the parasitoid. Ninety-two percent of mummies resulting from ovipositional activity were oviposited the first 13 days of the parasitoid’s life. Since mummification occurred 11 days after oviposition and emergence occurred 11 days after mummification, day 24 was determined to be the …

Historical Changes In The Ichthyofauna Of The Lower Rio Grande (Río Bravo Del Norte), Texas And Mexico, Robert J. Edwards, Salvador Contreras-Balderas

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

CT-Collections of fishes from the lower Rio Grande (Rio Bravo del Norte) during the past 138 years suggest two indigenous faunal assemblages. One fauna is upstream, composed of mostly freshwater species, and the other is a downstream assemblage composed of a mixture of the more abundant upstream elements and more estuarine species. Recent collections in the lower Rio Grande indicate that major alterations in these fish communities have occurred. The upstream fauna has lost many of its characteristic freshwater components; native freshwater species have been replaced by exotic (=non-native) or estuarine forms. The downstream fauna has many fewer freshwater taxa …

Comparison Of The Effects Of The Severe Freezes Of 1983 And 1989 On Native Woody Plants In The Lower Rio Grande Valley, Texas, Robert I. Lonard, Frank W. Judd

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Freeze damage to native woody plants was assessed at the same four sites in the lower Rio Grande Valley, Texas, in 1983 and 1989. The number of severely damaged species was greater in 1989 possibly because temperatures in 1989 were lower and longer in duration below freezing versus 1983. Thirty0five species (48.6%) had the same damage index value for the two freezes, and 24 (33.3%) species showed no damage in either year. More than half of the 72 species analyzed (55.5% in 1983 and 51.3% in 1989) showed no damage or only leaf damage, indicating most of the native woody …

Notes On The Vegetation And Flora Of North Padre Island, Texas, E. Glenn Carls, Robert I. Lonard, Dennis B. Fenn

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

No abstract provided.

Woody Plants Of The Lower Rio Grande Valley, Texas, Robert I. Lonard, James H. Everitt, Frank W. Judd

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Description of Common Vegetation of Lower Rio Grande Valley.

Seasonal Distribution Of The Ichthyofauna Of Santa Ana National Wildlife Refuge, Alamo, Texas, Matthew Albert Ciomperlik

Theses and Dissertations - UTB/UTPA

This study investigated the small aquatic ecosystems of Santa Ana National Wildlife Refuge, located in a predominantly agricultural area of the Lower Rio Grande Valley, Texas. Fishes and water quality data were collected for 13 months to determine the status of fish populations and the factors which influence their distributions on the refuge.

Sixteen fish species were collected during the study, however, more than 20 species are known to inhabit the Rio Grande in the vicinity of the refuge. Water source played a major role in influencing fish species richness in these aquatic ecosystems. Diverted river water offered the best …

Propagation Of Two Southern Texas Shrubs By Stem Cuttings, Michael R. Heep, Robin S. Vora

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

We successfully used stem cuttings to propagate two native shrubs, brush holly (Xylosma flexuosa) and devil's claw. (Pisonia aculeata), which are rare in the Rio Grande floodplain of southern Texas. Roots grew on 100 percent of the cuttings that did not receive root-promoting substances. Rooting success decreased when synthetic root promoting substances or a nutrient solution was used. Key words: asexual propagation; native shrubs.

Sea Urchins From The Brazos Santiago Pass Jetty, South Padre Island, Richard R. Fairchild, Lazern O. Sorensen

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Data on occurrence and distribution of sea urchins (Echinoidea) are presented for the Brazos Santiago Pass jetty on South Padre Island, Texas. Echinometra lucunter is recorded from the Texas coast.

Factors Influencing Cellulolytic Activity Of The Soil Fungus, Aspergillus Candidus, Jacobo Ortega, Ernest J. Baca

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Effects of pH, incubation time, nitrogen source and carbohydrate source upon production of carboxymethyl cellulase by Aspergillus candidus grown in liquid medium were studied. Maximal cellulase activity per unit of protein occurred in culture fluids with a pH of 5.5, after 10 days of cultivation of the fungus. Ammonium nitrate supported the highest production of the enzyme. However, in the nitrogen-source test, highest accumulation of extracellular protein was found in fluids from cultures with urea as the nitrogen source. Cotton fibers produced the greatest gain in cellulase activity when the carbohydrate source was incremented from 0.5 to 1.0 percent. The …

Effects Of A Severe Freeze On Native Woody Plants In The Lower Rio Grande Valley, Texas, Robert I. Lonard, Frank W. Judd

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The effects of a severe freeze in December, 1983 on the native plants of the lower Rio Grande Valley, Texas were determined for 75 species. Damage was initially assessed by examining leaves, apical meristems, and cambial tissues of stems. Initial assessments were confirmed by surveys in the spring when new leaves were present. Forty-three species were either undamaged or had only minor leaf damage. Twenty-two species with damaged leaves had intact apical meristems or showed evidence of damage for less than 10 cm below the apical meristem. Three species, Leucaena pulverulenta, Cordia boissieri, and Karwinskia humboldtiana, had more extensive damage, …

The Effect Of Hurricane Allen On The Near-Shore Vegetation Of South Padre Island, Frank W. Judd, Sammie L. Sides

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

The effect of Hurricane Allen (Aug. 10, 1980) on the near-shore vegetation of South Padre Island was assessed by comparing data obtained in line transects before and after the hurricane. Eight species of plants were present in the Backshore Zone prior to the hurricane; after the hurricane, only three species were present and percent cover was only 11% of that before the hurricane. The foredunes of this zone were completely leveled and a belt of Sesuvium portulacastrum was obliterated. Conversely, plants of the taller Primary Dune Zone were not greatly disturbed by the hurricane. Numbers of species and percent cover …

Habitat Selection Related To Resource Availability Among Cavity-Nesting Birds, Timothy Brush

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Variation in snag species and abundance appeared to explain most of the habitat selection patterns observed in five cavity-nesting riparian species over a three-year period. All species except Ash-throated Flycatchers were most common in areas with cottonwood or willow snags, which have relatively soft wood and are preferred nest sites. Classification of habitats on the basis of nest-site characteristics was useful and should be considered in other habitat selection studies.

Population Structure, Density And Movements Of The Texas Tortoise Gopherus Berlandieri, Frank W. Judd, Francis L. Rose

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Gopherus berlandieri was studied on a 3.3 ha grid in Cameron Co., Texas for five years. One hundred two tortoises were marked (43 males, 30 females, 26 juv., and 3 adults whose sex was not determined). Numbers of males and females did not differ significantly. Juveniles comprised 27% to 9% of the population and maximum population density was 15 to 16 tortoises per ha. The number of females remained constant, but males and juveniles declined gradually from 1972 to 1975, then markedly in 1976. The percentage of shared individuals in successive years was higher for females than males, but only …