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University of Texas Rio Grande Valley

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Articles 181 - 184 of 184

Full-Text Articles in Biology

Development Of Mass-Rearing Techniques For Aphelinus Asychis Walker For Use In A Biological Control Program Against Russian Wheat Aphid, Robin Lynn Whitaker-Deerberg Mar 1992

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 …


Seasonal Distribution Of The Ichthyofauna Of Santa Ana National Wildlife Refuge, Alamo, Texas, Matthew Albert Ciomperlik Jan 1989

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 …


Coastal Vegetational Communities Of The Two Texas Barrier Islands, Boca Chica And Brazos, Baltazar Cisneros Aug 1974

Coastal Vegetational Communities Of The Two Texas Barrier Islands, Boca Chica And Brazos, Baltazar Cisneros

Theses and Dissertations - UTB/UTPA

Two Texas barrier islands, Boca Chica and Brazos, have unique coastal vegetational communities that may be Influenced by several environmental factors. These environmental factors include temperature, precipitation, wind speed, sunshine exposure, day length, and dune height. The purpose of this investigation was to determine the total number of coastal plant species per station, season, and year and to consider environmental factors that may significantly affect the number and pattern of coastal species. Coverage comparison between aerial and land sampling and aerial vegetational zonation was also considered.

Results indicated the presence of 21 angiosperm families and a total of 54 species. …


Seasonal Periodicity Of Dominant, Benthic, Marine Macroalgae Of The North Jetty Of Brazos Santiago Pass, Texas, As Related To Environmental Factors, Gary J. Penn May 1974

Seasonal Periodicity Of Dominant, Benthic, Marine Macroalgae Of The North Jetty Of Brazos Santiago Pass, Texas, As Related To Environmental Factors, Gary J. Penn

Theses and Dissertations - UTB/UTPA

The seasonality of marine algae may be influenced by a large number of factors. These factors Include water clarity, water temperature, dissolved oxygen, conductivity, salinity, light Intensity, precipitation, air temperature, water turbulence, and daylength. The purpose of this study was to determine seasonal patterns and the effect of these variables on the algae.

The results Indicate that 24 dominant, benthic, genera of algae have two seasonal populations. A winter-spring population Includes algae in abundance between January and May. A fall population includes algae in abundance during September, October and November, Results of environmental studies indicate day-length dominant factors in algal …