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Life Sciences Commons

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Theses/Dissertations

Biological sciences

2003

Theses and Dissertations - UTB/UTPA

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Full-Text Articles in Life Sciences

Breeding Distribution And Habitat Use Of Audubon's Oriole In The Lower Rio Grande Valley Of Texas, Steven Gerald Monk Dec 2003

Breeding Distribution And Habitat Use Of Audubon's Oriole In The Lower Rio Grande Valley Of Texas, Steven Gerald Monk

Theses and Dissertations - UTB/UTPA

Audubon's Oriole ( Icterus graduacauda ) was known historically throughout the Lower Rio Grande Valley (LRGV) of Texas, but its breeding range has now declined to mainly riparian habitat in Starr County. Habitat loss, degradation, and fragmentation, and brood parasitism by Bronzed Cowbirds ( Molothrus aeneus ) are likely causes of this decline. Habitat patches where Audubon's Orioles were present were larger, with a larger vertical range of canopy, greater vegetation volume, greater richness of bird and woody plant species, less local deforestation, and less local habitat fragmentation than where Audubon's Orioles were absent. Bronzed Cowbirds showed no numeric correlation …


Chorionic Morphology Of Mayfly (Ephemeroptera) Eggs Of The Lower Rio Grande Valley, Maria D. De Leon May 2003

Chorionic Morphology Of Mayfly (Ephemeroptera) Eggs Of The Lower Rio Grande Valley, Maria D. De Leon

Theses and Dissertations - UTB/UTPA

External egg morphology of ten species of Lower Rio Grande Valley (LRGV) mayflies are compared using scanning electron microscopy (SEM) and a taxonomic key to the eggs is provided. The eggs of five species are described here for the first time. Preserved female adults or subadults were critical-point dried using liquid CO2 . The eggs were removed and placed on metal stubs for sputter coating with gold/palladium. The coated eggs were then observed and photographed by SEM. The morphological features described were the chorionic sculpturing, polar caps, accessory attachment structures, and micropyles. This is the first mayfly egg comparison and …