Life Sciences Commons^™

Effects Of Disturbance (Mowing) On Florivory And Floral Defenses In Solanum Elaeagnifolium, A Noxious And Worldwide Invasive Weed, Alejandro Rafael Vasquez Marcano

Theses and Dissertations

Chapter 1: Literature Review- In this literature review we have examined weed management as it concerns urban and agricultural ecosystems, as well as the need for mowing assessments as it relates to floral traits and defense against herbivory.

Chapter 2: Experiments- In the experiments we examined the role of mowing on floral growth traits, floral defense traits, and their effect on Manduca sexta specialist herbivores.

Chapter 3: Results- In the results we found SLN flowers to have larger diameters than unmowed flowers; however, flower mass was in line with our predictions as unmowed flowers were heavier in high mowing frequency …

Do Early-Successional Weeds Facilitate Or Compete With Seedlings In Forest Restoration? Disentangling Abiotic Versus Biotic Factors, Mylen Arias, Rupesh R. Kariyat, Kimberly Wahl-Villarreal, Stephany Mendez, Jesus Chavana, Bradley O. Christoffersen

Biology Faculty Publications and Presentations

1. Semi-arid forests need cost-effective restoration strategies to address their severe degradation. Tree shelters are often used to minimize abiotic and biotic stress during seedling establishment. We asked if early-successional weeds act as a natural shelter by facilitating native seedlings, contingent on abiotic and biotic stressors and seedling ecological strategy.

2. We conducted a manipulative weed exclusion experiment at a semi-arid site in South Texas targeted for large-scale forest restoration to discern the net effect of weeds on the growth and survival of target thornscrub tree and shrub seedlings. We assessed the roles of contrasting seedling ecological strategies (fast vs. slow growth …

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Tropical Milkweed Herbivore And Predator Dynamics In Suburban South Texas, Daniela Rivera, Jose Adrian Noval, Lilly Elliott, Hannah J. Penn

Biology Faculty Publications and Presentations

Tropical milkweed is commonly grown to conserve pollinators, but the presence of non-caterpillar herbivores may prompt treatment. Management is limited to non-chemical methods like biological control, but potential natural enemies have not been well studied in the Lower Rio Grande Valley (LRGV). We documented the arthropod community on tropical milkweed in garden and potted settings then analyzed associations between organisms. In the garden, oleander aphids and large milkweed bugs were the primary herbivores, overlapping on seedpods. Natural enemies (lady beetles, syrphid fly larvae, and aphid parasitoids) were positively associated with oleander aphids but not milkweed bugs. The arthropod community experienced …

Investigating The Potential Of Weeds As Host Reservoir For Plant Parasitic Nematodes In South Texas, Habraham F. Lopez

Theses and Dissertations

Presence and geographical distributions of three damaging nematode pest (R. reniformis, M. incognita, T. semipentrans) have been recorded in the LRGV. With year-round growing seasons, weed pest are a real problem for many LRGV growers. With some growers leaving the field fallow until planting season, these places can serve as potential host reservoirs for plant parasitic nematodes (PPN). This study examined the potential of weeds as host reservoirs for plant parasitic nematodes in the LRGV. Results demonstrated the presence of 5 of the 12 economically important plant parasitic nematode genus and demonstrated a difference in distribution of nematodes …

Impact Of The Biological Control Agent Tetramesa Romana (Hymenoptera: Eurytomidae) On Arundo Donax (Poaceae: Arundinoideae) Along The Rio Grande River In Texas, John A. Goolsby, Patrick J. Moran, Alexis Racelis, Kenneth R. Summy, Maricela Martinez Jimenez, Ronald D. Lacewell

Biology Faculty Publications and Presentations

Five years post-release of the arundo gall wasp, Tetramesa romana, into the riparian habitats of the lower Rio Grande River, changes in the health of the invasive weed, Arundo donax, or giant reed, have been documented. These changes in plant attributes are fairly consistent along the study area of 558 river miles between Del Rio and Brownsville, TX, and support the hypothesis that the arundo wasp has had a significant impact as a biological control agent. Plant attributes were measured prior to release in 10 quadrats at each of 10 field sites in 2007, and measured again …

Restoration Strategies To Migrate Shrub Encroachment Into Coastal Prairies, Erick Mark Verderber

Theses and Dissertations - UTB/UTPA

Shrub encroachment into grasslands is a phenomenon facilitated by fire suppression, climate warming, and overgrazing of grasses by cattle, and if left unmanaged, can alter ecosystem structure and function. In this study, I compare the effectiveness and cost/benefit of various restoration strategies (prescribed fire, mechanical, and chemical) used singly and in different combinations at decreasing two shrubs, honey mesquite (Prosopis glandulosa Torr.) and huisache (Acacia farnesiana (L.) Willd.), and promoting growth and survival of gulf cordgrass (Spartina spartinae (Trin.) Merr. ex Hitchc.), the dominant coastal prairie grass within the Laguna Atascosa National Wildlife Refuge-Bahia Grande Unit in deep south Texas. …

Establishment And Spread Of A Single Parthenogenic Genotype Of The Mediterranean Arundo Wasp, Tetramesa Romana1, In The Variable Climate Of Texas, John A. Goolsby, John F. Gaskin, Daniel V. Tarin, Alan E. Pepper, Don C. Henne, Allan Auclair, Alexis Racelis, Kenneth R. Summy, Patrick J. Moran, Donald B. Thomas

Biology Faculty Publications and Presentations

As part of a biological control program for the invasive weed, Arundo donax L., several genotypically unique populations of the parthenogenetic stemgalling wasp, Tetramesa romana Walker (Hymenoptera: Eurytomidae), from Spain and France were released in an infested riparian zone along the Rio Grande from Brownsville to Del Rio, TX. An adventive population of the wasp of unknown origin with limited distribution in Texas was also discovered, evaluated, and released as part of the program. More than 1.2 million wasps representing the mixture of genotypes were aerially released from 2009 to 2011. Wasps dispersed from their original release locations and now …