Impact and interaction of Samea multiplicalis (Lepidoptera: Pyralidae) and Cyrtobagous salviniae (Coleoptera: Curculionidae) on Salvinia minima in south Louisiana and the foraging behavior of Solenopsis invicta (Hymenoptera: Formicidae) on Salvinia minima
Master of Science (MS)
A field study was conducted in 2005 and 2006 to evaluate the impact and interaction of the herbivores Cyrtobagous salviniae Calder and Sands and Samea multiplicalis Guenee on common salvinia, Salvinia minima Baker in south Louisiana. It was a completely randomized experimental design in which treatments consisted of C. salviniae and S. multiplicalis feeding on common salvinia both independently and together along with a control. Our study revealed that treatments consisting of C. salviniae and S .multiplicalis feeding both independently and together had a significant impact on the biomass of common salvinia. Sampling done in October of both 2005 and 2006 showed that the lowest biomass was recorded for the treatment with both C. salviniae and S. multiplicalis. There was also a significant treatment by month interaction with a linear decrease in biomass for the treatment consisting of feeding by both C. salviniae and S. multiplicalis in 2005. Also, biomass showed a quadratic trend for the treatment with only S. multiplicalis in 2005. Percentage terminal damage (PTD) and percentage mat green (PMG) showed a significant treatment effect and a significant treatment by month interaction in 2005. Also, PTD showed a significant treatment effect and a significant treatment by month interaction in 2006. A field study was conducted in May of 2007 to document the foraging behavior of red imported fire ants (RIFA), Solenopsis invicta Buren, on common salvinia mats in flooded woodlands and dredged canals. RIFA mounds were found in flooded woodlands at the base of live trees and on dead tree stumps. The recruitment of RIFA to the bait stations was not uniform up to 100 m into the flooded woodlands and in most instances there was no linear relationship between distance from the levee and number of ants. Also, the recruitment at different times of the day was not the same. Results of this study provide evidence that RIFA forage extensively on common salvinia in both flooded woodlands and dredged canals, and could possibly have an adverse impact on the populations of native S. multiplicalis and also on the survival and establishment of C. salviniae.
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Tewari, Sunil, "Impact and interaction of Samea multiplicalis (Lepidoptera: Pyralidae) and Cyrtobagous salviniae (Coleoptera: Curculionidae) on Salvinia minima in south Louisiana and the foraging behavior of Solenopsis invicta (Hymenoptera: Formicidae) on Salvinia minima" (2007). LSU Master's Theses. 2292.
Seth J. Johnson