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1	The ecology and morphological variation of Opuntia (Cactaceae) species in the mid-south, United States Majure, Lucas C 11 August 2007 (has links) Opuntia species have been poorly studied ecologically and taxonomically in the eastern United States. This study deals with the ecology of Opuntia species in the mid-south United States and covers not only the high degree of morphological variation exhibited by taxa, but also the taxonomy and distributions of the group for Mississippi. The taxa in the mid-south have distinct habitat preferences and can be separated based on habitat characterization. Information from this work provides valuable data useful in predicting possible routes that an invasive species, Cactoblastis cactorum (the cactus moth), might use in its potential westward migration. Phenotypic plasticity exhibited by Opuntia pusilla subjected to experimental conditions exemplifies the care that should be taken when making species delineations. Spine production in certain species is more a function of abiotic environmental pressures than genetic heritage. Two taxa that previously were put into synonymy with other species are recognized from this work. Opuntia pusilla nopales prickly pear cacti Opuntia stricta morphological plasticity Opuntia humifusa Cactoblastis cactorum
2	The Ecology of Cactoblastis Cactorum (Berg) (Lepidoptera:pyralidae) in Florida Sauby, Kristen Erica 08 August 2009 (has links) I used a theoretical model to determine the conditions under which Cactoblastis cactorum populations would be expected to experience positive population growth. Results from simulations suggest that host species richness, host quality, and the C. cactorum death rate interact to determine the probability of C. cactorum positive population growth. I also studied the influence of host diversity empirically. Cactoblastis cactorum prevalence was significantly higher when O. stricta was present in the community. Also, higher species richness within host assemblages led to a higher prevalence of infestation than in single-species host assemblages. Finally, I explored cooccurrence patterns of native cactuseeding insects in an effort to document the impact of C. cactorum to native insect assemblages. The presence of C. cactorum in a community did not appear to affect the structure of native cactuseeding insect assemblages. species co-occurrence prickly pear cacti Opuntia null model net reproductive rate Melitara prodenialis invasive species insect herbivore host quality Dactylopius biodiversity Cactoblastis cactorum Chelinidea vittiger amplification effect

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The ecology and morphological variation of Opuntia (Cactaceae) species in the mid-south, United States

The Ecology of Cactoblastis Cactorum (Berg) (Lepidoptera:pyralidae) in Florida