James R. Ott

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This review reevaluates the importance of interspecific competition in the population biology of phytophagous insects and assesses factors that mediate competition. An examination of 193 pair-wise species interactions, repre­ senting all major feeding guilds, provided information on the occurrence, frequency, symmetry, consequences, and mechanisms of(More)
An enclosed colony of bumblebees (Bombus pennsylvanicus) was restricted to foraging on two artificial flower types. The means and variances were adjusted in the two flower types in order to detect risk sensitivity. Both the mean and the variance contributed to the bees' foraging decisions. A series of experiments was designed to construct the bees'(More)
Herein we report results of transplant experiments that link variation in host plant quality to herbivore fitness at the local scale (among adjacent plants) with the process of local (demic) adaptation at the landscape scale to explain the observed distribution of the specialist gall former Belonocnema treatae (Hymenoptera: Cynipidae) within populations of(More)
Ecological speciation occurs when reproductive isolation evolves as a consequence of divergent natural selection among environments. A direct prediction of this process is that ecologically divergent pairs of populations will exhibit greater reproductive isolation than ecologically similar pairs of populations. By comparing allopatric populations of the(More)
Populations of neotenic, spring-associated salamanders of the genus Eurycea occupy discontinuous sites throughout the Edwards Plateau of central Texas and many warrant conservation attention. Here we used DNA sequence data from a nuclear (rag1) and a mitochondrial (ND4) gene to determine (1) the extent of genetic isolation among seven Edwards Plateau(More)
The movement patterns of adult milkweed beetles, Tetraopes tetraphthalmus, were monitored via a mark-recapture technique. Movement or dispersal patterns were studied in two natural populations, one in which the host plant, Asclepias syriaca, was nearly continuously distributed over a 250×90 m area and another where Asclepias was distributed in 17 small(More)
Host-specific phytophagous insects that are short lived and reliant on ephemeral plant tissues provide an excellent system in which to investigate the consequences of disruption in the timing of resource availability on consumer populations and their subsequent interactions with higher tropic levels. The specialist herbivore, Belonocnema treatae(More)
The widespread occurrence of dispersal polymorphisms among insects is consistent with the hypothesis that fitness costs are associated with flight capability. Although trade-offs between flight capability and reproduction are well documented in the females of many wing-polymorphic insect species, the relationship between dispersal capability and(More)
A powerful approach to address the general factors contributing to ecological speciation is to compare distantly related taxa that inhabit the same selective environments. In this design, similarities among taxa can elucidate general mechanisms of the process whereas differences may uncover specific factors important to the process for individual taxa.(More)
Biofilm formation and function was studied in mixed culture using 20 bacterial strains isolated from a karst aquifer. When co-cultured in a glucose-limited chemostat, Vogesella indigofera and Pseudomonas putida were the dominant planktonic and biofilm organisms respectively. Biofilm formation and resistance to the iodine disinfectant betadine were then(More)