Children’s risk for overweight and obesity is particularly high in rural areas of the United States. Many health, psychosocial, and economic consequences are associated with childhood overweight and obesity, which concerns health researchers and professionals. But how and why might rural children be more at risk for being overweight and obese? This dissertation investigates childhood overweight and obesity in rural settings through three separate studies. First, a systematic literature review was conducted to identify determinants and mechanisms of childhood obesity-related behaviors that are specific to rural locations. The findings from the review show that lack of health resources and poverty within the rural environment may impact children’s social environment and individual factors. However, results are inconclusive and there continues to be a lack of studies focusing on linking environmental influence with individual factors. Second, a meta-analysis of current research evidence was conducted to assess the efficacy of rural interventions designed to reduce childhood overweight and obesity. Results showed that interventions have been efficacious yet modest, with a mean effect size of 0.18. Moderating variables were also examined. Mean intervention effect size was moderated by children’s age and intervention duration. Last, secondary data were used to examine the association between rural food stores and availability and affordability of fresh fruits and vegetables. A multilevel analytical approach was used to determine if rural location was associated with availability and affordability of fresh fruits and vegetables. After controlling for other variables, results showed that rural location was not associated with fruit and vegetable availability and affordability. The findings from this dissertation suggest that the area of rural childhood overweight and obesity remains understudied. More research is needed in order to understand the mechanisms of social ecological influences on diet, physical activity, and childhood overweight and obesity. This area of research, however, is rife with opportunities for public health education and promotion. Public health educators can help promote and advocate for environmental conditions that support healthy lifestyles.

Elucidation of mechanisms that generate and maintain population-level phenotypic variability provides insight into processes that influence within-species genetic divergence. Historically, color pattern polymorphisms were used to infer population-level genetic variability, but recent approaches directly capture genetic variability using molecular markers. Here, I clarify the relationship between genetic variability and color pattern polymorphism within and among populations using the Australian common froglet, Crinia signifera. To illustrate genetic variability in C. signifera, I used phylogenetic analysis of mitochondrial DNA and uncovered three ancient geographically restricted lineages whose distributions are consistent with other southeastern Australian species. Additional phylogeographic structure was identified within the three ancient lineages and was consistent with geographic variation in male advertisement calls. Natural selection imposed by predators has been hypothesized to act on black-and-white ventral polymorphisms in C. signifera, specifically through mimicry of another Australian frog, Pseudophryne. I used clay replicas of C. signifera to test whether predators avoid black-and-white coloration. In fact, black-and-white replicas were preferentially avoided by predators in some habitats, but not in others, indicating that differential selection among habitats plays a role in maintaining color pattern polymorphism. When black-and-white color patterns in a sample of C. signifera populations were compared with those in sympatric Pseudophryne, several color pattern characteristics were correlated between the species. Furthermore, where C. signifera and Pseudophryne are sympatric, color patterns are more similar compared to those in allopatry. Extensive phylogenetic variability suggests that phylogenetic history and genetic drift may also influence C. signifera color pattern. Fine-scale phylogenetic analysis uncovered additional genetic diversity within lineages and low levels of introgression among previously identified clades. Measures of color pattern displayed low levels of phylogenetic signal, indicating that relationships among individuals only slightly influence color patterns. Finally, simulations of trait evolution under Brownian motion illustrated that the phylogeny alone cannot generate the pattern of variation observed in C. signifera color pattern. Therefore, this indicates a minimal role for genetic drift, but instead supports either the role of stabilizing selection due to mimicry, or diversifying selection due to habitat differences, in color pattern variation in C. signifera. / text