No description available.

No description available.

No description available.

Kin-recognition abilities, first demonstrated 25 years ago in toad tadpoles, now appear to be widespread among amphibians. In some vertebrates kin recognition is based, at least in part, on highly polymorphic major histocompatibility complex (MHC) genes. Besides protecting animals from disease resistance, MHC genes regulate social behaviour. They allow relatives to recognise one another so that they can cooperate for mutual benefit. These two seemingly distinct functions of MHC genes may be integrally related, because animals need to outbreed to optimise the immune systems of their offspring. The ability to discriminate MHC-type is therefore likely to facilitate kin discrimination in tadpoles. I tested association preferences of African clawed-frog (Xenopus laevis) tadpoles in a laboratory choice apparatus. As in other anuran species, I found that tadpoles at earlier developmental stages preferentially associate with unfamiliar siblings over unfamiliar non-siblings but that this preference reverses during development. Tadpoles approaching metamorphosis demonstrated a reversal in their preference; they preferentially school with non-kin rather than kin. The ontogenetic switch in larval schooling preferences coincides with the onset of thyroid hormone (TH) controlled development and may be indicative of decreased fitness benefits associated with schooling with kin at later developmental stages. These may result from an increase in intraspecific competition, predation, or disease susceptibilities of prometamorphic individuals. Alternatively, the kin avoidance behaviours observed at later larval stages might reflect disassociative behaviour that facilitates inbreeding avoidance at reproductive maturity. This is the first study to find a shift from an association preference for kin to non-kin during amphibian larval development. Using allele-specific PCR techniques to MHC-type tadpoles, I tested association preferences among siblings based on shared MHC haplotypes. By using only full siblings in experimental tests, I controlled for genetic variation elsewhere in the genome that might influence schooling preferences. I found that X. laevis tadpoles discriminate among familiar full siblings based on differences at MHC genes. Subjects from four families preferentially schooled with MHC-identical siblings over those with which they shared no or one haplotype. Furthermore, the strength of tadpoles’ MHC-assortative schooling preferences significantly correlated with amino acid differences in the peptide-binding region (PBR) of both the MHC class I and II loci. Since MHC-PBR polymorphisms determine the pool of peptides that can serve as ligands for MHC molecules, these findings support the hypothesis that MHC peptide ligands mediate MHC type discrimination. As test subjects were equally familiar with all stimulus groups, tadpole discrimination appears to involve a self-referent genetic recognition mechanism whereby individuals compare their own MHC type with those of conspecifics. I also found that non-MHC-linked genetic differences contribute to tadpole association preferences in tests that contrast MHC and kinship. Tadpoles did not discriminate between MHC-similar non-siblings and MHC-dissimilar siblings and preferentially associated with MHC-dissimilar non-siblings rather than MHC-similar non-siblings. Although the MHC may be not solely responsible for the genetically determined cues that direct tadpole association preferences, it certainly is important in facilitating discrimination among conspecifics in X. laevis tadpoles. MHC-based discrimination may be retained through ontogeny and serve to maintain MHC-polymorphisms by facilitating disassortative mating.

No description available.

To assess the context dependence of kin discriminating behavior, I examined kin-biased aggregation behavior in tadpoles of R. cascadae in different ecological conditions. I manipulated food distribution, predator presence, thermal heterogeneity, and relatedness in a multifactorial mesocosm experiment. All four factors interacted to influence tadpole dispersion. My results suggest that kinship is an important factor in aggregation behavior dependent upon ecological conditions. Kin-biased predator defense mechanisms have been proposed as a possible functional explanation for kin discrimination in anuran larvae. Tadpoles may better cooperate in predator vigilance while in kin groups or release kin specific alarm pheromones when attacked by a predator. I examined predator avoidance and alarm response behavior in tadpoles of the Cascades frog (Rana cascadae) and tested whether such behavior is influenced by kinship factors. I found no evidence of an alarm response behavior in R. cascadae. My results suggest that crushed tadpoles appear to initiate a feeding response rather than an alarm response as has been previously proposed. Kin-biased competitive interactions have been proposed as a possible functional explanation for kin discrimination in anuran larvae. Tadpoles may direct competitive interactions away from kin. I examined the role of kinship in growth and development of tadpoles of the Cascades frog (Rana cascadae) in both laboratory and field studies. In the laboratory, individuals reared in kin groups had a significantly smaller mass at metamorphosis than individuals reared in mixed groups. However, kinship effects in the field depended upon the treatment context. Depending upon tadpole density and access to flocculent substrate, tadpoles survived better (after adjusting for differences in mass) in kin groups than in mixed groups. My results demonstrate that kinship factors can affect growth and development in tadpoles, depending upon the ecological conditions. Furthermore, my results provide a functional explanation for the kin discriminating behavior observed in R. cascadae and suggest why such behavior may be context dependent. / Graduation date: 1995

Kin-recognition abilities, first demonstrated 25 years ago in toad tadpoles, now appear to be widespread among amphibians. In some vertebrates kin recognition is based, at least in part, on highly polymorphic major histocompatibility complex (MHC) genes. Besides protecting animals from disease resistance, MHC genes regulate social behaviour. They allow relatives to recognise one another so that they can cooperate for mutual benefit. These two seemingly distinct functions of MHC genes may be integrally related, because animals need to outbreed to optimise the immune systems of their offspring. The ability to discriminate MHC-type is therefore likely to facilitate kin discrimination in tadpoles. I tested association preferences of African clawed-frog (Xenopus laevis) tadpoles in a laboratory choice apparatus. As in other anuran species, I found that tadpoles at earlier developmental stages preferentially associate with unfamiliar siblings over unfamiliar non-siblings but that this preference reverses during development. Tadpoles approaching metamorphosis demonstrated a reversal in their preference; they preferentially school with non-kin rather than kin. The ontogenetic switch in larval schooling preferences coincides with the onset of thyroid hormone (TH) controlled development and may be indicative of decreased fitness benefits associated with schooling with kin at later developmental stages. These may result from an increase in intraspecific competition, predation, or disease susceptibilities of prometamorphic individuals. Alternatively, the kin avoidance behaviours observed at later larval stages might reflect disassociative behaviour that facilitates inbreeding avoidance at reproductive maturity. This is the first study to find a shift from an association preference for kin to non-kin during amphibian larval development. Using allele-specific PCR techniques to MHC-type tadpoles, I tested association preferences among siblings based on shared MHC haplotypes. By using only full siblings in experimental tests, I controlled for genetic variation elsewhere in the genome that might influence schooling preferences. I found that X. laevis tadpoles discriminate among familiar full siblings based on differences at MHC genes. Subjects from four families preferentially schooled with MHC-identical siblings over those with which they shared no or one haplotype. Furthermore, the strength of tadpoles’ MHC-assortative schooling preferences significantly correlated with amino acid differences in the peptide-binding region (PBR) of both the MHC class I and II loci. Since MHC-PBR polymorphisms determine the pool of peptides that can serve as ligands for MHC molecules, these findings support the hypothesis that MHC peptide ligands mediate MHC type discrimination. As test subjects were equally familiar with all stimulus groups, tadpole discrimination appears to involve a self-referent genetic recognition mechanism whereby individuals compare their own MHC type with those of conspecifics. I also found that non-MHC-linked genetic differences contribute to tadpole association preferences in tests that contrast MHC and kinship. Tadpoles did not discriminate between MHC-similar non-siblings and MHC-dissimilar siblings and preferentially associated with MHC-dissimilar non-siblings rather than MHC-similar non-siblings. Although the MHC may be not solely responsible for the genetically determined cues that direct tadpole association preferences, it certainly is important in facilitating discrimination among conspecifics in X. laevis tadpoles. MHC-based discrimination may be retained through ontogeny and serve to maintain MHC-polymorphisms by facilitating disassortative mating.

Thesis (M.S.)--Michigan State University. Dept. of Zoology, 2008. / Title from PDF t.p. (viewed on July 27, 2009) Includes bibliographical references. Also issued in print.

No description available.

Research has shown that child abuse is a serious public health issue that may warrant child welfare agency intervention and removal of children from their homes. Placement with kin caregivers is considered the least restrictive placement option by social workers. It has been recognized that kin caregivers require some type of formal parental training to prepare them to care for relative children. A large city implemented the Caring for Our Own training program as prelicensing training to prepare relatives for roles as kin caregivers. Prior to this study, no research had assessed whether this training program adequately addressed caregivers' ability to adopt effective discipline practices in response to perceived child misbehavior. The purpose of the study was to examine how the Caring for Our Own prelicense training impacted kin caregivers' use of ineffective discipline practices, as measured by change in scores on the 3 subscales of the Parenting Scale. The theoretical framework for this study was based on Ajzen's theory of planned behavior. One-way repeated measures ANOVA revealed no statistically significant difference in kin caregivers' (n = 27) use of ineffective discipline practices as measured by the 3 subscales of the Parenting Scale over time. In light of this finding, the child welfare agency may create an evidence-based curriculum to assist in the development of competent kin caregivers. Social change to improve training and thus foster more effective responses from kin caregivers may occur within educational departments of child welfare agencies, through assessing and developing prelicensing kin caregiver training that allows for effective child behavior discipline management.