No description available.

Thesis (M.S.)--Miami University, Dept. of Zoology, 2005. / Title from first page of PDF document. Includes bibliographical references (p. 31-35).

No description available.

This study was initiated after finding two chromosomal types of Peromyscus maniculatus north and south of the Red River in Texas and Oklahoma. The problem was to explain the chromosomal variations and their implications to the systematics of the grassland subspecies of P. maniculatus in this region.

The systematic relationship of two species of the Peromyscus truei group (P. truei and P. difficilis) was analysed through the application of starch gel electrophoresis, numerical taxonomy, and chromosomal techiques. Of 20 loci examined, 11 were monomorphic in all populations, two exhibited variation in only two populations, and seven loci were polymorphic in two or more populations. The mean number of polymorphic loci per population was 0.186, the mean number of polymorphic loci per individual was 0.024, and the proportion of loci heterozygous per individual was 2.4%. Chromosomal forms of P. truei, P. t. gentilis (FN 54) and P. t. truei (FN 62), and P. difficilis, P. d. petricola (FN 56) and P. d. nasutus (FN 58), were consistent for their karyotypes throughout their geographic ranges. No chromosomal hybrids were detected. Numerical analysis of morphological characters and similarity values based on allelic frequencies utilizing Roger's coefficient (S) demonstrated a distinct seperation of karyotypic forms of P. truei (S = 0.902) and P. difficilis (S = 0.924) and were below the mean value of S for conspecifics (S = 0.950). All data indicates that each chromosomal form of the P. truei group examined represents four distinct species. The oldest available name for chromosomal forms of P. true with a fundamental number of 62 is Peromyscus truei Shufeldt (1885) and the oldest available name for chromosomal forms with a fundamental number of 54 is Peromyscus gratus Merriam (1898). The oldest available name for chromosomal forms of P. difficils with a fundamental number of 58 is PeromYSCus nasutus Allen (1891) and the oldest available name for chromosomal forms with a fundamental number of 56 is Peromyscus difficilis Allen (1891).

Graduation date: 1995

Thesis (Ph. D.)--Illinois State University, 2007. / Title from title page screen, viewed on April 8, 2008. Dissertation Committee: Sabine S. Loew (chair), Steven A. Juliano, Charles F. Thompson, Angelo P. Capparella, William L. Perry. Includes bibliographical references (leaves 143-173) and abstract. Also available in print.

Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 20-25). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 97-100).

A number of field studies suggest that some vertebrate populations are limited by spacing behaviour, , Small mammals of the genus Peromyscus and Microtus exhibit spacing behaviour by possessing home ranges, but they have contrasting patterns of population fluctuation, Deermice (Peromyscus sp.) fluctuate annually but maintain fairly constant numbers from year to year, whereas voles (Microtus sp.) 'cycle', reaching peak densities every 2 to 5 years. One use of the home range is for food-gathering, Therefore, these experiments were designed to investigate the influence of food availability on the home range and population dynamics of local deermice and voles (P. maniculatus austerus and M. townsendii). The addition of food in late winter resulted in a doubling of the number of deermice. Immigration was 2.5 times that of an unfed control. This could be explained since resident deermice reduced the size of their home ranges. Deermice populations with extra food increased their reproductive output compared with controls: larger numbers of mice bred, and for longer periods, more young were recruited, they grew faster and reached sexual maturity earlier. It is suggested that the onset and cessation of breeding in deermice are proximate responses to food availability, Deermouse dynamics may be closely tied to the temporal and spatial availability of food through the spatial organisation of individuals. It is also suggested that females, because of their energy demands for lactation, and their influence on the survival of young, may be more sensitive to these food conditions and hence exert a strong influence on deermouse population dynamics. Vole populations with, low- and intermediate-levels of food peaked at twice the control density, and a population with a high-level of food reached seven times control density. Voles immigrated to established populations, and colonized vacant areas in proportion to the food available. Like deermice, residents reduced the size of their ranges. Breeding was enhanced in all fed vole populations. Omnivorous deermice had larger ranges than did the herbivorous voles, but both species responded to extra food by reducing their range size, so the smallest deermouse ranges were the size of large vole ranges. The results indicate that home range size in both species is responsive to food availability, and that the concentration of food in the 'typical' habitats of these small mammals is different. If, as suggested, the heterogeneity of deermouse-food in the forest results in an annual cycle in numbers, then the reduced heterogeneity of vole-food in grasslands may influence vole dynamics. / Science, Faculty of / Zoology, Department of / Graduate