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Open Access Thesis

Keywords

Peromyscus--Iowa--Black Hawk County; Peromyscus--Iowa--Hardin County; Peromyscus; Iowa--Black Hawk County; Iowa--Hardin County;

Abstract

Deer mice (Peromyscus maniculatus bairdii) and white-footed mice (Peromyscus /eucopus noveboracensis) were collected from weedy and prairie habitats of Black Hawk County, and white-footed mice were collected from forested areas of Hardin County, Iowa. Twenty-three external and cranial characters were measured from 125 deer mice and 72 white-footed mice. Analysis of means by t-tests showed significant sexual dimorphism in deer mice in four cranial characters; palatine width at 3rd molar, width of foramen magnum, width of 3rd molar, and width of the incisor. Sexual dimorphism was also found in white-footed mice in three external and one cranial character: total length, body length, tail length, and width of the diastema. When sexes were pooled, t-tests revealed significant differences between the two species in all 23 characters measured. The two species are sometimes difficult to identify using external appearances. A discriminant function was developed using all 23 characters measured that showed, through posterior probabilities of group membership, that all specimens could correctly be identified to their respective species. A canonical analysis was conducted using deer mice from prairies, white-footed mice from prairies, and white-footed mice from forest habitats as group. A canonical discriminant function analysis of deer mice from prairie, white-footed mice from prairie, and white-footed mice from forest habitats had only one misidentification, a deer mouse that had a 0.57 probability of being a white-footed mouse. A plot of scores on canonical axes 1 and 2 showed that white-footed mice from prairies formed a distinct group that was intermediate to the other two groups. A one-way analysis of variance of the three groups showed that white-footed mice from prairie habitats differed from their forest counterparts in total length, body length, tail length, width of occipital condyle, width of 3rd molar, width of diastema, and length of mandible. The grouping of white-footed mice from prairie habitats was not an age or sex class of this species, and specimens were from widespread areas of Black Hawk County. Sexual dimorphism in Peromyscus has been attributed to the energy needs of females for reproduction. Females are larger and thought to displace males from better quality habitat. Differences in grassland- and forest-dwelling Peromyscus have been attributed to the harder diet of seeds of forest animals and the softer diet of vegetation of prairie dwelling animals. It is likely that these are the mechanism effecting the differences seen in this study.

Year of Submission

1997

Degree Name

Master of Science

Department

Department of Biology

First Advisor

Orlando A. Schwartz

Second Advisor

Paul D. Whitson

Third Advisor

Steve L. O'Kane

Comments

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Date Original

1997

Object Description

1 PDF file (52 leaves)

Language

en

File Format

application/pdf

Included in

Biology Commons

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