This thesis examines the existence of colour preferences in butterflies. Two polymorphic species - the Mocker Swallowtail (Papilio dardanus) and the Silver-Washed Fritillary (Argynnis paphia) are used as study species. Both the basis of colour preferences in mate choice and flower choice during feeding, and the implications of the preferences for the evolution of the species and morphs are investigated. In the Silver Washed Fritillary a non-genetically determined preference exists for highly saturated orange coloration in both mate and flower choice. This is shown not to be due to a bias for orange in colour reception through the use of electroretinograms, measuring the electrical output of the retina when exposed to light of varying wavelengths. It has not been possible, however, to rule out the possibility that the preference for the most common, orange, female morph is learnt. The flower colour preferences of the Mocker Swallowtail are investigated, and it is demonstrated that individuals show an initial preference for blue flowers, and also learn rapidly to feed off flowers of other colours that prove profitable. Their decision to try flowers of other colours is shown to be influenced by the behaviour of other individuals. In previous mate choice experiments, experienced males of the species have been shown to have a preference for the most common, black and white, morph. The colours of the morphs and the spectral sensitivities of the butterflies are analysed quantitatively. The initial and subsequent preferences of naive males are investigated in behavioural experiments, and a possible influence of learning on their subsequent choices is discovered. No influence of female choice is found. This information is then used to create a mathematical model of the population structure, for which it is also necessary to determine the relative payabilities of the model and mimic, and the mating frequency of wild males. The model demonstrates how the observed population structures might arise through evolutionary time. Measurements of the morphology of males and females of Papilio dardanus, and one of its putative models, Danaus chrysippus, shows that in Papilio dardanus females the centre of gravity is positioned significantly further back than in males and in Danaus chrysippus. This positioning far from the wing base has already been shown to handicap an individual escaping from a predator due to decreased acrobatic ability. It has also already been shown that mimetic species tend to have centres of mass positioned further back than non-mimetic species, and hence it is possible that the position of a centre of mass of a butterfly (and its effect on agility) may be a factor in the evolution of mimicry in a species or (where females carry a large egg load) in females of a species only.

This thesis investigates the evolution of two secondary sexual characters in birds, large male body size and exaggerated male tail length. To determine whether the elaboration of these two characters is associated with two correlates of sexual selection intensity, mating system and parental care, I collected and examined morphological information for 1,990 species and natural history data for 745 species. Comparative studies should account for the problem of related species sharing similarities through common descent, so here I investigate associations with contrast scores that measure the variation radiating from unique ancestral nodes in a phylogeny. I show that greater polygyny correlates strongly with increasing male size but only slightly with longer male tail length, and that lesser paternal care correlates strongly with both traits. These results indicate that the evolution of increased male body size and exaggerated male tail length in birds is substantially influenced by the intensity of sexual selection.

This study explores the morphology and electrical behavior of breeding weakly electric fish. Wave-type electric fish communicate by means of a continuous oscillatory electric signal produced by an electric organ. The electric organ discharges at frequencies which are sexually dimorphic in many species of electric fish. This dimorphism is thought to be attributed to female mate choice, although to date, there is no evidence for mate choice or intrasexual competition to have driven the evolution of this signaling dimorphism in wave-type electric fish. Here, I have tracked changes in body shape and electric organ discharge (EOD) frequency of A. leptorhynchus throughout a breeding conditioning period. I find that only females alter the shape of their bodies, presumably to account for increasing egg mass, during the breeding conditioning period. Throughout this period, both females and males do not alter their EOD frequencies significantly. Gravid females were used in an unforced preference test, where they were presented with two live, male A. leptorhynchus. Female preference was indicated by a passage of the female into one of the two male compartments. I find that females show a preference for higher EOD frequency males, while no preference is shown for longer, heavier or larger-amplitude males. Further investigations are needed to dissociate the role of EOD frequency from potentially correlated male traits, such as rate and type of modulations of EOD frequency. The finding of this study that female A. leptorhynchus prefer males of higher EOD frequency establishes wave-type weakly electric fish as a promising model system for the study of the evolution and the sensory mechanisms of female choice.

Thesis (Ph.D) -- McMaster University, 1999. / Includes bibliographical references [leaves 52-53]. Also available via World Wide Web.

Thesis (M.Sc.) - Carleton University, 2008. / Includes bibliographical references (p. 90-99). Also available in electronic format on the Internet.

Title from title page of PDF (University of Missouri--St. Louis, viewed March 22, 2010). Includes bibliographical references.

Thesis (M.S.)--The University of North Carolina at Greensboro, 2008. / Directed by Malcolm Schug; submitted to the Dept. of Biology. Title from PDF t.p. (viewed Aug. 14, 2009). Includes bibliographical references (p. 40-47).

Thesis (PH.D.)--Michigan State University. Zoology Ecology, Evolutionay Biology, and Behavior, 2008. / Title from PDF t.p. (viewed on Aug. 11, 2009) Includes bibliographical references (p. 64-72). Also issued in print.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 157-172). Available also in a digital version from Dissertation Abstracts.

Thesis (doctoral)--University of Stockholm, 1984. / Cover title. Added t.p. laid in. Includes bibliographical references (leaves 24-26 (1st group)).