Behavior and Ethology Commons^™

Influence Of Testosterone On Male-Male Competition In The Red-Sided Garter Snake, Thamnophis Sirtalis Parietalis, Isabella M. G. Bukovich

Senior Honors Projects, 2020-current

Female mimicry in the red-sided garter snake, Thamnophis sirtalis parietalis, is described in several well-studied evolutionary advantages, but an aspect that remains elusive is how reproductive traits are linked to the 3-fold higher circulating androgens in males with this phenotype. In this study, we implanted male garter snakes (n=15 per group) with either a blank implant (SHAM; control) or a T implant, the latter simulating the female mimic phenotype. Following simulated low-temperature dormancy, males were scored for courtship intensity over three days of behavioral trials with females housed in the same facility. Males were sacrificed, and sperm were collected …

Hind Wing Eyespots Of Brassolini Butterflies (Lepidoptera, Nymphalidae): Evolutionary Diversification And Functions In Anti-Predator Defense And Mating Behavior, Logan Crees

University of New Orleans Theses and Dissertations

Ventral hind wing eyespots are prominent pattern elements in Brassolini butterflies, likely functioning in predator-prey interactions and reproductive activities. Caligo and Opsiphanes differ in male mate-seeking behaviors and it has been suggested that Caligo females use the male cua1 eyespot as a mate-locating cue, but Opsiphanes females do not seem to do so. We predict Caligo males should have larger eyespots than congeneric females, but the sexes would not differ in eyespot size in Opsiphanes. Our analyses supported both these predictions. Displacing the eyespot to the center of the wing makes eyespots more conspicuous, we asked if eyespot position …

Encephalization In Commensal Raccoons: A Unique Test Of The Cognitive Buffer Hypothesis, Peter M. Anderson

Electronic Theses and Dissertations

This study investigated selective pressures associated with encephalization in mammals and discussed broader implications. Relative brain size as measured by EQ (Encephalization Quotient) was compared between ecological categories. Omnivores had higher average EQ than ecological specialists. Since specialists are disproportionately affected by extinction events, selection for ecological generalism is proposed as encephalization mechanism. This mechanism may reinforce the more widely known Cognitive Buffer Hypothesis (CBH)—the idea that possessing relatively large brains has buffered lineages against environmental change. CBH is tested here by comparing EQs in Procyon lotor (raccoon) in urban and rural environments. CBH predicts that raccoons in the most …

Extreme Offspring Ornamentation In American Coots Is Favored By Selection Within Families, Not Benefits To Conspecific Brood Parasites, Bruce E. Lyon, Daizaburo Shizuka

School of Biological Sciences: Faculty Publications

Offspring ornamentation typically occurs in taxa with parental care, suggesting that selection arising from social interactions between parents and offspring may underlie signal evolution. American coot babies are among the most ornamented offspring found in nature, sporting vividly orange-red natal plumage, a bright red beak, and other red parts around the face and pate. Previous plumage manipulation experiments showed that ornamented plumage is favored by strong parental choice for chicks with more extreme ornamentation but left unresolved the question as to why parents show the preference. Here we explore natural patterns of variation in coot chick plumage color, both within …

The Influence Of Breeding Density On Female Aggression, Parental Care, And Ornamentation In A Secondary-Cavity Nesting Warbler, Elsa B. Chen

Theses and Dissertations

Tradeoffs between individual survival and reproductive success associated with aggressive behaviors are a driving force of evolution, but these tradeoffs are often overlooked for aggressive conspecific interactions between females. For avian males, it is well documented that more aggressive individuals tend to provide less parental care. In the few studies that address this in females, the tradeoffs seem to be more context-dependent, varying due to factors such as predation pressure and habitat quality. The relationship between female ornamentation and aggression is similarly understudied, but evidence suggests that both aggression and ornamentation are important traits involved in social selection – the …

From Organisms To Ecosystems: Impacts Of Limb Loss And Regeneration On Crayfish Behavior, Luc Arnaud Dunoyer

Theses and Dissertations--Biology

The ability of some organisms to regenerate tissues and organs has fascinated naturalists since antiquity, dating back to the earliest accounts of scientific inquiry with Aristotle in Ancient Greece. Then, Darwin’s theory invigorated some scientists’ dream of stimulating (or reactivating) regenerative capacities in human beings by showing that we are related to highly regenerative organisms. More recently, a renewed interest in discovering the molecular and genetic basis for organ and tissue regeneration has led biologists to focus more specifically on a restrictive set of model organisms.

Although the process of limb regeneration is different between invertebrate and vertebrate organisms, it …