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Full-Text Articles in Life Sciences
The Incredible Shrinking Dewlap: Signal Size, Skin Elasticity, And Mechanical Design In The Green Anole Lizard (Anolis Carolinensis), Simon Lailvaux, Jack Leifer, Bonnie Kircher, Michele Johnson
The Incredible Shrinking Dewlap: Signal Size, Skin Elasticity, And Mechanical Design In The Green Anole Lizard (Anolis Carolinensis), Simon Lailvaux, Jack Leifer, Bonnie Kircher, Michele Johnson
Michele A Johnson
The expression of male secondary sexual traits can be dynamic, changing size, shape, color, or structure over the course of different seasons. However, the factors underlying such changes are poorly understood. In male Anolis carolinensis lizards, a morphological secondary sexual signal called the dewlap changes size seasonally within individuals. Here, we test the hypothesis that seasonal changes in male dewlap size are driven by increased use and extension of the dewlap in spring and summer, when males are breeding, relative to the winter and fall. We captured male green anole lizards prior to the onset of breeding and constrained the …
Convergent Evolution Of Brain Morphology And Communication Modalities In Lizards, Christopher Robinson, Michael Patton, Brittany Andre, Michele Johnson
Convergent Evolution Of Brain Morphology And Communication Modalities In Lizards, Christopher Robinson, Michael Patton, Brittany Andre, Michele Johnson
Michele A Johnson
Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modality is generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality. We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species (Anolis carolinensis and Leiocephalus carinatus) primarily use visual signals to communicate with conspecifics and detect potential prey, and two (Aspidoscelis gularis and Scincella lateralis) communicate and forage primarily …
Herbivory In The Northern Curly-Tailed Lizard (Leiocephalus Carinatus), Bonnie Kircher, Christopher Robinson, Michele Johnson
Herbivory In The Northern Curly-Tailed Lizard (Leiocephalus Carinatus), Bonnie Kircher, Christopher Robinson, Michele Johnson
Michele A Johnson
No abstract provided.
Relationships Among Reproductive Morphology, Behavior, And Testosterone In A Natural Population Of Green Anole Lizards, Michele Johnson, Rachel Cohen, Joseph Vandecar, Juli Wade
Relationships Among Reproductive Morphology, Behavior, And Testosterone In A Natural Population Of Green Anole Lizards, Michele Johnson, Rachel Cohen, Joseph Vandecar, Juli Wade
Michele A Johnson
Laboratory studies of reproductive systems have long supported the idea that neural and/or muscular structures used frequently are often enhanced in size. However, field studies integrating behavioral, morphological, and hormonal data are needed to better understand relationships in natural environments. We examined a natural population of green anole lizards (Anolis carolinensis) to determine whether variation in reproductive morphology both within and between the sexes paralleled differences in courtship and copulatory behaviors and circulating testosterone levels. Display rate in males was positively correlated with the sizes of the cartilage supporting the dewlap (a throat fan used in courtship and aggression) and …
The Burden Of Motherhood: The Effect Of Reproductive Load On Female Lizard Locomotor, Foraging, And Social Behavior, Michele Johnson, Jessica Caton, Rachel Cohen, Joseph Vandecar, Juli Wade
The Burden Of Motherhood: The Effect Of Reproductive Load On Female Lizard Locomotor, Foraging, And Social Behavior, Michele Johnson, Jessica Caton, Rachel Cohen, Joseph Vandecar, Juli Wade
Michele A Johnson
The costs of reproduction, involving demands associated with both current and future reproductive efforts, may place a substantial burden on females. However, animals may minimize these costs by modifying their behavior across the reproductive cycle. We examined the effects of reproductive load on three types of behavior (locomotion, foraging, and social displays) in green anole lizards (Anolis carolinensis) by comparing egg, follicle, and oviduct mass and volume with field observational data. We found that female locomotor and social display behaviors decreased as reproductive load increased, suggesting behavioral modification in these traits, but we detected no relationship between foraging and reproductive …
Colorful Displays Signal Male Quality In A Tropical Anole Lizard, Ellee Cook, Troy Murphy, Michele Johnson
Colorful Displays Signal Male Quality In A Tropical Anole Lizard, Ellee Cook, Troy Murphy, Michele Johnson
Michele A Johnson
Parasites influence colorful ornaments and their behavioral display in many animal hosts. Because coloration and display behavior are often critical components of communication, variation in these traits may have important implications for individual fitness, yet it remains unclear whether such traits are signals of quality in many taxa. We investigated the association between ectoparasitic mite load and the color and behavioral use of the throat fan (dewlap) by male Anolis brevirostris lizards. We found that heavily parasitized lizards exhibited lower body condition, duller dewlaps, and less frequent dewlap displays than less parasitized individuals. Our results thus suggest that highly parasitized …
The Evolution Of Copulation Frequency And The Mechanisms Of Reproduction In Male Anolis Lizards, Michele Johnson, Maria Lopez, Tara Whittle, Bonnie Kircher, A Dill, Divina Varghese, Juli Wade
The Evolution Of Copulation Frequency And The Mechanisms Of Reproduction In Male Anolis Lizards, Michele Johnson, Maria Lopez, Tara Whittle, Bonnie Kircher, A Dill, Divina Varghese, Juli Wade
Michele A Johnson
The evolution of many morphological structures is associated with the behavioral context of their use, particularly for structures involved in copulation. Yet, few studies have considered evolutionary relationships among the integrated suite of structures associated with male reproduction. In this study, we examined nine species of lizards in the genus Anolis to determine whether larger copulatory morphologies and higher potential for copulatory muscle performance evolved in association with higher copulation rates. In 10–12 adult males of each species, we measured the size of the hemipenes and related muscles, the seminiferous tubules in the testes, and the renal sex segments in …