Sexual dimorphism in neuromuscular junction size on a muscle used in courtship by green anole lizards

O'Bryant, Erin L.; Wade, Juli

doi:10.1002/neu.10004

Cited by 18 publications

(7 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Motoneuron soma size is not different in gonad-intact males between the breeding and nonbreeding seasons; and within the breeding season, neither motoneuron soma size nor cross-sectional areas of the nerve and muscle fibers are affected by testosterone treatment (O'Bryant and Wade 1999). Similarly, the malebiased sex difference in the size of neuromuscular junctions on the ceratohyoid muscle is present in both the breeding and nonbreeding seasons (O'Bryant and Wade 2002b).…”

Section: Neuroendocrine Effects On Reproductive Morphologymentioning

confidence: 99%

The Green Anole (Anolis carolinensis): A Reptilian Model for Laboratory Studies of Reproductive Morphology and Behavior

Lovern¹,

Holmes²,

Wade³

2004

ILAR Journal

112

View full text Add to dashboard Cite

The green anol (Anolis carolinensis) is an excellent reptilian model for studying reproductive behavior and the neural and muscular morphology that supports it. This lizard has been the subject of behavioral and ecological study for more than 100 yr, and a rich literature exists on its natural history. Both courtship and copulatory behaviors reveal sex and seasonal differences, which allow for the study of mechanisms regulation naturally occurring variation in performance at multiple levels within a single animal model. Green anoles are readily obtained due to their abundance in the wild; once in the laboratory, they are easily maintained, bred, and reared. Background on the natural history and husbandry of this lizard is provided, and the authors' research program on the regulation of reproductive anatomy and behavior is reviewed, Discussion includes the similarities and differences in the mechanisms mediating both structure and function compared with more traditional animal models. This type of comparative research will make it possible to identify the fundamental principles governing reproductive biology, thus advancing both basic and applied knowledge.

show abstract

Section: Neuroendocrine Effects On Reproductive Morphologymentioning

confidence: 99%

The Green Anole (Anolis carolinensis): A Reptilian Model for Laboratory Studies of Reproductive Morphology and Behavior

Lovern¹,

Holmes²,

Wade³

2004

ILAR Journal

112

View full text Add to dashboard Cite

show abstract

“…When the muscles contract, the two cartilaginous structures act as a lever to bow out the second ceratobranchial cartilage and unfold the skin along the throat and chest [Bels, 1990;Font and Rome, 1990; also see diagram in O'Bryant and . Parallel to the sex differences in behavior, many of the structures responsible for dewlap extension are larger or more numerous in males, such as motor neuron soma and nerve size [Wade, 1998;O'Bryant and Wade, 1999], size of neuromuscular junctions on the ceratohyoideus [O'Bryant and Wade, 2002], length of the second ceratobranchial cartilage [Wade, 1998], and size and number of fibers in the ceratohyoideus [O'Bryant and Wade, 1999]. We investigated in the present study whether sex differences also exist in fiber type composition of the ceratohyoideus.…”

Section: Introductionmentioning

confidence: 99%

Fiber Type Composition of the Muscle Responsible for Throat Fan Extension in Green Anole Lizards

Rosen

O'Bryant

Swender³

et al. 2004

Brain Behav Evol

View full text Add to dashboard Cite

Throat fan (dewlap) extension is sexually dimorphic in green anole lizards (Anolis carolinensis). Males have larger dewlaps which they display more frequently than females. Correlated with the behavior, sexual dimorphisms occur in the skeletal, muscular and neural structures responsible for dewlap extension in green anoles. We used histochemical techniques to stain for myosin ATPase and succinate dehydrogenase (SDH) to determine whether sex differences also exist in fiber type composition of the ceratohyoideus, the muscle that extends the dewlap. Based on the staining pattern for the two enzymes, four fiber types were identified: fast-oxidative-glycolytic (FOG), fast-glycolytic (FG), slow-oxidative (SO), and tonic. In the ceratohyoideus of both sexes, the predominate fiber types were FOG (∼43%) and FG (∼34%). Also in both males and females, the FOG and FG fibers had approximately twice the cross-sectional area of the SO and tonic fibers. No sex differences occurred in the percentages of FOG and FG fibers. However, males had a greater percentage of tonic fibers than females, whereas females had a greater percentage of SO fibers than males. The high proportion of FOG fibers in the anole ceratohyoideus makes it similar to other relatively fatigue-resistant muscles used in movements of moderate speed and duration. Although the precise role of tonic fibers in dewlap extension is not known, the greater percentage of these fibers in the male ceratohyoideus might be required to stabilize or maintain extension of the large dewlap apparatus in males.

show abstract

“…Past work has confirmed that the ceratohyoideus muscles are responsible for powering the dewlap lever mechanism (Bels ; Font & Rome ), but the specific attributes of the muscles that contribute to variation in V mc remain unclear. Several studies have found seasonal effects and sex differences in the overall size and histology of the muscles (O'Bryant & Wade , ; Rosen et al . ; Johnson et al .…”

Section: Methodsmentioning

confidence: 99%

The biomechanical basis of evolutionary change in a territorial display

2013

View full text Add to dashboard Cite

Summary1. Few studies have examined how the anatomy of an animal signal contributes to, or limits, the evolution of signal differentiation among closely related species. 2. In Anolis lizards, adult males extend a large, conspicuous dewlap as part of a territorial advertisement display. Males of species from the island of Jamaica rely on the rapid extension of the dewlap to facilitate display detection by territorial neighbours and conspecific females. Males of other species on the island of Puerto Rico extend the dewlap at considerably slower speeds and instead rely on other strategies to maintain an effective display. What initially prompted this divergence in display between the islands is unknown, but evidence suggests that it may have something to do with the way the dewlap is extended during display. 3. Our goal was to determine whether an innovation in the dewlap lever in Jamaican lineages, but absent in Puerto Rican lineages, accounted for the evolution of the high-speed dewlap on Jamaica. We began by modelling the performance of the Anolis dewlap as a first-order lever system. We then simulated changes to this system relating to its morphology, articulation and input force in biologically realistic ways to predict how such changes impact dewlap speed. Finally, we compared these predictions with data on the morphology of the dewlap lever system from museum specimens and actual dewlap speed recorded for lizards in the field. 4. This investigation revealed that changes to the dewlap lever have affected the performance of the dewlap display in at least two ways. Within islands, structural changes to the hyoid morphology seem to have led to differences in dewlap speed among species. Between islands, however, differences in dewlap speed were most likely the result of a major increase in muscle contraction velocity that powers the dewlap extension in Jamaican species, but has not originated in species on Puerto Rico. 5. Our study shows how the biomechanics of a social signal can have important implications for understanding why closely related species might differ in signal behaviour, despite apparent similarities in the selection pressures that act on the signal.

show abstract

Sexual dimorphism in neuromuscular junction size on a muscle used in courtship by green anole lizards

Cited by 18 publications

References 32 publications

The Green Anole (Anolis carolinensis): A Reptilian Model for Laboratory Studies of Reproductive Morphology and Behavior

The Green Anole (Anolis carolinensis): A Reptilian Model for Laboratory Studies of Reproductive Morphology and Behavior

Fiber Type Composition of the Muscle Responsible for Throat Fan Extension in Green Anole Lizards

The biomechanical basis of evolutionary change in a territorial display

Contact Info

Product

Resources

About