Sexually distinct development of vocal pathways in Xenopus laevis.
Deterministic rules, rather than experience, are thought to regulate the development of simple behaviors in vertebrates and invertebrates. We revisited this issue through examination of the sexually distinct vocalizations of African clawed frogs (Xenopus laevis), a reproductive behavior used by sexually mature males and females. We discovered that, as expected for simple behavior, female vocalizations develop through deterministic rules. The rare calls of juvenile females are indistinguishable from those of adult females. The vocal pathways of juvenile females, as measured by the contractile properties of the laryngeal muscles (the vocal muscles) and the laryngeal motoneuron somata (vocal motoneurons) size, are the developmental default and do not differentiate as they mature. Male Xenopus, in contrast, produce extensive vocalizations with rudimentary acoustic structure before reaching sexual maturity. Moreover, the functional properties of the vocal central pattern generator mature before muscle fibers and motoneuron size are fully masculinized. The results suggest that neuronal activity during development may be important in organizing the contractile properties of the muscle fibers in male, but not in female Xenopus.
Yamaguchi
Ayako
A
Biology Department, Boston University, Boston, Massachusetts, USA. ay@bu.edu
Muñoz
Martha M
MM
Bose
Tina O
TO
Oberlander
Joseph G
JG
Smith
Shane
S
D000818:Animals; D005260:Female; D007821:Laryngeal Muscles / Q000254:growth & development* / Q000294:innervation; D008297:Male; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D014828:Vocalization, Animal / Q000187:drug effects / Q000502:physiology*; D014982:Xenopus laevis / Q000254:growth & development* / Q000502:physiology