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Sexual behavior in animals. --- Courtship in animals. --- Animal courtship --- Animals --- Courtship behavior in animals --- Courtship of animals --- Mate choice in animals --- Mate selection in animals --- Mating behavior --- Sexual behavior in animals --- Breeding behavior --- Copulation behavior in animals --- Copulation in animals --- Copulatory behavior in animals --- Copulatory pattern (Animal behavior) --- Reproductive behavior --- Sex behavior in animals --- Animal behavior --- Courtship --- Sexual behavior
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Steroid-sensitive, vocal courtship behavior is a function of a specific, hypothalamic nucleus, the sexually dimorphic area pars compacta (SDApc) in the male adult gerbil. Gender-related differences in the number of neurons in this nucleus are evident immediately after birth. By using unbiased stereological estimates of cell numbers in Nissl-stained, paraffin-wax sections of brain, we investigated the mechanisms differentiating cell number between the sexes in the SDApc on postnatal days 0, 3, 6, and 15. Cell death, identified by pyknosis, was greatest in the SDApc between days 0-3 in males, whereas in females, maximum values were reached between days 3-6. Similarly, the ratio of pyknotic to normal neurons peaked between days 0-3 in males and 3-6 in females but then declined in both sexes. Pyknotic cells were seldom seen in either sex by day 15. Morphological characteristics of apoptosis including chromatin condensation, cell fragmentation, and ingestion of apoptic bodies by macrophages were all demonstrated by transmission electron microscopy. Macrophages showed specific morphological characteristics of microglia. Cell division (mitosis) was identified in the SDApc during postnatal days 0, 3, and 6 but the numbers of mitotic figures were low, negligible on day 15, and similar between the sexes. These results demonstrate that cell death and proliferation occur simultaneously in the neonatal gerbil brain. The stereological estimates of cell death in the developing SDApc indicated a lower incidence of neuronal death occurring earlier in males than in females. (C) 1996 Wiley-Liss, Inc
Adult. --- Androgens. --- Area. --- Behavior. --- Birth. --- Brain. --- Cell-death. --- Courtship behavior. --- Cytoarchitecture. --- Death. --- Degeneration. --- Development. --- Differentiation. --- Female. --- Females. --- Function. --- Gerbil. --- Gerbils. --- Male. --- Males. --- Mechanisms. --- Medial preoptic area. --- Mitosis. --- Neonatal. --- Nervous-system. --- Neuronal death. --- Neuronal. --- Neurons. --- Nucleus. --- Pars compacta. --- Postnatal-development. --- Pyknosis. --- Rat-brain. --- Sex-differences. --- Sex. --- Sexes. --- Sexually dimorphic area. --- Time. --- Transmission. --- Vocal function.
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Rather, population geneticists, ethologists, and organismal biologists alike continued to investigate this important theory throughout the twentieth century.
Courtship in animals. --- Evolution (Biology) --- Courtship in animals --- Animal courtship --- Animals --- Courtship behavior in animals --- Courtship of animals --- Mate choice in animals --- Mate selection in animals --- Mating behavior --- Sexual behavior in animals --- Animal evolution --- Biological evolution --- Darwinism --- Evolutionary biology --- Evolutionary science --- Origin of species --- Biology --- Evolution --- Biological fitness --- Homoplasy --- Natural selection --- Phylogeny --- Research --- History --- Courtship --- evolution. --- evolution --- Copulation --- reproduction. --- reproduction --- Human behaviour --- Sexual behaviour --- Reproductive behaviour --- Animal behaviour --- population genetics --- Evolution (Biology). --- Evolution. --- Courtship. --- Sexual Behavior, Animal.
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Animal ethology and ecology. Sociobiology --- Courtship in animals --- Sexual selection in animals --- Congresses --- 591.551 --- Animals, Sexual selection in --- Natural selection --- Sexual behavior in animals --- Animal courtship --- Animals --- Courtship behavior in animals --- Courtship of animals --- Mate choice in animals --- Mate selection in animals --- Mating behavior --- Congresses. --- Relation between the sexes. Pairing (cohabitation) of sexes. Devices for location and recognition of the sexes by each other. Rut. Fighting among males, sparring. Courtship rituals --- Courtship --- Conferences - Meetings --- 591.551 Relation between the sexes. Pairing (cohabitation) of sexes. Devices for location and recognition of the sexes by each other. Rut. Fighting among males, sparring. Courtship rituals
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