Páll Miklós K, Mayer Ian, Borg Bertil
Department of Zoology, Stockholm University, S-106 91, Stockholm, Sweden.
Horm Behav. 2002 Nov;42(3):337-44. doi: 10.1006/hbeh.2002.1820.
Courtship declines and ceases while parental care increases in the presence of developing eggs during the nesting cycle of the male three-spined stickleback, Gasterosteus aculeatus. Furthermore, circulating 11-ketotestosterone (11KT) levels are higher during the initial "courtship phase" than during the later "parental phase," similar to that found in other paternal fishes. This study aimed to investigate a possible functional relationship between changes in 11KT levels and changes in reproductive behavior during the nesting cycle. To this end, groups of nonspawned and spawned male sticklebacks were sham-operated, castrated, or castrated and treated with 11-ketoandrostenedione (11KA), and the effects of the treatments on courtship and parental care were studied. Castration removed circulating 11KT, while 11KA replacement prevented the natural decline in 11KT during the parental phase (11KA converts to 11KT extratesticularly), as assessed by radioimmunoassay. Regardless of treatment, parental care remained low and courtship was present in all nonspawned males, even at the end of the experiment. However, courtship did eventually decline in castrated nonspawned males compared to the other two nonspawned groups. In all treatments of spawned males there was a drastic decline in courtship and an increase in parental care. In castrated spawned males, however, the decline in courtship came earlier than in the other two spawned groups. 11KA treatment did not prevent the natural decline in courtship/increase in parental care in spawned males, indicating that the natural decline in 11KT is not responsible for the main portion of the rapid changes in these behaviors over the stickleback's nesting cycle. The limited effects of castration also exclude other gonadal hormones from being responsible for most of these changes.
在雄性三刺鱼（Gasterosteus aculeatus）的筑巢周期中，当有发育中的卵时，求偶行为减少并停止，而亲代抚育行为增加。此外，与其他具有亲代抚育行为的鱼类相似，在最初的“求偶阶段”，循环中的11 - 酮睾酮（11KT）水平高于后期的“亲代阶段”。本研究旨在探究11KT水平变化与筑巢周期中生殖行为变化之间可能存在的功能关系。为此，将未产卵和已产卵的雄性刺鱼分组，分别进行假手术、阉割，或阉割后用11 - 酮雄烯二酮（11KA）处理，并研究这些处理对求偶行为和亲代抚育行为的影响。通过放射免疫测定法评估，阉割去除了循环中的11KT，而11KA替代阻止了亲代阶段11KT的自然下降（11KA在睾丸外转化为11KT）。无论处理方式如何，所有未产卵雄性的亲代抚育行为仍然较少，且求偶行为一直存在，即使在实验结束时也是如此。然而，与其他两组未产卵雄性相比，阉割后的未产卵雄性的求偶行为最终确实减少了。在所有已产卵雄性的处理组中，求偶行为急剧下降，亲代抚育行为增加。然而，在阉割后的已产卵雄性中，求偶行为的下降比其他两组已产卵雄性来得更早。11KA处理并未阻止已产卵雄性求偶行为的自然下降/亲代抚育行为的增加，这表明11KT的自然下降并非这些行为在刺鱼筑巢周期中快速变化的主要原因。阉割的有限影响也排除了其他性腺激素是这些变化的主要原因。
