https://scholars.lib.ntu.edu.tw/handle/123456789/45068
標題: | 福山魚怪的生活史及性轉變 (II) | 作者: | 戴昌鳳 | 關鍵字: | 福山魚怪;生活史;性轉變;Ichthyoxenus fushanensis;parasitism;sex change;selection | 公開日期: | 2001 | 出版社: | 臺北市:國立臺灣大學海洋研究所 | 摘要: | 福山魚怪的生活史中具有二種性別間 殘食現象。其一是雌性個體於交配後 攝食雄性個體,通常稱為性殘食;另 一為雄性個體攝食雌性個體,我們稱 為反性殘食。二種殘食現象皆發生於 生殖季節(四至十一月),其中,性殘食 發生於生殖季初期,反性殘食則發生 於生殖季後期。此外,二種殘食現象 皆發生於寄主體長小於十公分,且雌 雄體長比例小於1.6, 而在殘食之後, 雌雄的體長比例迅速增大。我們認為 這種殘食現象是生物在資源不足情況 下的特殊適應;雌性生殖季初期攝食 較小的雄性,可以獲得能量用於生 殖;而在生殖季後期,雌性已無生殖 潛能,此時雄性攝食雌性,並迅速增 長及變性。因此,兩者皆是經濟性的 殘食現象。 Two types of inter-sexual cannibalism, based on the sex victim, were detected between heterosexual pairs of the parasitic isopod, Ichthyoxenus fushanensis, residing in the body cavity of the freshwater fish, Varicorhinus bacbatulus. One type was regarded as sexual cannibalism in which the male was consumed by the female before or after mating. Another was a reversed type in which the female was eaten by her mate during or after breeding. Both types of cannibalism occurred during the breeding season from April to November, with the female-on-male cannibalism occurring at earlier stages, and the reversed type occurring later. The availability of juveniles in the breeding season may ensure that a mating pair is formed immediately after the cannibalism occurs. Both types of cannibalism occurred in those pairs inhabiting smaller hosts (< 10 cm in body size) suggesting that resource limitation is possibly an important factor triggering the cannibalism. Cannibalism may lead to rapid growth or sex change of the cannibal. Both types of cannibalism occurred in mating pairs with a smaller size ratio (below 1.6, female to male), and both resulted in a great departure of female size from its mate. The increase in size ratio between paired individuals ultimately leads to an increase of clutch size. Since an individual of I. fushanensis may potentially display both male and female functions by undergoing protandrous sex change, the cannibalistic behavior would not have evolved in response to selection on either male or female. Both types of cannibalism may be regarded as the result of competition between paired individuals, which is a by-product in the evolution of a reproductive strategy rather than the consequence of sexual selection. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/14738 | 其他識別: | 892311B002081 | Rights: | 國立臺灣大學海洋研究所 |
顯示於: | 海洋研究所 |
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