Jaw brittle star - Jaw brittle star

In the latter case, the testes often turn into ovaries, but there is generally no significant change in secondary sexual characteristics. In addition to the parasitic relationships between crustaceans, there are also examples such as the case where the mesozoan orthozoan Rhopalura ophiocomae parasitizes the genital cavity of the hermaphroditic brittle star Amphiura squamata , suppressing ovarian development, and the case where the flatworm trematodes Sporocyst and Redia parasitize the ovaries or testes of their intermediate host snails, destroying these reproductive glands when they directly parasitize the ovaries or testes. There are various theories about the mechanism of parasitic castration, which seek to attribute the cause to changes in the host's substance metabolism or hormone secretion, but none is universally accepted.

*Some of the terminology that refers to "jaw brittle starfish" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…後者の場合にも精巣の卵巣化が見られることが多いが，一般に二次性徴に大きな変化はない。甲殻類間の寄生関係以外にも，中生動物直遊類のRhopalura ophiocomaeが雌雄同体のアゴクモヒトデAmphiura squamataの生殖腔に寄生すると卵巣の発育がおさえられること，扁形動物吸虫類のスポロシストやレディアが中間宿主の巻貝に寄生する際，卵巣または精巣に直接寄生するとこれら生殖腺は破壊されてしまうことなどの例もある。　寄生去勢の機構については，宿主の物質代謝あるいはホルモン分泌の変化などに原因を求める諸説があるが，普遍的に受け入れられるものはない。…

※「アゴクモヒトデ」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報