Variability in the larval development of Metasesarma rubripes (Decapoda, Grapsidae) reared in the laboratory
Variability in the larval development of Metasesarma rubripes (Decapoda, Grapsidae) reared in the laboratory
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实验室饲养的Metasesarma rubripes（十足目，禾科）幼虫发育的变异性
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
C. Bakker
中科院分区：
文献类型：
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作者：
M. Montú;K. Anger;C. Bakker
在实验室中饲养的半咸水蟹Metasesarma rubripes（Rathbun）原产于巴拉那（巴西南部）的红树林地区的幼虫从孵化到变态。幼虫形态进行了比较与以前的描述材料从委内瑞拉。形态上的差异，观察和描述在所有的幼虫龄期，这表明存在不同的地理小种内广泛分布的种。此外，M。巴西的红足果蝇（与委内瑞拉的红足果蝇不同）在其发育途径上表现出变异性，在大眼幼体之前有4或5个带状阶段。这些途径在孵化的相对频率被发现来自不同的女性之间的孵化不同，这表明发育龄期的数量可能取决于遗传或其他母体因素。只有那些已经通过了前三个zoeal阶段相对较快的幼虫（相比同胞幼虫从同一孵化）能够直接从zoeaIV的大眼幼体，而相对延迟的幼虫往往通过zoeaV阶段。蚤状幼体IV幼虫直接发育成大眼幼体与那些通过一个额外的zoeal龄的形态比较表明，前者不仅是更快的发展，但也比后者形态更先进。蚤状幼体M. rubripes是第一次被描述;它揭示了介于不太先进的蚤状幼体IV和大眼幼体之间的形态特征。发展途径的变异性被解释为对极端多变环境的可能适应，在这种环境中，发展的灵活性可能会增加遇到适合定居和变态的栖息地的机会。
Larvae of the brackish water crab Metasesarma rubripes (Rathbun) originating from a mangrove area in Parana (southern Brazil) were reared in the laboratory from hatching to metamorphosis. Larval morphology was compared with a previous description of material from Venezuela. Morphological differences were observed and described in all larval instars, suggesting the existence of different geographical races within this widely distributed species. Moreover, M. rubripes from Brazil (unlike that from Venezuela) reveals a variability in its developmental pathways, with 4 or 5 zoeal stages preceding the megalopa. The relative frequency of these pathways within a hatch was found to differ between hatches originating from different females, suggesting that the number of developmental instars may depend on genetic or other maternal factors. Only those larvae that had passed the first three zoeal stages relatively fast (compared to sibling larvae from the same hatch) were able to develop directly from the zoea IV to the megalopa, whereas relatively delayed larvae tended to pass through a zoea V stage. Morphological comparison between zoea IV larvae developing directly to a megalopa with those passing through an additional zoeal instar shows that the former are not only faster in development but also morphologically more advanced than the latter. The zoea V of M. rubripes is described for the first time; it reveals morphological characters that are intermediate between the less advanced form of zoea IV and the megalopa. Variability in developmental pathways is interpreted a possible adaptation to extremely variable environments, where developmental flexibility may increase the chance to encounter a suitable habitat for settlement and metamorphosis.