Mari Isabelle Pereira, Gigliolli Adriana Aparecida Sinópolis, Nanya Satiko, Portela-Castro Ana Luiza de Brito
Departamento de Biotecnologia, Genética e Biologia Celular, Universidade Estadual de Maringá, Avenida Colombo, 5790, 87020-900, Maringá-PR, Brazil.
Micron. 2018 Jun;109:11-21. doi: 10.1016/j.micron.2018.03.004. Epub 2018 Mar 20.
Lepidopteran species present an interesting case of sperm polymorphism and testicular fusion. The study of these features are of great importance in understanding the reproductive biology of these insects, especially in the case of those considered pests. Dione juno and Agraulis vanillae stand out as the most important pests of passion fruit (Passiflora sp.) crops in Brazil. Therefore, the objective of the present study was to characterize the testes and germ cells of Dione juno and Agraulis vanillae at different life stages, using light microscopy and scanning and transmission electron microscopy, to understand the maturation mechanisms of the male gametes in these species. The study showed that the larvae of both species have a pair of brown kidney-shaped testes, covered by epithelial cells which divide the organ into four follicles. The testes are full of spermatogonia which begin to differentiate in the third larval instar. In the fifth larval instar, spermatozoa can be observed. When they enter the prepupal stage the testes begin a fusion process that is completed in the adult insects, where they present as spherical organs divided into eight follicles, containing all the cells of the germ line. Spermatogenesis occurs centripetally, and in both species, sperm dimorphism is observed, where two different types of spermatozoa are formed, eupyrene (nucleated) and apyrene (anucleate), which differ in morphology and function. Apart from contributing to scientific basic research on the reproductive biology of these insects, the present study provides important data that can aid in research on the physiology, systematics, and control of these species.
鳞翅目昆虫呈现出精子多态性和睾丸融合的有趣案例。对这些特征的研究对于理解这些昆虫的生殖生物学非常重要，特别是对于那些被视为害虫的昆虫而言。在巴西，朱诺黛眼蝶（Dione juno）和香草蛱蝶（Agraulis vanillae）是西番莲（Passiflora sp.）作物最重要的害虫。因此，本研究的目的是利用光学显微镜、扫描电子显微镜和透射电子显微镜，对朱诺黛眼蝶和香草蛱蝶不同生命阶段的睾丸和生殖细胞进行表征，以了解这些物种中雄配子的成熟机制。研究表明，这两个物种的幼虫都有一对褐色的肾形睾丸，被上皮细胞覆盖，上皮细胞将器官分成四个滤泡。睾丸中充满了精原细胞，这些精原细胞在幼虫第三龄开始分化。在幼虫第五龄时，可以观察到精子。当它们进入预蛹期时，睾丸开始融合过程，在成虫中完成融合，此时睾丸呈现为分为八个滤泡的球形器官，包含生殖系的所有细胞。精子发生向心进行，在这两个物种中都观察到精子二态性，即形成两种不同类型的精子，有核精子（eupyrene）和无核精子（apyrene），它们在形态和功能上有所不同。除了有助于对这些昆虫的生殖生物学进行科学基础研究外，本研究还提供了重要数据，可有助于对这些物种的生理学、系统学和控制方面的研究。
