New findings on the male reproductive system and spermatozoa of Aedes aegypti (Diptera: Culicidae)
Abstract Background Aedes aegypti is one of the most important arbovirus vectors, characterized by its widespread distribution and exceptional reproductive capacity. This study reexamines the male reproductive system (MRS) of this species, focusing on its morphology throughout post-embryonic develop...
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BMC
2025-07-01
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| Series: | Parasites & Vectors |
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| Online Access: | https://doi.org/10.1186/s13071-025-06808-w |
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| author | Henrique Barbosa da Silva Renata Cristina Barbosa Paulo Henrique Rezende Dayvson Ayala-Costa José Lino-Neto |
| author_facet | Henrique Barbosa da Silva Renata Cristina Barbosa Paulo Henrique Rezende Dayvson Ayala-Costa José Lino-Neto |
| author_sort | Henrique Barbosa da Silva |
| collection | DOAJ |
| description | Abstract Background Aedes aegypti is one of the most important arbovirus vectors, characterized by its widespread distribution and exceptional reproductive capacity. This study reexamines the male reproductive system (MRS) of this species, focusing on its morphology throughout post-embryonic development and the structure of its spermatozoa. Methods We analyzed the MRS of A. aegypti in the larval L4, pupal, and adult stages using bright-field light microscopy, fluorescent microscopy, and transmission electron microscopy techniques. Spermatozoa measurements were made using the ImageJ software. Results In L4 larvae, the MRS was composed of the two testes, a thin deferent duct, and a pair of seminal vesicles. The MRS is fully developed in pupae and adults, with two testes, deferent ducts, seminal vesicles, accessory glands, and an ejaculatory duct. Histological sections revealed that each testis is formed by a single follicle, which appeared to spiral at all stages. In pupae and adults, the testes showed germ cells at different stages of development, while the goblet portion of the deferent duct contained cytoplasmic bodies and spermatozoa. In adults, the seminal vesicles were filled with spermatozoa soon after emergence. Secretions from accessory glands were of the apocrine type. The spermatozoa were thin and long, measuring around 335 µm in length. Ultrastructural analysis revealed a very short acrosome covering the apical nucleus, in the flagellar region, an axoneme with the 9 + 9 + ‘1’ microtubule pattern typical of mosquitoes, and two mitochondrial derivatives along the flagellum, narrowing at the terminal portion. Conclusions Our analysis revealed a clear link between testicular development and spermatogenesis. In addition, we identified seminal vesicles at all life stages and accessory glands visible only in pupae and adults. The characterization of sperm structure and ultrastructure indicated similarities with other mosquito species. Finally, our study provided valuable information that may support research in comparative biology and reproduction. Graphical Abstract |
| format | Article |
| id | doaj-art-5fbbfcc68e024872884b4bc2ffeb7150 |
| institution | Kabale University |
| issn | 1756-3305 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | BMC |
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| series | Parasites & Vectors |
| spelling | doaj-art-5fbbfcc68e024872884b4bc2ffeb71502025-08-20T03:37:28ZengBMCParasites & Vectors1756-33052025-07-0118111610.1186/s13071-025-06808-wNew findings on the male reproductive system and spermatozoa of Aedes aegypti (Diptera: Culicidae)Henrique Barbosa da Silva0Renata Cristina Barbosa1Paulo Henrique Rezende2Dayvson Ayala-Costa3José Lino-Neto4Department of General Biology, Federal University of ViçosaDepartment of General Biology, Federal University of ViçosaDepartment of General Biology, Federal University of ViçosaDepartment of Entomology, Federal University of ViçosaDepartment of General Biology, Federal University of ViçosaAbstract Background Aedes aegypti is one of the most important arbovirus vectors, characterized by its widespread distribution and exceptional reproductive capacity. This study reexamines the male reproductive system (MRS) of this species, focusing on its morphology throughout post-embryonic development and the structure of its spermatozoa. Methods We analyzed the MRS of A. aegypti in the larval L4, pupal, and adult stages using bright-field light microscopy, fluorescent microscopy, and transmission electron microscopy techniques. Spermatozoa measurements were made using the ImageJ software. Results In L4 larvae, the MRS was composed of the two testes, a thin deferent duct, and a pair of seminal vesicles. The MRS is fully developed in pupae and adults, with two testes, deferent ducts, seminal vesicles, accessory glands, and an ejaculatory duct. Histological sections revealed that each testis is formed by a single follicle, which appeared to spiral at all stages. In pupae and adults, the testes showed germ cells at different stages of development, while the goblet portion of the deferent duct contained cytoplasmic bodies and spermatozoa. In adults, the seminal vesicles were filled with spermatozoa soon after emergence. Secretions from accessory glands were of the apocrine type. The spermatozoa were thin and long, measuring around 335 µm in length. Ultrastructural analysis revealed a very short acrosome covering the apical nucleus, in the flagellar region, an axoneme with the 9 + 9 + ‘1’ microtubule pattern typical of mosquitoes, and two mitochondrial derivatives along the flagellum, narrowing at the terminal portion. Conclusions Our analysis revealed a clear link between testicular development and spermatogenesis. In addition, we identified seminal vesicles at all life stages and accessory glands visible only in pupae and adults. The characterization of sperm structure and ultrastructure indicated similarities with other mosquito species. Finally, our study provided valuable information that may support research in comparative biology and reproduction. Graphical Abstracthttps://doi.org/10.1186/s13071-025-06808-wSpiraled testicular follicleSexual developmentMosquito reproductionMicroscopy |
| spellingShingle | Henrique Barbosa da Silva Renata Cristina Barbosa Paulo Henrique Rezende Dayvson Ayala-Costa José Lino-Neto New findings on the male reproductive system and spermatozoa of Aedes aegypti (Diptera: Culicidae) Parasites & Vectors Spiraled testicular follicle Sexual development Mosquito reproduction Microscopy |
| title | New findings on the male reproductive system and spermatozoa of Aedes aegypti (Diptera: Culicidae) |
| title_full | New findings on the male reproductive system and spermatozoa of Aedes aegypti (Diptera: Culicidae) |
| title_fullStr | New findings on the male reproductive system and spermatozoa of Aedes aegypti (Diptera: Culicidae) |
| title_full_unstemmed | New findings on the male reproductive system and spermatozoa of Aedes aegypti (Diptera: Culicidae) |
| title_short | New findings on the male reproductive system and spermatozoa of Aedes aegypti (Diptera: Culicidae) |
| title_sort | new findings on the male reproductive system and spermatozoa of aedes aegypti diptera culicidae |
| topic | Spiraled testicular follicle Sexual development Mosquito reproduction Microscopy |
| url | https://doi.org/10.1186/s13071-025-06808-w |
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