Oogenesis of Hematophagous Midge Forcipomyia taiwana (Diptera: Ceratopogonidae) and Nuage Localization of Vasa in Germline Cells

Abstract

Forcipomyia taiwana is an irritating hematophagous midge that preferentially attacks humans and affects leisure industries in Taiwan. Understanding the female reproductive biology of such pests would facilitate the development of pest control strategies. However, knowledge about oogenesis in the genus Forcipomyia is unavailable. Accordingly, we examined the ovariole structure and features of oogenesis in terms of the oocyte and the nurse cell. After being blood-fed, we observed a high degree of gonotrophic harmony—the synchronization of developing follicles. The follicle of the F. taiwana has only one nurse cell connected to the oocyte, which is distinct among hematophagous midges. In the nurse cell, we identified the perinuclear localization of the germline marker, Vasa. The Vasa localization is reminiscent of the nuclear envelope-associated nuage observed by electron microscopy. To determine whether F. taiwana Vasa (FtVasa) is an authentic nuage component, we produced transgenic flies expressing FtVasa in the female germline and proved that FtVasa was able to be localized to Drosophila nuage. By characterizing the oogenesis and Vasa expression in the germline cells of F. taiwana, this study extends knowledge about the female reproductive biology of hematophagous midges.

Aedes aegypti exhibits a distinctive mode of late ovarian development

“…In nematoceran, some species contain short TFs and relatively short ovarioles with synchronous development. In addition, some unique features of ovarian development have been reported, such as germ cell divisions, a cluster formation, and a massive cell migration prior to ovariole formation [ 52 – 54 ]. In this study, our results show that the germline development of Ae.…”

Quantitative models for building and growing fated small cell networks

“…The first of these classes is the two-cell network, where the oocyte is connected to a single support cell (figure 2 a ). Such cysts are found in the polychaetous annelid worm Ophryotrocha labronica [75], the biting midge Forcipomyia taiwana [42], earwigs (order Dermaptera) [43,76,77] and multiple fungus gnats of the genus Sciara [78,79]. The next class is that of bilinear chains (figure 2 b ), composed of two long strings of support cells emanating from a central oocyte.…”

“…Oogenesis typically culminates with the generation of an oocyte that is competent to develop further and support early embryonic life when fertilized; however, there appear to be several paths towards that end, as there exists an incredible diversity in the size (number of cells), topology and collective behaviours of the intermediate germline cysts. For example, while some CLTs are linear, others are branched [39][40][41]; while the oocyte in some species is connected to a single support cell, in others it may be connected to several or even hundreds of support cells [42][43][44]; while some germline cysts form through synchronous divisions, resulting in clusters with 2 n cells, others do so asynchronously [41,45]. Germline cysts therefore represent a trove of developmental problems that lend themselves uniquely to mathematical modelling.…”

Tools to analyze the organization and formation of the germline cyst in zebrafish oogenesis

“…CLT networks can be categorized in five primary classes ( Świątek and Urbisz, 2019 ; Diegmiller et al, 2022 ). In the two-cell network class, an oocyte is connected to a single support cell (termed nurse cell) that transports material to the oocyte, and this class is found in annelid worms ( Brubacher and Huebner, 2009 ), the biting midge ( Wang et al, 2020 ), earwigs ( Yamauchi and Yoshitake, 1982 ; Tworzydło and Kisiel, 2010 ; Tworzydło et al, 2010 ) and multiple fungus gnats ( Berry, 1941 ; Gutzeit, 1985 ). In the bilinear chain networks class, cysts are composed of two long strips of support cells emanating from centrally placed oocyte.…”