The male genital tract and aedeagal components of the Diptera with a discussion of their phylogenetic significance
Author
Sinclair, Bradley J.
Author
Borkent, Art
Author
Wood, D. Monty
text
Zoological Journal of the Linnean Society
2007
2007-08-31
150
4
711
742
https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2007.00314.x
journal article
10.1111/j.1096-3642.2007.00314.x
0024-4082
5432328
TRICHOCERIDAE
Description (
Figs 2D
,
5A
)
Testis:
Each testis is oval to pyriform, with a thin epithelium continuous with the vasa deferentia.
Epididymis:
Not differentiated.
Vas deferens:
The vasa deferentia extend posteriorly to the base of the accessory glands, where they arch medially. Each duct abruptly terminates near the anteromedial margin of the accessory gland (
Neumann, 1958
;
Dahl, 1980
).
Accessory gland and seminal vesicle:
The accessory glands are paired spherical structures, divided internally into two functionally different chambers (
Neumann, 1958
; ‘Samenblase’). The chambers are lined with columnar cells, producing secretions that empty separately into the duct that separates the seminal vesicle and the ejaculatory duct. No spermatozoa have been observed within the chambers of the accessory gland (
Neumann, 1958
). The seminal vesicle is interpreted to occur at the apex of each of the vasa deferentia, adjacent to and fused with the accessory glands (
Dahl, 1980
). A narrowing of the duct separates the seminal vesicle from the anterior fork of the ejaculatory duct. The seminal vesicle and the accessory gland are enclosed in a continuous sheath of circular muscle (
Neumann, 1958
).
Ejaculatory duct:
Anteriorly, the ejaculatory duct is paired for a short distance before fusing into a single duct. The circular muscle is very thin and does not function as a pump (
Neumann, 1958
).
Ejaculatory apodeme, sperm pump, and aedeagus:
There is a small flexible ejaculatory apodeme at the base of a narrow sclerotized aedeagus (
Neumann, 1958
;
Wood, 1991
). The ejaculatory apodeme rotates, compressing the sperm pump and forcing the spermatozoa out through the narrow opening of the phallotrema.
Remarks:
The configuration of the male genital tract of the
Trichoceridae
was thoroughly investigated by
Neumann (1958)
. Our examination of material confirms his interpretation. The male genital duct of
Trichoceridae
is somewhat similar to
Culicidae
and
Chaoboridae
in basic configuration and no preformed spermatophore is produced.
Matsuda (1976)
assumed that one of the chambers in the accessory gland corresponded to the seminal vesicle in
Aedes
Meigen. This
appears unlikely as spermatozoa are not stored in the accessory gland chambers of
Trichocera
Meigen.