EMBRYOGENESIS OF THE SAND FLY PHLEBOTOMUS-PAPATASI (DIPTERA, PSYCHODIDAE) - ORGANOGENESIS OF THE NERVOUS-SYSTEM, TRACHEAL SYSTEM, MUSCULAR SYSTEM, HEART, AND GONAD RUDIMENTS
Mm. Abbassy et al., EMBRYOGENESIS OF THE SAND FLY PHLEBOTOMUS-PAPATASI (DIPTERA, PSYCHODIDAE) - ORGANOGENESIS OF THE NERVOUS-SYSTEM, TRACHEAL SYSTEM, MUSCULAR SYSTEM, HEART, AND GONAD RUDIMENTS, Annals of the Entomological Society of America, 88(6), 1995, pp. 821-826
Formation of the embryonic brain of the sand fly Phlebotomus papatasi
(Scopoli) starts at 108 h after oviposition with proliferation of the
ectodermal cells in the posterior region of the blastocephalon. Within
156 h, the brain is completely formed. The subesophageal ganglion is
formed by 156 h. The basic form of the ventral nerve cord is initiated
at 84 h with migration of the neuroblasts from the ectodermal layer.
These cells form the ganglionic lobes, which become fully differentiat
ed by 156 h and form a chain of 3 thoracic and 8 abdominal ganglia. Ey
e rudiments appear at 132 h and become fully differentiated by 156 h.
Cuticle surrounding all appendages and body segments is secreted by ec
todermal cells between 132 and 168 h. Rudiments of the tracheal system
begin to differentiate at 120 h, becoming well-defined tracheae and l
ongitudinal trunks by 168 h. Formation of the musculature of the gnath
al segments begins at 144 h and is completed during the course of embr
yogeny The true musculature is formed from the somatic mesoderm, which
also gives rise to the heart. The ventral and dorsal longitudinal mus
cles begin to form at 132 h and are completed by 168 h. A tubular hear
t is seen at 168 h. The gonadal rudiments are formed by 144 h in the m
idlateral position of abdominal segments 6 and 7. Each rudiment consis
ts of 6-8 pole cells that are surrounded by a layer of splanchnic meso
dermal cells. The pole cells in each rudiment begin mitosis at 180 h;
by 204 h the total number of cells in each rudiment is attained (6-10)
. No other part of the reproductive system is formed during embryogeny
of the egg stage.