The distribution of serotonin (5-HT) immunoreactive cells and their projections was mapped in the ganglia of the ventral nerve cord of the tobacco hornworm, Manduca sexta, during embryonic development, using an antiserum to 5-HT. Immunoreactive cells were first seen at 60% development. By 75% of embryonic development, a total of 94 immunoreactive cells were found in the ventral ganglia, including the suboesophageal ganglion. This number decreased to 80 neurons by 100% of development. About 50% of these cells were arranged in the abdominal ganglia and the rest were located in both the suboesophageal and thoracic ganglia. The suboesophageal ganglion exhibited immunoreactive segmental interneurons in areas corresponding to the mandibular, maxillary and labial neuromeres. Two pairs of immunoreactive interneurons were also observed to occur bilaterally in each of the thoracic and abdominal ganglia, with the exception of the prothoracic ganglion. This ganglion contained three pairs of bilaterally arranged immunoreactive neurons as early as 60% of embryonic development. Serotonin immunoreactivity was also found in a number of efferent neurons in the mandibular and labial neuromeres of the suboesophageal ganglion and in the prothoracic, mesothoracic and posterior abdominal ganglia. The occurrence of 5-HT in these efferent neurons suggests an involvement of serotonin in fore- and hindgut function via its effect on the visceral muscles. Immunoreactive lateral longitudinal fibers extended along the entire length of the ventral nerve cord together with dense segmental arborizations. The latter had regressed by the time the embryo was fully developed. This regression of the arborizations in the ganglia at the end of embryonic development indicates that a reorganization of 5-HT innervation occurs to support new larval functions. The time of appearance of 5-HT immunoreactive cells and fibers suggests that serotonin may play a role in the development of the ventral nerve cord.

Changes in the total protein titer in the haemolymph (HL) and ovaries (Ov) of mated fed normal and Lufox treated female Argas persicus during the reproductive cycle and in the HL of normal male were studied. Tick engorgement was followed by an intial drop of the HL total protein concentration immediately and up to the 2 nd and 3 rd day after feeding (daf), then by a gradual increase on next days to reach maximum on 4-7 and 6-7 daf in the female and male, respectively. The level in the female HL was much higher than that in the male during vitellogenesis and the onset of oviposition. In the ovaries of normal female the total protein level increased gradually immediately up to 2 daf and evidently on 3 daf to reach a maximum on 5-7 daf. The protein level in the HL and ovaries decreased after the completion of oviposition (20 daf). Topical application of a single dose of 50 ppm Lufox on the mated female A. persicus on the 3 rd daf interfered with protein production causing a significant reduction in the total protein level in the HL (43.04-55.57%) and ovaries (36.47-46.43%) during vitellogenesis on 4-7 daf and in eggs (15.38%) freshly deposited by the treated female. Also, application of Lufox on the 3 rd daf altered the normal pattern of change in the level of HL and ovary total protein during the reproductive cycle by preventing any appreciable increase in the level on next days (4-7 daf) where the level remained constant in the ovaries and even decreased in the HL (4-5 daf).

Treatment of one day old females (previtellogenic) of A. persicus with JHA (Admiral) showed a significant effect on viability of deposited eggs and on total mortality of post-embryonic stages. On the other hand, treatment of 3-days old females (vitellogenic) and 7-days old females (post-vitellogenic and ovulation) of A. persicus exhibited a highly significant effect on viability of eggs and on total mortality of post-embryonic stages (especially larval and younger nymphal instars). The topical application of JHA (Admiral) in different doses to newly laid eggs (0-1 h POP) of A. persicus has a highly significant effect on the development of treated eggs. This was also true in case of dipping of egg masses in solution containing different doses of Admiral for 1 minute. This effect increased by increasing the dose of the hormonal material.

Development of the serotonergic system in the brain and frontal ganglion of the Manduca embryo between 35 and 100% of development was studied immunocytochemically with an antiserum to serotonin (5-HT). Serotonin immunoreactivity was initially detectable at 40-45% development in short fibers in the head region, prior to differentiation of the brain. Immunoreactive cell bodies were first seen in the brain at 60% development, located in the protocerebrum and tritocerebrum. Thick fiber tracts crossing the midline (commissures) could also be observed at this early stage. As development of the embryo progressed, eight immunoreactive cell groups, containing a total of about 38-40 cells, and four commissures with terminal arborizations appeared successively in the brain. From 75 to 100% development, no obvious changes occurred in the number or distribution of cells, and the brain exhibited the same pattern of 5-HT immunoreactive cells, fiber tracts and arborizations as in last instar larvae of Manduca. However, an increase in the size of the cells in both the brain and frontal ganglion was noted between 75 and 80% development, followed by a decrease by 100% development. The frontal ganglion was found to contain three 5-HT immunoreactive cells, which appeared to send bilateral projections into the frontal connectives and the recurrent nerve. During embryonic development, the dendritic arborizations of these frontal ganglion cells increased, while the amount of 5-HT immunoreactivity in the cell bodies decreased. Thus, the serotonergic system first appears in the Manduca embryo at an early stage of development, similar to the situation in other insects as well as vertebrates. By the end of the embryonic period, the same number of serotonergic neurons are present in the brain as in larval and adult Manduca, suggesting that once formed, these cells persist through postembryonic development and metamorphosis.

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