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Fig. 6. A model for the interaction among metabolic reserves, hormones and oocyte
maturation in autogenous and anautogenous mosquitoes. A summary, from
Fig. 1, of teneral reserves of
lipid (L), glycogen (G) and protein (P) measured in Oc. atropalpus
and A. aegypti females derived from high-food larvae (termed high
reserve) or low-food larvae (termed low reserve) and resulting body size is
shown in the table. To the right of the summary table, hormonal responses,
presumably as a result of teneral reserves or adult nutrition, are depicted.
This model for the first egg development cycle depicts hypotheses generated
from the results of experiments presented in this paper, with the assumption
that females are mated. In autogenous high-reserve Oc. atropalpus
females, teneral glycogen and protein levels are sufficiently high to exceed
the threshold for stimulation of ovarian ecdysteroid production (high ov.
ecd.) and subsequent vitellogenesis (Vg) and egg maturation (eggs). In
addition, the biosynthesis of JH by the corpora allata (CA) is low (low JH).
In anautogenous high-reserve A. aegypti, glycogen and protein levels
fall below a threshold needed for ovarian ecdysteroid production and
vitellogenesis. Consequently, JH biosynthesis is high (high JH), ovarian
ecdysteroid production is low (low ov. ecd.), and oocytes are arrested (pre-VG
follicle arrest) until the females take a blood meal (Blood). Hormonal
profiles and stage of egg development observed in both autogenous and
anautogenous females emerging with low nutrient reserves are depicted
similarly. Notes: 1results from Caroci et al.
(2004); 2results
from Sieglaff et al.
(2005).
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