Oogenesis

in mosquitoes is a nutrient-limited process, triggered only if sufficient reserves are available (Briegel, 1990; Wheeler, 1996). The primary follicles of Aedes aegypti are undifferentiated at adult emergence and, during the next 60·h, they grow to double their size and reach the maximum previtellogenic length or resting stage (Hagedorn et al., 1977). This ovaric previtellogenic phase of development is initiated only when nutrients are appropriate (Gwadz and Spielman, 1973). Females must have some mechanism to restrain ovary development if nutrients are not available, and a hormonal control system activated by suitable nutritional stimuli is very appropriate. Juvenile hormone (JH) is the key hormone regulating previtellogenic ovarian development in mosquitoes (Hagedorn, 1994; Klowden, 1997). In newly emerged adult female mosquitoes (teneral females), an increase in JH signals that ecdysis of the adult has finished and reproductive processes should begin. JH levels in Ae. aegypti increase during the first day after adult emergence (Shapiro et al., 1986). This initial rise in JH is essential for reproductive maturation. JH acts on several tissues, including ovaries, fat body and midgut, making them competent to perform their adult-specific functions (Klowden, 1997). JH is synthesized and released from the corpora allata (CA), a pair of endocrine glands with nervous connections to the brain (Stay, 2000). An increase in rates of JH biosynthesis is responsible for the rise in JH levels observed during the first day after eclosion (Li et al., 2003a). Is there a relationship between the increase of JH synthesis in the CA and the presence of nutrient reserves? In this study, we report that low teneral nutrient reserves reduced JH biosynthesis and ovarian previtellogenic development in Ae. aegypti females. Materials and method