Ecdysteroid titre and metabolism and cuticle deposition during embryogenesis of the ixodid tick <i>Amblyomma hebraeum</i> (Koch)

Three embryonic cuticles are formed before larval cuticle deposition during embryonic development of <i>Amblyomma hebraeum</i>. The quantity of radioimmunoassay-positive material varied between 50 and 200 pg ecdysone equivalents per mg, but no significant peaks were detected. Maternally incorporated [³H]-20-hydroxyecdysone and [³H]-ecdysone contained in freshly laid eggs appear to be conjugated to C-22 fatty acid esters and 3 α epimers of those esters and, thus, appear doubly inactivated. In addition, ecdysone is converted to an unknown product called 2′. The role of these maternally derived ecdysteroids is unknown.