A new juvenile hormone mimic CGA-255′728, developed by Novartis, was tested for its efficacy on different life stages of the cat flea, Ctenocephalides felis (Bouché). The compound was mixed in bovine blood at concentrations of 1, 10, and 100 ppb and fed to adult fleas using an artificial membrane system. Less than 7% of the eggs from fleas fed 10 and 100 ppb hatched, compared with >70% hatch in eggs laid by control fleas or fleas fed 1 ppb. Histological studies demonstrated that ≈50% of the eggs from fleas fed 10 ppb contained unhatched larvae that died after completing embryological development. At 100 ppb, 24% of the fleas died as fully formed larvae within the egg, but at this concentration nearly 20% of fleas also died before embryogenesis was completed. In addition to embryonic and larval mortality, ≈28% of eggs from the 100 ppb-treated group were deposited as empty shells. Evidently these eggs were crushed by the muscular action of the oviduct and yolk was expelled into the oviduct during oviposition. None of the test concentrations showed adulticidal effects over a 10-d period. Fecundity was significantly increased with increased concentrations of CGA-255′728 indicating that the compound mimicked the effect of juvenile hormone.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 37 • No. 1