Palma K G, Meola S M, Meola R W
Department of Entomology, Texas A&M University, College Station 77843-2475.
J Med Entomol. 1993 Mar;30(2):421-6. doi: 10.1093/jmedent/30.2.421.
Adult cat fleas were exposed to residues of pyriproxyfen and methoprene in glass vials, then fed on a cat 24 h later to investigate the mode of action of juvenoid growth regulators on embryonic development in flea eggs. Eggs laid by pyriproxyfen-treated fleas within 70 h after exposure to this juvenoid were often devoid of yolk and frequently collapsed after oviposition. Minimal amounts of yolk were deposited in eggs laid after 70 h, and no blastoderm was formed. These results are significant because both modes of action were different than those observed earlier by investigators studying ovicidal effects in adult insects treated with juvenile hormone. In contrast to the pyriproxyfen results, eggs laid by methoprene-treated fleas showed no gross morphological effects, and these eggs remained turgid during embryogenesis. However, the eggs either did not hatch or the larvae died within hours after hatching. Histological examination of the eggs revealed that most of the eggs contained segmented embryos which had apparently died during blastokinesis. Although eggs of some insects exposed to juvenile hormone during oogenesis fail to undergo germ band formation, there was no evidence of this effect in methoprene-treated cat fleas.
将成年猫蚤置于装有吡丙醚和烯虫酯残留的玻璃瓶中，24小时后让其吸食猫血，以研究保幼激素类似物生长调节剂对蚤卵胚胎发育的作用方式。接触该保幼激素类似物后70小时内，经吡丙醚处理的蚤所产的卵往往缺乏卵黄，产卵后常塌陷。70小时后所产的卵中卵黄沉积量极少，且未形成胚盘。这些结果意义重大，因为这两种作用方式均与早期研究用保幼激素处理成年昆虫的杀卵作用的研究人员所观察到的不同。与吡丙醚的结果相反，经烯虫酯处理的蚤所产的卵未表现出明显的形态学影响，且这些卵在胚胎发育过程中保持饱满。然而，这些卵要么未孵化，要么幼虫在孵化后数小时内死亡。对这些卵进行组织学检查发现，大多数卵含有已分段的胚胎，这些胚胎显然在胚动期间死亡。虽然一些在卵子发生过程中接触保幼激素的昆虫的卵未能形成胚带，但在经烯虫酯处理的猫蚤中没有这种作用的证据。
