Bodin Aurélie, Jaloux Bruno, Delbecque Jean-Paul, Vannier Fabrice, Monge Jean-Paul, Mondy Nathalie
Université de Tours, IRBI UMR CNRS 6035, Parc Grandmont, Tours 37200, France.
J Insect Physiol. 2009 Jul;55(7):643-8. doi: 10.1016/j.jinsphys.2009.04.003. Epub 2009 May 3.
Oogenesis of the parasitoid wasp Eupelmus vuilleti is known to be dependent on host availability. However, examination of ovarian dynamics by microscopy showed that oogenesis and vitellogenesis are initiated before female eclosion and proceed 1-2 days after, independent of host presence. Oogenesis continued beyond the 2nd day only in the presence of hosts, otherwise it was replaced by egg resorption. It is thus possible to distinguish between host-independent and host-dependent periods of oogenesis. In the presence of host, each ovariole (three per ovary) contained generally three oocytes: a fully mature oocyte, a nearly mature one and an immature one. However, host deprived-females resorbed their most mature and their smallest oocytes, but kept one almost mature oocyte per ovariole. Comparison of zero, short and long host deprivation periods showed that females always had the ability to quickly lay eggs to exploit any new host. However, increased deprivation led to a reduction in the number and the viability of eggs. Enzymo-immunological measurements of ecdysteroids were made in whole females, in dissected ovaries and in newly laid eggs. Our results indicated that ecdysteroids play a major role as circulating hormones involved in the regulation of oogenesis.
已知寄生蜂尤氏真绥螨的卵子发生依赖于宿主的可获得性。然而，通过显微镜检查卵巢动态发现，卵子发生和卵黄发生在雌蜂羽化前就已开始，并在羽化后1 - 2天继续进行，与宿主的存在无关。只有在有宿主的情况下，卵子发生才会在第2天之后继续，否则就会被卵吸收所取代。因此，可以区分卵子发生的宿主非依赖期和宿主依赖期。在有宿主的情况下，每个卵巢管（每个卵巢有三个）通常含有三个卵母细胞：一个完全成熟的卵母细胞、一个接近成熟的卵母细胞和一个未成熟的卵母细胞。然而，剥夺宿主的雌蜂会吸收其最成熟和最小的卵母细胞，但每个卵巢管保留一个几乎成熟的卵母细胞。对零、短和长宿主剥夺期的比较表明，雌蜂总是有能力迅速产卵以利用任何新的宿主。然而，剥夺时间的增加会导致卵的数量和活力下降。对整个雌蜂、解剖的卵巢和新产的卵进行了蜕皮甾体的酶免疫测定。我们的结果表明，蜕皮甾体作为参与卵子发生调节的循环激素发挥着主要作用。
