Yamashita K, Zhang K, Ichiki R T, Nakamura S, Furukawa S
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan.
Bull Entomol Res. 2019 Oct;109(5):643-648. doi: 10.1017/S0007485318001049. Epub 2019 Feb 7.
The tachinid fly Drino inconspicuoides (Diptera: Tachinidae) is an ovolarviparous endoparasitoid whose larvae develop in the host haemocoel and avoids the host immune system. In this study, we investigated the immune evasion mechanisms of this species during infestation in the host Mythimna separata (Lepidoptera: Noctuidae). We discovered a unique 'cloak' that surrounded D. inconspicuoides larvae that penetrated into the host and determined through genomic polymerase chain reaction analysis that this structure originated from the host rather than the tachinid. The 'cloak' contained both haemocytes and fat body cells from the host, with the haemocytes assembling around the larvae first and the fat body cells then covering the haemocyte layer, following which the two mixed. Living D. inconspicuoides larvae that were wrapped in the 'cloak' were not melanized whereas encapsulated dead larvae were melanized, suggesting that this structure contributes to the avoidance of host immune reactions.
寄蝇科昆虫隐匿追寄蝇（双翅目：寄蝇科）是一种卵胎生内寄生蜂，其幼虫在宿主体腔中发育，并能避开宿主的免疫系统。在本研究中，我们调查了该物种在侵染宿主粘虫（鳞翅目：夜蛾科）过程中的免疫逃避机制。我们发现一种独特的“外衣”包裹着侵入宿主体内的隐匿追寄蝇幼虫，通过基因组聚合酶链反应分析确定，这种结构起源于宿主而非寄蝇。“外衣”包含来自宿主的血细胞和脂肪体细胞，血细胞先在幼虫周围聚集，然后脂肪体细胞覆盖血细胞层，随后二者混合。包裹在“外衣”中的活隐匿追寄蝇幼虫未被黑化，而被包囊的死幼虫则被黑化，这表明该结构有助于避免宿主的免疫反应。
