Previous observations have noted that in some species of higher termites the soldier caste lacks pigmented particles in its gut and, instead, is fed worker saliva that imparts a whitish coloration to the abdomen. In order to investigate the occurrence of this trait more thoroughly, we surveyed a broad diversity of termite specimens and taxonomic descriptions from the Old World subfamilies Apicotermitinae, Cubitermitinae, Foraminitermitinae, Macrotermitinae, and Termitinae. We identified 38 genera that have this “white-gutted” soldier (WGS) trait. No termite soldiers from the New World were found to possess a WGS caste. Externally, the WGS is characterized by a uniformly pale abdomen, hyaline gut, and proportionally smaller body-to-head volume ratio compared with their “dark-gutted” soldier (DGS) counterparts found in most termitid genera. The WGS is a fully formed soldier that, unlike soldiers in other higher termite taxa, has a small, narrow, and decompartmentalized digestive tube that lacks particulate food contents. The presumed saliva-nourished WGS have various forms of simplified gut morphologies that have evolved at least six times within the higher termites.

中文翻译：

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白内脏士兵：高等旧大陆白蚁（等翅目：白蚁科）的消化管的简化，用于非颗粒饮食


之前的观察表明，在某些高等白蚁物种中，士兵种姓的肠道中缺乏色素颗粒，而是以工蚁唾液喂养，从而使腹部呈现白色。为了更彻底地研究这一性状的发生，我们调查了旧世界亚科 Apicotermitinae、Cubitermitinae、Foraminitermitinae、Macrotermitinae 和 Termitinae 的广泛多样性的白蚁标本和分类学描述。我们鉴定出 38 个属具有这种“白内脏”士兵 (WGS) 特征。没有发现来自新大陆的白蚁士兵拥有 WGS 种姓。从外部来看，与大多数白蚁属中发现的“深色内脏”士兵（DGS）同类相比，WGS 的特征是均匀苍白的腹部、透明的肠道和比例较小的身体与头部体积比。 WGS 是一种完全成形的士兵，与其他高等白蚁类群中的士兵不同，它具有小而狭窄且分室的消化管，缺乏颗粒食物内容物。假定的唾液营养全基因组测序具有各种形式的简化肠道形态，这些形态在高等白蚁体内至少进化了六次。