We studied 12 species of Strumigenys and confirmed the existence of class-1 apicofemoral and apicotibial glands as exclusive exocrine structures in workers, queens and males in this ant genus. Contrary to the majority of Strumigenys species, these glands are lacking in workers of S. mutica although they are present in queens. This striking discovery may be related with the social parasitic lifestyle of this species; however, it remains entirely speculative in which way the absence of these glands in workers could be beneficial for their social parasitism. The ultrastructure of the glands displays unique epithelial characteristics which include their bowl shape, the occurrence of a swollen nerve wedged between the gland cells and a complex system of irregular microvilli that are separated from the overlaying cuticle by a cytoplasmic layer. Although the function of the glands is still unknown, their cytoplasmic appearance indicates the production of a possibly pheromonal secretion. In addition to the epithelial apicofemoral and apicotibial glands, we also found class-3 dorsodistal femoral and dorsodistal tibial glands as new structures in the exocrine repertoire of ants. As these glands are also present in S. mutica queens but absent in workers, it is a challenge to further study and understand the social parasitism of this species.

我们研究了 12 种Strumigenys，并证实 1 类顶股腺和顶胫腺的存在是该蚂蚁属工蚁、蚁后和雄性的专有外分泌结构。与大多数Strumigenys物种相反，这些腺体在S. mutica的工人中缺乏尽管它们出现在皇后区。这一惊人的发现可能与该物种的社会寄生生活方式有关；然而，工人体内这些腺体的缺失会以何种方式有益于他们的社会寄生，这仍然完全是推测性的。腺体的超微结构显示出独特的上皮特征，包括它们的碗形、楔入腺体细胞之间的肿胀神经的出现以及由细胞质层与覆盖的角质层分离的不规则微绒毛的复杂系统。虽然腺体的功能仍然未知，但它们的细胞质外观表明可能产生了信息素分泌物。除了上皮顶股腺和顶胫腺外，我们还在蚂蚁的外分泌库中发现了 3 类背远股骨腺和背远胫腺作为新结构。由于这些腺体也存在于S. mutica蜂后但在工蜂中不存在，进一步研究和了解该物种的社会寄生是一个挑战。