Morphology of the exocrine glands associated with the maxillolabial complex in the ant Camponotus japonicus Mayr, 1866 (Hymenoptera: Formicidae)

Abstract

In this study, we investigated the morphological characteristics of three glands that are associated with the labium and the maxillae in the female castes as well as males of the ant Camponotus japonicus Mayr, 1866 by using serial semithin sections and scanning electron microscopy (SEM). We propose to name these glands as the postmentum base gland, the stipes base gland and the cardo base gland. The cardo base gland represents what was previously known as the maxillary gland, the two other glands are novel findings. They all belong to class-3 glands and have no reservoir for the storage of secretion. Their morphology is similar among the studied categories (major worker, minor worker, queen and male). The postmentum base gland is made up by 10-15 secretory units that open through the articulation membrane on both sides of the base of the labial postmentum with no significant differences among castes. The stipes base gland is formed by a cluster of secretory units that open at the articulation membrane between cardo and stipes. This gland is much larger in major workers (almost 140 cells) than in the other castes (approx. 50-60 cells). The cardo base gland opens through the membrane that connects the cardo and stipes to the head capsule. The number of cells of this gland is much larger in major workers and queens (approx. 190 resp. 150) than in minor workers and males (approx. 45 resp. 40). No information is yet available on the function of the glands.

The First Reconstruction of the Head Anatomy of a Cretaceous Insect, †Gerontoformica gracilis(Hymenoptera: Formicidae), and the Early Evolution of Ants

“…Only present in Formica and Wasmannia in our taxon sampling, but also present in other species of Formicinae and Myrmicinae (Boonen and Billen 2016). Previously known as maxillary gland, but improved terminology introduced by Xu et al (2020). Category 1, 3.…”

Morphology and Ultrastructure of the Prepharyngeal and Pharyngeal Glands in the Ant Camponotus Japonicus

“…In order to evaluate the size of the prePG, the numbers of secretory units in each caste were counted (method described in Xu et al, 2021). However, the head size which can significantly affect the size and secretory capacity of the prePG varies considerably among different female castes and males.…”

Comparative morphology and ultrastructure of the labial gland among castes of Camponotus japonicus (Hymenoptera: Formicidae)

“…The labial gland (also known as salivary gland) is an epithelial gland with reservoir that belongs to class-1, which is formed by a monolayer of epithelial cells (Noirot and Quennedey, 1974). It opens at the distal tip of the labium (Gama and Cruz Landim, 1982;Xu et al, 2021), and although this opening site strictly speaking makes it a cephalic gland, the major secretory part is located dorsolaterally in the prothorax. It may even extend into the mesothorax, and thus represents a major exocrine structure in the thorax (Gama and Cruz Landim, 1982;Billen et al, 2013Billen et al, , 2017.…”