Zgradba in delovanje krpatih žlez enakonožcev (Crustacea: Isopoda)

Lobed glands, a unique feature of terrestrial isopod crustaceans (Oniscidea), are tricellular tegumental glands consisting of a secretory cell, an intermediate cell, and a canal cell. These glands, hypothesized to serve defensive functions, vary in presence, distribution, and morphology across Oniscidea species. This study examined 32 isopod species, representing diverse phylogenetic groups and eco-morphotypes, using histological and histochemical methods, confocal, and electron microscopy techniques. Lobed glands were absent in examined non-oniscidean species and some Oniscidea groups like the section Tylida and the family Armadillidae. We found lobed glands in the uropods, the lateral plates of the pleon and the pereon, the cephalothorax, and we report their presence for the first time in the antennae, under tergites, and in the pereopods. Gland distribution correlated with eco-morphotypes: epigean runners and clingers had more glands, while endogean creepers, rollers, and non-conformists possessed fewer or none. Gland size was species-specific, reflecting body size but showing no relation to eco-morphotype. Analysis of different developmental stages of different species revealed that the number of glands remains constant and their size increases with body growth. Histochemical and FTIR analyses showed protein-rich secretions, differing between different body regions. These secretions likely function as defensive glues, entangling predators rather than relying on toxicity. Gland discharge likely results from increased secretory product volume in the duct, with secretion triggered by rapid fusion of secretory granules with the secretory cell plasma membrane.