Changes in the structure of the cuticle of Ixodes ricinus L. 1758 (Acari, Ixodidae) during feeding.

Female Ixodes ricinus (ticks) are able to consume several times as much as their own weight in food. The body volume increases without the animal moulting. Special structural and material characteristics of the cuticular exoskeleton render this phenomenon possible. Only the alloscutum, which has a very pronounced lamellar structure, extends. The individual lamellae correspond to surface folds in the outer endocuticle and the epicuticle covering it. The degree of folding is correlated to the nutritional state of the animal, which can be differentiated into three significant phases. The phase-dependent morphology of the surface structure and the cuticular layers of the alloscutum are described qualitatively and quantitatively in this paper. Furthermore, the presence of systematic deposits of resilin in the alloscutum, which are significant for the flexibility, is demonstrated.