Comparative morphology of damsel bugs legs' microstructure (Insecta: Hemiptera: Nabidae)

Nabidae, damsel bugs (Hemiptera: Heteroptera: Cimicomorpha) is a small family of predatory insects with poorly understood phylogenetic relationships. They are characterized by their raptorial fore- and to a lesser extend also midlegs with modified tibiae and femora covered with diverse types of armature consisting of highly sclerotized cuticular structures. The legs of nabids are also covered by various sensory organs and other structures used for cleaning the body, facilitate movement or with unknown functions. In this study, we describe the fine morphology of all these structures on the fore-, mid- and hindlegs of nine species from both subfamilies and three tribes of Nabidae (Gorpini, Nabini and Prostemmatini). The comparison of raptorial legs of different taxa is provided, as well as a discussion on mechanisms of holding the prey and the utility of their morphology in phylogenetic analysis. The grasping apparatuses of the studied species were classified into four morphological types based on the specific structures found in different taxa and development of the fossula spongiosa. The descriptions of other cuticular structures occurring on the legs are also presented. They are subdivided by their morphological features into numerous types in each species individually. In the discussion we compare these structures between the studied species and with other groups of Cimicomorpha. Some of them are common and were found in all species (and also in other insects) and some are specific for subfamily or genera. We also discuss the most probable function for each type of structure.