Excitators: Female-Specific Secretory Structures in Marsh Beetles (Coleoptera: Scirtidae)

Females of many species of Scirtidae bear excitators – concave structures, often surrounded by modified setae. They are usually located on the elytra, but rarely also on the pronotum. Excitators are areas with openings of secretory glands. The present study is the first comprehensive and richly illustrated overview of these unusual structures in Scirtidae. The first histological study of elytra with excitators confirm that gland tissue is involved. The excitators of Scirtidae are compared to similar structures in other insects, with special emphasis on Coleoptera.