Surface Morphology of Legs in the Assassin Bug <I>Zelus longipes</I> (Hemiptera: Reduviidae): A Scanning Electron Microscopy Study with an Emphasis on Hairs and Pores

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Scanning electron microscopy observations are presented for freshly hatched nymphs and adults of Zelus longipes L., an hemipteran species of the family Reduviidae (assassin bugs). The emphasis is on the structure and distribution of pores and different types of hairs covering the tibiae of the forelegs in relation to a viscous substance associated with them. The substance is instrumental in catching prey. In both developmental stages of the animal, the legs are abundantly covered with two major types of hairs. There are the so-called sundew hairs characterized by spines on their upper part. The legs also carry smooth peg-like setae. In addition, the adult animals show a few smooth, needle-shaped hairs. At this developmental stage, the surface of the legs has developed ring-like invaginations. The animals catch prey using their raised forelegs that are covered with a layer of sticky substance. It is assumed that the sundew hairs in combination with the peg-like setae play a role in mechanically stabilizing the film of sticky substance covering the legs in both developmental stages. The ring-like invaginations found only in the adult animals are interpreted as the external openings of integumental glands, responsible for the production of the substance. The openings are missing in freshly hatched nymphs, and it is assumed that they use the sticky substance deposited by the female at the bases of the laid eggs to set up their sticky traps.