Morphology and structural organization of Gene's organ in Argas walkerae

Abstract

Electron microscopy revealed that Gene's organ in females of Argas walkerae Kaiser & Hoogstraal (Ixodida: Argasidae) is formed as a double-sac structure consisting of an outer epithelial and an inner cuticular sac. The latter emerges through the camerostomal aperture to the exterior in ovipositing ticks. The epithelial sac forms the corpus and the two blind-ending horns, which pass into the epithelium of the excretory duct of a gland at each side of Gene's organ and envelop the cuticular sac. Both excretory ducts open into the lumen between the epithelial and the cuticular sac. The cuticular sac is folded and consists of a fibrous endocuticula outwards towards the lumen between the epithelial and the cuticular sac and of a smooth epicuticula inwards. Parallel running grooves occur over the lateral epicuticular surface turning medially into cobble-stone pavement-like rises. Tubuli pass through the cuticular sac ending in pores on the epicuticular surface and open into the lumen between the epithelial and the cuticular sac. Muscle fibres pass through the epithelial sac at the horn tips and are inserted to the cuticular sac. In ovipositing females, the glands are fully developed and the lumen between the epithelial and the cuticular sac is filled with an amorphous mass.

Reproduction in a Metastriata Tick, Haemaphysalis longicornis (Acari: Ixodidae)

“…These proteinaceous secretions may act as a waterproofing agent for the egg surface and/or as a lubricant to facilitate egg passage (Robinson and Davidson, 1914;Douglas, 1943), as do those of the lobular accessory glands. 9) Gené's Organ and Tubular Glands Gené's organ of H. longicornis is basically similar to that of the other Ixodidae (Arthur, 1953;Balashov, 1972;Booth et al, 1984b;El Shoura, 1987b;Schöl et al, 2001a, b). In the unfed stage, Gené's organ located immediately beneath the anterior part of the scutum is small in size and covers the chelicerae.…”