How to distinguish the sex of a tick? - briefly
Male ticks possess a fully developed scutum that covers the entire back, while females have a smaller scutum limited to the anterior portion and a noticeably larger, often engorged, abdomen; additionally, the genital opening is positioned near the rear in males and near the ventral midline in females.
How to distinguish the sex of a tick? - in detail
Adult ticks can be sexed by examining external morphology. The following characteristics are reliable for most hard‑tick species (Ixodidae):
- Dorsal shield (scutum): males possess a scutum that extends over the entire dorsum, giving a uniformly hard back. Females have a reduced scutum covering only the anterior portion; the remainder of the abdomen is soft and expands dramatically after feeding.
- Ventral genital opening: in males the genital pore is located near the anal groove on the ventral surface, often accompanied by a pair of short, stout legs used for mating. In females the genital opening lies posterior to the anus, positioned centrally on the ventral side.
- Leg length and robustness: males typically have longer, more robust legs to facilitate movement on the host, while females exhibit relatively shorter legs.
- Size after engorgement: females can increase severalfold in weight and size when fully engorged, whereas males remain relatively small and retain a flat profile.
These features are discernible only in fully mature specimens. Larvae and nymphs lack differentiated genital structures and cannot be reliably sexed without microscopic examination of internal organs. Accurate identification requires a hand lens or stereomicroscope and careful orientation of the tick to view the ventral surface.