TABLE OF CONTENTS
Siphunculata (Anoplura) – Sucking Lice: Morphology and Characteristics
Siphunculata, also known as Anoplura, are sucking lice that are permanent, wingless ectoparasites of mammals. They are highly host-specific and possess specialized mouthparts adapted for piercing the skin and sucking blood. These lice have a dorsoventrally flattened body, short antennae, vestigial eyes, and clawed tarsi that enable them to remain attached to the host. Understanding their morphology and characteristics is important in veterinary parasitology because infestations can cause irritation, pruritus, anemia, and other health problems in affected animals.
Lice are highly host-specific. Earlier, lice were grouped under one order, Pthiraptera. Now, they are classified into two orders:
- Order: Mallophaga (Biting or chewing lice) – Mallo–wool, Phaga–eating
- Order: Siphunculata or Anoplura (Sucking lice)
NOTE
The above classification follows the traditional veterinary parasitology system used in many textbooks. In modern taxonomy, lice are generally classified under the order Phthiraptera, with Anoplura recognized as a suborder and the former order Mallophaga divided into the suborders Amblycera, Ischnocera, and Rhynchophthirina.
Morphology and Characteristics
- They are permanent ectoparasites and are highly host-specific.
- Wingless insects.
- Dorsoventrally flattened body.
- Antennae are short and 5-segmented.
- Eyes are vestigial.
- Thorax is indistinctly segmented; the prothorax is well developed, while the mesothorax and metathorax are fused together. One pair of spiracles is present on the ventral aspect.
- Six pairs of abdominal spiracles.
- Tarsi consist of two segments; each tarsus bears a single large claw adapted for grasping the host’s hair.
- Metamorphosis is incomplete. Eggs are operculated and are referred to as Nits. The young are known as Nymphs, and all three nymphal stages are spent on the body of the host. Transmission occurs mainly through direct contact with an infested host and, less commonly, through contaminated grooming equipment, bedding, or other fomites.
- Both males and females are obligate blood feeders. They pierce the skin with their specialized mouthparts and suck blood from the host.
