TABLE OF CONTENTS
Sucking Lice (Order Siphunculata or Anoplura): Morphology and Characteristics
Sucking lice, classified under the order Siphunculata or Anoplura, are wingless, obligate ectoparasites of mammals that feed exclusively on blood. They are characterized by specialized piercing and sucking mouthparts, a conical head, reduced or absent eyes, fused thoracic segments, and powerful claws adapted for grasping hair. Understanding their morphology is important for the identification and differentiation of these lice in veterinary parasitology.
Morphology and Characteristics
- Possess angular processes known as “ocular points” or “temporal angles” behind the antennae.
- Mouthparts are adapted for piercing the skin and sucking blood from the host. The mouth opening is situated terminally, and they possess circlets of small teeth.
- The antennae are prominent and consist of 5 segments.
- The head is conical in shape (pleurite is absent).
- Eyes are reduced or absent.
- The three thoracic segments are fused together.
- The abdomen is relatively large and has visible segments and 6 pairs of abdominal spiracles. The lateral aspects of the abdominal segments bear dark brown or black areas of thickened chitin known as paratergal plates. The posterior end of the abdomen in the male louse ends in a pair of lobes known as claspers.
- In the female, a pair of gonopods is present on either side of the genital opening. These help guide, manipulate, and glue the eggs to the host hair. In the male, the aedeagus (penis) is prominent.
- Sexual dimorphism is present and is mainly evident in the terminal abdominal and genital structures.
- Each leg ends in a powerful “crab-like claw” with a tibial pad that has a large number of spines. The first pair of legs is smaller, with weak claws, and the third pair is the largest. They are found only in mammals.
