Morphological Adaptations of Parasitic Arthropods

A set of practice flashcards covering key concepts from the lecture notes on morphological adaptations of parasitic arthropods.

What is the primary purpose of morphological adaptations observed in parasitic arthropods, and which features are most important for host associations?

Adaptations for parasitic relationships; body shape, mouthparts, and legs are the most important, with wings, eyes, and sensory organs also modified.

Name the two body-shape modifications that facilitate movement on the host and concealment off-host.

Dorsoventral flattening and lateral flattening.

Which body-shape modification is characteristic of bed bugs, bat bugs, lice, beaver beetles, parasitic dermapterans, louse flies, keds, and ticks?

Dorsoventral flattening.

Which body-shape modification is best exemplified by fleas?

Lateral flattening.

Do blood-feeding arthropods that have brief contact with hosts typically exhibit dorsoventral or lateral body compression?

No; they generally do not exhibit dorsoventral or lateral compression.

What wing modifications are common in parasitic arthropods?

Some are strong fliers; many have reduced or lost wings; hippoboscids (Lipoptena) may shed wings after reaching a suitable host, leaving a wing stump.

Give an example of an arthropod group that may shed its wings after finding a suitable host.

Hippoboscids (genus Lipoptena).

What are the two main categories of hematophagous mouthparts?

Telmophages (lacerate skin and feed on pooled blood) and Solenophages (pierce capillaries with refined piercing-sucking mouthparts).

Name examples of telmophagous hematophagous arthropods.

Black flies, biting midges, horse flies, and deer flies.

Name examples of solenophagous hematophagous arthropods.

Mosquitoes, bed bugs, kissing bugs, and sucking lice.

In mosquitoes, which structures form the feeding apparatus called the proboscis?

Labrum, mandibles, maxillae, hypopharynx, and labium.

What role does the labrum play in mosquitoes?

Protective sheath and guide for the fascicle; functions as the upper lip for insects with chewing mouthparts.

How are the mandibles and maxillae modified in mosquitoes?

They are elongated and adapted for piercing the host epidermis to access blood.

What is the role of the hypopharynx in mosquito feeding?

Tongue-like structure used to pierce host tissue and deliver saliva.

How are the mouthparts of bed bugs and kissing bugs (Hemiptera) organized?

Maxillae and mandibles are styletiform and held within a sheathlike labium; the rostrum is directed posteriorly; the labrum is relatively unmodified.

What is the rostrum in Hemipterans formed by?

Interlocking maxillae, mandibles, and labium forming the food canal.

Describe the mouthparts of sucking lice.

Haustellum formed by a highly modified labrum with prestomal/haustellar teeth; maxillae, hypopharynx, and labium are modified as piercing stylets.

In ticks, what are the roles of chelicerae and hypostome?

Chelicerae are short blade-like piercing structures; hypostome is an attachment organ that helps anchor feeding.

What is the primary function of the hypostome in ticks?

Attachment to the host during feeding.

What general modifications occur to legs in ectoparasites?

Enlarged legs with specialized grasping structures; stout, sclerotized, muscular appendages to attach to hosts and move through hair/feathers.

What are tibiotarsal claws and why are they important?

Claws formed by modifications of the tibia and tarsus for grasping host hair.

How many segments do mite legs typically have, and what are they generally called?

Seven segments: coxa, trochanter, femur, genu, tibia, tarsus, and pretarsus/apotele.

What is the empodium in arthropod legs?

A padlike structure at the end of the leg, which may bear claws, setae, or act as an adhesive pad.

What isSensilium and where is it found?

A modified dorsal portion of the terminal abdominal segments in fleas, used to detect host cues such as vibrations and temperature gradients.

What is Haller's organ and where is it located?

A complex sensory structure located on the dorsal aspect of the tarsus of the first pair of legs in ticks; detects temperature, air movements, host odors, and other cues.

What is the Johnston's organ and what does it detect?

A sensory organ in the basal segment of the antennae that detects airborne vibrations.

How are eyes modified in fleas and lice compared to mosquitoes, biting midges, and horse flies?

Fleas and lice have reduced or absent eyes; mosquitoes, biting midges, and horse flies have enlarged eyes.

Where are sensory receptors concentrated in solenophages and telmophages?

Solenophages: near the tip of the proboscis or rostrum; Telmophages: in a sensory organ on the enlarged third segment of the maxillary palp.

What is the overall takeaway from the summary about morphological modifications in ectoparasitic and blood-feeding arthropods?

Multiple advantageous modifications in body shape, feeding apparatus, locomotory appendages, and sensory structures enable efficient exploitation of vertebrate hosts.