Ticks and Mites Flashcards
Hypostome
Central mouthpart found only on ticks
Purpose is to anchor tick onto host
Haller’s Organ
Small circular vesicle on the tarsal segment of the first pair of legs.
Only in ticks
Purpose is to detect odours
Hard Tick Features
• Mouthparts visible from dorsal surface • Scutum present – an inflexible plate on the dorsal surface • Sexual dimorphism well marked • Attach to hosts for days, take one large bloodmeal
Hard Tick Female
Scotum only partially covers dorsal surface
Porose areas on the basis capitulum
Hard Tick Male
Scutum covers the entire dorsal surface
Basis capitulum lacks porose areas
Hard Tick Larva
Only 3 pairs of legs
Scutum present, only partially covers dorsal surface
Mouthparts are clearly visible from the dorsal surface
Basis capitulum is clearly defined
Hard Tick Nymph
4 pairs of legs
Scutum is present and only partially covers the dorsal surface
No genital aperture
No porose areas on the basis capitulum
Ixodes ricinus
Common sheep tick
Ixodes Genus
Inornate
No eyes
Anal groove runs anteriorly around the anus
Vector of Lyme disease
Hyalomma Genus
Has eyes
Scutum is inornate
Legs may have pale bands
Palps long - article II less than twice as long as III
Vectors of Crimean-Congo Haemorrhagic Fever (CCHF)
Amblyomma Genus
Ornate scutum
Has eyes
Long palps - article II more than twice as long as III
Vectors of rickettsiae
Dermacentor Genus
Typically ornate scutum Has eyes Basis capitulum is rectangular Short palps - article II and III together are shorter than the width of the basis Vectors of rickettsiae
Soft Tick Features
Mouthparts not visible from dorsal surface
Scutum absent
Sexual dimorphism slight
Take regular bloodmeals
Soft Tick Larva
3 pairs of legs
No scutum
Mouthparts are visible from the dorsal surface but partly recessed behind the body margin
Palps are more finger-like
Ornithodoros Genus
Possess a mammillated integument (one that is covered in rounded protuberances)
No distinct margin between the dorsal and lateral body surfaces
Vectors and reservoirs of the borreliae
Soft Tick Mouthparts
Located ventrally in nymph and adult soft ticks
Four-segmented palps are more flexible and finger-like than the palps of hard ticks
Chelicerae are used to cut into the host
Hypostome has several rows of back pointing teeth
Argas Genus
Bird ticks
Larval stages will remain attached to their hosts and feed for several days
Unfed ticks are dorso-laterally flattened
Clear marginal line between the dorsal and ventral body surfaces
Otobius Genus
Integument of the nymph is covered in small spines
No clear suture line between the dorsal and ventral body surface
Larvae enter the ear canals of animals (and occasionally man)
Nymphs may attach for several
months
Mite Features
Very small 0.09mm -15mm
Toothed hypostome/Haller’s organ absent
Trombiculid Adult
1.0 – 2.0 mm in length
Body is covered in feathery setae giving it a velvety appearance (kind of looks like a hairy spider)
Body outline is figure of eight
Palps and capitulum are conspicuous
Trombiculid Larvae
Very small, only 0.25 mm long
Circular in outline
Covered in many feathered setae
Prominent capitulum with toothed chelicerae
Conspicuous palps
Presence of a sclerotised scutum bearing 7 setae
Scabies Mites (Sarcoptes scabei)
Small, globose mites with a distinct capitulum and a finely striated cuticle
Legs are short and stumpy with the anterior pair ending in stalked pulvilli
Male Scabies Mites
Fourth pair of legs also end in pulvilli and help to secure during mating
Conspicuous genitalia
House Dust Mites (Dermatophagoides spp.)
Small (0.3 mm long) with well developed capitulum and legs
Thin skinned and lack shields or stigmata
2 pairs of long posterior marginal setae
