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Ticks are classified as insects and are closely related to spiders.
Answer: False
Ticks are arachnids, not insects, and are more closely related to mites within the superorder Parasitiformes, specifically to Holothyrida.
Hard ticks (Ixodidae) are distinguished from soft ticks (Argasidae) by the presence of a hard shield called a scutum on their dorsal surfaces.
Answer: True
Hard ticks (family Ixodidae) are characterized by a rigid scutum on their dorsal surface, a feature absent in soft ticks (family Argasidae).
Soft ticks have their mouthparts visible from a dorsal view, similar to hard ticks.
Answer: False
Unlike hard ticks, soft ticks have their mouthparts located on the underside of their bodies, making them concealed from a dorsal view.
Ticks belong to the Acariformes, the main group of mites, and are closely related to free-living scavengers.
Answer: False
Ticks belong to the Parasitiformes, a distinct group of mites, and are separate from the Acariformes. They are most closely related to the Holothyrida, a small group of free-living scavengers within the Parasitiformes.
The Ixodidae family contains approximately 200 species, while the Argasidae family has over 700 species.
Answer: False
The Ixodidae (hard ticks) family contains over 700 species, whereas the Argasidae (soft ticks) family comprises approximately 200 species.
Ticks have a distinct cephalothorax and abdomen, similar to many other arthropods.
Answer: False
Unlike many other arthropods, ticks have their cephalothorax and abdomen completely fused, forming a single main body region called the idiosoma, rather than distinct segments.
The hypostome on a tick's gnathosoma is primarily used for sensory perception.
Answer: False
The hypostome on a tick's gnathosoma is primarily used to anchor the tick's mouthparts to the host, while the palps are responsible for sensory perception.
Haller's organ, located on the first pair of legs, allows ticks to detect odors, chemicals, temperature changes, and infrared light.
Answer: True
Haller's organ, a specialized sensory structure on the first pair of legs, is crucial for ticks to detect a wide range of environmental cues, including host odors, chemicals, temperature fluctuations, and infrared radiation.
In female hard ticks, the scutum covers nearly the entire dorsal surface, similar to males.
Answer: False
In female hard ticks, the scutum is restricted to a smaller, shield-like structure behind the capitulum, whereas in males, it covers nearly the entire dorsal surface.
Soft ticks are characterized by a hard, decorated dorsal plate and visible mouthparts.
Answer: False
Soft ticks are characterized by a leathery cuticle, concealed mouthparts, and a dorsal plate that, if present, lacks decoration, contrasting with the hard, often decorated scutum and visible mouthparts of hard ticks.
To which larger group of organisms do ticks belong?
Answer: Arachnids
Ticks are classified as parasitic arachnids, belonging to the order Ixodida within the superorder Parasitiformes.
What is the key distinguishing feature of hard ticks (Ixodidae) compared to soft ticks (Argasidae)?
Answer: Hard ticks possess a scutum on their dorsal surface.
The presence of a hard, chitinous scutum on the dorsal surface is the primary morphological feature distinguishing hard ticks (Ixodidae) from soft ticks (Argasidae).
Where are the mouthparts of soft ticks (Argasidae) located?
Answer: On the underside of their bodies, concealed from a dorsal view.
Soft ticks (Argasidae) are characterized by their mouthparts being located on the ventral surface of their bodies, making them concealed when viewed dorsally.
Ticks are most closely related to which small group of free-living scavengers within the Parasitiformes?
Answer: Holothyrida
Within the superorder Parasitiformes, ticks are most closely related to the Holothyrida, a small group of free-living scavengers.
Approximately how many species are in the Ixodidae (hard ticks) family?
Answer: Over 700 species
The family Ixodidae, comprising hard ticks, is the larger of the two major tick families, containing over 700 recognized species.
Which two main body regions do ticks possess, with their cephalothorax and abdomen completely fused?
Answer: Gnathosoma and Idiosoma
Ticks possess two main body regions: the gnathosoma (mouthparts) and the idiosoma (main body), which is formed by the complete fusion of the cephalothorax and abdomen.
What is the primary function of the hypostome on a tick's gnathosoma?
Answer: Anchoring the tick's mouthparts to the host
The hypostome, a barbed structure on the tick's gnathosoma, serves the crucial function of securely anchoring the tick's mouthparts within the host's skin during feeding.
What specialized sensory structure on the first pair of legs allows ticks to detect odors, chemicals, and infrared light?
Answer: Haller's organ
Haller's organ, located on the tarsus of the first pair of legs, is a highly specialized chemosensory and thermosensory structure enabling ticks to detect a wide range of environmental stimuli, including host-emitted cues.
In hard ticks, how does the scutum differ between males and females?
Answer: It covers nearly the entire dorsal surface in males, but is restricted to a smaller shield in females.
Sexual dimorphism in hard ticks is evident in the scutum: in males, it covers almost the entire dorsal surface, while in females, it is a smaller, shield-like structure located anteriorly.
Which of the following is a distinctive external feature of soft ticks (Argasidae)?
Answer: A leathery cuticle.
A distinctive external feature of soft ticks (Argasidae) is their flexible, leathery cuticle, which contrasts with the rigid scutum of hard ticks.
Adult ticks typically measure less than 1 millimeter in length before feeding.
Answer: False
Adult ticks typically measure between 3 to 5 millimeters in length before feeding, significantly larger than 1 millimeter.
The oldest known tick fossils date back approximately 50 million years, suggesting a relatively recent evolutionary origin.
Answer: False
The oldest known tick fossils date back approximately 100 million years to the Cretaceous period, indicating a much older evolutionary origin than 50 million years.
The genus *Nuttalliella* is significant because it represents the most recently evolved lineage of ticks.
Answer: False
The genus *Nuttalliella* is significant because it represents the most primitive living lineage of ticks, providing insights into their early evolutionary history, rather than being the most recently evolved.
Phylogenetic analysis suggests the last common ancestor of all living ticks existed around 195 million years ago in the Northern Hemisphere.
Answer: False
Phylogenetic analysis indicates that the last common ancestor of all living ticks likely existed around 195 million years ago in the Southern Hemisphere, specifically within the supercontinent Gondwana.
What is the typical size range of adult ticks in length?
Answer: 3-5 millimeters
Adult ticks typically measure between 3 to 5 millimeters in length before feeding, though their size can increase significantly after engorgement.
Approximately how old are the oldest known tick fossils?
Answer: 100 million years
The oldest known tick fossils date back approximately 100 million years to the Cretaceous period, providing evidence of their ancient parasitic lineage.
What is the significance of the genus *Nuttalliella* in tick phylogeny?
Answer: It represents the most primitive living lineage of ticks.
The genus *Nuttalliella* is phylogenetically significant as it represents the most primitive extant lineage of ticks, offering crucial insights into their early evolutionary divergence.
In which ancient supercontinent is the last common ancestor of all living ticks thought to have lived?
Answer: Gondwana
Phylogenetic analysis suggests that the last common ancestor of all living ticks originated approximately 195 million years ago in the ancient supercontinent Gondwana.
Which of the following characteristics demonstrates the resilience of ticks?
Answer: Their survival in a near vacuum for up to half an hour.
Ticks exhibit remarkable resilience, including the ability to survive in a near vacuum for extended periods and to endure long intervals between blood meals due to their low metabolic rate during dormancy.
Ticks are obligate hematophages, meaning they feed exclusively on the blood of other animals.
Answer: True
As obligate hematophages, ticks are external parasites that rely solely on the blood of other animals for all their nutritional requirements.
Ticks primarily locate hosts through visual cues and direct physical contact.
Answer: False
Ticks primarily locate hosts using sensory cues such as odor, body heat, moisture, and vibrations, rather than visual recognition or direct physical contact as the primary means.
A hard tick's bite is typically painful and immediately noticeable to the host.
Answer: False
A hard tick's bite is typically painless and often goes unnoticed by the host, allowing the tick to feed for extended periods without detection.
Ticks prevent a host's blood from clotting by excreting an anticoagulant or platelet aggregation inhibitor through their saliva.
Answer: True
Ticks secrete anticoagulants or platelet aggregation inhibitors in their saliva to prevent the host's blood from clotting, ensuring a continuous blood meal.
Ticks are known to jump onto their hosts from vegetation.
Answer: False
It is a common misconception that ticks jump onto their hosts; they are incapable of jumping and instead employ strategies like questing to attach to passing animals.
'Questing' behavior involves ticks clinging to leaves and grasses with their third and fourth pairs of legs, holding their first pair outstretched to grasp passing hosts.
Answer: True
Questing is a host-seeking strategy where ticks position themselves on vegetation, using their posterior legs for stability and their outstretched front legs to latch onto a passing host.
A hard tick's weight can increase by 20 to 60 times after a full blood meal, facilitated by cuticle expansion.
Answer: False
A hard tick's weight can increase dramatically, by 200 to 600 times, after a full blood meal, a feat facilitated by the expansion of its cuticle through cell division.
Evasins are anti-inflammatory proteins in tick saliva that help hosts detect ticks more easily.
Answer: False
Evasins are anti-inflammatory proteins in tick saliva that actively suppress the host's immune response, allowing ticks to feed for extended periods without being detected.
What term describes ticks' exclusive feeding on blood?
Answer: Obligate hematophages
The term "obligate hematophages" precisely describes ticks' feeding behavior, indicating their exclusive reliance on blood meals for survival and development.
Which of the following is NOT a primary sensory cue ticks use to locate hosts?
Answer: Visual recognition
Ticks primarily rely on chemosensory and thermosensory cues, such as odor, body heat, moisture, and vibrations, to locate hosts, rather than visual recognition.
What is the typical experience of a host when a hard tick attaches?
Answer: The bite is usually painless and often goes unnoticed.
Due to the presence of anesthetic compounds in their saliva, a hard tick's bite is typically painless and often goes undetected by the host, facilitating prolonged feeding.
How do ticks prevent a host's blood from clotting during feeding?
Answer: By excreting an anticoagulant or platelet aggregation inhibitor through their saliva.
Ticks secrete a complex cocktail of bioactive molecules in their saliva, including anticoagulants and platelet aggregation inhibitors, to ensure uninterrupted blood flow during feeding.
What is a common misconception about how ticks move onto their hosts?
Answer: They jump onto their hosts.
A prevalent misconception is that ticks jump onto their hosts; however, ticks are incapable of jumping and instead rely on crawling or questing to attach to passing animals.
What is the 'questing' behavior primarily associated with in many hard tick species?
Answer: Clinging to vegetation with outstretched front legs to grasp passing hosts.
Questing behavior in hard ticks involves positioning themselves on vegetation with their front legs extended, ready to grasp onto a passing host.
By how much can a hard tick's weight increase after a full blood meal?
Answer: 200 to 600 times
A hard tick can increase its body weight by an astonishing 200 to 600 times after a complete blood meal, a feat enabled by the remarkable elasticity and growth of its cuticle.
What is the primary function of evasins in tick saliva?
Answer: To prevent the host's immune system from detecting the tick.
Evasins, anti-inflammatory proteins in tick saliva, play a critical role in immune evasion by neutralizing host chemokines, thereby preventing the host's immune system from detecting the feeding tick.
The life cycle of all tick families consists of four distinct stages: egg, larva, nymph, and adult.
Answer: True
All known tick families share a common life cycle pattern comprising four distinct developmental stages: egg, larva, nymph, and adult.
Larval ticks hatch with six legs and retain this number throughout their nymphal and adult stages.
Answer: False
Larval ticks hatch with six legs, but they acquire two additional legs after molting into the nymphal stage, resulting in eight legs for both nymphs and adults.
Nymphs and smaller tick species tend to quest higher in vegetation to find larger hosts.
Answer: False
Nymphs and smaller tick species typically quest closer to the ground to encounter smaller mammalian or bird hosts, while adult ticks climb higher for larger hosts.
'Nidicolous' ticks are primarily from the Ixodidae family and actively hunt hosts in open fields.
Answer: False
Nidicolous ticks are primarily from the Argasidae family and locate hosts within confined spaces like nests, burrows, or caves, rather than actively hunting in open fields.
The global distribution and increasing occurrence of ticks are partly linked to warming temperatures from climate change.
Answer: True
The expanding global distribution and increased incidence of ticks and tick-borne illnesses are partly attributed to rising global temperatures associated with climate change, which creates more favorable conditions for tick populations.
For an ecosystem to support ticks, it only needs a high population density of host species.
Answer: False
An ecosystem must satisfy two primary requirements to support tick populations: a sufficiently high density of host species and adequate environmental humidity for tick hydration and development.
In a one-host life cycle, the tick detaches from the host after each stage (larva, nymph, adult) to molt in the environment.
Answer: False
In a one-host life cycle, the tick remains on the same host through its larval, nymphal, and adult stages, feeding and molting without detaching until the engorged female drops off to lay eggs.
The cattle tick (*Boophilus microplus*) is an example of a tick species that follows a three-host life cycle.
Answer: False
The cattle tick (*Boophilus microplus*) is an example of a one-host tick, meaning it completes all its feeding stages (larva, nymph, adult) on a single host before the adult female detaches to lay eggs.
The three-host life cycle typically involves larvae, nymphs, and adults feeding on progressively larger hosts.
Answer: True
In a three-host life cycle, each active stage (larva, nymph, and adult) typically feeds on a different host, often progressing from smaller hosts for larvae to larger hosts for adults.
Ixodid ticks can undergo up to seven nymphal stages, each requiring a separate blood meal.
Answer: False
It is Argasid (soft) ticks that can undergo up to seven nymphal stages, each requiring a separate blood meal, whereas Ixodid (hard) ticks typically have only one nymphal stage.
What are the four distinct stages of a tick's life cycle?
Answer: Egg, larva, nymph, adult
The life cycle of all tick families progresses through four distinct stages: egg, larva, nymph, and adult.
How many legs do nymphal and adult ticks have?
Answer: Eight legs
After molting from the six-legged larval stage, both nymphal and adult ticks possess eight legs, characteristic of arachnids.
How does tick questing height typically relate to their desired hosts?
Answer: Questing heights are correlated with the size of their desired host, with nymphs lower for small hosts and adults higher for large hosts.
Tick questing height is strategically adapted to host size, with nymphs typically questing closer to the ground for smaller hosts and adults climbing higher to intercept larger mammals.
What are 'nidicolous' ticks, and how do they typically find their hosts?
Answer: Ticks that find hosts in nests, burrows, or caves, using stimuli like body heat and odors.
Nidicolous ticks are specialized to inhabit and find hosts within confined microhabitats such as nests, burrows, or caves, relying on cues like body heat, odors, and carbon dioxide.
What environmental factor is partly attributed to the increasing occurrence of ticks and tick-borne illnesses globally?
Answer: Warming temperatures associated with climate change.
The global expansion and increased incidence of ticks and the diseases they transmit are partly linked to warming temperatures resulting from climate change, which extends suitable habitats and activity periods for ticks.
What are the two main requirements an ecosystem must satisfy to support tick populations?
Answer: High host density and sufficient humidity.
For an ecosystem to sustain tick populations, it must provide both a sufficiently high density of suitable host species and adequate environmental humidity to prevent tick desiccation.
Which of the following describes a 'one-host' life cycle for Ixodid ticks?
Answer: The tick remains on the same host through its larval, nymphal, and adult stages.
In a one-host life cycle, the tick completes its larval, nymphal, and adult feeding stages on a single host individual, only detaching as an engorged female to lay eggs.
Which tick species is an example of a one-host tick?
Answer: Winter tick (*Dermacentor albipictus*)
The winter tick (*Dermacentor albipictus*) is a classic example of a one-host tick, completing all its parasitic stages on a single host animal.
In a two-host life cycle, when do adult ticks typically seek a second host?
Answer: After engorged nymphs drop off the first host and molt into adults in the environment.
In a two-host life cycle, adult ticks emerge after engorged nymphs detach from the first host and molt in the environment, subsequently seeking a second host for their final blood meal and reproduction.
What is a characteristic pattern of host involvement in a three-host life cycle?
Answer: Larvae feed on small hosts, nymphs on second hosts, and adults on third, larger hosts.
The three-host life cycle is characterized by each active developmental stage (larva, nymph, and adult) feeding on a different host individual, often with a progression from smaller to larger hosts.
Ticks cause harm to livestock primarily through direct blood loss, leading to anemia.
Answer: False
Ticks cause harm to livestock not only through anemia from blood loss but also significantly through pathogenic transmission, leading to diseases like heartwater disease, and by damaging wool and hides.
Migrating birds can spread ticks and foreign infectious diseases to new regions.
Answer: True
Migrating birds serve as significant vectors, carrying ticks and the foreign infectious diseases they harbor across vast distances to new geographical regions during their seasonal movements.
Diagnosing tick-borne diseases is straightforward because each tick typically carries only one type of pathogen.
Answer: False
Diagnosing tick-borne diseases can be challenging because a single tick is capable of harboring and transmitting multiple types of pathogens, leading to complex clinical presentations or co-infections.
Besides pathogenic transmission, what other harm do ticks cause to livestock?
Answer: Anemia due to blood loss and damage to wool and hides.
Beyond transmitting pathogens, ticks inflict economic harm on livestock by causing anemia through blood loss and by damaging valuable products such as wool and hides.
How do migrating birds contribute to the spread of ticks and tick-borne diseases?
Answer: They carry ticks with them during seasonal journeys, acting as reservoirs and vectors.
Migrating birds play a crucial role in the long-distance dispersal of ticks and the pathogens they carry, acting as both reservoirs and vectors for introducing infectious diseases to new regions.
Ticks prefer open, well-maintained areas like manicured lawns, making them easier to control.
Answer: False
Ticks prefer ecotones, which are unmaintained transitional edge habitats between woodlands and open areas, rather than open, well-maintained lawns. This preference makes control more challenging in such boundary zones.
What type of habitat do ticks prefer, and what management strategy is suggested for control?
Answer: Ecotones (unmaintained transitional edge habitats); remove leaf litter and brush at edges.
Ticks exhibit a preference for ecotones, which are transitional habitats at the edges of woodlands. Effective control strategies involve modifying these habitats by removing leaf litter and brush.
Ticks are highly susceptible to dehydration and cannot survive prolonged periods between meals.
Answer: False
Ticks are highly resilient, capable of enduring prolonged periods between meals due to their slow metabolism and possessing physiological adaptations, such as secreting hygroscopic fluid, to prevent dehydration in dry conditions.
Ticks rely on nutritional endosymbionts to synthesize essential B vitamins, which are deficient in their blood-only diet.
Answer: True
Ticks, whose diet is exclusively blood, depend on nutritional endosymbionts, such as *Coxiella* and *Francisella* bacteria, to synthesize essential B vitamins that are otherwise deficient in their diet.
Nutritional endosymbionts are transmitted horizontally between adult ticks during mating.
Answer: False
Nutritional endosymbionts are transmitted vertically through transovarial transmission, meaning they are passed directly from the female tick to her eggs, rather than horizontally during mating.
Adult female Argasid ticks excrete excess fluid through their coxal glands during feeding.
Answer: True
Adult female Argasid ticks possess a unique physiological mechanism where they excrete excess fluid ingested during a blood meal through their coxal glands.
How do ticks primarily prevent dehydration in dry conditions?
Answer: By secreting a hygroscopic fluid from their salivary glands and reingesting it.
Ticks employ a unique physiological mechanism to prevent dehydration, involving the secretion of a hygroscopic fluid from their salivary glands onto their external mouthparts, which then absorbs atmospheric water and is reingested.
Why do ticks rely on nutritional endosymbionts?
Answer: To synthesize essential B vitamins lacking in their blood-only diet.
Ticks rely on nutritional endosymbionts to synthesize essential B vitamins, which are scarce in their blood-only diet, thereby compensating for nutritional deficiencies.
How are nutritional endosymbionts typically transmitted within tick populations?
Answer: Through transovarial transmission from female tick to eggs.
Nutritional endosymbionts are typically transmitted vertically within tick populations via transovarial transmission, where they are passed directly from the infected female tick to her offspring through the eggs.
What evidence supports the essential role of B vitamins provided by endosymbionts for ticks?
Answer: Elimination of endosymbionts leads to decreased tick survival and reproduction, resolved by B vitamin supplements.
Experimental evidence demonstrates that the elimination of nutritional endosymbionts severely impairs tick survival and reproduction, and these detrimental effects can be reversed by supplementing the ticks with B vitamins.