23. Arthropods (Intro) Flashcards
1
Q
what are the three main groups of arthropods?
A
- crustaceans
- arachnids
- insects
2
Q
what is included in the crustaceans?
A
- crabs
- lobsters
- crayfish
- shrimp
3
Q
what is included in the arachnids?
A
- spiders
- scorpions
- ticks
- mites
4
Q
what is included in the insects?
A
- beetles
- bugs
- earwigs
- ants
- bees
- termites
- etc
5
Q
parasitic arthropods are ____-parasites
A
ectoparasites
6
Q
do parasitic arthropods have a coelom?
A
yes
7
Q
do parasitic arthropods have jointed limbs?
A
yes - this is where they get their name
8
Q
are parasitic arthropods segmented?
A
yes
9
Q
what is concentrated in the head region?
A
- their neutral elements
- sensory receptors
- feeding structures
10
Q
what is the rigid cuticular exoskeleton made of?
A
- tanned proteins
- chitin
11
Q
what does the exoskeleton provide?
A
physical and physiological protection and serves as a place for muscle attachment
12
Q
are the arthropods that cause harm, due to their venom, considered parasites?
A
NO
13
Q
what are the two body parts of arachnids?
A
- the cephalothorax
- the abdomen
14
Q
how are legs arranged on arachnids?
A
there are 8 legs on the cephalothorax arranged in 4 bilateral pairs
15
Q
do arachnids have wings or antennae?
A
no
16
Q
what are the 3 distinct body parts in insects?
A
- the head
- the thorax
- the abdomen
17
Q
what does the head of the insect have?
A
2 antennae
18
Q
what does the thorax of the insect have?
A
6 legs arranged in bilateral pairs
19
Q
Parasitic insect species include fleas, flies and lice which actively feed on ___________ and fluids at some stage in their life‐cycles.
A
host tissues
20
Q
how many species of insects are there?
A
1 million
21
Q
how many species of arachnids are there?
A
50 000
22
Q
why are insects and arachnids very adaptable organisms?
A
they have rapid and fertile reproduction rates
23
Q
how do they overcome the problem of growing in a non-expandable exoskeleton?
A
by molting
24
Q
what are the stages of development between molts referred to as?
A
instars
25
Molting is a complex process and its timing is mediated by _______________________________.
many environmental and physiological cues
26
what is the reproductive strategy of arthropods?
diecious
27
is fertilization internal or external for arthropods?
internal
28
a wide range of mating behaviours, ________ and __________ are involved
insemination
| egg production
29
what does the egg develop into (in most species)
a larva
30
what is a larva?
a life cycle stage that is structurally distinct from the adult and must undergo metamorphosis (structural reoganization) before it becomes an adult
31
what does it mean for the metamorphosis to be complete?
involving major changes during a pupation stage
32
what does it mean for the metamorphosis to be incomplete?
involving gradual changes in nymph stages
33
what is the life cycle sequence for complete metamorphosis?
egg (hatch)
larva (molt)
pupa (hatch)
adult
34
what is an example of complete metamorphosis?
the grub‐like larval stages of flies and fleas form cocoon‐like pupae where they undergo complete metamorphosis and emerge as radically‐different adult insects
35
what is the life cycle sequence for incomplete metamorphosis?
egg (hatch)
larva (molt)
nymph (molt)
adult
36
what is an example of incomplete metamorphosis?
the larval instars (or nymphs) of lice, ticks and mites undergo incomplete metamorphosis through a series of molts gradually becoming more adult‐like in appearance
37
what other organisms can arthropods be involved with in parasitic relationships, either as a host or the parasite?
- viruses
- bacteria
- protozoa
- helminths
38
T/F
•
arthropods are usually ectoparasitic on, or in, the skin of vertebrate hosts
T
39
define haematophagous
sucking blood
40
define histophagous
tissue-feeders, and bite or burrow in dermal tissues causing trauma, inflammation and hypersensitivity reactions
41
how are the two ways that infestations (of arthropods in general) can be transmitted from host-to-host?
either by direct contact, or by free-living larvae or adults actively seeking hosts
42
when does direct transmission of the infective stages occur?
when hosts come into close contact with each other or share quarters, bedding or clothing
43
________________, nymphs or adults may cross from one host to another, while ______________ may contaminate shared environments
larvae, nymps or adults
| eggs or pupae
44
what do insects (lice) and arachnids (mites) rely on?
close contact between hosts
45
how do winged insects (like mosquitoes and flies) find new hosts to feed off of?
by flying to the new host
46
how do non-flying insects, like fleas, find new hosts to feed off of?
by jumping on passing hosts
47
what is the mechanism of the botflies?
they do not feed on their host, but instead just deposit eggs which will allow larvae to emerge and feed on host tissues and exudates
48
how do tick larvae seek hosts?
by actively climbing vegetation and questing for passing hosts
49
what does "one-host ticks" mean?
when a species completes thei life cycle on the same host
50
what does two-host or three-host ticks mean?
when ticks detach and drop to the ground and molt before seeking new hosts as nymphs or adults
51
what are the three main groups of parasitic insect species?
- the jumping fleas (Siphonaptera)
- the winged flies (Diptera)
- the wingless lice (Phthiraptera)
52
what are the two main groups of parasitic non-spider arachnids?
- the macroscopic ticks
| - the microscopic mites
53
what are ticks?
epidermal parasites of terrestrial vertebrates and may transmit other infections
54
what are other infections that can be passed by ticks?
- viral
- bacterual
- rickettsial
- spirochaete
- protozoal
- helminth
55
what do ticks mainly feed on?
blood
56
what are tick's mouthparts armed with?
small, backward-facing teeth to aid in attachment
57
what kind of metamorphosis do ticks undergo?
gradual or incomplete metamorphosis whereby larval and nymphal stages resemble adults
58
what are the two major families of ticks that are recognized on the basis of morphological features?
- the Ixodidae
| - the Argasidae
59
what can be found in the Ixodidae?
- hard ticks with a tough cuticle with some 650 species that infest mammals, birds and reptiles
60
what can be found in the Argasidae?
soft ticks with a leathery integument with 160 species that infest mainly birds and some mammals
61
what are mites?
microscopic arachnids that undergo gradual or incomplete metamorphosis
62
how many legs do adults or nymphs have in mites?
4 pairs of legs
63
how many legs do larvae have in mites?
3 pairs of legs
64
how many species of mites have been described?
30k
65
what do most parasitic species of mites feed on?
skin or debris or suck lymph, and some burrow into the skin, some live in hair follicles, and some live in ear canals
66
do lice have wings?
no
67
T/F
•
lice are dorsoventrally flattened
T
68
do lice have eyes?
they are reduced or absent
69
what do lice use to cling?
enlarged tarsal claws
70
what kind of metamorphosis do all lice undergo?
gradual metamorphosis
71
are there any free living stages in lice?
no
72
what is different about the ways in which eggs vs. nymphs or adults stick to feathers and hair?
eggs are cemented
| nymphs and adults can cling to them
73
what are the two orders of lice?
- the Mallophaga
| - the Anoplura
74
what are the two orders of lice classified based on?
on their mouthparts
75
what is found in the Mallophaga?
- chewing/biting lice with some 3000 species infesting birds and mammals
76
what is found in the Anoplura
- sucking lice with 500 soecies found on mammals
77
in which way are fleas flattened?
bilaterally-flattened
78
do fleas have wings?
no
79
who has special hind legs and what is special about them?
fleas - they are enlarged hind limbs, specially adapted for jumping
80
do fleas undergo complete metamorphosis? what happens?
yes, grub-like larvae form pupae from which adult fleas emerge
81
are the larvae of fleas parasitic?
no, they feed on debris associated mainly with bedding, den or nest material
82
which flea stage is parasitic and what does it feed off of?
the adult stages are parasitic and feed off of host blood
83
how many flea species are there?
2,500
84
who are most flea speacies parasitic to?
mammals (especially rodents)
| some birds
85
are flies and mosquitoes winged-insects?
yes
86
how many pairs of wings do flies and mosquitoes have?
two pairs
87
what are flies and mosquitoes wings attached to?
the thorax
88
are the sensory organs of flies and mosquitoes well-developed?
yes
89
do flies and mosquitoes have feeding organs?
yes
90
what kind of metamorphosis do flies and mosquitos undergo?
complete metamorphosis
91
how many species of flies and mosquitos are there?
120,000, belonging to 140 families
92
what are the two main suborders of flies and mosquitoes?
- Nematocera
| - Brachycera
93
what are the suborders of flies and mosquitoes recognized based on?
structural differences
94
what is found in the Nematocera
- adult stages are parasitic
| - larval stages often free-swimming
95
what is found in the Brachycera?
- adult stages parasitic or free-living
| - larvae stages often predaceous
