ENTM 2050 final exam Flashcards
1
Q
what percentage of insects are herbivorous?
A
30-35%
2
Q
what are herbivorous insects called?
A
phytophagous insects
3
Q
polyphagous insects
A
generalists that feed on many plant groups
-ex: aphids, grasshoppers
4
Q
oligophagous insects
A
insects that feed on a few plant groups
-ex: monarch butterflies, caterpillars
5
Q
monophagous insects
A
insects that feed on only one plant group
-ex: galls
6
Q
what are the two types of plant defenses?
A
constitutive defenses, induced defense
7
Q
constitutive defense
A
defenses which are always present
-ex: bark on trees (always devoting energy towards it)
8
Q
induced defense
A
activated/synthesized only in the response to injury
-ex: toxins produced which harm feeding insects
9
Q
what happens when an induced defense is triggered?
A
when an injury occurs (ex insect saliva enters the plant), there is
1. an up-regulation of genes for producing semiochemicals and/or other defenses, and
2. a down-regulation for photosynthesis and other metabolic processes
10
Q
mechanical constitutive defenses
A
physical features of a plant which defend against insects (ex waxy or tough leaves, trichomes or scales, etc.)
-tough leaves impedes feeding due to high levels of indigestible fiber and lignin
-glandular trichomes: induce sticky substances which either trap or injure insects (toxic).
11
Q
mechanical induced defenses
A
only occur after injury
-ex: leaf drop or colour change (on leaves affected by herbivorous insects)
12
Q
pitching out
A
example of a mechanical induced defense
-only occur after injury
-some trees fill punctures in their bark with pitch (until it runs out); which is why bark beetles use mass attack
13
Q
what are the two groups of chemical plant defenses?
A
primary and secondary metabolites
14
Q
primary metabolites
A
-produce amino acids, nucleotides, lipids, and/or sugars as deterrents
-ex: some insects do not need high sugar concentrations, so they avoid eating high-sugar fruits
15
Q
secondary metabolites
A
produce a diverse array of components as a deterrent (most are metabolic by-products)
-most are toxic to insects, some attract parasitoids, others are feeding/oviposition deterrents, etc
-ex: caffeine, cocaine, essential oils, aspirin
16
Q
two types of secondary metabolites?
A
non volatile or volatile terpenes (does/does not warn the insect that it is toxic)
17
Q
non-volatile terpenes
A
may be distasteful to herbivores (ex: minonene)
18
Q
volatile terpenes
A
warns herbivores that the plant is toxic before feeding occurs (ex: menthol)
19
Q
phytoecdysones
A
plant stepids that are chemically similar to insect molting hormones. Can interfere with/inhibit molting when ingested
20
Q
what do acorn weevils use their “beaks” for?
A
used as a morphological adaptation
-allows them to create a passage into an acorn and lay their eggs into the acorn to allow their larvae to grow inside.
21
Q
trenching
A
example of a behavioural adaptation in response to plant defenses
- insects will chew rings into leaves, which prevents the plant from releasing defensive chemicals into that area
22
Q
detoxification as an insect response
A
by detoxification enzymes and saliva
-ex: webworms are able to metabolize toxins using detoxification enzymes
-saliva can be injected into plants to reduce production of toxins or break down the toxins
23
Q
sequestration
A
the storage of toxic/distasteful secondary plant metabolites in tissues
-beneficial to the insect, as it is distasteful to predators, reduce competition, and may create a warning coloration
-seen in milkweed bugs, turnip sawflies, monarch butterflies
24
Q
population level responses
A
move in large populations
-ex: pine beetles use aggregation pheromones to mass attack pine beetles (thousands of beetles can attack a single tree)
25
gall insects
insects which form a specialized plant-insect interaction in which the morphology of the plant is altered by the insect
-create "galls" which modifies the plants to grow around their developing eggs, providing food and/or protection for the inhabitant
26
what are the two processes involved in gall formation? how do they work?
1. Initiation: galls can only be grown on living plant tissue
2. Growth and maintenance: continued stimulation is needed to maintain the nutritive tissues in the gall. Growth ceases when insect development is complete
27
how many species of gall forming insects are known?
roughly 13,000
-from hemiptera, diptera, hymenoptera, and lepidoptera
28
what percentage of insects are predators, parasitoids, or parasites?
roughly 25%
29
what are some predator adaptations?
1. modified mouthparts
-enlarged or modified mandibles
2. limbs
-modified to grasp and hold prey
3. camouflage
-ex: some have sticky hairs which allow them to cover themselves in dust and lint; helping them to blend into their environment
30
how do ant lions hunt?
excavate a pit in very fine sand/dirt, sit at the bottom of the hole to catch ants which fall into the pit. Can throw sand at insects at the top of the pit to make them fall further down into the pit
31
what are the range of cues which are used to locate host/prey?
1. visual
2. tactile
3. auditory
4. chemical (indirect and direct)
32
how do volatile chemical released by plants after injury function?
-can act as kairomones which attract other herbivores, or
-as kairomones to attract parasitoids and/or other predators
33
parasitoids
-parasitic while immature, free living as adults
-ultimately kill the host to complete its own life cycle
34
which orders is the majority of parasitoids found in?
-how many?
-mostly seen in hymenoptera, coleoptera, and diptera (however, seen in 7 orders)
-3/4 of all hymenopterans are parasitoids
-1/4 of all flies are parasitoids
35
what percentage of all insects are parasitoids?
roughly 10%
36
example of a parasitoid dipteran
tachinid flies
-primarily attack caterpillars and larval sawflies
-generalist parasitoids, attack any species with the right general body form/size
37
example of coleopteran parasitoid
staphylinid beetles: not all are parasitoids; but the ones which are parasitoids are ALSO predators (parasitoids as larvae, predators as adults)
-some parasitize larvae of pest flies
38
examples of hymenopteran parasitoids?
braconid wasps, ichneumonid, wasps, chalcid wasps
39
braconid wasps
mainly attack larvae of other holometabolous insects or hemipterans
40
ichneumonid
attack a large range of insects AND non insects (spiders and centipedes)
41
chalcid wasps
huge superfamily of parasitoids containing roughly 20 families. Most are very small.
42
ectoparasitoid
larval stage feed from OUTSIDE of the host. common in most concealed hosts
43
endoparasitoid
larval stage feed from INSIDE the host (adults lay eggs into the body of a host; larvae develops in the host then eats them from the inside out)
44
solitary parasitoid
one larvae develops on/in the host
45
gregarious parasitoid
multiple larvae develop in/on the host, results from multiple eggs
46
polyembryonic parasitoid
multiple larvae from ONE EGG develop in/on the host
(polyembryony)
47
idobiont
parasitoid which stops the development of host at the time of parasitism
-inject substances into host which paralyzes or impedes development
-seen primarily in ectoparasites and endoparasites of eggs and pupae
48
koinobiont
host continues development after parasitism
-may inject substances to alter immune system (ex polydnaviruses)
-primarily seen in egg-larval, larval, larval-pupal, and adult parasitoids
49
primary parasitoids
attack non-parasitoid host (ex herbivore, predator, etc)
50
hyperparasitoids
attacks other parasitoids
51
what are ovipositors on parasitoids used for?
allow them to pierce through hosts or other materials to get to their hosts (ex trunks of trees)
52
host hemolymph defence against parasitoids
if eggs are deposited into hemolymph, hemocytes adhere and form a capsule around the egg. The capsule can then melanize to prevent successful hatching by suffocation
53
parasitoid venom uses (5)
-sometimes used as a counter-defense against host defenses (hemocytes)
-some can paralyze the host, causing them to become immobilized which allows for easy egg oviposition
-suppresses immune response, ensuring the eggs are more likely to survive
-prevent molting (seen in ectoparasitoids; to prevent being shed off when molting occurs)
-severe metabolic alterations (most of the nutrients go to the parasitoids)
54
polydna viruses
-some parasitoids inject viruses into hosts (occurs naturally and replicates within the wasps ovaries)
-when injected, the virus incorporates itself into the host’s genome and begins replicating
-causes immune response to breakdown which disrupts encapsulation and prevents nutrient uptake
55
what are the two categories of insect adaptations to avoid being eaten?
1. avoidance
2. reactionary
56
examples of types of avoidance strategies
1. crypsis
2. warning/startle displays
3. aposematism
4. mimicry
57
crypsis (camouflage)
blending into the environment which you exist in (living or non living things)
-includes behavioral and morphological adaptations
58
warning/startle displays
-used to scare away predators
-ex: eye spots; mainly seen in lepidoptera
59
Aposematism
-warning colouration (warns predators of danger)
-bright colours/colour combinations seen on body
60
Mimicry
attempting to appear a different species or object
61
fighting back
-biting, stinging, aggressive behaviour, spines, etc
62
Sclerotization
hardened exoskeleton
-most organisms cannot pierce/break through the exoskeleton
63
Waxes/powders as morphological defense
-some insects are covered substances to defer predators
-ex: lady beetles do not like eating insects covered in waxes
64
stream drift escape behaviour
-seen in mayflies
-when feeling threatened, they will let go of a rock/substance in order to flee the predator
-get carried away by the current
65
Feigning death
playing dead
-seen in weevils
66
how do monarchs use sequestration of plant metabolites?
-monarch butterflies sequester toxins from the leaves they consume instead of metabolizing it. If a predator eats them, it will be harmed from the toxins and learn not to eat monarchs
67
trash collectors
Pile corpses onto their body to chemically mask their own scent
68
bombardier beetles
capable of initiating a chemical reaction which produces strong carbon dioxide to spray on predators
-pulsate the gas to avoid being cooked by the hot material
69
self production of toxins
-created through metabolic processes, and is stored until needed
-ex: blister beetles create a toxin which causes blistering on tissue which come in contact with it.
70
reflex bleeding
-squeeze hemolymph into certain parts of the body, allows predators to come in contact with the chemicals within the hemolymph without actually being eaten
71
social/gregarious defenses?
-strength in numbers
-stinging/venom (use alarm pheromones)
-soldier insects
72
model
organism/object which species attempts to mimic
73
mimic
species which mimics the model
74
observer (dupe)
potential predators to models/mimics
75
Batesian mimicry
-dangerous model, displaying warning colouration
-edible mimic, displaying warning coloration
-negative frequency-dependent selection: the more common the mimic, the less effective the mimicry
76
Mullerian mimicry:
-model and mimic are both distasteful or defenses + display warning coloration
-no clear identity of the model or mimic (either may be the model)
-rarity of each species has no impact on success (since they are both defended anyway)
77
visual mimicry
-form of mimicry most obvious to observers
-ex: tephritid flies mimic spider predators by having a banding pattern on their wings which closely resemble the jumping spiders which feed on them. When threatened, they turn their back on the predator to show their wing pattern.
78
mimicry ring
a group of organisms within a close geographical area which have adapted to have similar appearances
79
Myrnecomorphy
the mimicry of ants by other organisms
-ex: spiders, bugs, flies, etc evolving to look like ants
80
Wasmannian mimicry
resembles a model along with which it lives. Mainly chemical
-ex: within an ants nest, you will find silverfish, spiders, etc. Which mimic ants.
81
Aggressive mimicry
share the same characteristics as a harmless species, allowing them to avoid detection by their prey
-ex: trash carrying insects
-mainly chemical
82
Reproductive mimicry
actions of the observer (dupe) directly aids the mimics reproduction
-mainly chemical
83
Automimicry
one part of an organism’s body resembles another body part
-ex: end of wing resembles their head. Can lose part of a wing, but not their head.
84
Example of chemical and Wasmannian mimicry?
-butterflies lay eggs on plants which are picked up and carried by the ants into their colony
-the eggs hatch and since the caterpillars smell like ants, they will be raised by the ants
85
Parasites
an organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host’s expense
86
pathogens
a biological agent that causes disease or illness to its host. May also be referred to as an infectious agent
-includes: bacteria, viruses, fungi, protists, nematodes
87
-Bacillus thuringiensis (BT)
bacteria naturally occurring pathogen found in soil. Causes disease when ingested by insects.
-used as insecticides (live BT is sprayed onto leaves to kill insects. Very effective against herbivorous insects)
-also used in transgenic plants (ex BT corn; kills insects when ingested)
88
-american foulbrood
bacteria which causes infection of larvae (only susceptible within the first three days of life)
-occurs if they eat a host with this bacteria. Will grow in the larvae and eventually kill it
89
why are insect-virus associations important?
1. kill/harm beneficial species such as honey bees
2. Naturally control forest and agricultural pests
3. Can be developed into biological insecticides to control pests
90
deformed wing virus
RNA virus in which affected cannot fly and have a shortened lifespan
91
NPVs (nucleopolyhedro viruses)
RNA virus which primarily impact butterflies and moths
-when the caterpillars are about to die, they climb to the top of a plant, and their virus-infected body droops down and infects other insects
-populations in caterpillars tend to build greatly, then crash and remain low for a long time until spiking again
92
fungi
Can cause mortality in insects when humidity is high
-does not require ingestion
-before dying, insects will climb to the top of a plant, to allow the spores to be dispersed from the body
-Cordyceps: many species which each attack one species of insect
93
Nosema ceranae
Microsporidians found in honey bees
94
nematodes
small, parasitic roundworms
-kill their host by releasing bacteria into the body cavity
-some cause mortality, some do not
-most require very moist conditions (commonly seen in soil)
-can be used as an insecticide, as some target pest species
95
varroa mite
parasitic mite heavily involved in pathogen transmission across honey bees
-primary issue occurs from feeding in the juvenile stage. Hide under the larvae until the cell is capped, then the female will lay eggs.
96
horsehair worms
lay eggs into water, ingested by insects when they visit the water. Parasitize the host insect until the worm is mature, when they modify the host insect behavior to move to a water source. When at water, they will leave the host and enter the water.
97
endosymbionts
organisms that live within the body or cells of an organism
98
examples of endosymbionts
1. tsetse fly endosymbiont
2. termite gut symbionts
3. aphid endosymbionts
4. wolbachia
99
tsetse fly endosymbiont
blood-feeding fly
-females feed solely on blood (lacks certain vitamins). The endosymbiont synthesizes the vitamins to make it available for the host.
-without the symbiont, the flies could not complete their development, as they will be lacking essential vitamins
100
termite gut symbionts
-termites feed on wood which is hard/impossible to synthesize. Some termites use endosymbionts harbored in their hind-gut to help breakdown the wood and more it more nutritious
-lower termites use protists, higher termites use bacteria
-termite ingests wood, passes it into the mid/hindgut where the symbionts break down + make the wood more nutritious, gets pooped out, then ingested.
101
aphid endosymbionts
-all aphids have a "primary endosymbiont": obligate association for both parties (both need it to survive)
-bacteria produces amino acids that aphids cannot obtain on their own
-some aphids also have SECONDARY symbionts. Some are implicated in processes such as defense against parasitism and protection against periods of extreme warm-temperatures
-secondary symbiotics very understudied. Hard to study because if you apply an antibiotic, it will kill ALL the symbionts, not just the one you want to study.
102
wolbachia
genus of bacteria that insects 15-60% of all insect species
-gets passed down through the eggs of insects (only females can pass it on)
103
what are examples of alterations wolbachia causes in insects?
1. male killing
2. cytoplasmic incompatibility
3. feminization
4. parthenogenesis
104
male killing wolbachia
male offspring is killed during larval development
-since only females can pass on the bacteria, reducing the number of males in the population will increase the rates of transmission
105
cytoplasmic incompatibility wolbachia
an infected male cannot successfully fertilize an uninfected female
-males are able to develop into adults, but can only reproduce with affected females
106
feminization wolbachia
infected males develop as females (destroys male-horming producing organs)
-some may develop into fertile females, or infertile “pseudo females”
107
parthenogensis wolbachia
in haplodiploid insects (where a female can choose whether to develop a fertilized egg or unfertilized egg), all offspring (fertilized or not) become females
108
benefits of wolbachia
-can reduce mosquito populations or reduce their ability to transmit certain pathogens
-also reduces their lifespan
-can allow some species (ex fruit flies) to produce up to 4x as many eggs
109
spectrum of social behaviour
-subsociality
-quasisociality
-semisociality
-eusociality
110
sociality
cooperative behaviours between individuals of the same species
111
examples of subsociality
-winter roosting (ex monarchs)
-paternal care without nesting
-parental cause with solitary nesting (create a nest for offspring)
-parental care with communal nesting (take care of own offspring)
112
Quasisociality
communal nesting within the same generation, but there is cooperation between all insects (all females are capable of producing eggs, and all contribute to reproduction)
-can take care of offspring that are not their own
113
Semisociality
communal nesting within the same generation, all individuals care for their own offspring as well as other offspring
-division of reproductive labeling (not all females contribute equally to the offspring)
-queens present (but have NO morphological differences from workers)
114
four elements of Eusociality
1. Live communally
2. Overlap of generations (longer term association). All contribute to the colony
3. Cooperative parental care (with division of reproductive labor)
4. Caste system: different individuals based on their rolls
-queens: only individuals who reproduce
-workers: assist queens
-soldiers: defense
115
two groups of eusocial insects
primitive and advanced
116
Primitive eusocial insects
all individuals are morphologically similar
-colonies are not as long term (usually last under one year)
-colony is founded by the queen. Maintains hierarchy by inhibiting workers from laying their own eggs
-mostly seen in wasps, and some bees
117
advanced eusocial insects
seen in termites, ants, some bees, and some wasps
-age polyphenism
-trophogenic caste differentiation
-morphological differences between workers + queens
118
age polyphenism
roles of workers change as they age (younger honey bees perform duties within the colony, older workers leave and collect resources for the colony)
119
trophogenic caste differentiation
difference between a worker and a queen depends on the food which they eat during development, as well as the type of egg they develop in
120
lower vs higher termites
-Lower termites: flexible, indeterminate caste system
-may lack true distinct worker caste
-“Higher” termites: lack symbiotic protists in hindgut
121
what percentage are animals responsible for pollinating wild flowering plants?
up to 80%
122
which insects regularly visit and pollinate flowers
hymenoptera, lepidoptera, coleoptera, diptera, and thysanoptera (thrips)
123
cantharophily
beetle pollination
124
myophily
fly pollination
125
psychophily
butterfly pollination
126
phalaenophily
moth pollination
127
sphecophily
wasp pollination
128
melittophily
bee pollination
129
beetle pollination (cantharophily)
-usually found on compound or bowl/dish shaped flowers
-some pollinate via moving from flower to flower, others feed on the plant
130
Fly pollination (myophily)
-attracted to flowers with very strong scents
-some flies are attracted to the same flowers that bees are, and therefore mimic bees/wasps
131
Butterfly pollination (psychophily)
-flowers pollinated by butterflies are typically sweet smelling and tubular
-flowers are typically upright, red, yellow, or blue, and open during the day
132
Moth pollination (phalaenophily)
-flowers are typically light coloured, pendant shaped, and open during the night
-many flowers are only pollinated from moths (ex aphids) and therefore we see a great amount of specialization in moths in association with specific flowers
133
Wasp pollination (sphecophily)
-many parasitoid wasps use pollen for energy, especially non-feeding adults
-fig wasps
134
fig wasps
males are degenerate in form (wingless, eyeless) and spend their entire life inside of a fig. Females are winged and move from fig to fig
-A mated female will enter a fig, lay eggs into it, and larvae will complete entire juvenile development within the fig. When they complete their development, the females and males will mate. After mating, the females will chew their way out (with their body covered in pollen), and will pollinate the next fig it enters.
135
Bee pollination (melittophily)
-most important group of pollinators
-collect pollen and nectar to support their offspring and for their own consumption
-plants which bees pollinate often have bright yellow or blue, sweet smelling flowers
136
how many species of bees pollinate?
roughly 20,000
136
bumble bees
used mostly for fruit pollination, as they do well in greenhouses
-honey bees CANNOT be kept in greenhouses
137
leafcutter bees
used for flowers which have “trip” mechanisms, which hit bees on the head with stamen when they are collecting nectar.
-honey bees do not like this and therefore are not good pollinators for these plants; but leafcutter bees do not mind
138
Blue vane trap
yellow tub with a funnel at the top, preservative at the bottom which drowns the bees which we can then sample
139
Pan traps
blue, yellow, white (represent most attractive colour to bees)
140
Aerial netting
used to catch bees (specifically for those who are not well caught by other traps)
141
Malaise traps
insects will fly upwards when hitting a surface as instinct. When they hit the net, they will fly towards the top and get funneled into a collecting cup
142
what percentage of all flowering plants require pollinators
80%
143
what percentage of crops rely on pollinators?
34%
-75% show yield increases with pollinators
144
what has caused the extinction of most wild and feral honey bee colonies in Europe and the US?
ectoparasitic mite Varroa destructor
145
how has worldwide honey bee hives changed since 1961?
increased by 45%
146
how has the dependence of agricultural crops on pollinators increased since 1961?
increased by over 300%
147
honey bee stressors
1. varroa mite
2. tracheal mites
3. nosema
4. RNA viruses
5. bacteria
6. fungi
7. small hive beetle
8. insecticides
9. malnutrition
148
tracheal mite bees
parasitic mites which live in the tracheal system of bees. Weaken individuals, which increases individual mortality
149
small hive beetle
does not directly hurt bees, however their larvae feed on the hive material, forcing the bees to abandon the area
150
malnutrition of bees
when honey is collected by beekeepers, they often supplement the honey with sugar alternatives, which are not as nutritious for bees
151
wild bee stressors
1. pesticides
2. habitat loss, fragmentation, agricultural intensification
3. competition, pathogen spillover between species
152
alien species
species which was introduced by human action outside of their natural past or present distribution
-introductions can be deliberate, accidental, harmful, and/or beneficial
153
invasive alien species
those whose introduction or spread threatens the environment, the economy, or society, including human health
154
threats posed by invasive alien species
1. Environmental: causes loss of biodiversity and/or ecosystem function
2. Economic: causes great economic losses
-ex: invasive species cost $100 billion annually in the U.S
3. Societal and human health
-ex: mosquitoes spreading diseases detrimental to human health
155
why do some alien species become invasive?
-free from its natural enemies or controls
-have less pressure in terms of predation and parasitization
156
characteristics observed in invasive species
-highly tolerant to environmental conditions, or the new environment offers ideal conditions
-high dispersal capabilities (can be nearly impossible to eradicate)
-able to escape eradication and control effects
157
enemy release hypothesis
-states that alien species have the potential to become invasive when they are free from their natural controls in the new area they are established in
-alfalfa weevils: high number of parasitoids for this species in Europe. After being introduced in North America over 100 years ago, they became extremely invasive because none of their natural enemies were present. To help control the spread, their natural enemies were released
158
invasional release hypothesis
-states that a group of alien species can facilitate the invasion of others, therefore creating a new alien species
-ex: soybean aphids overwinter on buckthorn, not on soybean. Therefore, if we did not have buckthorn in North America, soybean aphids would not have the resources needed to become an invasive alien species
159
niche utilization
-many alien species become invasive simply because they are better at doing a certain thing in their respective environment (ex: better predators than any native species in the area, therefore more likely to become successful)
-ex: native ladybird beetles are declining because of the high abundance of non-native ladybird species which face less pressures
160
spongy moth
-in 1869, an entomologist decided to start a silk industry in North America. He brought spongy moths over from europe (their caterpillars spin silk); and some of the moths escaped
-happened again, from a separate person, in 1920.
-incredibly invasive and harmful, feed on vegetation from most trees
-majority of their movement is from humans since females are mostly flightless
-post WW2, DDT sprays were used to spray and kill spongy moth caterpillars within entire forests
-biological controls using parasitoids and pathogens are now used as well
-there is a subspecies with flighted females who are attracted to lights at shipping ports in Asia and lay their egg masses on shipping containers. Massive efforts are in place to prevent the spread of these species
161
emerald ash borer
-has killed hundreds of millions of ash trees in the US, ON, and QC.
-feed through phloem of trees. When enough beetles are present, all nutrient flow is cut off from the tree, killing it.
-by the time a tree starts showing symptoms, it has already had multiple generations of beetles within it
-layers of bark are shaved down to try to find larvae; but this is hard to do
-was detected in Winnipeg in 2017/2018, but in very small numbers and has since been eradicated
162
Brown marmorated stinkbug
Brown marmorated stinkbug:
-herbivorous stinkbugs which feed on many plants
-first detected in 1998, very rapidly spread
-very hard to control by insecticides, no effective natural enemies present in North America
163
Asian longhorn beetle
-attacks and kills a broad range of trees; great economic threat
-detected in Toronto, infected trees were destroyed
-no longer detected in North America, however pose a very serious threat
164
Asian tiger mosquito
-now fairly widespread throughout parts of the US
-potential vector for many diseases
-made possibly from climate change, as more and more climates become desirable for pathogen-carrying insects
165
Asian giant hornet
-established in the west coast of the US, dangerously close to the BC border
-kills honey bees; bees have no defense against them
-dangerous to humans as well (kills a new people per year in Asia)
166
responses to invasive species threats
-regularly monitored and controlled by the CFIA
-protection (through knowledge, protection tactics, etc)
-early detection (through surveillance and monitoring)
-rapid response (having plans and funds in place in case of an outbreak)
167
when are insects considered a pest?
when they do one or more of the following:
-invade our space
-transmit disease
-destroy or reduce quality of plants
-damage human structures
-destroy or reduce quality of commodities (food, textiles, etc)
168
When should you control a pest?
-when the time and cost is less than doing nothing and less than the damage that the pest is inflicting
169
Economic-injury level concept
used to determine the density of insects required to justify control
EIL=C/X*I*D*K
170
economic threshold
-the number of insects which should trigger management action to prevent populations from reaching the economic injury level. If anything exceeds the economic threshold, the control action should be taken
171
avoidance strategies for biocontrol
-reduce the likelihood that they ever exceed the ET
-limiting, delating, preventing pest establishment
-limiting population growth
172
ecological control
-modifying the environment within the crop and disrupting pest requisites
-reduce favorable ecosystems
173
biological control
-the purposeful use or manipulation of natural enemies to reduce pest populations or pest status
174
sterile insect technology
srelease sterile male insects to reduce chances of females finding a male to mate with
-requirement is to have the ability to distribute the target insects, and that the insects being released are not capable of causing damage themselves
175
surveillance
insect population sampling for collecting information
176
sampling
lots of information about pests can be determined by sampling, including: presence/absence, population size/density, geographical distribution, status of migration/local movement, etc
177
types of sampling
1. quantitative
2. qualitative
178
quantitative sampling
directly enumerating things like density
178
qualitative sampling
general things like presence vs absence, current distribution
179
sampling tactics
1. Active sampling:
-sweet net, direct counts, indirect counts
2. Passive sampling
-traps
180
three aims of biocontrol programs
1. Reduce pest numbers (by modifying environment to increase numbers of natural enemies, add more natural enemies, etc)
2. Delay pest population growth (by adding natural enemies before the population grows to begin with)
3. Prevent pest establishment (ensure there are efficient natural enemies in the area to prevent the establishment of a specific pest species)
181
approaches to biocontrol
1. conservation/habitat modification
2. importation (classical biocontrol)
3. augmentation
182
conservation /habitat modification
working with the natural enemies already in the area to help improve the situation
183
Importation (classical biocontrol)
used for the control of alien pests who are free of natural enemies
-import natural enemies and allow them to become established
184
Augmentation
directly releasing natural enemies in an ecosystem where you need them to reduce pest populations in a short or medium term.
-two types: Inundative releases, inoculative releases
185
augmentation: Inoculative releases
release fewer insects, because you expect reproduction and continued control from the following natural enemies generations (can become established)
186
augmentation: Inundative releases
mass, continual, or periodic releases (used especially when the establishment of the NE is unlikely for one of more reasons, for example if they cannot overwinter in the area)
187
issues with generalists as biocontrol agents: spongy moth
-females flightless, males flighted. Overwinters as eggs
-chose a tachinid fly which is a parasitoid of spongy moth caterpillars as a natural biocontrol agent
-the issue: these are extreme generalists. Chose their prey based on general size
-also attack many non-pest species, and multivoltine (since spongy moths are univoltine, this means that the fly must kill two other species on top of a spongy moth in order to complete one life cycle)
-they also cannot overwinter in spongy moth eggs, meaning they had to use other insects
-primary driver for enormous declines for many other moth species (including beneficial species)
188
important notes on biocontrol
-don't import exotic pests
-MUST match biology of the natural enemy to the pest (same number of generations per year)
-try to choose and host specific natural enemy
-MUST assess the effects on non-target species
189
which tests are ran to choose a natural enemy for a biocontrol program?
1. No-choice tests: present the biocontrol candidate with the related (non target) species you are concerned about to determine efficiency
-does the insect cause similar damage to non-target species?
2. Control tests: present insect with choices between target host and other related species to assess non-target risks (does the enemy prefer one species over another?)
190
general characteristics of a successful biocontrol agent
-host specific (or close to)
-synchronous life cycle with pest
-high rate of population increase
-capability of surviving in the new environment (even when few prey targets are available)
-capability of finding its prey efficiently
191
weed biocontrol: prickly pear cactus
-got introduced into australia, where no natural controls were present, and became an incredibly invasive and harmful weed
-all other forms of control (chemical, mechanical, cultural), failed
-The cactus moth was found to only feed on prickly pear cactus. They were released into the impacted areas.
-established and spread rapidly, leading to a dramatic reduction in the cactus populations
192
weed biocontrol: houndstongue
-introduced in rangeland, spreads rapidly
-very poisonous to horses and cattle
-seeds accumulate on animals and cause infection
-biennial life cycle (live for two years)
-a weevil was identified as a potential biocontrol agent
-adults are defoliators, but larvae feed inside the stem, right at the crown of the plant (therefore, plants which are infested in their first year do not produce seeds in their second year, meaning they die without producing offspring)
193
how will climate change impact insects?
1. growing season length (increased numbers of pest species; ex aphids)
2. life cycle synchrony (may not have plants which they depend on present if active too early in the season)
3. increased frequency of severe weather (impact beneficial species such as parasitoid wasps)
4. overwinter survival (insects rely on snow covering to survive winters)
5. changes in species distribution (harmful species becoming adapted to more climates)
194
which insects cause issues in animals?
1. lepidoptera
2. coleoptera (blister beetles)
3. hemiptera (kissing bugs)
4. pscocodea (chewing/sucking lice)
5. siphonaptera (fleas)
6. diptera
7. acari (ticks and some mites)
195
adaptations of parasitic insects
1. flattened body shape
2. loss of wings
3. movement and dispersal (claws, jumping legs, flight at specific times of life cycle, etc)
196
strategies for finding host
1. Live close to the host (ex bed bugs)
2. Actively search for required host (ex ticks, who use vibrations/motion/temperature to find a host)
197
mouthparts of skin feeders
usually have chewing mouthparts
198
strategies of blood feeders
1. telmophage (pool feeders)
2. solenophage (tube feeders)
199
telmophage (pool feeders)
create a big hole, breaking blood cells, in order to create a pool of blood (ex: horse flies)
200
Solenophage (tube feeders)
pierce through skin and feed directly from a blood vessel through a tube (ex mosquitos)
201
what is present in host saliva?
-vasodilators (dilate to allow for more blood flow)
-platelet aggregation inhibitors (prevent clotting)
-anti-coagulants (prevent clotting)
202
lifestyles of hosts
1. free living blood suckers
2. nest or borrow blood suckers
3. rapid feeding temporary parasites
4. slow feeding temporary parasites
5. permanent ectoparasites
203
Free-living blood suckers
-do not live on host. Visit host periodically when needed
-ex mosquito
204
Nest or borrow blood suckers
-bound to host by habitat
-live with host (provides food and home)
-ex bedbugs
205
Rapid feeding temporary parasites
-stay in fairly close association with the host (ex on back of a cow)
-feed often, and leave when it is time to lay eggs
-ex horn flies
206
Slow feeding temporary parasites
-spend most of life not on host
-feed for 5-7 days, then drop of host to produce offspring
-takes ONE big batch of blood instead of multiple small batches
-ex ticks
207
Permanent ectoparasites
-adapted to host
-take small blood meals often, lay eggs often
-entire life cycle is spent on host; die if they are removed
-ex sucking lice
208
myiasis
invasion of tissues from fly larvae
209
flesh flies
facultative and obligatory myiasis (some larvae feed on dead flesh, others feed on live flesh)
-larviparous: females keep eggs until they are ready to hatch
210
Wohlfahrita spp.
obligatory myiasis (live tissues): enter through moist body openings (such as ear) or fresh wounds
211
bot flies (oestridae)
obligate myiasis. Adults do not feed, but larvae feed on host
-create a hole in host’s flesh, stick their spiracles out to breathe, and feed until ready to pupate
212
what is needed for transmission to occur?
the HOST, VECTOR, and PATHOGEN (or parasite) must all be present in the same area
213
dog heartworm
caused by a nematode which aggregate within the heart of dogs
-transmitted by mosquitoes (mostly) and sometimes fleas
-infest the right ventricular and pulmonary arteries
-reduces amount of blood flowing to the body, leads to weakness, lethargy, and heart failure
-develops partly within the mosquito (aka the vector (mosquito) is necessary for transmission
214
bluetongue virus
transmitted by biting midges to sheep and cattle
-most animals are asymptomatic, others develop acute, fatal disease (Reoviridae)
-swelling of tongue, problems with circulation, ulcers, hoof issues, curved back (because of sore hooves) are symptoms
215
problems caused by arthropods for humans
1. annoyance
2. fear
3. toxins and venoms
4. allergic reactions
5. food contamination
6. invasion of host tissues (myiasis)
7. pathogen transmission
216
delusional parasitosis
psychological disorder where you feel that insects are always crawling on/in you
217
envenomation
the act of injecting venom into animal tissues
218
toxins
poisons of plant or animal origin
219
Venoms
a poisonous mixture of compounds containing one or more toxins
220
vector
the arthropod responsible for transmission of parasites or pathogen (ex mosquito)
221
pathogen
called a pathogen when a parasite causes a disease
222
how are pathogens transmitted?
1. biological
2. mechanically
223
Biological transmission
part of the development of the pathogen occurs within the host (ex dog heartworm)
224
Mechanical transmission
pathogen is transmitted mechanically (ex through a bite) but does not develop within the host
225
what is needed for biological transmission?
1. A parasite that can multiply within the vertebrate and invertebrate host tissues
2. A vertebrate host that develops a level of infection with the parasite that is infectious to the vector (ex a cat can become infected with heartworm, however a mosquito cannot pick up the parasite from the cat and pass it on)
3. An arthropod vector that acquires the parasite from the infected vertebrate host and is capable of transmission
226
fleas
-the plague was transmitted by fleas which lived on small rodents
-vector: flea
-hosts: small mammals (rats) and humans
-pathogen: bacteria called Yersinia pestis
-has claimed more lives than all wars ever fought (75-200 million people)
-still present in North America in wild rodent populations (1,000-3,000 cases annually worldwide)
227
lice
-transmit a number of pathogens, most impactful pathogen is typhus
-thrives in overcrowded, unsanitary conditions (ex: during war, in homeless populations, prisons, etc)
-transmitted in lice by feeding on infected humans
228
typhus
infection caused by scratching, crushed lice, inhalation of feces (viable in dried feces for 60 days)
-symptoms: delirium, high fever, photophobia, severe headaches and muscle pain, death
229
ticks
-transmit a number of pathogens of human and veterinary importance
-three life histories: one who completes entire lifecycle on host, some that spends life on two hosts, and others with three hosts (larvae, nymph, and adult stages on different hosts)
-three-host ticks
-three host ticks tend to be most dangerous
230
lyme disease
caused by bacteria Borrelia burgdorfi, transmitted from ticks
-most commonly reported vector-borne disease in the US and Europe
231
mosquitos
-most important arthropod vectors affecting human health (historically and currently)
-transmit many diseases which are incredibly impactful to humans (ex malaria, dengue, yellow fever, etc)
232
malaria
caused by sporozoan protists
-1.6 billion people are at risk of malaria via mosquitos
-estimated 300-500 million causes occur annually, with 500,000-1 million deaths annually
233
how many cases and deaths from malaria annually?
estimated 300-500 million causes occur annually, with 500,000-1 million deaths annually
234
dengue fever
fastest growing mosquito-borne disease.
-affected 50-100 million people each year, causes 25,000 deaths
-spread by Aedes aegypti and Ades albopticus
-Nicknamed “breakbone fever” because of the bone pain associated with it
235
how many cases and deaths from dengue fever annually?
affected 50-100 million people each year, causes 25,000 deaths
