Week 3 Flashcards
why do insects move
Access resources
-Food
-Shelter
-Mates
-Oviposition (where to lay offspring)
Avoid crowding
Ecological escape
-Escape from adverse environment
Escape predators
what are the only true invertebrates that can fly
insects
what are some examples of passive flying
Mites that hitchhike on other insects
Ballooning on silk (spiders, caterpillars)
how long ago were first flying insects and what were they
400 mil yrs ago
pterygota
when did first cockroaches (flying) evolve
350 mil yrs ago
when did first dragonflies evolve
300 mil yrs ago
why were insects so much bigger 300 mil yrs ago
There was more vegetation which created lots of oxygen
Their way of getting oxygen is more passive which means higher oxygen made them bigger
when were first beetles true flies and flying pterosaurs (dinosaur thing) evolved
250 mil yrs ago
when were first birds and gliding lizards evovled
150 mil yrs ago
when were most modern insect orders and first bats evovled
50 mil yrs ago
how fast do insects generallu fly
Most are slow with some very fast for very short distance
Horse fly can fly 98km/h for very short distance
Butterfly & honeybee can fly 5km/h
what is wing polyphenism
genetically same insect can have different kinds of wings
what are macropterous insect morphs
Full wings developed can fly
what are Brachypterous insect morphs
have partial wings
what are apterous insect morphs
no wings
what insect orders exibit wing polyphenism
most orders
ie. orthoptera, Psocoptera, Thysanoptera, Hemiptera, Heteroptera, Coleoptera, Diptera, Lepidoptera, and Hymenoptera
what is polyphenism in insects in general
Different phenotypes (morphs) determined by environmental conditions (not genetic)
what type of insect often exibits polyphenism
aphids
what are the 2 phenotypes of aphids
Alate adult (has wings)
Apterous adult (no wings)
why do alate aphids have wings
Find new resources (food and plants)
Spread new areas
Avoid crowding
If too many, next generation will have wings
why do apterous aphids have no wings
Lay more offspring
Exploitation of food and reproduction
what happens in the aphid life cycle
Have different forms (morphs) at different times of the year but genetically identical
- mostly Based on day lengths
Move between hosts (plants) during the seasons
-Different plants
-migrate
what are some ways insects orient themselves
Sun compass
polarized skylight
eaths geomagnetic field
local landmarks
how do insects (and what kind) use sun compass for orientation
Use suns position to know where they are
Constant heading relative to sun’s azimuth
Endogenous chronometer - internal clock
-Know when sun comes up
Butterflies
what types of insects use polarized skylight to orient
Bees, ants, crickets, flies, butterflies
what types of insects use earths geomagnetic field to orient
Dragonflies and butterflies
why do insects use local landmarks to orient themselves
For drift compensation (wind that deviates them)
what is the flight boundary layer
what divides wind insects can move faster than and can’t
what is insect flight within flight boundary layer
Zone where flight speed > wind speed
They can choose where they go because they can fly faster than wind
what do insects do when flying above flight boundary layer
Visual cues from ground indicate backward motion
-Insects turn and fly downwind
-Or go to ground and wait for wind to die down
Can’t choose where they go
what is it called when insects fly within flight boundary layer
directed flight
what is it called when insects fly above flight boundary layer
flight is downwind
what is non-migratory insect flight used for and what is it like
Used to find daily resources
Flight is responsive to local cues
Flight duration is often short
Turns and stops are frequent
Flights typical occurs within the boundary layer
Flight type is directed
what is migratory insect flight used for and what is it like
Used to find new resources; ecological escape
Flight is not responsive to local cues
Flight duration often long and persistent
Turns and stops are infrequent
Flight typically occurs within or above the boundary layer
Flight type is directed or downward
where did insect migratory flight originate and what orders is it common in
Originated independently multiple times
Common in odonata, orthoptera and lepidoptera
what are some experiments done that found how common insect migration is
Nets attached to planes at 4600m over LA collected 210 families of 18 insect orders and 2 orders of spiders and mites
Live grasshoppers found at sea 1500 km from land
what type of flight do monarch butterflies exhibit in migration
directed flight
what do bright colors on monarch butterflies indicate
they are toxic
why are monarch butterflies toxic
feed on milkweed which is toxic plant
what is monarchs summer feeding range
all over us and southern canada
where do eastern vs western monarch butterflies go during winter roosting
Roosts are communal on evergreen trees
All go to a small area
Eastern population in mexican mountains
Western population on coastal S. california
what reproductive state are monarchs in during winter roosting and are they in true hibernation
Insects are in reproductive diapause
Not true hibernation
-Active on warm days
where do overwintered monarchs go during spring migration and how fast
Overwintered insects fly north and lay eggs on milkweed, then die
Northern flight up to 30 km/h
when does northern expansion of monarchs continue to
wherever milkweed continues until Fall migration and reproductive diapause triggered by environmental cues
what environmental cues trigger monarch Fall migration and reproductive diapause
Shorter days
Variable temperatures (cool nights)
Decreasing food and plant quality
how long and fast is fall migration in monarchs (do they rest)
~3000km, averaging 20-94 km/day
Roost communally often for 2+ days
how do monarchs orient during fall migration
sum compass / polarization light / electromagnetic
what did henry bates discover and when
first observations of mimicry in mid 1850s on amazon expedition
many similar brightly marked butterflys immune to predators
what is aposematism
Warning coloration, signaling danger or unpalatability (usually toxic)
Common adoption of colors that warn of danger is prevalent in many animal taxa
what is mimicry and why is it used
Resemblance of a mimic to a model
Mimic gets protection from predation
what is batesian mimicry
System with 3 players:
model
-inedible/distasteful/dangers
Displaying warning coloration
mimic
-edible; displaying warning coloration
Observer (dupe)
-Predator
what evolution process explains evolution of most forms of mimicry
Positive adaptive process, increasing fitness of mimics
Classical natural selection adequately explains the evolution of most forms of mimicry (higher chances of surviving if developed)
what happens when batesian mimics become more common relative to model species
mimicry is less effective
predators adapt
Negative frequency-dependent selection
what is polymorphic batesian mimicry and why is it useful
Mimic with more than one model species
Balances risk of becoming too common
-Unlikely predators will adapt to all mimic forms
give an example of polymorphic batesian mimicry
Ex. african butterfly
12 female mimics, males 1 color
what is mullerian mimicry
Both Model and mimic are distasteful and display warning coloration
Both species are models and mimics
why is mullerian mimicry so successful
Rarity of each species has no impact on success, since individuals of each species defended in some way
give an example of mullerian mimicry
Ex. Repeated evolution in overlapping mimicry rings among north american velvet ants
They all resemble each other and are toxic
what is visual mimicry
Form of mimicry most obvious to observers
Observers duped by physical appearance of mimic
what is wasmannian mimicry
Mimic resembles model along with which it lives (inquiline) in a nest or colony
what is myrmecomorphy
type of wasmannian mimicry
Mimicking ants to live in nest
Very common
Spiders, beetles, mantis, hoppers
Allows good protection (ants very successful)
what is aggressive mimicry
Predators or parasites which share same characteristics as harmless species
Avoids detection by prey
what is reproductive mimicry
Actions of observer (dupe) directly aid the mimics reproduction
give an example of reproductive mimicry
Ex. Orchid mimicry
Wasps think orchid is a mate and tries to mate
Pollinates orchid
Deceit pollination
pseudocopulation
what is automimicry
One part of organisms body resembles another part
what is Intraspecific variation of toxicity and an example
Danaus chrysippus feeding on toxic and less toxic milkweeds
Depending on what larvae feed on, some might be toxic some might not be in same species
what is sexual mimicry
Males mimic females or vice versa
what is emsleyan mimicry and why is it useful
Deadly prey mimic less dangerous species
Allows predators to know you are to be avoided but still have a deadly defense mechanism
If too deadly without mimicry, predators won’t learn, just die
what is avoidance mimicry
warning/startle displays
Eye spots
give an example of avoidance mimicry
Larva of hemeroplanes triptolemus moth
Capable of expanding anterior body segments to give appearance of snake w/ simulated eyes
Extends to point where it will harmlessly strike at potential predators
what is crypsis
Resemblance of background or inedible objects
what is camouflage
takes a form resembling its surroundings
give some examples of species using crypsis
Phasmatodea
-Avoid predators
Peppered moth
Spurge spanworm moth
Indomalayan orchid mantid
-Avoiding prey detection
-Looks like orchid
what is masquerade or mimesis
resembling an object from environment
give some examples of what insects resemble when using masquerade or mimesis
Sticks, thorns, poop
what is pseudocopulation
behaviour that mimics copulation but does not involve any sexual union
what are some benefits of monarch migration
larval food and nectar
avoidance of lethal winter conditions
what are some costs of monarch migration
predation risk
- have to educate predators about toxicity
energetic costs of flying
why do desert locusts migrate
crowding
what is desert locust synchronization
Pheromones that hasten development of other individuals
makes sure they all develop at same time
what are to forms of desert locusts (polyphenism)
gregarious form
solitary form
what are desert locusts like in their gregarious form
darker/yellowish
More active
Long wings
More robust
Happens when more of them and need to migrate
what are desert locusts like in their solitary form
Green
Less robust
When theres less of them
how many locusts can be in a swarm
10 000 to 10 billion individuals
how much area does a locust swarm cover
1-1000 km^2
how far do locust swarms travel per day
100 - 200 km
how big of an area and how many people to locust swarms effect
29 million sq km
60 countries
More than 20% of total world land surface
1/10 of world’s pop
what areas are locusts swarms most common
Many arid areas
Sahara and middle east
what causes desert locust outbreaks
Crowding: induced by concentrations of host plant determined by patchy rainfall
Rain causes host plant to grow in biomass
Locusts reach massive numbers and migrate
Very hard to predict migrations
what is phylogeny
study of the evolutionary history of organisms and the relationships between them
what is linnean classification and when was it created
(1758)
Binomial system for names,hierarchical classification
what is darwinian evolution and when was it created
(1859)
Natural selection as an explanation for evolution
what did hennig (1950) show
Derived traits support shared ancestry
what are some important insect hiearchy classifications
Phylum
Class
Order
Family
Genus
Species
what do people use to classify insects
Detailed study of traits of species
Morphology
Examination of DNA sequences
what is morphology
careful study of anatomy
why is examination of DNA sequences so common for phylogeny
Examination of DNA sequences
DNA data is getting cheap
Data sets getting bigger and easier to generate
More direct
Simple to generate lots of data
Sequence data makes process much more repeatable
Not as much opinion
less ambiguity
how do we compare dna sequences
Take individual species data and line them up next to each other
Look at rows to see which species have same letters at different positions
what do phylogenetic trees display
philogyny of different species
which species are related and how
groupings of different species
what is the order of a phylogentic tree (where is top)
base of tree represents earliest species
leaves of tree represent modern day species
what does a branch in a phylogentic tree show
lineage through time
what does a node in a phylogentic tree show
Represents shared common ancestor
More closely related to each other than to any other taxa on tree
Common ancestors represented by nodes
what are sister taxa
Two taxa that split from node
Things most closely related to each other
they have same common ancestor
what data is used to make phylogenetic trees
Genetic
Morphological
Behavioral
Ecological
DNA sequence data most convenient
what is a monophyletic group
group that Includes most recent common ancestor and all of its descendants
All children of parent node and parent
what is a paraphyletic group and why is it bad
Includes some, but not all of descendents of a common ancestor
Common Ancestor included
Common Ancestor Would probably look like group members
removes meaning from phylogenetic tree
what is a polyphyletic group
Includes some but not all of descendants of common ancestor
Common ancestor is not included
Common Ancestor Would probably not look like group members
what are shared derived characters and what do they tell us about recent common ancetry
Synapomorphy
Shared, derived state
Characteristic that isn’t an ancestral trait
what are shared ancestral characters and what do t hey tell us about recent common ancestry
Shared ancestral characters not evidence of recent common ancestry
symplesiomorphy
-Shared ancestral state
why are cockroaches and termites now in the same order
DNA sequencing revealed termites just highly derived cockroaches
without being the the same order blattodea would be a paraphyletic group
how can we use phylogeny to find out about the past
Reconstructing ancestral states
-Can use phylogenies to predict how ancestral insects looked and behaved
ex. social behaviour not end of tree
Historical biogeography
-How insect diversity wound up where it is
-Events that transpired millions of years ago
-Shows how things moved very long times ago
-Where familys of insects originally evolved
what are the two primary uses of DNA barcoding
specimin identification
Species discovery
should DNA barcoding be the only way to identify species and why
Species are hypotheses
In science test hypotheses and try to falsify
One type of data (DNA barcode) can’t be test to itself
Should be used in conjunction with morphology, geography, behaviour, etc.
Always looking for evidence species are wrongly grouped
what has DNA barcoding revealed about cryptic species
Separating cryptic species
what genome is used for DNA barcoding
Takes specific gene from mitochondrial genome
S-equences that genome for all animals
-4 possibilities for each part of dna
what does DNA barcoding reveal about sexual dimorphistic species
identifys when extreme sexual dimorphism
what are some benefits from easy identification resulting from dna barcoding
Associating the sexes
Associating immatures with adults
Pest management and ecology
Identification of disease vectors
why is accuate species identification so important
Cornerstone of all biological studies
Essential to understanding specific organisms biology
Understanding food webs and evolution
Time since death forensic entomology
Pest control and appropriate management strategies
Invasive species at ports of entry
Controlling vectors of disease
what is PCR - Polymerase Chain reaction
Allows for rapid duplication (aplimification) of specific sequences
what are 3 steps of PCR - Polymerase Chain reaction
Denaturation
-DNA template denatured into 2 single stranded molecules
- raise temp a lot
Annealing
- lower temp a lil
Extension
- raise temp a lil
how long does PCR take
about 2 hours
