Lecture 4

Question 1

What is the red queen evolution?

Answer 1

. Refers to running but not getting anywhere
. Used to describe the evolutionary arms race between predator and prey
. Leads to a situation where both species co-evolve due to the antagonistic interactions
. These adaptions provide no advantage long term however as overall success of hunting/ escape will remain the same

Question 2

Give an example of red queen evolution

Answer 2

As Cheetah become faster they increase their hunting success. So the idea is that cheetahs are running in evolutionary terms, going fast in every generation so catch these gazelle but they will evolve counter adaptations not to be caught, so they are both evolving every generation but in the end neither are any more successful as their adaptations are cancelling each other out but they are evolving quite quickly
(So it drives the rapid evolution of their prey running faster)

Question 3

How do you test red queen evolution?

Answer 3

. Need to test past and current prey against current predators or vice versa
. Not an easy task

Question 4

Who achieved testing red queen evolution?

Answer 4

Was in a study by Decaestecker et al (2007)

Question 5

Decaestecker et al (2007) tested red queen evolution. How did they do this?

Answer 5

They studied the water flea Daphnia magna and a bacterial parasite Pasteuria ramose in the wild, these die every year and settle in sediments and they had about 40 years (he thinks) worth of sediment data if each. So, each year is an account of what happened and in tern the evolutionary relationship of that predator and prey relationship.
Both produce resting stages which accumulate in the sediment of ponds.
Creates a loving fossil record.

Question 6

What did Decaestecker et al (2007) find when they tested red queen evolution?

Answer 6

So they took a layer and expose the Daphnia to past and future parasites, and they tend to do worse because they are not perfectly adapted to them and they tend to do worse.
Additionally, there was no change in infectivity among the same generations- so if you look at it year by year then the infectivity doesn’t change because they are evolving with each other

Question 7

What do you findings when Decaestecker et al tested the red queen hypothesis suggest?

Answer 7

Suggest that relative success of host/ parasite interactions remains stable. So basically, this showed that there is a huge amount of evolution (rapidly) going on but cancelling each other out. So, these adaptions don’t get them anywhere

Question 8

Who came up with search image?

Answer 8

Luc Tinbergen (1960)

Question 9

Luc Tinbergen (1960) suggested that predators create a search image when they begin to encounter cryptic prey. What does this mean?

Answer 9

So the predators that come across cryptic prey, they will look at that prey very carefully and they create an image in their head of what it looks like and that image can be applied to other cryptic prey when they find it. It was predicted that their success in finding cryptic prey should go up because they form this search image

Question 10

What is cryptic prey?

Answer 10

When you can’t see them very well

Question 11

Marian Dawkins (1971) demonstrates that Tinbergens idea of search image was correct. How did she do this?

Answer 11

. She used domestic chicks attacking prey (rice grains)
. The grains were coloured to either match (cryptic) or stand out from their background (conspicuous)
. After a short time chicks were eating the cryptic prey at the same rate as they had the conspicuous ones (so they eventually formed a search image)

Question 12

Birds are major predators that of underwing moths. These moths have apparently cryptic forewings and brightly coloured hind wings (by will usually keep this hidden because this bit is not cryptic but the forewings are). What are the 2 hypotheses for these moths having these wings?

Answer 12

1) that the forewings decrease detection
2) the hindwings may have a ‘startle effect’- (so if they get spotted they will expose the hind wings) which slows the predator allowing the moth a greater change of escape. So probs not sexually selected but predatory selected

Question 13

What are cryptic moths?

Answer 13

Apparently have cryptic forewings and brightly coloured hind wings which they will usually keep hidden because this bit is not cryptic but the forewings are

Question 14

Who used blue jays and cryptic moths to study search images?

Answer 14

Pietrewicz and Kamil (1980)

Question 15

How did Pietrewicz and Kamil (1989) use cryptic moths and blue jays to study search images?

Answer 15

. Blue jays facing a screen were shown slides with either a moth present or no moth
. They could select either the screen or an advance key to advance the slide
. Correctly identifying a moth produced a mealworm reward
. Incorrectly selecting either a slide with no moth or advancing when a moth was present was punished by a delay in the appearance of the next slide
. In the slides the moths could be on either conspicuous or cryptic backgrounds

Question 16

What are the results of Pietrewicz and Kamil (1980) experiment using blue jays and cryptic moths to study search images?

Answer 16

The jays made many more mistakes when faced with moths on cryptic backgrounds.
This supports the crypsis hypothesis

Question 17

Pietrewicz and Kamil (1979) tested the ability of blue jays to create search images. How did they do this/ what were the results?

Answer 17

. Birds were presented with images of moths (either Catocala retecta or C. Relicta)
. When a series of images containing the same species were run bird accuracy improved
. When the two species were mixed bird accuracy reduced
. Good evidence for search image

Question 18

What is apparatus selection?

Answer 18

When you preferentially select the most common prey.

Where are one type of prey starts to go then they just switch on to it and go for it almost exclusively

Question 19

Why is apostatic selection important?

Answer 19

This kind of selection is very important evolution because it maintains polymorphisms and they are just genetic diversity

Question 20

Give an example of apostatic selection

Answer 20

If you have a bird that has chosen to go for one type of polymorphism because it is common then the other polymorphism doesn’t get taken and increases in frequency so it maintains these polymorphisms

Question 21

Explain how apostatic selection works

Answer 21

. If a predator builds a search image of the most common morph then less common ones will be overlooked even when present
. Apostatic selection relies on the most common prey being over represented in the predators diet
. By maintaining the equilibrium between morphs polymorphism is promoted as rarer morphs will have greater survival rates

Question 22

Explain how Bond and Kamil (1998) used virtual prey to test apostatic selection

Answer 22

. They used three cryptic moths in equal population sizes against a patterned background (these were virtual moths on a screen)
. One moth type was more cryptic than the other two
. Jays were allowed to attack these moths on the screen
. Each day the population of moths was restored to its original number but maintaining relative abundance of surviving moths
. If apostatic selection has worked these should reach an equilibrium and the 3 moths should coexistence at some point
. After 30 days that is what they found as the blue jays could maintain the 3 type polymorphism with 75% being the most cryptic moth

Question 23

What are the categories of proximate factors controlling seasonal reproduction in birds?

Answer 23

. Initial predictive information
. Supplementary information
. Synchronising and integrating information
. Modifying information

Question 24

What is proximate factor controlling seasonal reproduction initial predictive information when talking about categories of proximate factors controlling seasonal reproduction in birds?

Answer 24

Stimulates the development of the reproductive system- so for these longer term events such as reproductive system it is energetically expensive to have large gonads (testes or fully developed ovaries) throughout the whole year so when they are not needed for breeding then the reproductive system will be in a regress/ shrunken state and is only activated at a particular time of year. It will take some time to do that so the birds predict when they are actually going to breed and make sure their reproductive system is activated ahead of time so they are ready when the optimal time in the environment is reached. So uses cues to predict what their physiological state needs to be in the future e.g. photoperiod

Question 25

What does The proximal factor controlling seasonal reproduction supplementary information do in birds?

Answer 25

Stimulates final reproductive development (e.g. temp, food)

Question 26

Give examples of the proximate factors controlling seasonal reproduction synchronising and integrating information

Answer 26

. Behavioural interactions
. Birds that are selected to breed in very large colonies so behaviour can influence the timings of these events, migrating in groups rather than solitary, defending a territory, finding a mate, parental care

Question 27

What does the proximate factor controlling seasonal reproduction ‘modifying information’ in birds do? Give examples

Answer 27

Tends to disrupt breeding.
E.g. storms, human or animal disturbance I.e. if a bird lays eggs and a predator eats them that will cause changes in behaviour and physiology, only comes into play when the chicks have hatched and vulnerable to other things in the environment

Question 28

Why is the annual cycle of daylength a reliable source of predictive information?

Answer 28

Entirely predictable as it will always happen- very useful. Other environmental things such as temp vary but day length doesn’t (photoperiod varies with latitude)

Question 29

How did William Rowan (1920s) study photoperiodism in birds? What did the experiment show?

Answer 29

. Exposed dark-eyed juncos to artificial long day lengths in late autumn and winter than they would usually get at that time of year, saw that in these birds the reproductive system grew, let the birds go and see where they migrated some still went the right way that they would go at that time of year
. Induced growth of reproductive system
. Demonstrated that lab studies could be informative

Question 30

Who studied photoperiodism in birds in the 1920s?

Answer 30

William Rowan

Question 31

The last 6 or 7 flashcards in lecture 7 animal ecophysiology are supposed to be on this

Answer 31

Transfer them over!

Question 32

What are the two ideas for how aposematism evolved? What would be true if the second hypothesis was correct?

Answer 32

1) Possible conspicuity evolved first as some signal such as mate attraction, so sexual selection. This increased threat from predators therefore selecting for distastefulness
2) distastefulness evolved first (more likely in insects especially but they are often eating unpalatable food) and then colours evolved after. Plant feeding species toxins making them unpalatable
If the second hypothesis is true then bright colouration evolved specifically as a warning

Question 33

What are the problems with the hypothesis that aposematism evolved through distastefulness first?

Answer 33

If you have a toxic individual that all of a sudden evolves to be red and there is just one individual that evolves this and all the other individuals are bland/ cryptic then it is going to stand out like a sore thumb and easy prey and it will just be taken out/ predated on so the mutation will be lost
So if warning colours evolved after distastefulness them how did it spread…

Question 34

What solution did Fisher propose to the problems with the hypotheses that aposematism evolved through distastefulness first

Answer 34

He noted that brightly coloured insects tend to gather in family groups, so if the mutation arose in a mother then all the babies will have it (e.g. red colouration) as well so you will have a little group and that will give the predator 100 things to chose from and that will give the mutation a chance to survive.
If this was the case then predators could eat a distasteful, brightly coloured prey leaving behind siblings which are also brightly coloured (known as kin selection).
So the mutation could persist and spread

Question 35

What are the problems with Fishers proposed solutions as to how aposematism could have evolved through distastefulness?

Answer 35

. Two assumptions that do not appear to be true
. Fisher assumes that individuals are killed by the predator, so he assumed that if this new mutation evolved then it would automatically be killed- this may not be the case due to armour, hairs etc.
. Predators are often neophobic so could even ignore the mutants, especially if they are low density (so this whole search image with them forming a search image for the more common prey)
. Secondly the suggestion that warning colouration evolved after aggregating behaviours could also be incorrect
. Phylogenetic analysis (so family trees have been constructed for insects) of butterfly lines suggests that warning colours evolved before gregariousness (means friendliness, so they all come together in groups)
. Most likely that warning colouration evolved due to the direct advantage to the individual

Question 36

What is Mullerian mimicry?

Answer 36

Is when two distasteful organisms copy each other. So, when two toxic/ harmful individuals copy each other’s pattern.
So it is the idea that distasteful organisms living in proximity will look similar to facilitate learning avoidance in predators

Question 37

Why is Mullerian mimicry beneficial?

Answer 37

Because it has been shown that it is easier for predators to learn one pattern rather than two, so they will learn more efficiently

Question 38

How did Benson (1972) test the idea of Mullerian mimicry? And what did it show?

Answer 38

Used Heliconius Melpomene and H. erato

Painted the wings of these butterflies so that they were non-mimetic caused increased predation

Question 39

Some Mullerian mimicry work has been done in crossing experiments to investigate the genetic basis of the morphs. What were the results?

Answer 39

The work found that wing patterns were controlled by the same genes in 2 species

Question 40

It remains unknown if the work on Mullerian mimicry that found that wing patterns were controlled by the same genes in 2 species whether this holds true across taxa. However, what is a possibility?

Answer 40

It is possible that the same genes responsible for coloured rings of a butterfly could also be responsible for markings of wasps etc.

Question 41

Moths were taken to a place they didn’t belong/ evolve and moved them to somewhere where they were not mimetic with another species. Would were the outcomes of this?

Answer 41

Showed that both species got predated more. So, if you have two harmful species in an area that look the same they will get predated less but if you transfer one to a place where it is not mimetic with another then they both do worse

Question 42

What is Batesian mimicry?

Answer 42

Is when a palatable species (mimic) mimics a distasteful one (model)

Question 43

What has lab work on Batesian mimicry shown?

Answer 43

That predators that learn that a model is distasteful will avoid the mimic m. (Additionally, the mimic does better the more closely it matches the model)

Question 44

What are the issues with Batesian mimicry?

Answer 44

. It promotes polymorphism (unlike Mullerian mimicry) or promotes genetic variation
. This is because the mimic will do better only if it is rare compared to the model species
. If the number of mimics is high then predators will not be repelled as many of the prey are palatable
. So, the mimic doesn’t get picked off very much when it is in low numbers. So is another example of ESS where rare forms are at an advantage, another thing that can lead to a stable polymorphism

Question 45

Bond and Kamil who carried out the the experiment with the three cryptic moths with one more so than the others also simulated an arms race. How did they do this? What was the issue with this experiment?

Answer 45

. They used a generic algorithm which could modify the pattern and brightness as well as recombine or mutate ‘genes’
. They looked at the moths these blue jays were picking off and then they bred these virtual moths that survived together so they can evolve their morphology through time
. Again Jays were used as the predator
. The virtual moths became harder to spot over time and had increased phenotypic variance
. Only one side of the arms race however- no rapid predator evolution keeping pace with it