12. Alternative reproductive strategies

Question 1

describe the reproductive strategies of the natterjack toad

Answer 1

• males call to attract females to mating pools
• females follow the sound gradient towards the pool
• large males make the louder calls and mate first
• non calling males act as satellites and intercept the arriving females

Question 2

in natterjack toads, what age are the satellite males

Answer 2

they are younger, when they age they become the callers

Question 3

where do coho salmon mature, where do they then go

Answer 3

at sea

they then go to freshwater to spawn and then die

Question 4

what are the two types of male salmon, describe

Answer 4

hook noses-fight for access to spawning females

jacks- don’t fight- sneaky spawner

Question 5

how do we know about reproductive success

Answer 5

fish tagging tells us of their survival, dan analysis tells us of reproductive success

Question 6

what does frequency dependent selection mean in terms of breeding

Answer 6

each male does best when it is rare in the population

Question 7

in waders there are three different coloured ruffs, which one is the satellite and which are the aggressive

Answer 7

white= satellite

black & brown= aggressive

Question 8

when do white ruffs get to mate

Answer 8

when there are too many females for the brown and black ruffs to monopolise

Question 9

what happens for soay sheep on st.kilda

Answer 9

two types of males:

• horned
• scurred

the scurred always back down to the horned males who get exclusive access to females
-scurred mate by chasing around females just as they come into oestrus