week 2 - ovulation mode modifies paternity monopolisation in mammals - SOULSBURY 2010

Question 1

author

Answer 1

soulsbury 2010

Question 2

what are the 2 forms of ovulation?

Answer 2

spontaneous and induced

Question 3

why may males have greater paternity monopolisation in induced ovulators?

Answer 3

because copulation triggers ovulation, and therefore the first male to mate an induced ovulator will stimulate ovulation and is likely to be the father. in spontaneous ovulators males have to predict ovulation.

Question 4

What did soulsbury 2010 do?

Answer 4

using cross species comparison examined the percentage of offspring sired within a litter (single paternity) and in social species the percetnage of offspring sired by the dominant male (alpha paternity)

Question 5

what did soulsbury 2010 results show?

Answer 5

ovulation mode alters the ability of males to monopolise paternity, with males of induced ovulators having higher single paternity and greater alpha paternity where male-female association is intermittent.

Question 6

How did Conaway 971 define induced and spontaneous ovulators?

Answer 6

spontaneous ovulation - where a females ova are released without the need for copulation
induced ovulation - where female ovulation is stimulation by copulation

Question 7

what and who suggested that selective pressures may have differed for various species?

Answer 7

bakker and baum 2000
induced ovulation has been demonstrated in several mammalian taxa but not all species within these taxa are induced ovulators

Question 8

for induced ovulators, copulation triggers ovulation and therefore it is thought that the ____ male to copulate with a female will fertilise most of her ova (lacey et al 1997)

Answer 8

first

Question 9

for spontaneous ovulators the male who copulates with the female _____ to the time of ovulation will sire most of her ova

Answer 9

closest

Question 10

Males of induced ovulators who copulate may be expected to sire a greater proportion of a litter than spontaneous ovulators because??

Answer 10

spontaneous ovulators cannot accurately predict the exact timing of ovulation and it is more likely that his ejaculate will undergo competition to fertilise her ova

Question 11

the ability of male mammals to monopolise paternity has been linked to several factors including?? (4)

Answer 11

oestrous synchrony
family structure
male-female associations
ovulation mode (soulsbury 2010)

Question 12

Detailed account of what soulsbury 2010 did

Answer 12

examined the effect of ovulation mode on two measures of paternity: the percentage of the litter sired by a single male (single paternity) and the percentage of offspring sired by a dominant male (alpha paternity) in group living species

HOW:
using genetic data from published sources they carried out a phylogenetically corrected cross species comparison to see whether ovulation mode alters the degree of single and alpha paternity

Question 13

what did Soulsbury 2010 find? (2)

Answer 13

single paternity was significantly greater in induced ovulators
induced ovulators sired a greater percentage of offspring in a litter

Question 14

what do the results of soulsbury 2010 show? (3)

Answer 14

there was a significant difference in the ability of males of induced and spontaneous ovulators to monopolise paternity
males of induced ovulators sired a greater percentage of the litter than males of sponataneous ovulators
ovulation mode is therefore an important variable modifying individual paternity across mammals

Question 15

why would single paternity be predicted to be higher in induced ovulators?

Answer 15

because the predictability of timing of the ova release for the first copulating male means that he would be expected to sire the majority of the litter

Question 16

why would tactics such as mate-guarding appear to be important for paternity monopolisation in spontaneous ovulators but less so in induced ovulators?

Answer 16

this may be because following copulation the males of induced ovulators may be more certain of paternity than spontaneous ovulators

Question 17

Exact reason as to why females have evolved different modes of ovulation is unknown but what are 2 suggestions?

Answer 17

induced ovulation allows optimal gamete synchronisation and assurance of fertilisation, something that is important for solitary species (conaway 1971) however, induced ovulation occurs frequently in group living species suggesting this is unlikey to have driven its evolution.

induced ovulation decreases male intrasexual competition and high levels of male competition may hinder female mate choice. induced ovulation may have evolved as one way of decreasing male intrasexual competition while at the same time acting as a post copulatory mechanism based on the level of stimulation (lariviere and ferguson 2003)