8: Adèlie penguin seminar Flashcards
what may prevent male mallards from mate guarding to prevent their female engaging in EPC?
environmental and social constraints
what does it mean if the male mallards cant mate guard?
- his sperm is in competition with other males
- timing and frequency of copulation will determine who gains paternity
in American Kestrels why cant males always mate guard and what do males do to try to compensate for this?
have to hunt for food for female
- copulate up to 690 times for each clutch
when are copulations only valid?
if sperm transferred
in each what % of copulations fail to result in sperm transfer?
- zebra finches
- chickens
- 36%
- 50%
in Hunter et al study:
a) where was it?
b) how many penguin pairs breed here?
a) Antarctica, 650 miles from south pole at the edge of the ross ice shelf at cape bird
b) 300,000
what is the social/breeding system of adelie penguins?
socially monogamous
a) what do male penguins often do before females arrive?
b) who do the penguins pair up with?
c) which sex defends the nest?
a) set up a nest site and will engage in displays to claim a nest
b) partner from previous year but if not there then the nearest male. BUT if pervious male returns then will switch to pair with him
c) both
a) how many eggs are laid?
b) who takes the first incubation and for how long?
c) after how long do chicks hatch?
a) 2 or 3 if first is lost
b) father for 10-12 days then swap
c) 35 incubation days
a) what is the main predator to chicksand eggs?
b) what is the main predator in the sea for parents searching for krill?
a) Antarctic skua
b) leopard seals
a) how long was the study?
b) how many copulation attempts in the data set?
a) 4 years
b) 10,000
if the female accepts the males courtship display what happens and what does her cloaca do?
mounts and cloacal contact
- contracts her cloaca to draw sperm inside
what are the 3 possible outcomes of the male ejaculate?
- ejaculate enters female cloaca
- ejaculate misses (either sex responsible)
- no ejaculate seen
how did they look for the outcome of ejaculate?
- clocal smears
- stained sperm fluorescent
can you assume successful copulation results in insemination?
no
is sperm inseminated if ejaculate missed or wasn’t seen?
- when was it inseminated?
no
only if ejaculate enters cloaca
what are the 2 sources of sperm competition?
- EPC
- mate switching after one has inseminated to a male to help raise offspring
what % of females:
a) took place in successful EPCs?
b) switched mates?
a) 9.8%
b) 14.9%
what is an indication that the female is control of who mates with her?
wont mate with males that force copulation
- will throw off males or keep tail down
what is the prostitution in the penguins?
females exchange EPC for nest material of stones
what happens to pairs with inadequate stone platforms?
will lose eggs and chicks
in terms of prostitution in how many cases did ejaculate successfully inseminate the female whereby after the female would steal a stone from his nest?
8/10
what are the 2 male benefits of prostitution?
- extra offspring that he doesn’t have to care for
- potential future mate
what are 3 female benefits to prostitution?
- source of stones
- fertility assurance incase the pair male is infertile
- good genes
why is sperm competition a risk for pair males?
may loose paternity
how many in the breeding season:
- copulation attempts
- cloacal contacts
- inseminations
- 57
- 42
- 25
what causes most failed copulations?
- when male dismounts halfway
- if no sperm is deposited
after clocal contact what %:
a) ejaculate enters cloaca
b) ejaculate misses
c) no ejaculate seen
a) 59%
b) 18%
c) 23%
why may a male not be able to produce ejaculate?
if sperm/seminal fluid is limited
what happens if not enough time is given for sperm to replenish?
next copulation will likely fail
how long did it take from a successful ejaculate to:
a) the nest successful copulation
b) an unsuccessful copulation
- what idea does this support?
a) 4hrs 35min
b) 3hrs 59min
semen is limited
how is it predicted that males will respond to sperm competition?
decrease inter-ejaculate time interval and increase insemination
what happens to inter-ejaculate time in the pre-laying period of males with limited semen supply?
increase
what is limited in the species?
sperm/seminal fluid
overall what happened to the ejaculate interval time in the pre-laying period?
increased
what 2 things can males do if sperm is limiting?
- carry on copulating
2. conserve sperm and allocate ejaculates strategically
in some species males will have sperm depletion if they produce frequent ejaculates- give 2 examples
- zebra finch: results in fewer and less motile sperm
- house sparrow: sperm reserves decline in the day and replenish at night
when a fake female was used did the study find that males produced more sperm after a long ejaculate?
no
what did Jeff Parker suggest?
males strategically allocate ejaculates to females that bring them the greatest returns in terms of paternity
what are some other species that strategically allocate sperm?
- mealworm beetles
- mediterranean fruit flies
- some fish
compared to paired copulations what were successful EPCs less likely to result in?
failed ejaculation
when is ejaculate almost always produced by males?
when with an EP female
prior to cloacal contact what % of copulation attempts failed ?
25%
in females and in males what caused copulation failure?
males- falling or dismounting
females- throwing off males or keeping tail down
what mountings did males terminate fewer of?
those with extra pair females rather than pair
by what 2 mechanisms could strategic allocation be achieved by?
- male attempts EPC only when they have sperm available
2. males withhold ejaculate from partners to conseve sperm
if males withhold sperm what is predicted?
they will engage in EPC attempts and ejaculate less often
in terms of clocal contact and ejaculation what did males engaging in EPC attempts have?
fewer
what do males withhold sperm for?
EPC
what happens if males ejaculate during EPC?
fewer ejaculates available for pair females
if males withhold sperm is there a difference between males that did or didn’t ejaculate during EPCs?
- is there a difference if clocal contact results in ejaculation
no
no
what may be the risk of withholding sperm?
may lose paternity of offspring
when must a male mate with an EP male if he wishes to?
at the same period as his pair female as all females are fertile at the same time
what is paternity determined by?
frequent copulations
in females with EP partners which males did better and why?
pair males gained more successful inseminations
after collecting blood samples and carrying out a paternity analysis:
- what % extra pair broods were fathered by EP males?
- what % extra pair chicks fathered by EP males?
- 2.2%
- 3%
do pair males father the chicks they raise and why?
- mostly yes
- initial males can outcompete EP males by copulating frequently
out of the 300,000 pairs how many males achieve EP offspring?
2,400
why allocate sperm to EP females if unlikely successful in fathering offspring?
potential benefits fathering EP offspring high even if unlikely
a) what is limited in the penguins
b) what is withled/allocated?
c) what do paired males gain?
a) semen supplies
b) withold ejaculates from partners and strategically allocate them to EP females
c) most copulations and father the offspring they raise
