14-dunnock + alpine accentor Flashcards
what can studying a single species give?
valuable insights into evo of mating systems, especially if variation in this system
what is the ecological basis for mating system variation based on?
distribution of resources, determining F ranges which in turn determines
describe the dunnock mating system basis + territory (4)
- F have discrete territories + defend them against other F
- Alpha/dominant + beta males never related
- polyandrous F have larger territory size with larger range
- mating system depends on F territory size
what differs for the males if females have small vs large ranges?
small: M can defend + monopolise single F
large: M cant defend territory so beta M will set up territory
what did Davies + Lundberg 1984 find for territory size and food availability?
F territory size dependent on resource distribution/ food availability
- when F more fed occupied smaller range
give 5 points about alpine accentors
- all polygynandrous
- usually 3 F + 3 M in territory
- overlapping ranges
- large ranges needed to exploit spatially + temporally patchy prey distribution
- large range so M cant defend single F so 2-4 M share undefended range
which of the species has a larger range?
alpine accentors
why are alpine accentors only polygynandrous?
large ranges of alpine are undefendable by M
what is the result of the difference in altitude for the 2 bird species and which has the higher altitude?
alpine: higher altitude> variable conditions with more insects in summer
dunnocks: lower altitude> food more predictable + abundant
what kind of range do alpines have and where?
large- over N + S sides of mountains
where do alpine accentors live?
where do dunnocks live?
french alps
cambridge
what does variation within and between species depend on?
distribution of resources
give 5 points about accentor breeding biology
- F build nest
- lays 3-5 eggs
- F incubates
- both sexes feed chicks
- pair often have 2 broods per year
according to Hartley et al 2013 what can determine offspring behaviour?
mode of parental investment/ hatching asymmetry
in the dunnocks what did davies + hatchwell 1983 discover (3)?
- M detected when F fertile
- when F delayed start of incubation 1 day after clutch completion, M guarded less intensely
- when model egg put in nest it was used as a cue to value copulation
give 4 points about monogamy in dunnocks
- M guard F
- F solicits, M pecks cloaca, until F ejects sperm from earlier matings
- copulate 1-2 times hour
- M monopolises matings
in dunnocks what % paternity do monogamous M gain?
100%
is chick feeding equal between M and F in the dunnock?
yes
give 3 points about polygyny in dunnocks
- polygynous M guard + copulate with 2 F
- M either invest in brood of 1 F but not the other or divide investment between the 2 if fertile at the same time
- M gain 100% paternity
give 7 points about polyandry in dunnocks
- M compete to copulate
- alpha M get the most
- F may sneak off with beta M
- paternity may be shared
- M parental care varies
- alpha M always cares
- beta M sometimes do nothing but sometimes care
in polyandry what often happens to paternity?
shared between alpha or beta males
how big are the territories for F and M for dunnocks and alpine accentors?
dunnocks: F= 0.2-1ha, M= 0.2-2ha
alpine accentors: F= 6-30ha, M= 9-38ha
what is the association between paternity + chick feeding for beta M in trios?
beta male decision to feed or not was dependent on if they had paternity
how do M know they have paternity?
- could be based on mating success
- could monitor own mating success relative to alpha male
what does care invested by dunnock beta males correlate with?
- but what else may it be?
the proportion if matings obtained
- could be variation in quality of beta males is due to more matings as a result of higher quality male
what is parental care by dunnock beta males affected by?
- do alpine accentors also show this?
mating success
yes
what is the alpine accentors breeding biology?
- M compete to mate with F
- variable mating success reflected in paternity
- variable male parental care explained by paternity
in F dunnocks what % of F desert eggs?
a) monogamy
b) polyandry
c) polygyny
a) 20%
b) 8%
c) 39%
what is the competition like between F dunnocks?
often poly F would fight to the death to interrupt breeding attempt of another F and encourage beta M to mate with them
what should F do to maximise parental investment?
copulate with both M in her group
aiming for a 50:50 share of matings between alpha and beta M
what do F alpine accentors do to convince M they have some paternity?
copulate up to 1,000 times per clutch
what do alpine accentors have?
huge testes and large cloacal protuberance
how do F alpine accentors solicit copulations?
bright red cloaca to display M to attract them + sing to attract M when fertile
in the dunnocks what % chick starvation was there with each level of male help?
a) none
b) 1 part time
c) 1 full time
d) 2 full time
a) 81%
b) 74%
c) 27%
d) 6%
what did hatchwell + davies 1990 discover for reproductive success of dunnocks (7)?
- 1 full time: mono
- 2 full time: polyandry
- M + F provision at similar rates in pairs
- in trios F + alpha M fed chicks at similar rates, higher than beta M
- F gained max help if 2 M shared provisioning equally
- if alpha M removed beta male increased provisioning
- paternal care critical for F reproductive success
in alpine accentors what did more feeds/parental care by M result in?
a positive effect on conditions of nestlings so have higher mean weight + more likely survive after fledging
what were davies et al 1995 findings for alpine accentor? (3)?
- secual conflict similar ro dunnocks where F gain through increased M help with shared paternity with multiple M
- alpha M do best by monopolising all matings
- diff in dunnock + accentor mating systems is related to ecology where dunnocks varibale mating system reflects derivation from mountain living ancestor
under what conditions are F worse off?
polygyny
what does monogamy provide?
intermediate success
why do M do better in polygyny?
even though F have lower success they produce more young together than mono
why does F prefer polyandry?
more young produced but M worse off as have to share paternity with other M
In F dunnocks where is the highest reproductive success?
polyandry as mroe young raised (6.7 young vs 3.8 for polygyny) BUT M have to share paternity
In M dunnocks where is the highest reproductive success?
polygynous as more young raised (7.6 young)
when do M and F dunnocks have the same reproductive success?
if monogamous
what ‘sets the scene’?
ecological factors
