13-conflict over mating systems Flashcards
what are M and F limited by in the mating system?
M: access to F
F: access to resources
what is the mating system evolution?
resources> F dispersion > M dispersion
if parental care is introduced then what are M to F and so what is their dispersion dependent on?
critical
dependent on access to M
what does the link between M and F dispersal determine?
operational sex ratio and therefore the mating system
what does sex role reversal depend on and in turn what does that depend on?
potential reproductive rate
which depends on relarive provision of parental care
in seahorses usually M reproductive rate higher but when is F reproductive care higher?
- what is sex role closely linked to?
- if lots of M care
- linked to potential reproductive rate
what does the intensity of conflict over care vary within and between?
mating systems
what are the 3 main mating systems?
monogamy, polygyny, polyandry
according to who what % of all bird species have biparental care?
cockburn 2006
81%
what is obligate monogamy?(4)
- both parents essential for successful reproduction
- parents forage long way from nest
- parents have specialised caring roles
- M provision incubating F with food foraged for
what is the hornbill example of obligate monogamy? (5)
- F stays inside nest
- moult of feathers which need to be regrown
- F entirely dependent on M
- F and chicks depend on M for all food up to 137 days
- F will eat young if M don’t provide enough provision
describe Birkhead + Moller 1996 findings for obligate monogamy (3)
- interests of parents aligned so conflict between parents reduced
- expect less conflict between M and F when obligate monogamy as dependent on each other
- extra pair paternity rate lower when male care essential
what is facultative monogamy?
- failed polygamists
- male care no essential but usually increases productivity so monogamy is facultative
- due to limited opportunity for polygamy as M + F competition
- usually M deserts as greater opportunity to desert (internal fertilisation) + more to gain (higher reproductive rate)
what occurs in desertion has no effect on reproductive success?
- what if it reduces the success to 1/x
desert
- desert if you can get more than x partners
in male removal experiments what was the % effect on reproductive success for each of these species?
a) song sparrow
b) seaside sparrow
c) dark eyed junco
d) ptarmigan
a) 51%
b) 66%
c) 38%
d) 100%
which sex may do better by desertion?
either
why is monogamy considered failed polygamy?
M should prefer to be polygynous
F should prefer to be polygynandrous
What is Mollers example of failed polygyny for 122 european passerines? (3)
- 39% M european passerines polygynous
- 20% of these have >5% polygyny
- M looking for opportunities to become polygynous
what is Korpimaki’s example using owls for desertion? (3)
- F desert rather than M
- may desert 1st brood and pair with another male
- if F successful will fledge 79% more young
what is mainly polygynous?
+ give an example
most mammals
- montezuma oropendola: 1 M may have up to 20 F in colony
when is there no cost to F in a polygynous system?
- no M care provided
- F settle in relation to resources and other F determining fitness
under what 2 scenarios will F accept the cost of polygyny?
- F have no choice
- benefits outweigh costs
explain using marsh wrens as an example when females have no choice
- F biased pop
- 1M:5F biased sex ratio
- better to breed with polygynous M than to not breed at all
explain using pied flycatchers as an example when females have no choice
- F deceived by m
- attract F to nestbox then fly away to set up a nest with another F
- F believed M was monogamous
- 10-15% M polyterritorial
- reproductive success of 1st F unaffected but it is 40% lower for 2nd F
what is the polygyny threshold model? (6)
- F either joins mono M or breed polygynously with paired M
- expect F to choose monogamy
- choice depends on quality of breeding opportunity
- reproductive success higher if monogamous
- choose polygyny if difference in quality exceed polygyny threshold
- paired M may be better than unpaired or may defend better resources
what may the cost of polygyny be outweighed by?
benefit of access to good resources/benefit of conferring M good genes on offspring
give 2 sources of evidence for polygynous threshold model
- good genes: little evidence
- better resources: limited evidence
describe the great reed warbler example for evidence for polygynous threshold model and how good is the evidence?
- F visits lots of M territories
- radio tagged F visit 3-11 M
- no sig diff in no. of recruits + survival with F breeding mono or poly
- limited evidence
- poly F may not suffer cost relative to mono F
what is polyandry? + what are the 2 types?
F prefer this as benefit from gaining access to paternal care of multiple mates but M have to share access to F with other males
- cooperative polyandry
- sequential polyandry
what is cooperative polyandry?
increased productivity from more parental care outweighs costs of shared paternity, often in harsh conditions or when chance of M reproducing is low
give an example for cooperative polyandry
galapagos hawk
- 1F: 1-8M
- raising single chicks needs >1 male as poor habitat
- copulation, paternity, parental care shared amicably among M
- M team up with little conflict
what is sequential polyandry?
F lay series of clutches for multiple M and M provide care
give an example of sequential polyandry (7)
spotted sandpiper
- F compete for territories
- M settle + care for clutches
- abandon M to find another
- M biased sex ratio
- F increase reproductive success by attracting more M
- abundant food + advanced chick allow uniparental care
- caring for clutch is M best option
list 3 things that determine the intensity of conflict
- life history constraints
- ecologica differences
- social conflicts
give 3 points about life history constraints
- whether both parents can provide care or not + how much care offspring need
- mammals: F can provide all care
- birds: M and F care but depends on if offspring are independent or not and if not would need shared pairing
what do ecological differences depend on?
- what is the mating system if breeding far away from food vs close to food
distribution + abundance of resources which influences mate dispersion + potential for polygamy
- far away: obligate monogamy
- close: polyandry/polygyny
explain what is meant by social conflict
individuals try to maximise reproductive success at partners expense often through coercion or deception
how do M and F interests differ between obligate monogamy and other monogamy, polygyny, polyandry?
closely aligned
there is sexual conflict
what does the intensity of conflict depend on and what is it reflected in?
many factors + is reflected in interspecific diversity of mating systems + varies across + within mating systems
what is the difference between M and F preference?
- M prefer polygyny to access multiple F to increase reproductive success
- F reproductive success increases by gaining access to parental care of multiple M in polyandrous system
according to cockburn 2006 what is more common than previously thought?
F only care + coop breeding
according to Emlen et al 1977 in what groups is SS more intense + why?
polygamous rather than mono as more multiple mate monopolisation
according to Emlen et al 1977 what affects the degree to which SS can operate?
ecological constraints
according to Emlen et al 1977 under what conditions is polygamy more common?
- when 1 sex predisposed to have most parental care
- when parental care requirements minimum
- when lots of food so one parent can provide full care
according to Emlen et al 1977 how do mating systems differ according to food availability?
lots of food: monogamy + resources shared evenly
less food: more mates needed
according to Emlen et al 1977 when is it difficult for M to monopolise all F?
if all F fertile at same time
according to Emlen et al 1977 what tends to occur if the environment leads to clumping of F?
polygyny
according to Emlen et al 1977 what allows M to monopolise F?
if M monopolise resources that F need
according to Emlen et al 1977 when does polygyny benefit F?
if genetic access to high quality M outweighs cost of reduced parental care
according to Emlen et al 1977 what is the relationship between F and M hummingbirds?
F incubate and rear young alone + M provide F with nectar + get rid of other M
according to Emlen et al 1977 what is a lek?
an organised aggregation with dominance hierarchy to attract and court F
according to Emlen et al 1977 what strategy can double reproductive potential?
F may lay 2 clutches : one that she incubates and one that the males incubate
according to Emlen et al 1977 how is the member of the limited sex expected to maximise inclusive fitness?
by controlling access to mates of limiting sex
according to Emlen et al 1977 when is SS more intense?
if more potential to monopolise resources or mates
according to Emlen et al 1977 what does the form of the mating system depend on?
which sex is limiting and how they control resources or mates
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MATING SYSTEMS
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