L16 - Mating Systems 2 Flashcards
(12 cards)
what are 4 different types of polygyny
resource defence, female defence, lek polygyny, scramble competition and explosive breedingw
in what conditions does resource defence occur
in a heterogenous environment, polygyny threshold models, is it of benefit o be polygynous in a better territory or monogamous in a worse territory, better territory will have a greater number of matings for the male
what are harems and what are the two types
where males have control over which females they will mate, can be permanent (primates) or seasonal (elephant seals), can also have a multimale harem
what are other explanations (outside of kin selection) for male lekking
hotshot hypothesis - males mollow hotshot for higher chance of copulation
hotspot hypothesis - males will aggregate aroundhigher fruit biomass
what are the characteristics of scramble competition in polygynous mating systems
resources and females both dispersed, competitive mate seaching so there’s little sexual dimorphism and no combat, tactic will depend on male density
give an example of scramble competition in dung flies
once a pat forms, resource is accessible to all competitior and quantity declines with higher population density, need to maximise mating opportunity and ensure paternity, distribution should conform to IDF if all females of equal value, optimal time should conform to marginal value theorem
what is explosive breeding and how can it change morphology
when there is a lot of mating in one place, eg in frogs males with proportionally larger nuptial pads will have a higher chance of pairing as they wont get supplanted
in what conditions is polyandry possible and what are the 2 types
when males give paternal care in sex-role reversed species, females compete for males and form social bodns with monogamous males during season simultaneous polyandry and sequential polyandry
explain simultaneous polyandry and give an example
eg in shore birds like watted jacana, where female territory is superimposed upon 1-4 male territories and females fight for the male territories, rich food supply is needed so only one parent needs to be present (+precorcial), the driver is high predation so more offspring needed, males take care of nests although paternity mixed (my eggs are in another or my nest)
explain sequential polyandry and give an example
spotted sandpiper, female defends a mae and lays a clutch of eggs for him to incubate and then goes off to slag off, driver is productive deeding ground so female reproduction only limited by egg incubation time, if freed from parental care rate of laying eggs increases
why does polygynandry occur
when reproductive interests of males and females dont coincide (females might do better in polyandry, males opposite)
give an example of polygynandry
dunnocks, where mating system depends on food availability, territory area needed and how territories of males and females overlay each other
