mating systems and parental care Flashcards
lecture 4
mating systems…
aren’t synonymous with social systems
aren’t always easy to classify
represent resolution of basic conflict of interests between sexes
evolution of mating systems
monogamy, polygyny, polyandry, polygynandry
what is monogamy
one female/one male
with/without pair bonding
what is polygyny
several females per male
simultaneous/sequential
what is polyandry
several males per female
simultaneous/sequential
what is polygynandry
females and males each have several mates
monogamy - what about the Bateman principle
male RS increases with number of mates -> males are interested in mating with many females
female RS doesn’t increase with number of mates -> females are interested in mating with high quality males
mate guarding hypothesis
female finds it easy to acquire other male partners
for the male, access to receptive females may be more difficult
its in the best interest of the male to remain with his first partner (guarding)
parental care under monogamy
both parents care for the young
occurs when 2 parents better provide care than 1 parent
european staring - Wright _ Cuthill
raising young - collaborative effort by male and female
1. male weighted, 2. female weighted, 3. control
conclusion - monogamous parents may compensate each other, compensation is partial
how faithful are monogamous pairs
many socially monogamous animals aren’t truly monogamous
extra pair copulations (EPC) and extra pair fertilisations (EPF) are common
detection of EPF by DNA fingerprinting
female range size - mammalian mating size
females mainly solitary (>60%)
range size is small - male territories can overlap several female territories -> polygyny
range size is large - males can’t defend more than a single females territory -> monogamy
female sociality - mammalian mating systems
females gregarious - group size determines mating system
Neff - bluegill sunfish
fathers were less likely to provide care if they had seen other males in the vicinity around fertilisation
males used olfactory cues to determine whether they should care or not
causal chain determining mating systems
ecology -> female distribution -> male distribution
role of parental care - birds
many species have helpless young - heavy male investment required, pair bonding, tending to monogamy
ecology -> female distribution <-> male distribution
role of parental care - mammals
heavy investment by females
pair boding
monogamy is more rare
sexual conflict - dunnock mating systems
dunnock is a small dull looking passerine, feed their altricial chicks with insects
dunnock mating systems - females
do best out of polyandry
less well out of monogamy
least well out of polygyny
dunnock mating systems - males
do best out of polygyny
less well out of monogamy
least well out of polyandry
dunnock mating system - ecological influence
dunnock has highly variable mating system
monogamy, polygyny, polyandry and polygynandry may all occur in the same population
difference in RS -> sexual conflict over mating
observed mating system is a compromise between interests of males and females
polygyny
some males mate with several females, whereas other males remain unmated
females mate with single male
females provide most or al care in polygynous animals
male size > female size
occurs in many mammals and some birds
types - female defence, resource defence, lek
female defence polygyny
females aggregate in favourable sites, where males can monopolise >1 female
resource defence polygyny
males settle on breeding territories
females choose a mate
some males are chosen by several females
secondary female pays a cost, since the male helps only the primary female to raise the young
