INTRASPECIFIC RELATIONSHIP (part 2)

BREEDING BEHAVIOUR

behaviours associated with breeding (courtship) are adaptations to ensure reproductive success

breeding pairs often establish territories to ensure reliable access to resources during breeding

ritualised courtship behaviours reduce conflict between sexes so that mating can be achieved without injury

courtship behaviour

behaviour of animals occurs just before, during and after mating

a potential mate can be attracted by a call, or by offering a gift of food

females often choose their mates as females have more invested in offspring, so mate choice is important

intersexual selection occurs when members of the same sex choose mates of the other sex to mate with

reproductive effort

the amount of energy used for reproduction, including production and care of young

generally, the amount of energy remained after production will be allocated to parental care

at one extreme, all of the reproductive effort is put on production and hence no parental care

low percentage of offspring survive

broadcast spawners release millions of gametes into the water and very few planktonic larvae will survive

at another extreme, most of the reproductive effort is put on parental care of a small number of offsprings

high percentage of offspring will survive

mammals have high level of parental investment in offsprings before and after birth

bird parents incubate their eggs in a nest and then feed the chicks until they are independent

amphibians, fishes and reptiles also provide care until the offsprings are capable of fending themselves

MATING SYSTEM AND PARENTAL CARE

polygynandry

polygyny

monogamy

polyandry

the breeding pair forms a partnership

shared care improves survival of youngs, especially when the environment becomes harsh

both parents look after the young

multiple mating takes place between group member

all group members contribute to the care of young

increase genetic diversity

decrease male competition for mates

females mate with more than one male

females gain nutritional benefit when males provide prenuptial gifts

males may care for their own offspring and females leave the males

males control access to more than one female

the best and strongest male is selected

provide the offspring the best gene

males often show parental care after mating and leave it to the female

TERRITORIES

TERRITORIAL BEHAVIOUR

Territories are small areas where are defended by aggressive behaviour

The behaviour that an organism will defend aggressively for its nesting site

Advantages

reduce direct competition between large number of individuals

provide access to rich food source

provide a safe and secure place to rear youngs

increase the offspring chance of survival from predators

provide a safe place to court

enhance reproductive success

costly in terms of time and energy exerted

where the organisms need for successful breeding

dividing resources between groups or individuals

rich resources for exclusive access

strong individuals more likely to own big territories

better protection

more likely to attract mates and breed

pass on strong genes to the offsprings

more likely to get access rich food source

Yellowhead territories

occupied by cooperating individuals which helps to support breeding pair

each breeding group contains primary pair that breed, and secondary birds acting as nesting helpers but not breeding (e.g. provide additional food for the clutch)

HOME RANGES

the area where animals roam but is not defended
may overlap with other home ranges

home ranges in baboons

each home range has its own population

spend nearly all day travelling in search of food, but still returns to safe core area before dusk to sleep

most activities concentrate in core area where contain best food source, water holes and trees for sleeping

home ranges in Karearea

reproductive success is higher in commercial pine forests with a mixed of different aged status than in native forests

prey availability is enhanced in pine plantation

home ranges are larger when resources are scare

the home range size in the pine forest is much smaller than that in native forest