Reproductive Behaviours And Mating Systems Flashcards
(19 cards)
What are the different types of mating systems?
- monogamy
- polygamy (polygyny and polyandry)
Monogamy
The mating of a pair of animals to the exclusion of all others
Polygamy
When individuals of one sex have more than one mate. This tends to be one male mating with many females but not always. The term ‘promiscuity’ may also be used for this type of mating system.
What is the difference between polygyny and polyandry?
- polygyny is when one male mates exclusively with a group of females
- polyandry is when one female mates with a number of males in the breeding season
Why are female courtship displays much less common than male displays in nature?
Investing energy in both exaggerated traits and gamete production would be challenging
Species specific sign stimuli examples
- sounds
- displays
- releasing certain chemicals
Purpose of species-specific stimuli
These indicate to the other member of sex that they are fertile, and thus chances of successful reproduction are maximised.
Why is it important that these signals are species-specific?
It avoids unnecessary attention from members of a different species. It makes no evolutionary sense to copulate with members of another species.
Fixed action pattern
An innate sequence or series of actions that occur as an organism’s response to a specific stimulus called a sign stimulus.
Sign stimulus
Any outside environmental interaction that elicits some response from an organism.
Reversed sexual dimorphism
In some species, the female is larger or more conspicuous than the male. Some males have to travel long distances to find a female, so a smaller size may be advantageous in terms of speed and stealth.
Common examples of sexual dimorphism
- insects
- spiders
- fish
- reptiles
- birds of prey
- spotted hyenas
- blue whales
Female choice
Involved females assessing honest signals of the fitness of males.
Lekking behaviour
In lekking species, males gather to display at a lek, where female choice occurs. Dominant males occupy the centre of the lek, with subordinates and juveniles at the fringes as ‘satellite’ males. During the display, female choice occurs.
What are the three hypotheses for why species form less?
- The preference model
- The hotshot model
- The hotspot model
The preference model
They are more advantageous for males and/or females than mating at isolated sites, in ways such as decreasing the costs associated with searching for a mate or giving honest signals as to the strength and fitness of the males on lek.
The hotshot model
Due to inherent variation in mating success, less successful males tend to cluster around successful males in order to intercept some of the females that are attracted to the “hotshots”.
The hotspot model
Suggests that female movement patterns and behaviours are the cause of lek formation and males lek in areas of highest female density.
How might males without such dominance gain access to females?
They may use sneaking behaviours. This allows less threatening mates to stealthily access a female partner without having an altercation with a bigger, more fearsome male.
