Lecture 15 Flashcards
Define female choice
Any female trait (behaviour/morphology) that bases the mating success of males toward the preferred type (creates a mating bias)
Mechanisms of choice (4)
Visual stimulation
Tactile stimulation
Acoustical stimulation
Olfactory stimulation
What was the conclusion to the long-tailed widow bird study where the tails were manipulated and nesting was observed to measure female preference?
Quickly describe the results
Females had a preference for longer tails when compared to normal, sham surgery and reduced tails
After treatment, R/N/S birds had few newer nests while L birds had many new nests
What was the conclusion to the peacock study where the eyespots were manipulated and copulations was observed to measure female preference?
Quickly describe the results
Females had less preference for fewer/non-iridescent eyespots
Peacocks w fewer eyespots had fewer copulations than those w many/unaltered eyespots
Hypotheses of female choice (2)
Direct benefits: benefits onto female (produce more offspring due to achievement of resource from male)
Indirect benefits: benefits onto females’ offspring (offspring become of a higher quality/more fit)
What is the relationship between direct benefits and male elaboration?
Males evolve these traits as an indicator of parental investment/ability to donate resources
Also indicate that males are healthy
(think: hangingfly/katydid and donation of large prey/nutritious blob)
Other direct benefits (4)
Territory quality
Parental care
Defense
Lack of parasites (STIs)
What is the relationship between indirect benefits and male elaboration?
Males evolve these traits as an indicator of higher gene quality that should lead to offspring of better fitness
Also indicate that males are healthy
(think: male peacocks w a large display size produced higher fitness offspring)
Male choice arises under what situation?
When males provide the limited reproductive success, females must compete for access to it
Increased male PI -> male choice -> female-female competition
What was the conclusion to the pipefish study where the males had limited reproductive success and copulation was observed to measure male preference?
Quickly describe the results
Males were indeed practising male preference
Males copulated more often w females who were longer/had longer back folds
How does changing environmental resource abundance influence sex roles in Katydids?
Abundant resources: females disregard nutritious male blob (as it is everywhere), male competition increases (female choice)
Scarce resources: females compete for now scarce male blob, female competition increases (male choice)
What is human sexual selection based off of?
Diversity at the MHC loci
What is MHC? Why is diversity there good? (2)
MHC/HLA loci encodes for the antigen recognition system of the immune response
Lots of diversity is good bc: avoid inbreeding, increase genetic variation in immune response of offspring
What was the conclusion to the MHC preference study where females smelt shirts and attraction was recorded to measure female preference?
Quickly describe the results
Females (not influenced by pregnancy hormones) found males of dissimilar MHCs more attractive while pregnant females found males of similar MHCs more trustworthy
