Lecture 14 Flashcards
(42 cards)
Drivers of sexual selection:
male-male competition and female choice
why does bright red, orange and yellow plumage signal good health?
carotenoid pigments are vitmain precursors and must be obtained from the diet. Must be good foragers
what does the comb size of a chicken tell you?
comb size is reduced in chickens with nematode parasites and large combs also are associated with more testosterone.
what does it tell you if long ornamental feathers are frayed or shortened?
probably done so by feather parasites or not grow as long f the brd is not in good health.
what does the bobolink do to display its health?
does a costly flight display
How do bowerbirds attract mates?
build complex display structures instead of using their plumage. Shows male quality as they still have to compete for objects
are birds predominantly promiscuous or socially monogamous making pair bonds?
90% are mongamous
how do bonds end?
death or divorce
Frequency of divorce depends on what?
life history! costs and benefits of pair fidelity
what are 3 reasons why a pair might divorce?
- trying to find them after migration 2. Costs of mainting the bond year round, just give up. 3. Assess partners performance and decide whether to change mates
what are 3 hypotheses for divorce?
- Improve reproductive success: incompatibility, better option, cuckoldry (CHEATER) 2. CHOICE OF TERRITORY: not the prtner but his house 3. Salvage strategy: accidental loss after migration. 4. forced divorce.
Blue tits divorced 59% of the time because of what?
to get a better habitat
female black capped chickadee left their partners because?
for a male of higher social rank.
species with higher mortality rates have ——– divorce rates
higher
High variance in territory or mate quality in the populations leads to ——– divorce rates
higher
High quality individuals are —— likely to divorce a bad partner but are —— likely to be divorced.
more/less
———– ——– impact divorce rates a lot because it impacts the chance of finding a replacement
environmental factors
Black tailed Godwit has migration strategy to arrive when?
when their partner does!
Divorce and extra pair copulations allows for what?
Both involve intra-sexual competition for mates and both allow birds to improve their mating status
Only –% of socially monogamous species to date are genetically monogamous
14%
copulations with individuals other than a mate or social partner is ———
common. 75% of birds
why do woodpeckers have no EPC’s in their nests?
the males do most of the incubation and brood pair. She doesnt want to risk the contribution of the male by cheating on him
what are the benefits to EPCs?
- Males increase females 2. Females may gain better genes or gain access to more territory 3. Insurance against infertile sperm from husband
wht are the costs to EPCs?
- Risk of losing care from social mate 2. Risks of parasites and STDs.
