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70 Cards in this Set
- Front
- Back
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The Stages to reaching reproductive success |
Survive to maturity. Attract a mate. Produce as many offspring as possible. Eggs survive to hatching. Nestlings survive to fledging. Fledglings survive post-fledging. Offspring reach maturity |
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Male strategy to increasing reproductive success ? |
produce as many offspring as possible by mating with multiple females ensure offspring survival by contributing parental care or resources to maximize his fitness. |
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Female strategy to increasing reproductive success ? |
Are constrained by the number of eggs they can produce Depends on fecundity and the survival of their offspring which depends on resource availability and parental care. |
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socially monogamous, promiscuous, polygynous or polyandrous? |
Majority are socially monogamous |
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Avian Monogamy And what is involved with reproductive success of males and females? |
Male and female pair bond To raise young Duration: One breeding season - entire life Reproductive success of males and females is similar * Many socially monogamous but sexually promiscuous, EPC (Extra Pair Copulations) (Male commonly helps raise chicks that aren't theirs) - DNA fingerprinting techniques |
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When does Avian Monogamy occur? |
when male parental care is essential territory qualities or resource availability is not highly variable. (males unable to monopolize resources) |
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Avian Polygyny And what is involved with reproductive success of males and females? |
One male and 2+ female mates in a breeding season Male reproductive success = territory quality= resource defense polygyny Female reproductive success = polygyny threshold model |
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Polygyny Threshold Model |
Females may gain a higher level of biological fitness by mating with a male who already has a mate. The female makes this choice despite other surrounding males because the choice male's territory, food supply, or other important characteristics are better than those of his competitors, even with two females on the territory. |
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When does Avian Polygyny Occur? |
marsh or grassland habitats
'patchy' habitats with much variation in productivity/quality Some parts with abundant resources |
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Why did the evolution of a variety of breeding systems occur with Acrocephaline Warblers? |
Due to environmental changes highly productive habitats = polygyny and promiscuity of males Poor habitats = monogamy and helpers. Mating systems can be easily altered |
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Lekking ("Male dominance Polygyny") |
Males compete for dominance & mates in communal displays (leks) Females chose (status, age & quality of display) and mate and raise young alone Male reproductive success highly variable |
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What other purposes can Leks have? |
form for protection from predation |
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3 primary models for the evolution of leks: Hot Spot Model |
males gather at sites where there are most likely to encounter roaming females |
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3 primary models for the evolution of leks: Hot shot model |
males gather around experienced, attractive, dominant males to increase their chance of being noticed |
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3 primary models for the evolution of leks: Female preference model |
females prefer to visit large clusters of males over small clusters or solitary males |
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Greater Prairie Chicken |
video |
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Lek mating Arena (Sage Grouse) |
Alpha, beta and lesser males in arena Higher dominance = larger "person space bubble" and closer to middle 25-30 individuals 2-3 birds get most of the copulations, others some or none |
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Why do lesser males stick around dominant males in a lek? |
Probably younger Waiting and hoping to get to middle of lek eventually |
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Manakins |
video |
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Cooperative Courtship (Blue manakins) |
several line up on a branch and perform the cartwheel display (all must cooperate to attract female) Then the dominant male does a precopulatory display and mounts the female |
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Why would the other blue manakins join in with cartwheel display? |
subordinate males occasionally get the opportunity for copulation when dominant male is absent they establish themselves in social queue (possibly one day becoming dominant male) |
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Calfbirds |
video |
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When do Leks form? |
When males have access to easily reached abundant/exclusivefood sources |
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Lekking Hummingbirds |
Hummingbirds are polygynous Form leks when there are abundant resources Do nonterritorial foraging in areas of rich and predictablefood sources |
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Alternatives to Lekking for Hummingbirds |
Males defend feeding territories Females: exploit less rich food patches or temporarily hosted in male territories for mating purposes Still Polygynous |
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Exploded Leks (some Birds of Paradise) |
Males have there own court (separate from other males) but act as if they were lekking |
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Avian Polyandry |
One female mates with multiple males over a breeding season Sex role reversal is often seen Female reproductive success is more variable then males |
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Sequential Polyandry (Spotted Sandpiper) |
Females arrive first on breeding ground / fight and display for mates Early males get first clutch Females lay eggs and males incubate them (might not be his due to sperm storage) Females either go and find another mate or fail and help with the incubation |
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When would polyandry occur? |
When there is shortage of males instead of shortage of food resources |
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Changes of testosterone levels in females and males with polyandry |
During his incubation task male levels plummet Mated females levels are much higher than non-mated females |
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Reverse Sexual Dichromatism (Wattled Jacana Females) |
Females larger than males with wing spurs Take over competitors territory and kill their young Mate with many males and lay with many clutches (crocodiles eat the eggs) Males look after clutch (40% look after clutches that aren't their own) Females stay and help if she has failed to mate with other males |
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Why do Wattled Jacana Males stay around to look after eggs that might not even be theirs? |
High population, competition and limited reproduction opportunities Better than alternative Being part of it in some way "adding something of their own to the gene pool" |
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Promiscuity |
No pair bonds or biparental care Male & female mate, then one parent incubates and raises young Can include polygynandry & lekking Male reproductive success: Highly variable |
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Tinamous and Ratite Promiscuity (Polyandry) |
Males mate serially with multiple females, who also are mating serially with multiple males Males incubate & raise young |
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Bonobos Promiscuity (Polyandry) |
Communal nest And have a similar structure to the Ratites and Tinamous: (Males mate serially with multiple females, who also are mating serially with multiple males Males incubate & raise young) |
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Dunnock Mating System |
exhibit monogamy, polygyny, polyandry and polygynandry; all in one population Males & Females have own, overlapping territories, territory size depends on the distribution of food resources Intense sexual conflict Polyandry favors female reproductive success, while polygyny favors male reproductive success |
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Which forms of mating system for Dunnocks would be beneficial for males and what one for females? |
female reproductive success: Polyandry The most with paternal investment male reproductive success: Polygyny Neither have a reproductive advantage with monogamy and polygynandry |
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When do Dunnocks do certain mating systems and why? |
Food is more abundant and dense female territories = smaller Male + female territories don't overlap monogamy (or more males monopolize more females) Food is dispersed and Less abundant female territories = larger Male + female territories overlap Polyandry |
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Lekking shorebird (Common Eurasian Sandpiper) Male mating Strategy? Different Roles for Males |
Majority of males: Dark plumage neck ruff and own court in a lek Satellite males: (15%) Light plumage neck ruff, not territorial, share a court with dark ruff male, submissive and help him attract females Faeders (female mimickers): (1%) Look like and hang around females, take any possible opportunity to mate |
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Why do males in socially monogamous relationships seek extra pair copulations (EPCs)? |
increase their reproductive success by increasing the number of offspring he sires without having to provide parental care balance his time between: guarding mate parental care seeking EPCs |
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Why do females in socially monogamous relationships seek extra pair copulations (EPCs)? Why is it more risky for them? |
Cheating is risky for females = Male Desertion (And it doesn't increase the quantity of offspring) To seek: Material benefits (access to resources, parental care Genetic benefits (good genes) OR just fooled or forced |
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Bicknell's Thrush Mating System? |
Migratory Bird "Cooperative Polygandry" Socially Monogamous but most egg clutches have in them different fathers |
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When (why) does social monogamy (but not genetic monogamy), aka "Cooperative polyandry" |
When there aren't enough females to each male and there is an "understanding" between them all Helps increase male reproductive success |
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What is a common practice in socially monogamous species which increases only the males reproductive success? |
Sometimes females are unwilling participants; they get duped (fooled or forced) |
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What are Purple Martins' Mating Strategy (Cuckoldry)? |
Experienced (older) males arrive first at "nest" site Establish at higher (safer) levels and have females and clutches "Sing a song" to call younger males to come with their young females Older males (socially monogamous) take advantage and mate with young females |
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How can males limit female's EPCs? (To maximize own reproductive success) |
Guard her (Cost = time, energy, & opportunity costs) Copulate with her often (last male to copulate with a female fertilizes more eggs) After "fertility" period then he can spend energy on EPCs of his own |
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Cuckolded |
Female cheating on male |
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Forced Extra pair copulations with Waterfowl (Mallards)
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Part of the male reproductive strategy Females completely unwilling Males exhibit no parental care Most of the time monogamous though |
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What allows Water fowl to do forced copulations |
Intromittent organ - corkscrew like Coevolution of male and female genitalia due to sexual conflict evolving to keep up with female's ever changing vagina shape which is evolving to try and prevent forced copulations |
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Intraspecific (or conspecific) brood parasitism |
Add their eggs to nests of the same species waterfowl (grebes, gulls, pigeons & doves, & songbirds)
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When does Intraspecific brood parasitism occur |
increases when there is a shortage of nest sites & when population density is high may reduce host fitness (if host responds by laying fewer eggs) may be first step in evolution of obligatory brood parasitism [with occasional (or facultative) inter-specific brood parasitism the next step] |
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Obligate brood parasites |
always lay their eggs in nests of other birds has evolved independently at least 7 times cowbirds, old world cuckoos |
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What adaptations do the eggs and their growth undergo for brood parasites |
egg mimicry, song matching in some hard shelled eggs & destruction/removal of host eggs relatively small eggs baby brood parasites may dispose of competitorrapid incubation period, rapid nestling growth |
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Obligate Parasitism of the Common Cuckoos |
Cuckoos are generalists and others specialists Common cuckoo Over a range: The species itself will parasitize over 100 species In a locality: will parsitize only a few species and each individual will partisitize only one (=gens) |
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Gens (gentes) |
All the female cuckoos parasitizing one host species some gentes lay eggs that mimic those of their host Possible but not yet supported hypothesis: Maternal inheritance of egg type combined with imprinting of the juvenile cuckoo on her host. |
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Cuckoos |
video |
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Evolutionary “arms race” of Indigobird Parisitizeres |
Each parasitizes a different host species (closely related Estrildid finches) They imitate their host's song males learn in the nest females learn to recognize it and chose males with the same song Their nestlings mimic the unique gape pattern of host species' |
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Cowbird Parasitism |
Generalists No egg mimic or song matching Don’t kill host young Only a few species will eject cowbird eggs Evolutionary lag hypothesis |
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Why do host species tolerate the parasitism (like of cowbirds)? Why don't they just eject the eggs? |
Evolutionary lag hypothesis Cost-benefit equilibrium hypothesis Recognition error Egg damage Mafia hypothesis |
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Why the difference between Old World and New World Brood parasite systems? |
Cuckoos have been brood parasites much longer Co-evolution in OW system has led to greater host specificity Cowbirds More recent parasites |
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Cooperative Breeding (Florida Scrub jays) |
In permanent, group-defended territories Group permanently bonded monogamous pair 1-6 helpers (1-2 normal) generally previous offspring (relatives) |
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Why do helpers helps in Cooperative Breeding? |
Habitat saturated. |
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Communal Nesting (Groove-billed Ani)
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small groups 1-5 breeding pairs (usually with an unmated “helper”). Defend a single territory Lay their eggs in one communal nest. All incubate the eggs and care for the young Some eggs not received proper treatment |
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Why communal nesting? |
Multipair groups manage to fledge more young per individual than do single pairs in similar habitats |
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Difference between cooperative breeders and communal nesting |
With communal nesting female sabotage (tossing of other females' eggs from the nest) Though overall more successful in these groups |
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Why does cooperative breeding evolve? (Old and new hypothesis) |
Ecological constraints limit successful dispersal and reproduction of young birds Old hypothesis: kin selection New hypothesis: temporal variability hypothesis (ecological constraints) |
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Cooperative Breeding of African Starlings Explaining and supporting temporal variability hypothesis |
more prevalent in species that occupy savannas which are temporally variable and unpredictable, allows for both reproduction in harsh years and sustained breeding during benign years young adults put off the start of their own breeding in order to maximize their lifetime reproductive output, and in the process occasionally promote genes identical with their own via kin selection |
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Evolutionary Lag Hypothesis explaining why cowbirds are generalists |
Cowbirds are trying to catch-up with their host species They haven't been around long enough Are generalists and prey on nieve birds |
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How do host species sometimes fight back |
Will wait for the best time to have their own eggs (so they won't end up at the bottom of the nest) Eject the eggs |
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Cooperative Mating System of Seychelles Warblers and what hypothesis (old or new) does it show |
On a small island Cooperative mating system On a large island Split up in different directions only until populations got too big and reverted to Cooperative mating system Cooperative mating system reason = ecological constraints |
