Jim Briskie Lectures Flashcards
Define “proximate”
Proximate explanations include developmental and causation explanations. They focus on mechanisms, the “how”.
Define “ultimate”
Ultimate explanations include evolutionary and survival value explanations. They focus on adaptation and evolution, the “why”.
Define migration
Regular, usually seasonal, movement of all or part of an animal population to and from a given area. Typically a round-trip event with predictable movements between breeding & non-breeding ranges.
How do Bar-Tailed Godwits migrate?
Bar-tailed Godwits fly 11,500km during eight days non-stop from Alaska breeding grounds to overwinter in NZ.
How do Monarch butterflies migrate?
Monarchs fly >9000 km in a multi-generation migration.
Define altitudinal migration
Migration to high altitudes to breed and return to low altitudes for non-breeding season.
Define irruptive mirgation
Migrating periodically in response to rainfall.
Define partial migration
Migration of only a portion of a species.
How is banding used in migration?
The invention of bird bands meant it was possible to follow individuals over their life cycle and find out where they go on migration.
How is radar used in migration?
Swarms of migrating birds can be seen on radar images.
How are isotope ratios used in migration?
Hydrogen isotope ratios (which correlate with local precipitation and becomes incorporated into feathers during moult) can demonstrate origins of bird species.
How are trackers used in migration?
The miniaturisation of tracking devices has allowed us to track individuals with detail and accuracy (geolocator). Geolocators can track an animals location within 50km using the sunlight time and date.
What is a downside of using geolocators?
Having to recapture the same bird to get the data of the tracker.
Define homing
Homing is an animal’s ability to find their way home. This ability decreases with increasing displacement distance. Homing is primarily a result of familiarity with area.
What is navigation by piloting?
Some animals learn features of their environment (landmarks) and use there to orientate and navigate their way home.
What is navigation by path integration?
Some animals keep track of all turns and speed on an outward, integrating this information to make a straight line return home. If displaced at start of return trip, it runs parallel to the one it would have taken.
What is navigation by odour cues?
Some animals learn the “odour” of their stream and use this for homing.
What is navigation by celestial compass?
Some animals navigate using stars and/or sun as a compass. They need to determine direction and distance.
What is an “Emlen” funnel?
An Emlen funnel is a bird cage shaped like an inverted cone, used to study bird behaviour, in particular birds’ migratory instincts.
What is navigation by sun compass?
Some animals use the Sun’s position in the sky as a directional guide.
What is navigation by magnetic compass?
Some animals use the earth’s magnetic field to orient.
What are the benefits of migration?
- Avoid food shortage
- Exploit temporarily favourable conditions
- Escape disease
What are the costs of migration?
- Energy
- Predation risk
- Exposure to new diseases and parasites
Define dispersal
A more or less permanent movement of an individual from one area to a new area. Usually juvenile moving away from its natal area.
What are the benefits of dispersal?
- Inbreeding avoidance
- Intraspecific competition
- Avoiding local competition
What are the costs of dispersal?
- Unfamiliar with location of food and shelter
- Predation risk
- Unfamiliar neighbours and relatives
What is the inbreeding avoidance hypothesis?
Dispearl can minimise risk of breeding with a relative, which can lead to inbreeding depression. Timing of dispersal typically coincides with timing of sexual maturity in offspring.
What is the intraspecific competition hypothesis?
In polygynous mammals, dispersal can reduce competition with other (more experienced) males for access to females.
What does habitat selection refer to?
When animals disperse and settle, some areas are selected and others are not; some areas are preferred (high density).
What are habitat barriers?
A species may be absent due to inability to disperse across a barrier such as presence of competitors or predation risk.
What are the steps of studying behaviour?
Observation, hypotheses predictions, and tests.
What is the ideal free distribution hypothesis?
Habitat varies from good to moderate to poor. In all cases fitness declines as population density increases.
Animals should first settle in good habitats, because at low density individuals do best. As the best habitats fill up, fitness declines to a point where it pays for some individuals to settle for moderate (same fitness payoff as good habitat where density is high).
The model assumes animals have complete and accurate knowledge (ideal) about the distribution of resources. It assumes animals are passive and can go to the best possible site (they are free to move).
Define monogamy
A mating system with one male and one female. Both sexes care for the young.
Define polygyny
A mating system with one male and several females. Simultaneous or sequential. Females care for young.
Define polyandry
A mating system with one female and several females. Simultaneous or sequential. Males care for young.
Define promiscuity/polygynandry
A mating system with females and males each pairing with several members of the opposite sex. Simultaneous mix of polygyny and polyandry.
How do different social mating systems arise?
In males: Polygyny maximises reproductive success.
In females: Polyandry maximises reproductive success.
Why do males in some species pair to only one female?
- Dispersed resources
- Female enforced monogamy
- Mate guarding monogamy
- Male assistance hypothesis
Why does dispersed resources result in monogamy?
Female reproductive success usually limited by resources. Male reproductive success usually limited by females. Dispersed resources (and thus females) results in monogamy as males cannot defend more than one female at a time.
What is female enforced monogamy?
Females can block polygyny. Females can physically prevent males from advertising for additional females. When females are tethered they are unable to prevent males from attracting additional females and polygyny results.
What is mate guarding monogamy?
Occurs in species where males have little chance of finding a second female. Male reproductive success highest with monogamy. Breakage of genitalia and/or sexual suicide lessens risk of female re-mating (allows male to guard female).
What is the male assistance hypothesis?
In some species, male care is a resource for females. Male care is rare in mammals but common in birds. The need for male care can influence evolution of mating systems and enforce monogamy on males.
Why is polygyny limited?
- Strong competition among males (limits ability to monopolise females)
- Female aggression (prevents additional females from settling)
Most species that are monogamous are because males cannot obtain more than one mate.
What are the polygynous mating systems?
-Harem-defence polygyny
-Resource-defence polygyny
-Scramble-competition polygyny
-Lek polygyny
Why do secondary females accept polygyny?
After pairing with first female, a male defends second territory and attracts second female. She is unaware he is already paired.
What is the polygyny threshold?
Polygyny is female’s best interest. Females may mate polygynously on high quality territory is increase in territory quality compensates for sharing.
What is the sexy-son hypothesis?
Unmated males are hard to find. Females compensate by having sons who inherit father’s ability to be polygynous.
What is harem-defence polygyny?
A type of mating system in which a single male defends a group of females, known as a “harem,” from the advances of other males.
What is resource-defence polygyny?
A mating system in which males defend and control access to critical resources, such as food, territory, or nesting sites, to attract and mate with multiple females.
What is scramble-competition polygyny?
A type of mating system in which males compete for access to multiple females without defending territories or forming pair bonds. Male roams widely in search of multiple females.
What is lek polygyny?
A type of mating system observed in some animal species, particularly among certain birds and ungulates, where males gather in specific display areas called leks to attract and mate with females.
In lek mating systems, why don’t males defend a large territory?
Because females are too widely distributed or unpredictable in time.
Or the population density is too high to make defence of territories economic.
In lek mating systems, what is the hotspot hypothesis?
Males cluster because females travel or aggregate in predictable areas or “hotspots”.
In lek mating systems, what is the hotshot hypothesis?
Males cluster around attractive males or “hotshots” to obtain matings with females attracted to hotshots.
In lek mating systems, what is the female preference hypothesis?
Females prefer males in groups to reduce cost of mating choice.
What is simultaneous polyandry?
A mating system in which a single female mates with multiple males at the same time or within a short timeframe.
What is an example of polyandry?
In Pukeko, 2-6 males share a single female. Their breeding habitat is patchy and limited; therefore males have to cooperate and share paternity.
What is sequential polyandry?
A mating strategy in which a single female has multiple male partners, but not simultaneously. Instead, she mates with different males at different times or during separate breeding events.
What is an example of sequential polyandry?
In Jacana, Phalarope, and Spotted Sandpiper, females mate with several males and lay a clutch for each male. Males incubate and care for young alone.
What is female desertion in polyandry?
When a female leaves one or more of her male mates after mating. It can occur for genetic diversity, resource benefits, sperm competition, avoiding harassment, bet-hedging, or finding a higher-quality mate.
Why do males accept polyandry?
-Forced by shortage of females.
-If males desert they obtain no reproductive success.
-Answer not clear and polyandry still a big mystery.
What is cloacal pecking?
Female ejects sperm from prior male so new male can mate.
What are the types of parental care?
-Incubation of eggs
-Drive away predators
-Warn young (alarm calls)
-Provide safe rearing areas
-Feed young
-Sanitation
-Teach skills
-No care provided
What is female only care?
This is the most common pattern in animals. Males desert after mating. Common in mammals and lekking species.
What is male only care?
Females desert after mating. Occurs in some fish, frogs, and polyandrous birds.
What is bi-parental care?
Males and females both care for young. Sex roles may vary (e.g. Female only incubation). Common in birds, canids, primates, and dung beetles.
What is pairs with helpers parental care?
Parental pair are helped by non-breeding individuals. Helpers feed young and defend against predators.
What are some examples of different parental care?
In Florida scrub-jay and Rifleman, parental care helpers are mature young of previous brood. This is a product of kin selection. Helpers increase the amount of food delivered to offspring.
What is parental investment?
Any activity that increases the survival of current young but reduces the chances of adult producing young in the future.
What are the benefits of parental care?
It increases the survival of offspring e.g. Removal of male leads to lower reproductive success in dark-eyed junco.
What are the costs of parental care?
-Raising young can increase energetic costs
-Increased predation risk on adults
-Loss of future matings
-Which sex deserted depended on their opportunities for future matings
Male vs female parental care
In most species, females invest more because they have already invested more in laying eggs (more costly than sperm). Cost/benefit ratio of parental care is usually lower for females than males due to risks of cuckoldry.
What is “concorde” fallacy?
"”Concorde” fallacy is to invest because of past investment e.g. females most invested in care because of past investment in laying eggs. However, should only continue to invest if this increases reproductive success.
What is phylogeny?
The representation of the evolutionary history and relationships between groups of organisms.
What is the phylogenetic pattern of parental care in mammals?
-Female care is universal (lactation)
-Female only care in 97% of species
-Males can defend against predators, carry young (primates), and feed young (carnivores)
What is the phylogenetic pattern of parental care in birds?
-Parental care universal
-Biparental care most common (90% of species) but females often invest more
-Type of care varies but females typically incubate and brood
-Males typically defend against predators and feed young
What is the phylogenetic pattern of parental care in reptiles?
-Parental care absent in most species
-In crocodiles, females care for eggs and young
What is the phylogenetic pattern of parental care in amphibians?
-Parental care occurs in some frogs
-Male only and female only care equally frequently (biparental care very rare)
-Parents brood eggs and protect from predators
What is the phylogenetic pattern of parental care in insets?
-Parental care is rare but female only when present
-Male only in waterbugs
-Biparental in Necrophorus beetles
What is the phylogenetic pattern of parental care in fish?
-Parental care absent in 80% of fish species
-When present shows great diversity in roles of each sex
-Ratio of male only care to biparental care to female only care is 9:3:1
What is the paternity certainty hypothesis as an explanation for patterns of parental care?
-Fertilisation at oviposition (i.e. External), males more certain of paternity
-Internal fertilisation (i.e. Internal), risk of sperm competition and male less sure of paternity
What is the gamete order hypothesis as an explanation for patterns of parental care?
-Internal fertilisation: Male able to “desert” after mating (female cannot desert until after eggs laid).
-External fertilisation: Males must wait until eggs laid in order to fertilise them, giving female opportunity to desert.
What is the association hypothesis as an explanation for patterns of parental care?
-Prior association with embryos “pre-adapts” a sex for parental care
-Internal fertilisers: Females already closely associated with embryo
-External fertilisers: Eggs laid in male territory and he is already associated with brood
Why don’t cuckolded males reduce their care?
Male care is essential and/or males are unaware of cuckoldry
Why does “male care essential” stop cuckolded males reducing their care?
-If benefits of care are large but costs are small, reduction in paternity may not favour decrease in male care
-Costs are small when opportunity for future matings by males are low
-Benefits are high if feeding greatly increases survival of young
-May not be misdirected care but only way to ensure own offspring survive
How do animals respond to parasites and disease?
An animal’s immune response is “after the fact”. Natural selection has led to the evolution of behavioural strategies to reduce risk of contracting an infection in the first place.
What are some of the ways animals reduce risk of infection?
-Avoiding disease filled habitats
-Avoiding diseased individuals
-Selective foraging
-“Self medicating”
How do animals avoid disease filled habitats?
-Avoid areas that contain pathogens
-Avoid individuals that are already infected/ill
-Animals can detect infected individuals through chemical/olfactory cues
How do animals selectively forage?
In Dik-diks, they have seperate foraging and defecation sites.
In Eastern Bluebirds, they prefer unused nexts vs used to avoid parasites.
How do animals “self-medicate”?
Blue tits add aromatic plants to their nest to deter bacteria.
Animals groom/preen themselves and others to reduce parasite load.
Birds squeeze ants onto themselves to repel parasites.
Geophagy is eating dirt and animals do it to alleviate stomach discomfort.
Some animals eat clay to to absorb dangerous compounds.
