Animal behaviour semster 2

What is Parental care

Any parental behaviour that increases the fitness of the offspring

what are some examples of parental care

nest construction, incubating, feeding, provisioning (teaching), Transport, protection,

what are some benefits of parental care

survival, growth, future performance, development

what needs to happen for parental care to be given

optimal benefits, can be costly to raise too many or put too much effort into offspring.

what are costs of parental care

energy, time, risks, future reproduction

what can change the benfits of parental care

off spring (brood size, age condition), environment (recourses available, predation, prtection), effectiveness of care (will only be selected for if increases fitness)

what changes costs to parental care

parent (condition, age health, energy reserves), environment, oppurtunities elsewhere

residual reproductive value

an individuals future reproductive success

terminal investment

Invest now, may not have future opportunities, low residual reproductive value.

reproductive restraint

invest less or not at all, may be due to resource availability or body condition.

taxonomic pattern for mammals, birds, fish

mammals= predominately maternal, birds= bi parental, fish= male only common

why is maternal care more common

Anisogamy- female invest more in offspring

when will biparental care occur

favoured when additional fitness gained by having two carers exceed the fitness that either parent could gain by deserting and seeking alternative reproduction opportunities.

what does discrimination require

relatedness, need, value

benefits of recognising offspring

avoid caring for unrelated offspring, directed limited care to only offspring

Costs of recognising offspring

risk rejecting their own offspring, development of recognition ability,

solitary

individual primarily lives alone

aggregation

individauls brought together by a shared recourse or environmental feature

social group

individual actively associate and maintain social relations.

benefits of group living

predator avoidance, access to food thermoregulation

costs of group living

competition, disease and parasite, conflict

how does group liveing help predator avoidance

detection, dilution, selfish herd, defence

how does group size effect foraging and vigilance

as group size increases individuals foraging increases, vigilance decreases

Parental care

Any parental behaviour that increases the fitness of offspring, often incurring fitness costs to the parent.

Examples of parental care behaviours

Nest construction, egg incubation, food provisioning, transport, grooming, and defense against predators.

Benefits of parental care for offspring

Increased survival probability, accelerated growth rates, enhanced future physiological performance, and improved developmental outcomes.

Evolutionary condition required for parental care

The fitness benefits conferred to the offspring must exceed the direct and indirect fitness costs incurred by the caring parent ($B > C$).

Costs of providing parental care

Depletion of energy reserves, substantial time investment, increased exposure to predation risk, and reduced opportunities for future reproduction.

Factors influencing the benefits of parental care

Offspring characteristics (such as brood size, age, and nutritional condition), environmental quality (resource abundance and predation danger), and how effectively the care boosts offspring fitness.

Factors influencing the costs of parental care

Parental physical condition (age, health status, and energetic reserves), environmental harshness, and alternative mating opportunities available elsewhere.

Residual reproductive value (RRV)

An organism's total expected future reproductive success across the remainder of its lifespan after the current breeding event.

Terminal investment hypothesis

The evolutionary prediction that an individual with low residual reproductive value should invest maximally in its current offspring, as future breeding opportunities are unlikely.

Reproductive restraint

The adaptive strategy of withholding current reproductive effort to preserve body condition and survival for future breeding events.

Taxonomic patterns of parental care

• Mammals: Predominantly maternal care

• Birds: Predominantly biparental care (~90% of species)

• Teleost fish: Predominantly male-only care when care is present

Evolutionary driver of prevalent maternal care

Anisogamy, in which females produce larger, nutrient-rich gametes and therefore begin with a much greater initial investment per offspring than males.

Conditions favouring biparental care

When the combined care of two parents yields a fitness gain that exceeds the fitness either parent could achieve by deserting to pursue additional mating opportunities.

Key criteria required for parent-offspring discrimination

Reliable assessment of genetic relatedness, offspring need, and reproductive value.

Benefits of parent-offspring recognition

Prevents misdirecting costly resources toward unrelated young and ensures limited care is allocated exclusively to genetic descendants.

Costs of parent-offspring recognition mechanisms

The danger of misidentification (mistakenly rejecting one's own offspring) and the physiological or neural investment needed to produce and process signature cues.

Solitary living

A lifestyle in which an individual primarily lives alone, interacting with conspecifics almost exclusively for mating encounters or territorial disputes.

Aggregation

A grouping of organisms brought together passively by an external environmental feature or shared localized resource, rather than by social attraction.

Social group

A collection of individuals that actively seek out one another's company, coordinate activities, and maintain ongoing social relationships.

Primary benefits of group living

Enhanced predator avoidance, increased foraging efficiency and information sharing, and cooperative thermoregulation.

Primary costs of group living

Elevated intraspecific competition for limited resources, increased transmission rates of parasites and infectious pathogens, and heightened social or reproductive conflict.

Mechanisms of predator avoidance in animal groups

• Detection: More sensory organs detect threats sooner (many-eyes effect)

• Dilution: Individual risk of capture decreases with group size

• Selfish herd: Movement toward the group center reduces vulnerability

• Defence: Collective mobbing and coordinated counter-attacks

Relationship between group size, vigilance, and foraging

As group size increases, individual vigilance decreases while individual foraging time increases, because corporate vigilance across the whole group remains high.

Dilution effect

The decrease in an individual's probability of being killed during a predator attack as group size increases, provided the predator cannot consume the entire group at once.

Selfish herd hypothesis

The principle that individuals aggregate and maneuver toward the center of a group to place conspecifics between themselves and approaching predators.

Confusion effect

The reduced capture success of a predator caused by the visual difficulty of singling out and tracking an individual target within a large, moving group of prey.

Optimal group size

The specific group size that maximizes the net fitness payoff (benefits minus costs) for an individual group member.

adaptionist approach

Confer higher genetic success compared with individual with alternative traits

Cost benefit approach

analyse behaviour in terms of their fitness benefits vs cost effect of a trait on the number of surviving offspring

comparative approach

divergent vs convergent evolution

aggregation

individuals in the same space often for common recourse or environmental feature

dilution effect

significant reduction of risk of being captured

constraints on adaptive perfection

failure of appropriate mutation, pleiotropy, coevolution

failure of appropriate mutation

selection does not keep up with environmental change, results in maladaptive or nonadaptive traits.

pleiotropy

most genes have multiple effects, not all are positive, if positive outweighs the costs it will persist.

co evolution

when different species interact in ways that affect the fitness of each other, evolution stability may never be reached

camoflauge

evolved ability to select background where they would be hard to see

batesion mimicry

palatable species mimics unpaletable ones

mimic

sounds, colouring, and behaviours