ESP 100

midterm

Parasites

Take energy from hosts, but do not kill hosts.and reproduction, often causing harm or disease. Manipulate host behavior or appearance to increase their own spread

• Endoparasites:

• Attach to exterior/skin of prey

  • Lampreys, mites, ticks, fleas

• Ectoparasites:

• Live outside hosts, e.g., of direct lifecycle (only 1 host)

  • Roundworms, Giardia, a heartworm, hookworm

• Life cycles:

• Indirect (Parasitic Flatworm) & Direct (Parasitic Barnacle)

Parasitoids:

kill their one host, mostly insects, lay eggs in body of host, manipulate host behavior

defense against parasitoids

• wriggle. Movement to miss ovipositor, hide,  protect from hyperparasites

  • Secondary parasite whose host is a primary insect parasitoid

• Self medicate

• Dust baths, self grooming, allogrooming, between same and different species

Ecology:

study of interactions between organisms and their environment

• The environment:

• abiotic and biotic factors

Organizational units:

organism, population, community, ecosystem

• Biomes:

• Diversity increases in warm, tropical environments 

• Fitness:

• survival and reproduction

• Designing an experiment

Hypothesis, Treatments, Control, Replication, Randomization

1. Hypothesis:

1. “Raccoons learn to open boxes faster by directly watching others."

   1. Testable explanation for an observed pattern

1. Treatments:

1. Manipulate one group in a way that you think will cause a useful effect

1. Control 

1. Try your best to only change that one thing of interest and keep everything else the same.

2. We need a baseline group that we can compare the treatment group to

3. Account for unintended effects of the treatment

Replication:

We use multiple trials of the same test to account for unknown variables

1. Randomization:

1. Trying to reduce error from experimenter bias, sequence effect, inconsistencies, etc.

• Independent variable:

• explanatory variable, or the thing you are changing)

• Dependent variable:

• response variable - what are you measuring?

Optimality

general options are “stay or leave”, maximize reward rate (rr)- compare reward of staying vs leaving

• Foraging:

• most adaptive strategy 

• Patch use:

• if patches with high RR are rare, spread out to use both

Ideal free distribution

• If all individuals use the stay vs. leave rule, then at the IFD all patches should have equal RR

• E_net = E_gross / (s + h)

• E net: Net rate of energy intake (energy gained per total time spent searching and handling)\(E_{gross}\)

• E_gross: Total energy (caloric value) obtained from the food item

• s (or s): Search time required to find the food item

• h (or h): Handling time required to capture, kill, and eat the food item

• Undermatching:

• animal distribution should match resources: There are fewer foragers at better patches than expected

E_net

Net rate of energy intake (energy gained per total time spent searching and handling)\(E_{gross}\)

E_gross

• Total energy (caloric value) obtained from the food item

s

Search time required to find the food item

h

Handling time required to capture, kill, and eat the food item

Group

a set of organisms that remain together for a period of time, interacting to a distinctly greater degree than with others

group charactersitics

Coordinated behavior, ingroup/outgroup, collective action, conflict/cooperation

antipredator benefit in group

• Early detection of predators

• Confusion of predator (schooling)

• Dilution effect

• Cooperative fighting 

• Foraging benefits

• Dilution effect-

• smaller chance of you getting eaten

• Selfish herd hypothesis 

• Putting others in between you and the predator

• Foraging benefits

• Find food faster

• Catch food more easily

• Spend less time looking for food

• Inadvertent vs advertent communication

cues and signals

• Cues:

• benefit the receiver 

• Signals:

• intentionally change the behavior of the receiver

Reasons to live alone

• Attracts predators 

• stronger competition 

• disease transmission

Rifkin et al. 2012 American Naturalist-

• bigger groups sometimes have fewer parasites:

  • More vigilant and defended against parasites through grooming

  • More time foraging-better conditions, more immunity against parasites

  • More able to forage in areas with fewer parasites

• Altrusim

• Helping others while hurting yourself- generally not favored by natural selection

• Kin selection (exception)

• Natural selection favors the ability to pass down your genes to your kin, who share your genes

• Hamilton's rule (altruism if: rB > C)

• c=cost (decrease fitness)

• b=benefit (increase fitness)

• r=coefficient of relatednes

• Q: how can you help your kin

• Parental care, Eusocialty, reciprocrity

eusociality

• 1 reproductively active queen- males act as sperm (rare), many sterile, female workers, division of labor

  • Queen convinces workers through social cues and haplo-diploid sex determination in bees 

reciprocity

reciprocal altruism (Trivers, 1971), allogrooming, food sharing, Cooperation game, caring for non-kin, humans

Intersexual (between sexes) selection

• Mate choice, typically by females,coercion or sexual conflict

• Cryptic female choice, Genital coevolution

Intrasexual

• Competition to select members of different sex, typically by males

• selection: Male-male or female-female competition

• Sperm competition, mate guarding 

Reproductive  cycle

Attract /Search → Mating →Fertilization →Parental Care →Recovery

anisogamy

gametes differ in size and investment

sex roles

reproductive success = quantity of offspring x quality of offspring (fitness of offspring)

Male gametes

easier to produce→ more gametes→males focus on maximizing quantity over quality 

Female gametes

harder to produce but quality over quantity 

Kokko & Jennions et al. (2003; 2008)

Male gametes are easier to produce than female gametes. Female gametes are therefore rarer than male gametes

• This makes male paternity uncertain, and favors males who can better compete for limited female gametes.

There is an elite group of a few adult males that are "eligible to mate"

Large variation in mating success between males (some males mate, other males never mate) but females have low variation in mating success (all females mate

EPP

Environmental Potential for Polygyny (Emlen & Oring 1977)

Parental care-

1. how many parents needed to raise young, more care = less epp

   1. Better off helping offspringAvailable potential partners

Available potential partners

Likelihood of finding another partner

Distribution of resources

1. Can males monopolize the resource? Defense polygyny

1. Distribution of females

1. Females monopolizable → higher epp

Monogamy

• Biparental care required: food availability, time until maturity, predation risk

  • Birds, mammals 

Social monogamy

• cohabit w another partner, may mate with other indivuals

  • Extra pair copulations, more important bi-parental care is for success the less EPCs 

  • Serial monogamy → one seasonGenetic monogamy

Genetic monogamy

•  all offspring from one partner

  • Mate for life scenarios are rare

• Polygyny-

• one male, multiple females

  • Each female mates with one male

• Resource defense polygyny

• Resources cant be monopolized, signals to competitors and females

Female defense polygyyny

Females can be monopolized, defending the females

Lek polygny

• Elaborate courtship, self advertisement, males show off and attract females w not material offers

Polyandry

• one female multiple males

  • Sex role reversal

  • Females compete for males who can provide parental care

• Promiscuity

many partners between both sexes

Scramble promiscuity

• Move around and look for as many partners are possible

• Promiscuous group living

Hyenas, some primates, some lekking species

Intersexual selection

female choice models

precopulatory

• Direct benefits, 

  • Females choose based on traits that indicate direct benefits to the female- 

    • territory, nuptial gifts, lack of parasites

good genes hypothesis

• Females choose based on traits that indicate the male being able to pass down good genes

  • Eg great reed warbler, repertoire size as indicator of age, survivorship and offspring

  • Red jungle fowl comb size

• Fisherien runaway model “sexy sons”

• Arbirary prefernces with no direct benefit

• No quality information about condition/genes

• Only favored because of mating advantages

Intersexual selection- Post copulatory

• sperm competition

  • Faster swimming or bettwe condition

  • Prolonged copulation

  • Mating plugs

    • Lepidoptera and dipera

  • Mate guardian