• Long and Long and “long”“long”• Coevolution Coevolution –Arms raceArms race

• ParasitismParasitism• MutualismMutualism

Long-lasting interactions

• The problem of The problem of exploitationexploitation

• Oxpeckers & cattleOxpeckers & cattle– Birds defectBirds defect

• Honeyguides & Honeyguides & humanshumans– Humans ceased to Humans ceased to

benefitbenefit

Stability of mutualisms

• The behaviorThe behavior– StationsStations– Eat parasites, Eat parasites,

dead tissuedead tissue

• Cleaners gain Cleaners gain food, risk being food, risk being eateneaten

• Clients may gain Clients may gain cleanliness, risk cleanliness, risk territories & territories & mucusmucus

Cleaner fishCleaner fish

• Animals often Animals often provide provide mobilitymobility

• Pollination and Pollination and seed dispersalseed dispersal– Rewards are Rewards are

often requiredoften required– Manipulation Manipulation

when possiblewhen possible

• ““Ant plants”Ant plants”

Plant / animal interactions

• The extended The extended phenotypephenotype

• The wasp and The wasp and the spiderthe spider

Parasitic manipulation

• The host’s survival The host’s survival / reproduction / reproduction tradeofftradeoff

• The parasite’s The parasite’s interestinterest– CastrationCastration– Behavioral Behavioral

castrationcastration• In In GammarusGammarus

…when parasites are transmitted horizontally

• Intracytoplasmic Intracytoplasmic parasites in eggsparasites in eggs

• Feminization by Feminization by WolbachiaWolbachia– In rolly-polliesIn rolly-pollies– Increases Increases

transmissiontransmission– Males prefer real Males prefer real

femalesfemales

……when parasites are when parasites are transmitted verticallytransmitted vertically

• Trophic Trophic transmission to final transmission to final hosthost

• GammarusGammarus– Polymorphus laevisPolymorphus laevis• Final host: FishFinal host: Fish• Attracted to lightAttracted to light

– P. minutusP. minutus• Final host: BirdsFinal host: Birds• Swim near the surfaceSwim near the surface

…when parasites have complex life cycles

1.1. Alters complex characterAlters complex character2.2. Favors infection in final hostFavors infection in final host3.3. Changes evolve more than Changes evolve more than

onceonce4.4. Parasite benefits from Parasite benefits from

changechange

Proving manipulation

• DefinitionDefinition– CareCare is exploited is exploited– IntraspecificIntraspecific– InterspecificInterspecific

• Diversity: InterspecificDiversity: Interspecific– Slave-making antsSlave-making ants– MaculineaMaculinea– FishFish– BirdsBirds

Brood parasitism

• Evolved Evolved independently independently several timesseveral times

• In cuckoosIn cuckoos– Specialist “gentes”Specialist “gentes”• Matched eggsMatched eggs

– Rapid layingRapid laying– Egg ejectionEgg ejection– High begging rateHigh begging rate

Brood parasitism in birds

• The host’s optionsThe host’s options– IncubateIncubate– Abandon (or bury)Abandon (or bury)– Recognize and disposeRecognize and dispose• Some hosts do discriminateSome hosts do discriminate

• Parasite’s options given Parasite’s options given recognitionrecognition– Switch hostsSwitch hosts– Mimic the host’s eggsMimic the host’s eggs

• Do host defenses lag?Do host defenses lag?• Or are they at equilibrium?Or are they at equilibrium?

An evolutionary arms race

• A test for equilibriumA test for equilibrium• In native Africa, village In native Africa, village

weaverbirds reject cuckoo eggsweaverbirds reject cuckoo eggs• 150 years after introduction to 150 years after introduction to

Hispaniola, no more discriminationHispaniola, no more discrimination• Ability regained shortly after shiny Ability regained shortly after shiny

cowbird introductioncowbird introduction• Mechanism: intrabrood variabilityMechanism: intrabrood variability

Weaverbirds and cuckoos

Parasitism and sociality• Horizontally transmitted Horizontally transmitted

parasites excel in group living parasites excel in group living hostshosts

• Free living parasites may be Free living parasites may be subject to dilution effectsubject to dilution effect

• AllogroomingAllogrooming• Group as quarantineGroup as quarantine