Long-lasting interactions

• • • •

Long and “long” Coevolution

–

Arms race

Parasitism Mutualism

• • •

Stability of mutualisms

The problem of exploitation Oxpeckers & cattle

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Birds defect Honeyguides & humans

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Humans ceased to benefit

• • •

Cleaner fish

The behavior

– –

Stations Eat parasites, dead tissue Cleaners gain food, risk being eaten Clients may gain cleanliness, risk territories & mucus

• • •

Plant / animal interactions Animals often provide mobility Pollination and seed dispersal

–

Rewards are often required

–

Manipulation when possible “Ant plants”

Parasitic manipulation

• •

The extended phenotype The wasp and the spider

…when parasites are transmitted horizontally

• •

The host’s survival / reproduction tradeoff The parasite’s interest

– –

Castration

•

Behavioral castration In Gammarus

…when parasites are transmitted vertically

• •

Intracytoplasmic parasites in eggs Feminization by

Wolbachia

– –

In rolly-pollies Increases transmission

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Males prefer real females

• •

…when parasites have complex life cycles Trophic transmission to final host

Gammarus

– • •

Polymorphus laevis

Final host: Fish Attracted to light

– • •

P. minutus

Final host: Birds Swim near the surface

Proving manipulation

1. Alters complex character 2. Favors infection in final host 3. Changes evolve more than once 4. Parasite benefits from change

Brood parasitism

• •

Definition

– – –

Care is exploited Intraspecific Interspecific Diversity: Interspecific

– – – –

Slave-making ants

Maculinea

Fish Birds

• •

Brood parasitism in birds Evolved independently several times

– – –

In cuckoos

– •

Specialist “gentes” Matched eggs Rapid laying Egg ejection High begging rate

• • • •

An evolutionary arms race The host’s options

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Incubate

– –

Abandon (or bury)

•

Recognize and dispose Some hosts do discriminate Parasite’s options given recognition

– –

Switch hosts Mimic the host’s eggs Do host defenses lag?

Or are they at equilibrium?

• • • • •

Weaverbirds and cuckoos A test for equilibrium In native Africa, village weaverbirds reject cuckoo eggs 150 years after introduction to Hispaniola, no more discrimination Ability regained shortly after shiny cowbird introduction Mechanism: intrabrood variability

• • • •

Parasitism and sociality

Horizontally transmitted parasites excel in group living hosts Free living parasites may be subject to dilution effect Allogrooming Group as quarantine