Island evolutionEvolutionary forces on islandsEvolutionary forces on islandsEvolutionary trends on islands

Development of tameness

MorphologyMorphologyBehaviour

Falkland Islands fox, Dusycion australis, Falkland Islands

Blue-footed booby, Sula nebouxii, Galapagos

Tamar wallaby, Macropus eugenii, Kangaroo Island

Avera

ge fl

igh

t in

itia

tion

dis

tan

ce

20

0

10

30

Tutanning GardenIsland

KangarooIsland

New Zealand

House mice, Mus musculus, feeding on Tristan albatross, Diomedea dabbenena, Gough Island

Island evolutionEvolutionary forces on islandsEvolutionary forces on islandsEvolutionary trends on islands

Development of tamenessDevelopment of tamenessRelaxation in territoriality

MorphologyMorphologyBehaviour

House mouse, Mus domesticus, Isle of May and UK mainland

05

10152025

investigate

00.5

11.5

22.5

3

defend

0

1

2

3

4

attack

00.5

11.5

22.5

chase

0

0.2

0.4

0.6

0.8

shove

0

0.5

1

1.5

sit by

Gray & Hurst 1998House mouse, Mus domesticus, Isle of May and UK mainland

Relaxation in territoriality• smaller territories• increased overlap• tolerance towards subordinates• reduced aggressiveness• abandonment of territorial defence

Resource hypothesis

Competition release

Abundant resources

Defence hypothesis

Predation release Mild climate

Increased survival of "have-nots"

Increased territorial defence costs

Island evolutionEvolutionary forces on islandsEvolutionary forces on islandsEvolutionary trends on islands

Reduced fecundity

MorphologyMorphologyBehaviourBehaviourLife history

reduced clutch sizehigher quality young

Energy reallocation hypothesispredation relaxation, density compensation select for investment in fewer,higher qualityyoung

Resource predictability hypothesismilder climate, reduced seasonality favours a reduction in clutch size

clutch size ~ instant food availability

population density

winter

breeding season

Island evolutionEvolutionary forces on islandsEvolutionary forces on islandsEvolutionary trends on islands

Reduced fecundityReduced fecundityChanges in reproductive strategy

MorphologyMorphologyBehaviourBehaviourLife history

Dioecy

Tag alder, Alnus serrulata

Monoecious

male

female

malefemale

Holly, Ilex aquifolium

Dioecious Hermaphrodite

male

female

Lily, Lilium

hermaphrodite85%

dioecious6-7%

monoecious5-6%

worldwide

hermaphrodite62.4%

dioecious14.7%

monoecious7.6%

Hawaii

dioecy

avoidinginbreeding depression

sex allocation theory

proportion of investment in male flowers

0.0 0.2 0.4 0.6 0.8 1.0

Fert

ility

0.0

0.2

0.4

0.6

0.8

1.0

1.2

proportion of investment in male flowers

0.0 0.2 0.4 0.6 0.8 1.0

Fert

ility

0.0

0.5

1.0

1.5

2.0

proportion of investment in male flowers

0.0 0.2 0.4 0.6 0.8 1.0

Fert

ility

0.0

0.2

0.4

0.6

0.8

1.0

1.2

proportion of investment in male flowers

0.0 0.2 0.4 0.6 0.8 1.0

Fert

ility

0.0

0.5

1.0

1.5

2.0

Island evolutionEvolutionary forces on islandsEvolutionary forces on islandsEvolutionary trends on islands

Reduced fecundityReduced fecundityChanges in reproductive strategy

MorphologyMorphologyBehaviourBehaviourLife history

DioecyDioecyLoss of flower attractiveness

Sun orchid, Thelymitra longifolia, New Zealand Psychopsis papilio, South America

Bellflower, Campanula punctata, Izu Islands

Bombus diversus

Bombus ardens

Lasioglossum

0 100 km

Oshima

Toshima

Niijima

KozuMiyake

Mikura

Hachijo

Honshu

Coro

lla w

idth

(m

m)

20

0

10

30

1 2 3 4 5 6Pollinator width (mm)

Kozu

MiyakeHachijo

ToshimaNiijimaOshima

Honshu

Island evolutionEvolutionary forces on islandsEvolutionary forces on islandsEvolutionary trends on islands

Reduced fecundityReduced fecundityChanges in reproductive strategy

MorphologyMorphologyBehaviourBehaviourLife history

DioecyDioecyLoss of flower attractivenessLoss of flower attractivenessAnemophily

Rhetinodendron berteroi, Juan Fernandez Islands

Plocama pendula, Canary Islands

Anemophily

Windy conditionsallow wind pollination

Lack or paucityof animal pollinators

Inbreedingavoidance

Island evolutionEvolutionary forces on islandsEvolutionary forces on islandsEvolutionary trends on islands

Reduced fecundityReduced fecundityChanges in reproductive strategy

MorphologyMorphologyBehaviourBehaviourLife history

DioecyDioecyLoss of flower attractivenessLoss of flower attractivenessAnemophilyAnemophilyUnusual pollinators

Bumble bee, Bombus canariensis, Canary Islands

88%

Mauritius ornate day gecko, Phelsuma ornata, Ile aux Aigrettes, Mauritius

71%

Aeonium holochrysum, Canary Islands

80%

Madeira wall lizard, Teira dugesii, Madeira

Lilford's wall lizard, Podarcis lilfordi, Balearic Islands

Island evolutionEvolutionary forces on islandsEvolutionary forces on islandsEvolutionary trends on islands

Reduced fecundityReduced fecundityChanges in reproductive strategyChanges in reproductive strategyUnusual dispersal agents

MorphologyMorphologyBehaviourBehaviourLife history

Podarcis lilfordi, Balearic Islands

Podarcis pityusensis, Balearic IslandsGallotia atlantica, Fuerteventura

Robust skink, Cyclodina alani, New Zealand

Aldabra giant tortoise, Dipsochelys dussumierri, Ile aux Aigrettes (Mauritius)

Ile-aux Aigrettes ebony, Diospyros egrettarum, Ile aux Egrettes, Mauritius