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Island evolution. Evolutionary forces on islands Evolutionary trends on islands. Morphology Behaviour. Development of tameness . Falkland Islands fox, Dusycion australis , Falkland Islands. Blue-footed booby, Sula nebouxii, Galapagos. Tamar wallaby, Macropus eugenii , Kangaroo Island.
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Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Behaviour Development of tameness
30 20 Average flight initiation distance 10 0 Kangaroo Island New Zealand Tutanning Garden Island
House mice, Mus musculus, feeding on Tristan albatross,Diomedea dabbenena, Gough Island
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Behaviour Development of tameness Relaxation in territoriality
House mouse, Mus domesticus, Isle of May and UK mainland Gray & Hurst 1998
Resource hypothesis Defence hypothesis Competition release Predation release Mild climate Abundant resources Increased survival of "have-nots" Increased territorial defence costs • Relaxation in territoriality • smaller territories • increased overlap • tolerance towards subordinates • reduced aggressiveness • abandonment of territorial defence
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Behaviour Life history Reduced fecundity
breeding season instant food availability clutch size ~ population density winter Resource predictability hypothesis milder climate, reduced seasonality favours a reduction in clutch size Energy reallocation hypothesis predation relaxation, density compensation select for investment in fewer,higher quality young reduced clutch size higher quality young
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Behaviour Life history Reduced fecundity Changes in reproductive strategy Dioecy
Monoecious Dioecious Hermaphrodite male male female female male female Tag alder, Alnus serrulata Lily, Lilium Holly, Ilex aquifolium
Hawaii worldwide monoecious 5-6% monoecious 7.6% dioecious 6-7% dioecious 14.7% hermaphrodite 85% hermaphrodite 62.4%
avoiding inbreeding depression sex allocation theory dioecy
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Behaviour Life history Reduced fecundity Changes in reproductive strategy Dioecy Loss of flower attractiveness
Psychopsis papilio, South America Sun orchid, Thelymitra longifolia, New Zealand
Honshu Bombus diversus Oshima Toshima Niijima Kozu Miyake Bombus ardens Mikura 0 100 km Hachijo Lasioglossum
30 Honshu 20 Oshima Niijima Toshima Corolla width (mm) Kozu Hachijo Miyake 10 0 1 2 3 4 5 6 Pollinator width (mm)
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Behaviour Life history Reduced fecundity Changes in reproductive strategy Dioecy Loss of flower attractiveness Anemophily
Windy conditions allow wind pollination Inbreeding avoidance Anemophily Lack or paucity of animal pollinators
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Behaviour Life history Reduced fecundity Changes in reproductive strategy Dioecy Loss of flower attractiveness Anemophily Unusual pollinators
88% Bumble bee, Bombus canariensis, Canary Islands
Mauritius ornate day gecko, Phelsuma ornata, Ile aux Aigrettes, Mauritius 71%
80% Aeonium holochrysum, Canary Islands
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Behaviour Life history Reduced fecundity Changes in reproductive strategy Unusual dispersal agents
Podarcis lilfordi, Balearic Islands Podarcis pityusensis, Balearic Islands Gallotia atlantica, Fuerteventura
Aldabra giant tortoise, Dipsochelys dussumierri, Ile aux Aigrettes (Mauritius)
Ile-aux Aigrettes ebony, Diospyros egrettarum, Ile aux Egrettes, Mauritius