Download Territoriality migration

Chap. 13 Habitat selection,
territoriality and migration
鄭先祐 (Ayo) 教授
國立台南大學 環境與生態學院
生態科學與技術學系
環境生態研究所 + 生態旅遊研究所
Habitat selection, territoriality, and
migration
Models of habitat choice
 The ideal free distribution model(IFD) and
habitat choice
 The IFD model and foraging success
Territoriality
migration
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Habitat selection, territoriality and
migration
Habitat selection
 The decision-making process is
complicated.
• Mates, food, and predators
Home range
Nomads (遊牧民), constantly wandering
and never returning to the same place
with any regularity.
Territory: an area occupied and
defended by the owner. To keep
intruders outside of this area.
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Model of habitat choice
The ideal free distribution model
(IFD) and habitat choice
 Habitat 1(H1) with resource 1(R1)
 Habitat 2 (H2) with resource 2 (R2)
• At equilibrium, R1/N1 = R2/N2
• Resource matching rule
The IFD model and foraging
success
 Stickleback fish
 Mallard ducks
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The matching resource rule in stickleback fish
Experiments：Each tank had two
feeders that distributed food at opposite
ends of a tank.
 Two treatments
• food (water fleas) were released from the
two feeders in a 5:1 ratio
• the ratio was 2:1.
 Results: the fish distributed themselves
under feeders in a ratio similar to the
resource matching rule (Fig. 13.2)
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In mallard ducks
Two observers who were stationed 20
meters apart throw bread (food) into
the pond.
 When equal amounts of food were thrown
into patches by both observers, ducks
quickly distributed themselves in a 1:1 ratio
(Fig. 13.4).
 When one patch had twice as much bread
as the other, the ducks distributed
themselves in a 2:1 ratio.
 But not all individuals were receiving the
same amount of food across patches.
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The two foraging
patches created
when two
individuals threw
bread into a pond
from different
locations had
equal profitability.
The dashed line
represents the
predicted number
of ducks at site 1.
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Group Territoriality in chimpanzee
Group territoriality, are defended by
a group of unrelated individuals.
 Between-group raiding (侵襲)
 To be War-like
 Larger group eradicating(消滅) a smaller
group of chimps.
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Territoriality and learning in Anolis lizards
 材料：Anolis aeneus lizards (Stamps, 2001)
 Despite numerous experiments manipulating food
availability, she did not uncover a clear-cut effect
of food availability on territory formation.
 Rather, she found that safety from predators and
suitable temperature appeared to be the most
important attributes of a desirable territory.
 How do juvenile lizards determine which
territories are suitable with respect to
temperature and predation pressure?
 Do lizards learn what areas are best from their
interaction with other lizards?
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(A) Juveniles not
only spent more
time on
experimental (E)
versus control (C)
homesites, but they
also arrived at
experimental
homesites more
quickly
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(B) Juvenile lizards were drawn to experimentally manipulated
homesites (E) over control (C) homesites.
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Territoriality and learning in Anolis lizards
 Conspecific cueing hypothesis
 A juvenile would be allowed to observe two very
similar territories, one that was currently occupied
and one that was vacant.
 When given the choice between these two areas,
with the territory owner now removed, juveniles
showed a strong preference for the previously
inhabited area.
 The other juveniles displayed no preference for
the previously occupied territory.
 A strong visual component to conspecific
cueing in A. aeneus.
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Territory owners and satellites in
pied wagtails
Territory ownership often requires
constant vigilance (警戒) against both
predators and conspecific intruders.
Owners, satellites, and territory defense
in pied wagtails.
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Fig. 13.8 pied wagtails and food search.
Pied wagtails systemically search
for food on their territories along
riverbanks
 (A) a single bird can complete a circuit of
the riverbank in 40 minutes and gets all the
food it finds
 (B) when a territory is shared by two birds,
however, the circuit is divided up as well,
and so each bird primarily gets the food
that it finds in its 20 minutes of walking the
riverbank.
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Owners often allow “satellite” individuals to forage on territories. Some
territorial defense is provided by the satellites.
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How to keep a territory in the family
Fig. 13.9 Scrub jays
and territories.
Territories are
“inherited” across
generations, leading to
the establishment of
“family dynasties”.
Territory size is
increased through a
process called budding.
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Migration and navigation
Navigation
 The sun compass
 By the stars
 The Earth’s magnetic field
The heritability of migratory
restlessness
Defense against parasites
Phylogeny
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(A) Here we see migration in geese
(B) gnu.
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Migration and the sun compass
 Monarch butterflies migrating each year fro
North America in the mountain ranges of
central Mexico.
 During their annual migration, the branches of
trees have been known to collapse from the
weight of too many butterflies (Fig. 13.11).
 Monarch butterflies traverse up to 6,000 miles
on their migratory trip, and they almost always
navigate successfully without getting lost,
even on their first migration.
 To examine the role of solar navigation in
the Monarch butterflies.
 ran a classic “clock-shift” experiment
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Monarch butterflies
Raised two group of monarch butterflies
in a laboratory
 One group was slowly shifted the
butterflies’ body clocks bake six hours.
 The second group, were not shifted
During the period of autumn migration,
released them
 The control butterflies headed south
 The clock-shifted butterflies, however,
flew almost due west. (Fig.12.12)
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Clock-shifted
butterflies fly west
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Laboratory raised
butterflies, who were
raised on a normal
light-dark cycle
Butterflies from
natural
populations fly
south
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The pipe at the bottom of the
simulator directed a constant
flow of air up toward the
butterfly so that it could fly; a
video camera was connected to
the bottom of the simulator; an
encoder was attached to the
butterfly from the top of the
simulator and was connected to
a computer that kept a timed
record of all the butterfly’s
movements.
With this setup, researchers
could track the direction the
butterfly was orienting toward
and whether it was actively
flying or gliding.
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Indigo buntings and navigation by the stars
Emlen began by creating funnel-shaped
test cages for buntings, at the bottom
of which he placed an ink pad.
The cages were constructed such that
each time a bunting tried to fly out, the
location of its footprint was marked by
ink, and so its orientation pattern was
easily recorded (Fig. 13.15)
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The Earth’s magnetic field
 Evidence that the magnetic field of the earth is
important in migration has been found in a
wide diversity of animals, including birds,
amphibians, reptiles, and insects.
 Bobolink (rice bird) has one of the longest
round-trip annual migrations of any animal–
12,400 miles.
 These birds spend the summer months in the
northern US and Canada and then undertake a
migration to South America (primarily Brazil,
Paraguay, and Argentina) before they return to
the Northern Hemisphere.
 Do they use the magnetic field of the earth?
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Magnetic fields and bobolinks
 Bringing birds into a planetarium and
projecting the star patterns, also to
manipulate the magnetic polarity.
 When the visual cues and magnetic polarity
provided the same information, the birds
oriented in the correct southern direction.
 A visual cues were correct, but the magnetic
polarity was reversed, birds headed toward the
magnetic south.
• Magnetic cues were critical in the annual round-trip
migration.
• High levels of an iron-rich, magnetically sensitive
substance in bobolinks.
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The heritability of migratory restlessness
 Compared the onset of migratory activity between
laboratory and wild birds in 18 different species.
 A strong correlation between onset of migratory activity
in both groups of birds, suggesting that the timing of
departure for migration may be under genetic control.
 Migratory restlessness during the autumn migratory
season.
 Collected 40 blackcaps from the field
 The 10 birds with the latest dates for migratory
restlessness were selected and allowed to mate. They
produced a total of 26 offspring, and from that group 4
pairs with late-onset migratory birds.
 In only two generations, migratory restlessness was
delayed for an average of 7.65 days (Fig. 13.17)
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In each generation,
German blackcap
birds with the latest
onset of migratory
activity were chosen
to breed. In just two
generations, the
onset of migratory
activity was set back
more than a week.
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Defense against parasites
 The energy expended during long migration
can reduce immune responsiveness, making
animals more susceptible to disease.
 In addition, long-distance migrants also face new
parasites and diseases upon arrival at their
migratory end point.
 Migratory birds should therefore invest more
heavily in immune function compared to related
resident relatives. (hypothesis)
 Test:
• the bursa of Fabricus was larger in birds from the
migratory species, while in nine of thirteen pairwise
comparisons.
• The spleen was larger in birds from the migratory
species.
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Phylogeny and migratory behavior
 In the avian family Motacillidae
 Evolutionary precursor model of migration
 Migration will be associated with species that live
in open or edge habitats (so-called non buffered
areas) rather than species that live in forests
(buffered areas).
The pied wagtail
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The golden pipit
The yellow-throated longclaw
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Evolutionary precursor model
 49 spp. In the Motacillidae family
 As either “migratory” or “sedentary”, and their
habitat as either open/edge or forest.
 They found that
 there was no association between habitat in terms
of open/edge versus forest
 Species that were associated with open/edge
habitats were no more likely to migrate than were
species that lived in the forest.
 Species that lived at higher altitudes were much
more likely to migrate than species that live at low
altitudes.
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Interview with Dr. Judy Stamps
Of all the systems you could have
chosen to study territoriality, how did
you end up working with small lizards?
Dr. Judy Stamps is a professor at the
University of California at Davis. Her
long-term work on lizards and
territoriality has produced
fundamentally new ideas on both
territoriality and the role of learning in
territory formation.
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問題與討論
Ayo NUTN website:
http://myweb.nutn.edu.tw/~hycheng/