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Chap.03 Proximate
factors
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
Proximate factors
1. Ultimate and proximate perspectives
2. Hormones and proximate causation
3. Neurobiological underpinnings of
behavior
4. Molecular genetics and animal
behavior
5. Development and animal behavior
6. Foraging in Honeybees: an
integrated proximate analysis
7. Interview with Dr. Geoggrey Hill
Significant natural variation exists in house finch coloration.
Artificially brightened (top left to top right photo) or lightened (bottom left to
bottom right photo) the plumage coloration of male house finches.
Hill examined how brightening and lightening plumage coloration
affected a suite of variables in male house finches. There were 40
males in the brightened condition, 20 males in the same control, and 40
males in the lightened condition.
Hormones and Proximate causation
 introduction
 Endocrine system (Fig. 3.7)
 Neuro-hormones
 兩個案例：
1. The long-term effects of in-utero
exposure to hormones
2. Stress hormones and spatial memory in
rats
Hormones can affect input systems (sensory systems like
those for smell, sight, or hearing), central nervous system
function (processing), and output systems.
1. The long-term effects of in-utero exposure to hormones
When male
Mongolian gerbils
were castrated,
they spent more
time with pups
than did “sham”
castrated males
that had
undergone a
similar operation
but were not
actually castrated.
2. Stress hormones and spatial memory in rats
The swimming path of the
control rat was consistently
near the target (T), indicating
that its memory for the
location of the platform was
not impaired, while the
swimming path of the rat that
was shocked thirty minutes
before being put in the water
maze was random, indicating
that its memory for the
location of the platform was
impaired by the shock.
(A) Rats that
receive a shock
thirty minutes
before their trial in
the water maze
spend less time
near the platform
(target) than did
rats in the other
three groups.
Corticosterone levels
 Only rats in Group 1 (the group with
decreased ability to find the area of the
platform) had higher levels of corticosterone,
suggesting an important memory inhibiting
role for this hormone.
 Injected rats with a drug called methrapone,
rats did not show impaired memory compared
to control one.
 Methrapone, inhibits the production of
corticosterone by blocking certain cheical
reactions in the adrenal glands, where
corticosterone is produced.
Neurobiological
underpinnings of behavior
Neurobiology and learning in voles
Meadow voles
 Males showed superior spatial learning
abilities.
 From a neuroethological perspective,
we can
1. Examine the neural substrate underlying
the differences in male and female spatial
learning abilities
2. Examine how components of the nervous
system change as a function of a spatial
learning experience.
Male meadow
voles spent
more time near
the platform in
water maze
trials than did
female
meadow voles.
In meadow
voles, males
have more
dentritic spines
in both the
frontal and the
parietal cortex
of the brain
than do
females.
Neural plasticity
The rats went through the spatial
learning trails would have more
dendritic spines than the control
animals.
This is a good example of neural
pasticity.
 The ability of neurons to undergo change
as a function of experience.
Vocalizations in plainfin midshipman fish
(A) The two smaller fish on the ends are type II sneaker
males (who do not sing), while the fish that is second from
the left is a “singing” type I parental male.
Sleep and predation in Mallard ducks
 Sleeping individuals are more susceptible to
being attacked by predators.
 Sleeping with one eye open and one eye
shut.
 This type of sleep was first recorded in chickens
and is best examined in mallard ducks.
 Birds are capable of putting one hemisphere of the
brain– the hemisphere active during – into what is
called slow-wave sleep.
Slow-wave sleep
 “slow-wave” refers to the frequency of the
brain waves that investigators record using a
device called an electroencephalogram
(EEG).
 This slow-wave state allows quick responses
to predators, but it does not interfere with the
sleeping half of the bird’s brain until danger is
present.
 EEG recordings indicate that the part of the
brain controlling the open eye during
unihemispheric sleep showed the low
frequency range characteristic of slow-wave
sleep, while the other half showed EEG
patterns that were similar to those of true
sleep.
In some aquatic mammals, like the fur seal,
unihemispheric sleep is thought to allow individuals to
swim to the surface and breathe during sleep.
4. Molecular genetics
1) Ultraviolet vision in birds
•
•
•
A wide array of animals, including fish,
amphibians, reptiles, birds, insects, and
mammals. (Table 3.3)
In mammals, is used in the context of mating,
foraging, hunting, and social signaling.
UV vision in zebra finches.
2) Song acquisition in birds
 The zebra finch has become a model system
to illustrate the relationship between gene
expression and birdsong.
 Habituation
A single amino acid change
 Zebra finches are able to see in UV, and via a
single amino acid change (C84S), the
researchers were able to transform the
ultraviolet pigment– the substance that allows
the birds to see in UV– into a violet pigment
that doesn’t allow for UV vision.
 Using sections of DNA that were very similar
to those found in the finch, the researchers
were able to generate ultraviolet pigments
from violet pigments.
 One change in amino acid, and pigeons and
chickens were able to see in UV.
Song acquisition in birds
 The FOXP2 gene in brain regions is
associated with both song perception in birds
and language acquisition in humans.
 Zebra finch, a model system, to illustrate the
relationship between gene expression and
birdsong.
 Neostriatum in the forebrain,
 A gene called zenk, increased after the birds
heard zebra finch songs, and that was associated
with an increase in the number of neurons in the
neostratum (Fig.3.30)
(A)Induction of zenk mRNA in the forebrain of a male
zebra finch that has been exposed to zebra finch song
for forty-five minutes.
(B) same area in male who was not exposed to song.
if a zebra finch is played the same song repeatedly, all of the
strong responses begin to decrease, and slowly return to their
baseline levels. (habituation).
5. Development
Early development and its effect on
parental behavior in the oldfield mouse.
 Mice in the Brookfield Zoo.
 IF = inexperienced female
 EF = experienced female
 The broods of EF survived with a higher
probability than those of IF, in part due to
the superior nest-building behavior
displayed by EF. (Fig. 3.32)
Development, Temperature, and ovipositing
behavior in wasps
Foraging in honeybee
Mushroom bodies, at the front brain
 Both the mushroom bodies and the
hippocampus are often associated with
spatial navigation.
 Mushroom bodies play a central role in
spatial navigation and foraging behavior
in honeybee. (Fig. 3.35)
 Mushroom bodies were larger in foragers
than in bees that remained in a colony
(Fig.3.36)
Mushroom bodies – shown in light blue– are clusters of
neurons located at the front of the bee brain. The yellow
denoted the optic lobes of the bee brain.
Genes, mRNA and honeybee foraging
When compared to younger bees that
remained at the hive, per mRNA in
the brain was significantly greater in
older individuals that foraged for food.
(Fig. 3.37)
Both of the amount of manganese and
the amount of mRNA in the head were
high in pollen foragers and nectar
foragers, and low in nurses. (Fig. 3.38)
Hormones
 Four groups
 One is allatectomized bees, remove the corpus
allatum, the gland that produces JH, juvenile
hormone.(Fig. 3.39)
 One went through a similar surgical procedure but
did not have their corpus allatum removed.
 One, anesthetized only.
 One is control.
 Results:
 Allatectomized bees began foraging significantly
later.
Hormone: octopamine
Octopamine, neurohormone, has
been linked to increased foraging
activity in honeybees.
Octopamine modulates learning and
memory in honeybee, and also affects
their visual, olfactory, and gustatory
senses.
 Increase flight activity related to
foraging
問題與討論
Ayo NUTN website:
http://myweb.nutn.edu.tw/~hycheng/