How does an animal organize its priorities?
1
5/21/08: Organization of Behavior
Lecture objectives:
1.
Develop a proximate understanding for
why animals don’t exhibit several
behaviors simultaneously
2.
Understand how behavioral schedules
are regulated and how they allow
animals to meet the demands of a
changing environment
3.
Recognize the role that hormones play
in eliciting behavioral change
2
Short-term scale: Neural command centers are
responsible for activating a particular response
- Center is activated through animal’s
- Inhibition: active center can suppress or inhibit other centers
- These inhibitory relationships may change
b, a, c, d
a
a, c, d, b
b
c
d
3
Example: praying mantis nervous system
Sex is a “no-brainer” for a
male praying mantis
4
Animals need to modulate behavior to meet the
demands of environmental cycles
Daily light/dark cycle
active/asleep
Lunar cycle
forage/don’t forage
Annual cycles:
temperature/food supply
Migration, breeding,
hibernation
How do animals do this?
5
Do animals track their environment
or have an internal clock?
6
Humans have a circadian rhythm
7
Circadian rhythms likely serve an adaptive function
Environment-independent component:
Environment-dependent component:
8
Proximate basis of circadian clock
Location:
Rhythmic changes in gene activity:
9
Other behavioral schedules
Circannual
Lunar, and
food-dependent
10
Hormones play an important role
in the organization of behavior
Changes in environment
Detection by neural centers
Translated into hormones
Physiological and behavioral changes;
i.e. control of reproductive behavior
11
Hormones and how they work
Hormone:
12
Effects of hormones can be organizational or activational
Organizational
Activational
Hormone action during early
development
Hormone action on tissues
Effects are often
Effects are often
Female egg
Light
feeding
Heavy feeding +
royal jelly
Concentration
of JH
nurse
forager
13
Example:
Hormones mediate the effects of mating
on the behavioral priorities in male Japanese quail
Organizational or
activational?
Time at
window
Before
mating
After
mating
+T
+ T + A.I.
14
Example:
Photoperiod alters effects of estrogen (via T)
on male beach mouse aggressiveness
15
The precise role of hormones varies across species
16