How does an animal organize its priorities? 5/13/08

5/21/08: Organization of Behavior Lecture objectives: Develop a proximate understanding for why animals don’t exhibit several behaviors simultaneously Understand how behavioral schedules are regulated and how they allow animals to meet the demands of a changing environment Recognize the role that hormones play in eliciting behavioral change

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, c, d, b a b c d

Example: praying mantis nervous system Sex is a “no-brainer” for a male praying mantis

Migration, breeding, hibernation Animals need to modulate behavior to meet the demands of environmental cycles Daily light/dark cycle Lunar cycle Annual cycles: temperature/food supply active/asleep forage/don’t forage Migration, breeding, hibernation How do animals do this?

Do animals track their environment or have an internal clock?

Humans have a circadian rhythm

Circadian rhythms likely serve an adaptive function Environment-independent component: Environment-dependent component:

Proximate basis of circadian clock Location: Rhythmic changes in gene activity:

Other behavioral schedules Circannual Lunar, and food-dependent

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

Hormones and how they work

Effects of hormones can be organizational or activational Hormone action during early development Effects are often Activational Hormone action on tissues Effects are often Female egg Concentration of JH Light feeding Heavy feeding + royal jelly nurse forager

Organizational or activational? 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.

Example: Photoperiod alters effects of estrogen (via T) on male beach mouse aggressiveness

The precise role of hormones varies across species