Introduction

Question 1

Behavioural Endocrinology

Answer 1

study of relationship between hormones and behaviour

Question 2

Summarise historical roots of behavioural endocrinology

Answer 2

some relationships between endocrine glands/hormones and behaviour have been recognised for centuries
e.g. behavioural and physical effects of castration

Question 3

Berthold’s Experiment (1849) - Groups

Answer 3

Group 1: Castration -> caponization
- small comb and wattles
- no interest in hens
- no aggression towards other males

Group 2: Castration and reimplantation of testis -> normal male development
- normal comb and wattles
- normal male behaviour

Group 3: Castration and transplantation of testis -> normal male development
- normal comb and wattles
- normal male behaviour

Question 4

Berthold’s Experiment (1849) - Conclusions

Answer 4

• testes are transplantable organs
• transplanted testes can function and create sperm
• non-neutral control of behaviour
• “secretory blood-borne product”

Question 5

Frank A. Beach (1911-1988)

Answer 5

founder of scientific discipline behavioural endocrinology

course on endocrinology at NY university -> lacked hormone-behaviour interactions -> professor allowed him to teach one lecture -> wrote review as term paper -> his book marked the beginning of the formal study of behavioural endocrinology (1948)

Question 6

Stages of behavioural research

Answer 6

Complete range of behaviours
-> trivial behaviours
-> relevant behaviours -> description of action + -> description of consequence

Description of action + Description of consequence
-> mechanisms (this is what behavioural endocrinology is based on)
-> development
“How” or proximate questions

-> evolution
-> function
“Why” or ultimate questions

Question 7

explain how hormones can affect behaviour

Answer 7

hormones affect behaviour + behaviour feeds back to affect hormones

hormones do not “cause” behaviour

hormones change probability that particular behaviour will be displayed in the appropriate context - hormones simply influence behaviour

Question 8

Hormone-behaviour interactions

Answer 8

1. hormone dependant behaviour should disappear when the source of hormone is removed/hormone actions blocked
2. restoration of source/hormone should reinstate behaviour
3. hormone concentrations and behaviour should co-vary

Question 9

Hormone-behaviour covariation

Answer 9

hormones may have long latency of action + many hormones released in pulsatile manner - single blood sample will not provide an accurate picture of an animal’s endocrine status

may come to different conclusions about hormone effect on behaviour if measure hormone concentrations when at peak rather than nadir -> obtain multiple measures

e.g. cortisol awakening response (cortisol peak approx 30 mins after awakening)

biologically effective amounts of hormones are small and difficult to measure accurately
measured in micrograms (ug), nanograms (ng), or picograms (pg)

lab environment may cause changes in an animal’s hormone concentrations and behaviour that may confound the results of experiments. Hormone-behaviour relationships established in lab should be verified in natural environments -> requires suitable methods