Week 3: Development of behavior

Question 1

The nature vs nature controversy

Answer 1

The relative importance of an individual’s innate qualities (“nature”) versus personal experience (“nature”) in determining or causing individual differences in physical and behavioural traits.

Question 2

Nature

Answer 2

the basic neural circuitry for receiving stimuli in the early stages of development control much of an animal’s behavior

Question 3

Nurture

Answer 3

contend that environment plays a major role in learning behavior

Question 4

Other terms used for nature vs nurture

Answer 4

“innate” vs “learned”

“genetically determined” vs “environmentally determined”

“instinct” vs “learning”

Question 5

Development of worker behavior

Answer 5

Young nurse bee: feeding larvae, feeding nest mates, packing pollen

Old forager: foraging

The tasks adopted by worker bees are linked to their age.

What causes a worker to go through these stages?

Question 6

Central dogma of molecular biology

Answer 6

DNA <–> RNA –> protein –> behavior

Molecular building blocks —> behavior

Information flow in biological systems

Question 7

Microarray technology

Answer 7

is used in interpreting the data generated from experiments on DNA, RNA, and protein microarrays.

allows researchers to investigate the expression state of a large number of genes - in many cases, an organism’s entire genome - in a single experiment.

generates very large volumes of data, allowing researchers to assess the overall state of a cell or organism.

Question 8

Gene activity in the brains of workers

Answer 8

The active components of a worker bee’s genotype change between her nurse phase and her forager phase

Question 9

Juvenile hormones (JHs)

Answer 9

JHs regulate development, reproduction, diapause, and polyphenisms

JHs are secreted by a pair of endocrine glands behind the brain called the corpora allata

Young nurse bee: low JH concentration

Old forager: high JH concentration

Young bees — (+) JH —> precocious foragers

Young bees – (-) corpora allata–> the bees delays its transition to foraging

Bees without corpora allata – (+) JH –> bees switch to foraging

Question 10

Social environment and task specialisation

Answer 10

In experimental colonies composed exclusively of young workers, the young bees do not forage if older forager bees are added to their hive.

If young bees are added instead, the young residents develop into foragers very rapidly.

In honey bees, hormone production responds to the social environmental of individuals

Question 11

Honey production

Answer 11

Foragers collect nectar from flowers

Foragers regurgitate nectar and transfer it to nurse bees

Nurse bees deposit nectar in cells

A deficit in social encounters with older foragers may have stimulated an early developmental transition from nurse to forager behavior

Question 12

Ethyl Oleate

Answer 12

Is a primer pheromone composed of a fat acid compound.

Is released by foragers to slow maturing of nurse bees

Is transferred from foragers to nurses with nectar

Acts as a distributed regulator to keep the ratio of nurse bees to forager bees in the balance that is most beneficial to the hive

Ethyl oleate works as a negative feedback. When there’s ethyl oleate, then JH won’t be produced.

Ethyl oleate is an environmental signal

Question 13

DNA is both inherited and environmentally responsive

Answer 13

Worker foraging behavior cannot be purely “genetically determined” because the behavior is the product of literally thousands of chemical interactions between the bee’s genes and its environment.

The information in a gene is expressed only when the gene is in the appropriate environment.

Environmental signals influence gene activity.
When a gene is turned on or off by changes in the environment, the resulting changes in protein production can alter the activity of other genes.

Therefore, no trait can be purely “genetic.”

Question 14

Problems of the traditional view off behavioural development

Answer 14

It’s impossible to rear an individual in complete isolation from the environment

Interaction between the internal and external environment of the organism during key stages of the development may have effects on behavior

Question 15

Interactive view of behavioural development

Answer 15

The individual organism continually interacts with its internal and external environment

The individual and its environment are different at different times during development

Question 16

Development is an interactive process

Answer 16

1. Some of the genes can be turned on and off by the appropriate signals, which are ultimately derived from the environment
2. The development of any trait is the result of an interaction between the genotype of a developing organism and its environment

Question 17

Differences between individuals

Answer 17

Although no behavior is either purely genetic or purely environmental, differences between individuals can arise as a result of developmental differences stemming from differences in either their genes or their environments.

Environmental differences cause behavioral differences
Kin recognition in Belding’s ground squirrels

Genetic differences cause behavioral differences
Overwintering sites in blackcap warblers

Question 18

Belding’s ground squirrel

Answer 18

group-living, burrowing rodents found alpine and subalpine regions of the western USA

socially active above ground

Each mother produces one litter annually of 5-8 pups.

The squirrels possess scent-producing glands, including one around the mouth and another on the animal’s back.

These squirrels regularly sniff the oral glands of other individuals, as if they were acquiring odor information.

Question 19

Kin discrimination in Belding’s ground squirrels

Answer 19

The newborn offspring of captive females were switched around at birth, creating four classes of individuals
(1) siblings reared apart
(2) siblings reared together
(3) nonsiblings reared apart
(4) nonsiblings reared together

After having been reared and weaned, the juvenile ground squirrels were placed in an arena in pairs and given a change to interact.

Animals that were reared together, whether actual siblings or not, tolerated each other.

Question 20

Armpit effect

Answer 20

Biological sisters reared apart displays less agression towards each other than other combinations of siblings reared apart

The squirrels had some way of recognising their siblings that was not dependent on living with them as youngsters

Armpit effect:an individual learns to identify closely related individuals by their door, comparing it to its own smell for phenotype matching

Question 21

Odor-testing methods

Answer 21

Pregnant squirrels were captured and were moved to laboratory enclosures.

Juvenile squirrels had no prior experience with the odors of relatives.

Plastic cubes were rubbed on the dorsal glands of squirrels.

Odor donors: self, varying degrees of relatives, nonkin

Can inexperienced young squirrels discriminate between unfamiliar relatives and nonrelatives on the basis of odor cues alone?

Question 22

Belding’s ground squirrels learn their own odor

Answer 22

Juvenile squirrels were first given 3 trials during which they could investigate their own odors applied to plastic cubes.

The squirrels’ decline in responsiveness to their own dorsal gland scents over these initial trials → learning

Cubes with scent from close relatives received less attention than those with scents from distant relatives or nonkin.

They have the capacity to treat individuals differently on the basis of this highly specific learned label of relatedness.

Question 23

Different wintering sites of blackcap warblers

Answer 23

Blackcaps living in southern Germany and Scandinavia first go southwest to Spain before turning south to Western Africa

Blackcaps living in Eastern Europe migrate southeast before turning south to fly to Eastern Africa

Where do the birds that winter in Great Britain come from?

It turns out they do not come from Scandinavia

Question 24

Migration experiments

Answer 24

Wild blackcaps were captured in Britain during the winter and were taken to a laboratory in Germany.

The birds were kept indoors. Pairs of warblers were released into outdoor aviaries, where they bred.

Once the young birds were several months old, the young warblers and parents were placed in a funnel cage to determine the direction in which the birds intended to travel.

Question 25

Genetic differences can cause behavioural differences

Answer 25

Experienced adults and young novices alike, oriented due west.

These data showed that the adults, which had been captured in wintery Britain, must have traveled there by flying west from Belgium or from central Germany.

This point is confirmed by the discovery of some blackcaps in Britain that had been banded earlier in Germany.

Furthermore, young birds whose parents oriented in a southerly direction did the same in fall.

Behavioral differences in migratory orientation were caused by genetic differences between the two populations of individuals.