Biology 484 – Ethology

Chapter 3 – The Development of Behavior: Genetic and Environmental Factors

Chapter 3 Sanderling growth & behavioral development depend on genes & environment

All species depend on the interaction of their genes and how these genes interact with the environment to guide their growth, development, and ultimately their behavior.

Honey Bee

(Apis melifera)

This social insect is found in large colonies with typical population sizes numbering in the thousands.

Three different “types” of bee are easily identified:

Queen - an adult female capable of reproducing. She is usually the mother of all the bees in the hive.The queens are developed from larvae selected by worker bees and specially fed in order to become sexually mature.

Worker - is any female that lacks reproductive capacity.

Drone – male

TypeBipotentialityRemains

Cell capped

Average Developmental Period

Start of Fertility

Body Length

Hatching Weight

Queen up to Day 3 Day 7½ 16 daysDay 23 and up

18-22 mmnearly 200 mg

Worker up to Day 3 Day 921 days (range: 18-22 days)

N/A 12-15 mmnearly 100 mg

Drone up to Day 3 Day 10 24 daysapprox. 38 days

15-17 mmnearly 200 mg

Some Basic Development Milestones in Various Types of Honey Bee Development

Development of worker behavior in honey bees

Worker bees exhibit behaviors grouped into age related castes. This means that at certain ages, the be will tend towards certain behaviors and functions.

Thought question: Can you suggest potential values to the order of the behaviors displayed by the bees as opposed to other orders for these behaviors?

Gene activity varies in the brains of nurse bees and foragers

An early version of what is known as a microarray analysis…. a genetic tool that can show functional activity of genes (is the geen actively functional, or is it “off”

17 genes are displayed in this image, and correspond to similar genes in fruit flies with similar presumed (putative) function. Note how the colony designations:

YN – young nursing worker beesOF – old foraging worker beesYF – young foraging worker beesON - old nursing worker bees

The single cohort colonies are experimental manipulations of the honey bee hive in which researchers have limited the workers to only one unified age group.

As these data show, expression changes in bees as the adopt/adapt to a atypical behavior they learn to display.

Social environment and task specialization by worker honey bees

In an interesting elaboration of the single cohort data is seen in similar single cohort colonies in which more of that same age are added:

1.When older bees are added to older bee colonies, the added bees adopt the role of forager.

2.However, when young bees are added to a young colony, the established bees become the forages.

Thought Question: How could you hypothesize about the evolutionary significance of these induced results?

Konrad Lorenz’s classic work on imprinting is especially useful in highlighting that tremendous linkage between genes, the environmental dependence for expression of the genes, and how these interactions affect behavior.

Imprinting is the term used in ethology to describe any kind of phase-sensitive learning that is rapid and independent of the consequences of behavior.

Imprinting in greylag geese

Cross-fostering has different imprinting effects in two related songbirds

GT = species called “Great Tit” BT = species called “Blue Tit”

Interpretation of data shown suggests:

Great Tits cross fostered with parents of a different species have low rates of pairing success, and even when they are successful, it is often with the host parent species.

Blue Tits cross fostered with parents of a different species have high rates of pairing success, and most instances it is with other members of their species, and only low rates with the host parent species.

This shows a greater significance of ENVIRONMENT for the Great Tit and a greater role for GENETICS in the blue tit.

Furthermore, the role of genetics seems more stable in the blue tit and less shaped by the environment (the low rate of mating with Great Tits).

Spatial learning by chickadees

Spatial learning is learning about location and position. In this study, the bird shows it is able to display this learning by searching far longer in sites where the bird had stored food.

Differences within a species in learned behavior

The environment plays a significant role in how well learning occurs.

Here chickadees in the harsh environment of Alaska show better memory of where stored food is located than do the same species in Colorado.

Nests of Polistes paper wasps contain odors that adhere to the bodies of the wasps

The odor cues that remain in the home next of these wasps are unique to other homes of the same species. This odor is recognized because of the larvae being closely associated with the nest and walls. These odor cues allow nest mates to recognize each other in adulthood.

Different wintering sites of blackcap warblers

Different populations of this bird choose distinctly different wintering sites.

Notice how SOME birds actually winter in the location where others exist in the summer.

Thought Question: How do you explain these differences, especially the OVERLAP of areas in the SAME SPECIES?

These data show flight points that were observed in the birds from each Summer locale. Notice the clustering of the directionality.

These data are not in the text, but show what is called “circular orientation data” that is examined through the use of “Circular Statistics” a special category of statistics.

When animals are collected and taken to a different location, you see that each population maintains a flight path that is unique to its Summer group.

Funnel cage for recording the migratory orientation of captive birds

Here is an example of an in-lab method to study orientation behavior. The same sort of situation can be used to study ANY orienting animal.

These type of data require “Circular Statistics” for analysis.

Whole fields of study IN statistics are devoted to analysis of directionality. The cutting edge nature of the statistical tools used for analysis of orientation data, makes it more challenging for biologists who want to enter the field of study.

Differences in the migratory behavior of two closely related birds

Black Redstarts begin to display “migratory restlessness” far later than do Common Redstarts.

Whatever environmental/genetic factor that influenced onset of this behavior has affected the wintering site location for each species.

Thought Question: Do the data concerning the hybrids suggest the potential causes of this behavior? Why or why not?

To successfully study the data on the next slide, we need to first look at the predicted and actual correlation of IQ for different groups of humans.

Why do people differ in their test scores? (Part 1)

P – O = parent and offspring

MZ – identical twins

DZ – fraternal twins

Points to Ponder:

a)What do the data comparing MZ groups adopted apart and DZ groups raised together suggest about genes and the environment?

b)What do the P-O data comparing the together group and the adopted apart group suggest about genes and the environment?

3.16 Why do people differ in their test scores? (Part 2)

These data for Spatial ability are similar in TREND to that of Verbal ability.

However, in examining the same two groups as suggested on the last slide…. What sorts of hypotheses can you make concerning genes and the environment relative to verbal and spatial ability?

What test(s) would you recommend to further understand these ideas?

The Fruit Fly

(Drosophila melanogaster)

This species is known as the common fruit fly (or sometimes the vinegar fly).

Thanks to Charles W. Woodworth and Thomas Hunt Morgan, this species is a model organism that is widely used for biological research in studies of genetics, physiology, and behavior.

Charles W. Woodworth (left) is credited with first breeding Drosophila in quantity while he was at Harvard. Thomas Hunt Morgan (right), in his biography says that Woodworth suggested that Drosophila might be used for genetics work.

The six behaviors displayed (A F) represent the sequence of mating behaviors shown in Drosophila melanogaster. These behaviors are able to be quantified in terms of occurrence, but also in terms of time intervals.

All of the developmental stages of Drosophila are potential stages for the observation of behavior.

Fruit Fly Developmental Stages & Life Cycle

Figure 3.24 Genetic differences cause behavioral differences in fruit fly larvae (Part 1)

“Rover” and “sitter” behaviors are displayed by larvae of fruit flies.

Measurement is taken as the larva moves across an agar plate.

In the work displayed, female sitters were mated with male rovers.

Figure 3.24 Genetic differences cause behavioral differences in fruit fly larvae (Part 2)

In this example, we can see when female sitters mate with male rovers, the larvae primarily show the rover phenotype in the F1 generation, suggesting that if a single allele drives this rover behavior, the inheritance is via autosomal dominance.

Question to Ponder:

What alternative explanations are there?

A Female Fruit FlyCarrying Fertilized Eggs

Fertilized Eggs are Laid in Culture Media Containing Chemical Being Studied

Larvae develop having been exposed through egg and larval stage

OR… WITH FURTHER MATURATION

OR… WITH FURTHER MATURATION

Pupae develop having been exposed through egg, larval and pupal stage

Adults develop having been exposed through entire life

Rover/Sitter Tests

Pupation Distance Measures

Adult BehaviorTests

3.17 A single gene affects maternal behavior in laboratory mice

Gathering and crouching behavior is a stereotypical behavior seen in wild-type mice.

The genes believed responsible for driving these behaviors are the fosB genes.

Females who are “knockout” mice for fosB genes do not exhibit typical parental care behaviors.

3.18 Social amnesia is related to the loss of a single gene

In this example, a gene referred to as Oxt is associated with recognition behavior. In the study, the male that is a “knockout” mouse for Oxt will not show a decline in “inspections” of a female in his cage. The inspection rate of an Oxt intact mouse shows a rapid decline across trials, suggesting recognition of the female.

3.20 A coastal Californian garter snake about to consume a banana slug

Could there be a genetic component to food choice….. In Garter Snakes?!?

3.21 Response of newborn, naive garter snakes to slug cubes

In the experiment shown, the researchers obtained newborn snakes (that had never fed) from two different regions and compared their responses to banana slugs.

3.22 A tongue-flicking newborn garter snake senses odors from a cotton swab

3.23 Density effects on the foraging behavior of fruit fly larvae

This is the end of Chapter 3 Part A