ENT104 - Social Behavior: Simple to Complex (L19)

How do Sawflies defend themselves against predators?

Form tight aggregations that move together for group defense

Sequester (obtain from food) toxic secondary compounds for group defense

What does social behavior evolve from?

Parental care

Social groups are _____

Family groups

What is eusociality?

Societies with:

Overlapping generations

Cooperative brood care

Division of labor (caste systems)

(I use "OCD" to remember this)

Eusocial means ________ (2 words)

"Truly Social"

What are 3 minor groups of eusocial insects?

Aphids

Thrips

Ambrosia Beetles

(True/False)

Eusocial behavior is rare outside of major groups of social insects

True

Where do social aphids form their colonies?

Inside galls

All social aphids within one gall are _____

Clones

How do social aphids defend the colony?

Specialized sword-like appendages on soldiers are used to attack predators (the aphids might also be venomous)

Why do we care about eusociality? (3 main reasons)

Ecological dominance (eusocial insect biomass greatly outweighs vertebrate biomass)

Interesting evolutionary questions (such as bee suicide)

They are the most complex animal societies

What is the simplest eusocial pattern?

Alternative reproductive tactics

How many individuals might be in a colony that uses alternative reproductive tactics?

Very few (2-6) individuals

What do subordinates do in a colony that uses alternative reproductive tactics?

Forage food and build the nest (sometimes guards)

What do dominant individuals do in a colony that uses alternative reproductive tactics?

Reproduce, guard the nest, build the nest

Alternative reproductive tactics in insects and cooperative breeding in birds is an example of what type of evolution?

Convergent evolution

How many workers might be in a team-like insect society?

Dozens to hundreds of workers

What does the Queen of a team-like society do?

Lays eggs and stays in the nest

(True/False)

Queens of a team-like society are physiologically specialized and usually overtly dominant

True

How do insects in a team-like society communicate?

Through pheromones and mechanical signals

(True/False)

Team-like societies have distinct caste systems

False

Team-like societies do not have real castes. Workers work on and off the nest

How many workers might be in a factory-like insect society?

thousands to millions of members

Factory-like societies have ______ worker/queen dimorphisms

Permanent

Factory-like societies have (Flexible / Inflexible) physical or temporal castes

Inflexible

Workers have limited task repertoires

Caste switching is a slow process (inflexible)

What is the division of labor in a Factory-like society based on?

Age

Physiological specialization in workers for nursing and foraging

What are physical castes?

Castes based on morphological differences

What are temporal castes?

Castes based on age

What are two trends in the evolution of eusociality?

Evolving more divisions of labor

Evolving more communication signals

(True/False)

Factory-like societies have more elaborate communication systems than team-like societies

True

What are the main differences between Team-like societies and Factory-like societies?

Team:

- Flexible workers can fill in for other workers

- Individuals can perform several different tasks (flexible castes)

- Uncertainty is handled by flexible workers

Factory:

- All workers are specialized and cannot fill in for other workers

- Individuals perform specific, highly-specialized tasks (inflexible castes)

- Uncertainty is handles through elaborate plans and procedures

How are organisms and superorganisms similar?

Organisms are societies of cells, Superorganisms are societies of individual organisms

How are organisms organized compared to superorganisms?

Organisms

- Anatomical organization of organs and tissues

Superorganisms

- Organization of castes by age and morphology

How are organisms coordinated compared to superorganisms?

Organisms

- Physiological coordination through hormones and nerve cells

Superorganisms

- Communication through pheromones, acoustics, and mechanical signals

What does anatomy refer to?

The specialization of cells into tissues or organs

What roles do organs play in the body?

Specialized roles depending on the organ (digestion, detoxification, movement, sensory processing, etc.)

What does physiology coordinate?

Functioning of all specialized organs

What is the function of the endocrine system?

Send slow development messages throughout the entire body

What is the function of the nervous system?

Send fast messages between particular organs

What kinds of signals do the endocrine systems of eusocial insects pick up?

Pheromones (chemical signals)

What kinds of signals do the nervous systems of eusocial insects pick up?

Mechanical signals (visual signals)

How many different pheromones are found in Apis (honeybees)?

50

How many different mechanical signals are found in Apis (honeybees)?

10-15

Bee bodies and bee colonies are _______ in design

Convergent

An individual animal is an organism in which the units are ______

Cells

A colony of animals is an organism (superorganism) in which the units are ________

Highly specialized individual animals

Colonies are (Simple / Complex) organisms

Simple

What are some examples of simple colonial organisms?

Sponges (Porifera), Jellyfish (Cnidaria), Urchins (Echinodermata)

What are the 4 major social lineages of insects?

Social wasps

Social bees

Ants

Termites

What are two examples of social wasps?

Polistes wasps (Paper wasps)

Polybia wasps (Swarm-founding wasps)

Polistes wasps have (Team / Factory) -like societies

Team

Polybia wasps have (Team / Factory) -like societies

Factory

(True/False)

Polybia wasps have advanced eusociality similar to honeybees

True

(True/False)

Polistes wasps have advanced eusociality similar to bumblebees

False

Polistes wasps and bumblebees have primitive eusociality (Team-like societies)

What social bees are incipiently (simple) eusocial?

Halictids and Allodapine bees

What social bees are primitively eusocial (team-like)?

Bumblebees and some Halictids

What social bees are advanced eusocial (factory-like)?

Honeybees and Stingless bees

Bullent ants, meat ants, and bulldog ants are all examples of _____

Ponerine ants

(True/False)

All ants are highly social

True

What kinds of ants have team-like (primitive) societies?

Ponerine ants (bullet ants, bulldog ants, meat ants)

What kinds of ants have large colonies?

Harvester ants, wood ants, fire ants, argentine ants

(True/False)

All termites are highly social

True

Ant colonies and Termite colonies are examples of ______ evolution

Convergent

How are some ant colonies and termite colonies similar?

both have soldier castes

both can raise fungi (fungi gardening)

What are the 4 main differences between social aculeates (bees, ants, wasps) and termites?

Termites have:

- male AND female workers

- kings AND queens

- Workers undergo several molts

- Complex molts

What are the two major social classes of termites?

Lower termites and higher termites

Differentiate between lower termites and higher termites

Lower:

- flexible castes (similar to team-like society)

- small colonies

- simple organization

Higher:

- specialized castes (mound builders, soldiers, etc.)

- large colonies

- some grow fungi

(True/False)

Higher termite colonies are very complicated and poorly understood

True

Why does aggregation alone not constitute social behavior?

Animals can live in dense concentrations and aggregate due to clumped resources like food or nesting sites

What does social behavior refer to?

Animals living in groups for behavioral reasons alone

What are the 3 main forms of social behaviors?

Cooperative breeding/incipient eusociality (mother and offspring)

Aggregation for group defense, feeding, adaptation, thermoregulation, etc.

Parental care (any care provided after laying of eggs)

(I use "CAP" to remember this)

(True/False)

Subordinate individuals in a society that uses alternative reproductive tactics cannot become solitary

False

Subordinate individuals in simple societies can become solitary but choose to play a role in the colony

(True/False)

Individuals in a simple society can switch between subordinate and dominant

True

Colonial metazoan anatomy and advanced social insect colony anatomy are examples of _______

Convergent evolution of colonial behavior

What is Convergent evolution?

When unrelated organisms evolve similar traits/behaviors in response to similar selective pressures by natural selection

Same basic adaptations to the same problem

What is the common selective force in superorganism species?

The need to specialize and coordinate individuals to work with a unity of purpose

Social anatomy refers to ____

Castes

What is social physiology?

Communication systems that keep all individuals in a colony coordinated through chemical, mechanical, and acoustic signals

What is social physiology convergent with?

Metazoan physiology (endocrine and nervous system)