Insects and People: Insect Sociality

Categorizing Socialism

All insects fall under a socialism category based on their interactions.

• Solitary
• Subsocial
• Communal
• Quasisocial*
• Semisocial
• Eusocial

*Quasisocial was not originally described as a form of socialism (until Michener 1969)

Solitary

Solitary insects: defined by an insect living most of its life alone

• Do not live with other insects!
• Only really interact with other insects when it’s time to mate

Communal

Communal insects: members of the same generation that live together

• No cooperative broodcare
• They take care of themselves and their own young

Subsocial

Subsocial insects: we define any insect that displays only parental care as subsocial

• Parents taking care of the next generation

Semisocial

Semisocial insects: insects in the same generation living together with reproductive division of labor

• Members of same generation living together
• Cooperative brood care
• Reproductive division of labor
• Quasisocial insects only differ by lacking reproductive division of labor

Eusocial

Eusocial insects: these are “True” social insects similar to human socialization

• Demonstrate cooperative brood care
• Reproductive division of labor
• Overlapping generations

Casting Systems

Polymorphism: casting system on eusocial insects

- Literally means “many forms”

Ant Colonies

Ants can cooperate in ways that are not common in the insect kingdom

• How do ants hunt and find prey?
  • Trail pheromones
• The first real “farmers”
• Workers, Soldiers, Queen, Dispersing (Alates)
• Multiple queens

Alates: an insect that has wings or winglike structures

Honeybees

• Honeybees are the “White man’s fly”
• Castes:
  • Drones
  • Queen
  • Workers
• Worker duties can be anything from food collection to tending for young to guarding against invaders
  • The age of bees decides what they do
• Royal Jelly
  • Every bee is fed royal jelly at first, but the queen consumes it her entire life, giving her wings
• What do bees eat?
  • Adults can only drink liquids
  • Larvae eat pollen, bee bread, royal jelly

Honeybee Communication

• Honeybees use a variety of “dances” to communicate to other bees
• They also use pheromones (alarm pheromone, swarming pheromone, etc.)
• Round dance: a dance bees use to provide information on food
  • Provides information on food sources close to the hive
  • New bees can smell the flower on the bee, scent gland leaves odor on flowers
• Waggle dance: a dance bees use to provide info on how far away food is
  • Provides information on distant food sources
  • The number of times the dance is completed = how far away it is
  • Direction is also given based on the orientation of the sun

Termites

Termites are similar to ants

• Caste Systems:
  • Workers
  • Soldiers
  • Queen
  • Dispersing (Alates)
• May either create colonies below (subterranean) or above ground
• Termite colonies may be very large with many compartments
• The form of soldiers depends on the type of termite

Matriarchy

Eusocial insects are a Queen-dominated society.

• Males are essential for mating… but that’s it.
• Why not just use parthenogenesis?
  • Parthenogenesis can lead to a lack of genetic variation, which can be harmful to a species when there is a change in the environment.
• There can be more than one queen (in ants)!

Eusocial Behaviors

• Trophallaxi: Insects share gut contents through regurgitation or poop
• Grooming: cleaning dust particles from sensory organs
• Trail marking with chemicals: leave chemical on ground to find the way back to food
• Nest odors
  • Why have one?
  • Myrmecophiles: interspecies associations between ants and other organisms
  • Paussus beetles can mimic the vibrations of queen ants and be treated like “royalty”. Once in the colony, it preys on ant larvae and adults.
• Complex nesting structures have heating and cooling dynamics
  • Behaviors to offset
• Reproductive swarms

Differences Among Termites, Ants, and Honey Bees

• Termites and bees are mostly vegetarian
  • Ants are both herbivores and carnivores
• Termite king are present and help in mating
  • Ants and honey bees have a promiscuous queen and dead kings
• Termite workers/solider are blind, sterile, and can be both male or female.
  • Ant and honey bee workers/soldiers are all sterile females, often sighted, and some have stingers.
• Termite nymphs work
  • Ant and honey bee larvae live the easy life
• Termites have gut microbes transferred from adults to nymphs
  • Ants and honey bees have no gut microbes
• Termites build with bricks and mortar, bees with wax
  • Ants only excavate