Social Insects
Social Insects
“The little things that run the world”- E.O. Wilson
Social Insects
I. Levels of sociality II. Castes and Polyethism III. Social insect examples IV. Ecological success
Society
• A group of individuals that belong to the same species and are organized in a cooperative manner.
Aggregations
• Non-social grouping of individuals
Monarch butterflies aggregating
Levels of Sociality
• • • • • Solitary Subsocial Parasocial Eusocial Presocial
Classification system for presocial and eusocial insects
Common nest Cooperative site brood care Reproductive castes Generational gap Solitary Subsocial or communal No Yes No No No No No No
Quasisocial Semisocial Eusocial
Yes Yes Yes
Yes Yes Yes
No Yes Yes
No No Yes
Solitary
• Interactions among individuals limited to sexual behavior and competiton • Adult-to-offspring relationship limited to oviposition • EXAMPLES: phasmids, solitary bees
Subsocial
• Adults protect/and or feed the young after hatching, but parents take off or die prior to maturity of offspring (limited parental care) • Some provide food (progressive provisioning)
Female shield bug protects her brood from a predatory spider
Parasocial
• Interactions among adults of the same generation • Includes communal, quasi-social, and semisocial behavior
– Communal (aggregate to build nests together, but construction & provisions is done individually) – Quasi-social (while making provisions for own eggs, individuals share their provisions) – Semisocial (females are mated and lay eggs as queens)
Semi-social: Polistes (paper) wasps
“Presocial”
• Any social behavior beyond sexual behavior, yet short of eusocial behavior
Myschocyattarus spp. Vespidae Paper wasps from Indonesia
Eusocial
“true sociality” requires: 1) Cooperative brood care 2) Reproductive division of labor 3) At least 2 generations overlap (kids aid parents in colony work)
Honey bees on brood comb
Eusocial Insect Groups
“The little things that run the world”- E.O. Wilson
Social Insects
I. Levels of sociality II. Castes and Polyethism III. Social insect examples IV. Ecological success
Society
• A group of individuals that belong to the same species and are organized in a cooperative manner.
Aggregations
• Non-social grouping of individuals
Monarch butterflies aggregating
Levels of Sociality
• • • • • Solitary Subsocial Parasocial Eusocial Presocial
Classification system for presocial and eusocial insects
Common nest Cooperative site brood care Reproductive castes Generational gap Solitary Subsocial or communal No Yes No No No No No No
Quasisocial Semisocial Eusocial
Yes Yes Yes
Yes Yes Yes
No Yes Yes
No No Yes
Solitary
• Interactions among individuals limited to sexual behavior and competiton • Adult-to-offspring relationship limited to oviposition • EXAMPLES: phasmids, solitary bees
Subsocial
• Adults protect/and or feed the young after hatching, but parents take off or die prior to maturity of offspring (limited parental care) • Some provide food (progressive provisioning)
Female shield bug protects her brood from a predatory spider
Parasocial
• Interactions among adults of the same generation • Includes communal, quasi-social, and semisocial behavior
– Communal (aggregate to build nests together, but construction & provisions is done individually) – Quasi-social (while making provisions for own eggs, individuals share their provisions) – Semisocial (females are mated and lay eggs as queens)
Semi-social: Polistes (paper) wasps
“Presocial”
• Any social behavior beyond sexual behavior, yet short of eusocial behavior
Myschocyattarus spp. Vespidae Paper wasps from Indonesia
Eusocial
“true sociality” requires: 1) Cooperative brood care 2) Reproductive division of labor 3) At least 2 generations overlap (kids aid parents in colony work)
Honey bees on brood comb
Eusocial Insect Groups