1. Differentiation in eusocial colonies
How bees differentiate into queen vs workers?
Differential feeding
Epigenetics – DNA methylation, 20+% of genes have differential expression in bees

2. Eusocial colony can be considered a “superorganism”-

3. Coordination of colony members can create remarkably complex structures
weaver ant nest
honeybee hive
inside a weaver ant nest

4. Leaf cutter ants

5. Queen termite
pic of bee queen
Queen bee
Reproductives

6. Complexity in cooperation
Communication within colonies relies on chemical, tactile and visual signals
Activities are coordinated without any centralized ‘overseer’
Queen signals only control new queen production

7. Queen control over queen rearing

8. Coordination comes from workers and external cues
leaf damage recruits carriers
honeybee foragers dance
to recruit more foragers
high colony humidity, temperature
increases worker fanning
time to unload nectar indicates
colony nutritional status
ants following pygidial gland extract

9. Ant recruitment

10. Honeybee dance communication
Sound cues and dance provide information on distance and direction of food Honeybee communication

11. Honeybee dance communication
Controversy regarding true function of bee dances was resolved with use of robot bee
Robot needed dance and sound to recruit foragers

12. Colony decision making
“Voting” for a new colony site
Scouts communicate locations and site quality
Eventually one dance wins out

13. Life in an ant colony… Text uses black garden ant as example:
Colony founding
First generation of workers
Eventual reproductive generation
Death of queen
How did species evolve to such eusociality?
rB – C > 0

14. How does eusociality start?

15. Pathways to eusociality
1. Subsocial route (“staying at home”)
supported by intermediately social Polistes wasps,
hover wasps
Like helpers at the nest species
2. Parasocial route (“sharing a nest”)
supported by allodapine bees, some paper wasps,
Like communal breeding groups

16. Subsocial route
rB – C > 0 more likely Can involve parental manipulation or mutualism Solitary Parental Offspring Sterile care may stay castes

17. Subsocial route Halictid (sweat) bees have a range of sociality
In some spp, founding female lays an initial set of offspring that are ‘manipulated’ to be workers
Indirect fitness can still be high when raising siblings and mom lays tons of eggs