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

Eusocial colony can be considered a “superorganism”-

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

Leaf cutter ants

Queen termite pic of bee queen Queen bee Reproductives

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

Queen control over queen rearing

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

Ant recruitment

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

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

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

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

How does eusociality start?

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

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

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