to restrict disease transmission. organisational disease defence — or organisational immunity — refers to patterns of social interactions which could, hypothetically, mitigate disease transmission in a social group. as disease transmission occurs through social interactions, changes in the type and frequency of these interactions are expected to modulate disease spread. organisational immunity is predicted to have both a constitutive and an induced component. the innate, organisational substructure of social insect colonies may provide constitutional protection of the most valuable colony members, the queens and brood, as disease will be contained within subgroups. social insect colonies are segregated into worker groups that experience different disease hazards, where the young and reproductive individuals interact minimally with the workers performing the tasks with higher disease risk (e.g. foragers). this segregation can arise as a result of the physical properties of the nest or the differences in space usage of the individuals. it can also result from age- or task-biased interactions. distinct activity patterns between group members (e.g. individuals with relatively higher number of interactions, or high number of interaction partners) has also been hypothesized to influence disease spread. it is further assumed that social insects may further modulate their interaction networks upon disease coming into the colony. however, the organisational immunity hypothesis is currently mainly supported by theoretical models and awaits empirical testing.