Abstract
It is well known that organisms defend their fitness against attack from parasites and pathogens by mounting a personal immune response. However, there is increasing evidence that organisms from diverse taxa also exhibit immune responses for the purpose of protecting other individuals as well as themselves. We argue that any type of immunity that has fitness consequences for both the challenged individual and one or more recipients should be referred to as ‘social immunity’. We show that social immune systems are a widespread yet relatively neglected component of immunity, ideal for the study of social evolution. Whereas personal immune systems protect lifespan, social immune systems effectively defend the fecundity component of fitness, commonly protecting offspring or reproductive kin. We suggest that there are likely to be close links between life history and the extent of investment in each form of immunity. Furthermore, trade-offs between social and personal immunity may explain individual variation in personal immune responses, including sex-specific immune defences.
Highlights
Many organisms defend their fitness against attack from parasites and pathogens by mounting an immune response
Applying the same logic to immune function, we suggest that any type of immune response that has been selected to increase the fitness of the challenged individual and one or more recipients should be classified as social immunity
Where there is biparental care, such as in the burying beetle, and both parents contribute to social immunity (Cotter and Kilner, 2010), each potentially gains additional benefits, in some cases this may be because there is increased genetic diversity in the immune service, which may well make it more effective (e.g. (Sherman et al, 1988) and partly because the cost of investing in social immunity is shared
Summary
Many organisms defend their fitness against attack from parasites and pathogens by mounting an immune response. There is increasing evidence that immune systems can provide fitness benefits to others, besides the individual mounting the response.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
