Spreading disease through social groupings in competition

Many animal populations live in social groups which avoid contact with other conspecific groups for at least part of the year. This may give rise to competition between groups for items such as shelter, land and mates. We couple intra-specific group competition with disease dynamics to investigate how infectious diseases may spread through population subgroups, particularly with reference to the contact rates between groups. Our model uses a nonlinear systems of ODEs for which steady-state analysis is carried out in the simplest two-group system. This indicates that coexistence of social groups is possible with the disease or that competitive exclusion occurs with one group dying out whilst the other retains disease. Moreover, we show that in certain circumstances the model can exhibit multistability and we discuss the ecological implications of this result in relation to contact between social groups.