article published yes Sylvia Cremer author 2F64EC8C-F248-11E8-B48F-1D18A9856A870000-0002-2193-3868 Christopher Pull author 3C7F4840-F248-11E8-B48F-1D18A9856A870000-0003-1122-3982 SyCr department Socially living animals can counteract disease through cooperative defences, leading to social immunity that collectively exceeds the sum of individual defences. In superorganismal colonies of social insects with permanent caste separation between reproductive queen(s) and nonreproducing workers, workers are obligate altruists and thus engage in unconditional social immunity, including highly specialised and self-sacrificial hygiene behaviours. Contrastingly, cooperation is facultative in cooperatively breeding families, where all members are reproductively totipotent but offspring transiently forgo reproduction to help their parents rear more siblings. Here, helpers should either express condition-dependent social immunity or disperse to pursue independent reproduction. We advocate inclusive fitness theory as a framework to predict when and how indirect fitness gains may outweigh direct fitness costs, thus favouring conditional social immunity. https://research-explorer.ista.ac.at/download/17461/18816/2024_TrendsParasitology_Cremer.pdf application/pdfno Elsevier2024 eng 1471-4922 1471-5007 39152078 00130781570000110.1016/j.pt.2024.07.014 409780-787 Cremer, Sylvia, and Christopher Pull. “Unconditional versus Condition-Dependent Social Immunity.” <i>Trends in Parasitology</i>. Elsevier, 2024. <a href="https://doi.org/10.1016/j.pt.2024.07.014">https://doi.org/10.1016/j.pt.2024.07.014</a>. S. Cremer, C. Pull, Trends in Parasitology 40 (2024) 780–787. Cremer, Sylvia, and Christopher Pull. “Unconditional versus Condition-Dependent Social Immunity.” <i>Trends in Parasitology</i>, vol. 40, no. 9, Elsevier, 2024, pp. 780–87, doi:<a href="https://doi.org/10.1016/j.pt.2024.07.014">10.1016/j.pt.2024.07.014</a>. S. Cremer and C. Pull, “Unconditional versus condition-dependent social immunity,” <i>Trends in Parasitology</i>, vol. 40, no. 9. Elsevier, pp. 780–787, 2024. Cremer, S., &#38; Pull, C. (2024). Unconditional versus condition-dependent social immunity. <i>Trends in Parasitology</i>. Elsevier. <a href="https://doi.org/10.1016/j.pt.2024.07.014">https://doi.org/10.1016/j.pt.2024.07.014</a> Cremer S, Pull C. 2024. Unconditional versus condition-dependent social immunity. Trends in Parasitology. 40(9), 780–787. Cremer S, Pull C. Unconditional versus condition-dependent social immunity. <i>Trends in Parasitology</i>. 2024;40(9):780-787. doi:<a href="https://doi.org/10.1016/j.pt.2024.07.014">10.1016/j.pt.2024.07.014</a> 174612024-08-25T22:01:08Z2025-09-08T09:01:42Z