Mądra-Bielewicz, AnnaMatuszewski, Szymon2026-02-022026-02-022026Mądra-Bielewicz, A., Matuszewski, S. Parent-offspring competition for food constrains parental care in communal carrion beetles. Animal Behaviour, 2026, 233: 123471https://hdl.handle.net/10593/28431Parents and offspring of many animals regularly share food resources, which may promote competition among kin for food and ultimately constrain the development of family life. We hypothesize that parent-juvenile competition for shared food is especially intense in communal systems, particularly those that exploit ephemeral resources (e.g. carrion), promoting early dispersal of adults from a shared resource and in this way constraining parental care. We tested this hypothesis in communal carrion beetles Necrodes littoralis (Staphylinidae), a species colonizing cadavers of large vertebrates that exhibit no post-hatching forms of parental care. By manipulating the number of adult beetles, the time they stay on food resources and the quality of that resources, we provide evidence that parent-juvenile competition for food on carrion has a constraining effect on parental care in communal carrion beetles. When we doubled the time spent by adult beetles on shared food, there was a clear negative effect on juvenile fitness, but doubling the number of the beetles had no significant effect. Therefore, parent-juvenile competition for shared food resources limits primarily the time adult communal beetles stay on carrion. By promoting earlier dispersal of adult beetles from a nesting site, this form of competition reduces the time window for potential adult-juvenile interactions, which makes post-hatching care virtually impossible to develop in these beetles. These findings highlight the importance of competitive adult-juvenile interactions in the large communal groups that use high-quality ephemeral resources.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/intraspecific competitionfood sharingparental careephemeral resourcesparent-offspring conflictcarrion insectsNecrodesinfo:eu-repo/semantics/articlehttps://doi.org/10.1016/j.anbehav.2026.123471