Molecular gut content analysis has revolutionised trophic ecology and provided precious insights for biological control. It allowed for the determination of the diet of many organisms and the identi cation of predators of speci c pests in natural conditions. However, DNA detectability depends on many parameters, notably on digestion rates that vary according to the predator-prey pair considered and the amount of prey consumed. When not considered, these factors may lead to an underestimation of the frequency of certain interactions compared with those for which the detection time window is wide, and to distortions in the conclusions of ecological studies.Here we study to which extent the identity of the prey and the predator affects the detection half-life of their interaction when using a diagnostic multiplex PCR. We focused on an omnivorous family of arthropods, carabid beetles, regarded as major natural enemies in many agroecosystems. To this purpose, the effects of digestion time, predator size, and voracity on DNA detectability were assessed for ve common prey types. Based on this study, a correction factor was generated for each species of predator and type of prey. Finally, predation intensity indexes of carabid communities on the ve prey types were calculated with and without the correction factor on a dataset containing observations from conventional and conservation winter wheat elds to illustrate the extent to which the inclusion of a digestion-based correction factor may alter the study's conclusions.Key Messages for many trophic interactions, the digestion process and its impact on DNA detection are unknown Size and voracity of the predator and prey identity impact digestion rates Assessment of predation intensity on agricultural pests is modi ed when considering digestion rates