Major disturbances can alter basal resource availability and reorganize energy pathways in stream food webs, yet their effects on the trophic basis of secondary production remain poorly resolved in tropical systems. We examined changes in the relative contribution of allochthonous and autochthonous carbon sources to the diets, assimilation, and production of dominant macroconsumers in a tropical stream before and after a major disturbance. Using stable isotope analysis (δ¹³C and δ¹⁵N), we quantified the proportional contribution of basal resources (i.e., leaf litter, biofilm, and algae) to consumer assimilation, with particular emphasis on taxa known to shift resource use following disturbance, such as freshwater shrimps, while contrasting them with taxa that maintained more consistent dietary signatures. Across both periods, macroconsumer biomass was dominated by freshwater shrimps; however, their trophic role shifted markedly following disturbance. Pre-disturbance conditions were characterized by greater reliance on allochthonous carbon sources, whereas post-disturbance conditions showed increased assimilation of autochthonous, algal-derived carbon by shrimps, consistent with patterns observed for scraper taxa in other systems. In contrast, several insect taxa exhibited limited changes in isotopic composition, indicating relatively stable reliance on detrital resources and a comparatively minor contribution of algal carbon to their assimilation. These patterns suggest that although autochthonous resources became more available following hurricane disturbance, their incorporation into secondary production was strongly taxon-specific. We propose that biotic interactions, particularly the dominance of shrimps, may mediate access to algal resources and potentially constrain dietary shifts in insect consumers through competitive displacement. Because shrimps represent non-emergent consumers, increases in their secondary production may further alter aquatic–terrestrial energy fluxes by retaining a greater proportion of carbon within the aquatic food web. Together, these results indicate that major disturbances can differentially modify the trophic basis of production in tropical streams through both changes in resource availability and consumer interactions.