eng International Academy of Ecology and Environmental Sciences Arthropods 2224-4255 2026-9-1 15 3 154 174 2 article Rajendra Singh 1 2 K. M. Tiwari 1 2 Department of Zoology, Deen Dayal Upadhaya Gorakhpur University, Gorakhpur, Uttar Pradesh, India Department of Zoology, K.S. Saket P.G. College, Ayodhya, Uttar Pradesh, India The present study documents the tri-trophic associations among aphidiine parasitoids, aphid hosts, and host plants in Uttarakhand. A total of 51 parasitoid taxa were recorded in association with 59 aphid species infesting 69 host plant species, forming 131 tri-trophic associations (triplets). Species of Aphidius were dominant, with Aphidius matricariae exhibiting the widest host range (10 triplets), while Binodoxys indicus showed the highest ecological associations (12 triplets). Diaeretiella rapae also demonstrated broad host associations. In contrast, many parasitoid taxa exhibited high host specificity, being associated with only a single aphid and host plant species. Among aphids, Aphis gossypii showed the greatest ecological diversity, forming 10 triplets, followed by Brachycaudus helichrysi and Sitobion miscanthi with 7 triplets each. Most aphid species, however, displayed narrow ecological associations. Among host plants, Cestrum nocturnum and Rosa spp. supported the highest number of triplets (7 each), while economically important brassicaceous and cereal crops harboured several parasitoid-associated aphid species. Overall, the study reveals considerable diversity and complexity in aphidiine parasitoid-aphid-host plant interactions in Uttarakhand, comprising both highly specialised and broadly polyphagous species. The findings provide valuable baseline information for ecological studies, biodiversity assessment, and biological control programmes in Himalayan agroecosystems. http://www.iaees.org/publications/journals/arthropods/articles/2026-15(3)/catalogue-of-tri-trophic-associations.pdf tri-trophic interactions aphidiine parasitoids checklist host plants aphids Braconidae biodiversity conservation