Caryocar brasiliense (Malpighiales: Caryocaraceae) trees, protected by Brazilian federal laws, are the main income source in many communities. The transformation of the Cerrado (savanna biome) into grazing or agricultural areas has been isolating these trees species in an agro-urban landscape. We studied the effects of environmental diversity on the abundance of galling insect communities inhabiting C. brasiliense trees in three different environments: Cerrado, pasture, and an urban area. Eurytoma sp. (Hymenoptera: Eurytomidae) adults and their galls, its parasitoid Sycophila sp. (Hymenoptera: Eurytomidae) and the predator Zelus armillatus (Hemiptera: Reduviidae) were present in larger numbers on the C. brasiliense leaflets in the urban area. The percentages of totally galled leaflets (exhibiting all kinds of galls) and the number of trees were negatively correlated. Greater habitat diversity favored that of galling insect species and their natural enemies.