Emergence traps and plant quadrat samples were used to survey insects associated with monocultures of Pistia stratiotes (L.) in an abandoned aquaculture pond and a roadside drainage ditch in St. Lucie County, Florida, USA. From 12-14 months of biweekly or monthly sampling, 47,251 specimens representing 13 orders, 90 families, and more than 300 species were identified. Of the 20,221 individuals from emergence traps, 96.5% were Diptera, of which 87.1% belonged to the Chironomidae. Plant quadrats yielded 27,030 specimens of which 55.0% were aquatic Diptera, 22.3% Odonata, 13.3% Hemiptera, and 8.7% Coleoptera. Mosquito larvae of the genus Mansonia accounted for 86.9% of the aquatic Diptera. Mean numbers of individuals from both trapping techniques were highest in the fall and lowest in the winter and spring. The more protected aquaculture pond had consistently more species of aquatic insects, but the emergence traps in the drainage ditch caught more species of aerial insects. These results are interpreted on the basis of differences in plant cover at the two sites. The two trapping techniques are regarded as complementary for surveying the insects of P. stratiotes, although the fauna from quadrat samples are more likely to be associated directly with the plant. Surveys of the insect faunas of water lettuce in Ghana, Argentina, and in Florida show many similarities in the relative abundances of representatives of the same orders and families, suggesting comparable community structures. Many of the abundant Diptera (Ceratopogonidae, Chironomidae, Culicidae) and Odonata (Coenagrionidae, Libellulidae) associated with water lettuce in southeastern Florida and the Chaco of Argentina belong to the same genera and are probable ecological homologs.