| Abstract: | Tropical forests accommodate rich species diversity, particularly among insects. Habitat heterogeneity along the vertical gradient extending from the forest understorey to the tree canopy influences diversity. The vertical distribution of forest insects is poorly understood across Africa, most especially eastern Africa. Food‐baited traps were used to study the vertical stratification of adult fruit‐feeding nymphalid butterflies in Mtai Forest Reserve, north‐eastern Tanzania. Traps were located in the forest canopy and understorey. A total of 277 individuals of 24 species were captured. Species composition differed by trap locations: 33% of the species captured were found in both the canopy and understorey strata; however, significantly more species were captured in the understorey (54%) than canopy (13%). Males were significantly more abundant than females and captured in both strata. A greater proportion of females were captured in the understorey than the canopy. The time of day affected capture rates, with more individuals caught in the afternoon; however, there was no association between the time period and the sex of individuals captured in canopy versus understorey locations. Understanding how the sexes of butterflies vary in understorey versus canopy offers new biological insights into the vertical stratification of insects. |
